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Fire management, climate change and their interacting effects on birds in complex Mediterranean landscapes: Dynamic distribution modelling of an early-successional species - The near-threatened Dartford Warbler (Sylvia undata)
Abstract
The current challenge in a context of major environmental changes is to anticipate the responses of species to future landscape and climate scenarios. In the Mediterranean basin, climate change is one the most powerful driving forces of fire dynamics, with fire frequency and impact having markedly increased in recent years. Species distribution modelling plays a fundamental role in this challenge, but better integration of available ecological knowledge is needed to adequately guide conservation efforts. Here, we quantified changes in habitat suitability of an early-succession bird in Catalonia, the Dartford Warbler (Sylvia undata) ― globally evaluated as Near Threatened in the IUCN Red List. We assessed potential changes in species distributions between 2000 and 2050 under different fire management and climate change scenarios and described landscape dynamics using a spatially-explicit fire-succession model that simulates fire impacts in the landscape and post-fire regeneration (MEDFIRE model). Dartford Warbler occurrence data were acquired at two different spatial scales from: 1) the Atlas of European Breeding Birds (EBCC) and 2) Catalan Breeding Bird Atlas (CBBA). Habitat suitability was modelled using five widely-used modelling techniques in an ensemble forecasting framework. Our results indicated considerable habitat suitability losses (ranging between 47% and 57% in baseline scenarios), which were modulated to a large extent by fire regime changes derived from fire management policies and climate changes. Such result highlighted the need for taking the spatial interaction between climate changes, fire-mediated landscape dynamics and fire management policies into account for coherently anticipating habitat suitability changes of early-succession bird species. We conclude that fire management programs need to be integrated into conservation plans to effectively preserve sparsely forested and early succession habitats and their associated species in the face of global environmental change.
Supplementary resource (1)
... At the Catalonia level, we characterized land cover types (2000-2003 period) and time since last wildfire period) based on two raster layers at 100-m resolution. These land cover layers were projected to 2050 using the MED-FIRE model under different combinations of six wildfire management and two climate change scenarios (Table 1 and Regos et al. 2015Regos et al. , 2016b for scenario and variable details). MEDFIRE is a spatially-explicit dynamic fire-succession model designed to simulate the main processes in Mediterranean ecosystems (Brotons et al. 2013). ...
... Each scenario is a combination of a climate change scenario (A2 and B2) and a wildfire management policy. For more details see Regos et al. (2015Regos et al. ( , 2016a Table A2.1). ...
... Previous research has shown that landscape-level wildfire management policies that allow small and low-intensity fires to burn under controlled, mild fire-weather conditions will likely decrease the impact of large forest fires under adverse climate conditions (Houtman et al. 2013, Regos et al. 2014). These policies have also proved to be effective tools for creating new habitats for early-successional species (De Cáceres et al. 2013, Regos et al. 2015, without strong side effects on forest species, as the land abandonment processes in the study area have largely counterbalanced the negative effect of wildfires in the past few decades (Gil-Tena et al. 2009, Herrando et al. 2014. However, given the increasing severity of wildfire regimes, high-efficiency wildfire suppression policies (as typically implemented to date) were predicted to be more effective in mitigating climate change impact on our bird community than policies based on 'let-burn' strategies (compare business-as-usual scenarios with 'let-burn' in Fig. 3 and 4). ...
Community-level climate change indicators have been proposed to appraise the impact of global warming on community composition. However, non-climate factors may also critically influence species distribution and biological community assembly. The aim of this paper was to study how fire–vegetation dynamics can modify our ability to predict the impact of climate change on bird communities, as described through a widely-used climate change indicator: the community thermal index (CTI). Potential changes in bird species assemblage were predicted using the spatially-explicit species assemblage modelling framework – SESAM – that applies successive filters to constrained predictions of richness and composition obtained by stacking species distribution models that hierarchically integrate climate change and wildfire–vegetation dynamics. We forecasted future values of CTI between current conditions and 2050, across a wide range of fire–vegetation and climate change scenarios. Fire–vegetation dynamics were simulated for Catalonia (Mediterranean basin) using a process-based model that reproduces the spatial interaction between wildfire, vegetation dynamics and wildfire management under two IPCC climate scenarios. Net increases in CTI caused by the concomitant impact of climate warming and an increasingly severe wildfire regime were predicted. However, the overall increase in the CTI could be partially counterbalanced by forest expansion via land abandonment and efficient wildfire suppression policies. CTI is thus strongly dependent on complex interactions between climate change and fire–vegetation dynamics. The potential impacts on bird communities may be underestimated if an overestimation of richness is predicted but not constrained. Our findings highlight the need to explicitly incorporate these interactions when using indicators to interpret and forecast climate change impact in dynamic ecosystems. In fire-prone systems, wildfire management and land-use policies can potentially offset or heighten the effects of climate change on biological communities, offering an opportunity to address the impact of global climate change proactively. This article is protected by copyright. All rights reserved.
... For instance, forest birds are benefited from vegetation encroachment and forest spread (Gil-Tena et al., 2009;Regos et al., 2016aRegos et al., , 2016b, being the species more dependent on open habitats (such as grasslands and farmlands) the most negatively affected by agricultural abandonment (Scozzafava and De Sanctis, 2006;Wretenberg et al., 2007;Zakkak et al., 2014). In these abandoned landscapes, wildfires offer a window opportunity for early successional habitat species (Brotons et al., 2005;Campos et al., 2021;Regos et al., 2015a) -an adaptative response that strongly depends on burn severity and post-fire vegetation recovery Puig-Gironès et al., 2022;Taillie et al., 2018). In areas with large-scale land-use changes, legacies from previous land-use can persist and affect post-fire vegetation dynamics (Puerta-Piñero et al., 2012). ...
... These results are in line with previous studies that suggest that early 13 of 21 successional species, such as Dartford warbler, have peaks of abundance around 4-8 years after fire in Mediterranean ecosystems (Birdlife International, 2014;Pons et al., 2012). Fire creates habitat conditions to allow these species to occupy areas previously lost due to vegetation encroachment or afforestation processes driven by the joint effect of rural abandonment and fire suppression (see e.g., Regos et al., 2015a). In fact, recent studies suggested the use of fire as a tool to enhance bird conservation in this region, since fire could offset the negative effects of land abandonment on ecotone and open-habitat species (Campos et al., 2021;Regos et al., 2016b). ...
Fire regimes in mountain landscapes of southern Europe have been shifting from their baselines due to rural abandonment and fire exclusion policies. Understanding the effects of fire on biodiversity is paramount to implement adequate management. Herein, we evaluated the relative role of burn severity and heterogeneity on bird abundance in an abandoned mountain range located in the biogeographic transition between the Eurosiberian and Mediterranean region (the Natural Park ‘Baixa Limia–Serra do Xurés’). We surveyed the bird community in 206 census plots distributed across the Natural Park, both inside and outside areas affected by wildfires over the last 11 years (from 2010 to 2020). We used satellite images of Sentinel 2 and Landsat missions to quantify the burn severity and heterogeneity of each fire within each surveyed plot. We also accounted for the past land use (forestry or agropastoral use) by using a land cover information for year 2010 derived from satellite image classification. We recorded 1,735 contacts from 28 bird species. Our models, fitted by using GLMs with Poisson error distribution (pseudo-R2-average of 0.22 ± 0.13), showed that up to 71% of the modelled species were linearly correlated with at least one attribute of the fire regime. The spatiotemporal variation in burnt area and severity were relevant factors for explaining the local abundance of our target species (39% of the species; Akaike weights > 0.75). We also found a quadratic effect of at least one fire regime attribute on bird abundance for 60% of the modeled species. The past land use, and its legacy after 10 years, was critical to understand the role of fire (Akaike weights > 0.75). Our findings confirm the importance of incorporating remotely sensed indicators of burn severity into the toolkit of decision makers to accurately anticipate the response of birds to fire management.
... Climate is one of the main elements used to describe plant niches, and climate change is considered one of the major threats to biodiversity [1][2][3][4]. One of the main challenges today is to forecast how the various climate-change scenarios might affect species and communities in the future [2,[5][6][7][8]. ...
... Climate is one of the main elements used to describe plant niches, and climate change is considered one of the major threats to biodiversity [1][2][3][4]. One of the main challenges today is to forecast how the various climate-change scenarios might affect species and communities in the future [2,[5][6][7][8]. To reduce the effects of climate change on biodiversity, we should be taking precautionary measures, in the long term to reduce emission gases, and in the short term to design appropriate networks of Protected Areas (PAs) for conservation [9]. ...
It is thought that climate change will have a major impact on species distributions by changing the habitat suitability for species. Species distribution modelling is a modern approach to assess the potential effect of climate change on biodiversity. We used 11 environmental variables with the MaxEnt algorithm to model the distributions of 114 Egyptian medicinal plant species under current conditions, then projecting them into three different future times (2020, 2050, and 2080) under two different climate-change emission scenarios (A2a and B2a), under two hypotheses about the capability of the species for dispersal (unlimited and no dispersal). Species richness maps for current and future times were produced. We tested the value of Egypt’s Protected Areas under climate change by estimating the species richness inside and outside under each scenario. We assessed Egyptian medicinal plants based on IUCN Red List categories and criteria, and then used the SDMs for conservation planning with and without consideration of socioeconomic factors using Zonation software. The A2 emission scenario was more harmful than B2 under all assumptions. Species richness inside Protected Areas was significantly higher than outside for all models. Based just on the records, between 75% and 90% of species could be classified as Least Concern, according to the assumptions made. Similarly, based on SDMs all species could be classified as LC at the current time, whilst in the future under climate change, up to 18% of species face the risk of extinction, depending on assumptions and based on the absolute time gap between the two future times. Based on 10 years, most species were assigned as Least Concern. Areas within PAs were no better in conservation prioritization value than area outside when socioeconomic costs (especially the Human Influence Index) were taken into account. Species distribution models appear to be extremely useful for conservation planning under climate change, particularly when only sparse data are available. Socioeconomic information adds a new dimension to conservation planning, which is actually misleading and incomplete without it.
... As changes are unpredictable, the consideration of different scenarios of change can help identify and quantify uncertainties in models, and both on species vulnerability to different magnitudes of change and the areas that will be most impacted (Barbet-Massin, Thuiller, & Jiguet, 2012;Pompe et al., 2008). Modelling dynamic environmental variables is particularly important for fine spatial resolution studies, in areas affected by different threats and when variables may interact with each other (Barbet-Massin et al., 2012;Regos, D'Amen, Herrando, Guisan, & Brotons, 2015). However, so far, most studies have assumed untransformed land use over time (e.g., Pearson et al., 2014) or included single land use scenarios (Hughes, Satasook, Bates, Bumrungsri, & Jones, 2012; but see Jetz, Wilcove, & Dobson, 2007;Pompe et al., 2008;Barbet-Massin et al., 2012). ...
... (ii) Risk hotspots: overlap of the high-risk areas with the 25% of the grid cells with the highest bat richness. Colours indicate the number of scenarios that coincide in identify an area with the strongest projected impacts 2015; Regos et al., 2015;Travis, 2003). The analysis of single threats can mislead losses estimates because threats affect differently each area and species, and models calibration without important variables cause commission errors by overestimating suitable habitat (Lehsten et al., 2015;Sohl, 2014;Yates, McNeill, Elith, & Midgley, 2010). ...
Abstract
Aim - Climate and land use change are among the most important threatening processes driving biodiversity loss, especially in the tropics. Although the potential impacts of each threat have been widely studied in isolation, few studies have assessed the impacts of climate and land cover change in combination. Here, we evaluate the exposure of a large mammalian clade, bats, to multiple scenarios of environmental change and dispersal to understand potential consequences for biodiversity conservation.
Location -Mexico
Methods - We used ensemble species distribution models to forecast changes in environmental suitability for 130 bat species that occur in Mexico by 2050s under four dispersal assumptions and four combined climate and land use change scenarios. We identified regions with the strongest projected impacts for each scenario and assessed the overlap across scenarios.
Results - The combined effects of climate and land use change will cause an average reduction in environmental suitability for 51% of the species across their range, regardless of scenario. Overall, species show a mean decrease in environmental suitability in at least 46% of their current range in all scenarios of change and dispersal. Climate scenarios had a higher impact on species environmental suitability than land use scenarios. There was a spatial overlap of 43% across the four environmental change scenarios for the regions projected to have the strongest impacts.
Main conclusions - Combined effects of future environmental change may result in substantial declines in environmental suitability for Mexican bats even under optimistic scenarios. This study highlights the vulnerability of megadiverse regions and an indicator taxon to human disturbance. The consideration of combined threats can make an important difference in how we react to changes to conserve our biodiversity as they pose different challenges.
... Climate is one of the main elements used to describe plant niches, and climate change is considered one of the major threats to biodiversity [1][2][3][4]. One of the main challenges today is to forecast how the various climate-change scenarios might affect species and communities in the future [2,[5][6][7][8]. ...
... Climate is one of the main elements used to describe plant niches, and climate change is considered one of the major threats to biodiversity [1][2][3][4]. One of the main challenges today is to forecast how the various climate-change scenarios might affect species and communities in the future [2,[5][6][7][8]. To reduce the effects of climate change on biodiversity, we should be taking precautionary measures, in the long term to reduce emission gases, and in the short term to design appropriate networks of Protected Areas (PAs) for conservation [9]. ...
Climate change is one of the most difficult of challenges to conserving biodiversity, especially for countries with few data on the distributions of their taxa. Species distribution modelling is a modern approach to the assessment of the potential effects of climate change on biodiversity, with the great advantage of being robust to small amounts of data. Taking advantage of a recently validated dataset, we use the medicinal plants of Egypt to identify hotspots of diversity now and in the future by predicting the effect of climate change on the pattern of species richness using species distribution modelling. Then we assess how Egypt's current Protected Area network is likely to perform in protecting plants under climate change. The patterns of species richness show that in most cases the A2a ‘business as usual’ scenario was more harmful than the B2a ‘moderate mitigation’ scenario. Predicted species richness inside Protected Areas was higher than outside under all scenarios, indicating that Egypt’s PAs are well placed to help conserve medicinal plants.
... Similarly, increased drought frequencies are expected to further stress ecosystems in impounded rivers worldwide (Palmer et al. 2008). Such interactions between land-use and a changing climate can cause major alterations to landscapes and the biological communities they support (Paine et al. 1998, Cochrane and Laurance 2008, Regos et al. 2015. Furthermore, stressed ecosystems are often less resilient to climate change impacts (Staudt et al. 2013). ...
... Climate change could reduce extinction risk and improve abundance by increasing the frequency of high-flow disturbances, ultimately increasing habitat availability. This beneficial climate change effect, however, depends on the interplay between climate change and land-use policies in this and other disturbancedependent landscapes (e.g., Regos et al. 2015). With reduced mountain snowpack, reduced summer precipitation, and higher temperatures, droughts and reduced summer flows are also a possibility in the Great Plains and Midwestern United States (Wuebbles andHayhoe 2004, Chien et al. 2013). ...
Humans have altered nearly every natural disturbance regime on the planet through climate and land-use change, and in many instances, these processes may have interacting effects. For example, projected shifts in temperature and precipitation will likely influence disturbance regimes already affected by anthropogenic fire suppression or river impoundments. Understanding how disturbance-dependent species respond to complex and interacting environmental changes is important for conservation efforts. Using field-based demographic and movement rates, we conducted a metapopulation viability analysis for piping plovers (Charadrius melodus), a threatened disturbance-dependent species, along the Missouri and Platte rivers in the Great Plains of North America. Our aim was to better understand current and projected future metapopulation dynamics given that natural disturbances (flooding or high-flow events) have been greatly reduced by river impoundments and that climate change could further alter the disturbance regime. Although metapopulation abundance has been substantially reduced under the current suppressed disturbance regime (high-flow return interval ~ 20 yr), it could grow if the frequency of high-flow events increases as predicted under likely climate change scenarios. We found that a four-year return interval would maximize metapopulation abundance, and all subpopulations in the metapopulation would act as sources at a return interval of 15 yr or less. Regardless of disturbance frequency, the presence of even a small, stable source subpopulation buffered the metapopulation and sustained a low metapopulation extinction risk. Therefore, climate change could have positive effects in ecosystems where disturbances have been anthropogenically suppressed when climatic shifts move disturbance regimes toward more historical patterns. Furthermore, stable source populations, even if unintentionally maintained through anthropogenic activities, may be critical for the persistence of metapopulations of early-successional species under both suppressed disturbance regimes and disturbance regimes where climate change has further altered disturbance frequency or scope.
... Forest fires (FFs) affect many regions in the United States, Australia, Russia, Brazil, China and Mediterranean Basin European countries, among others [1][2][3][4]. Fire consumes vast areas of vegetation, compromises ecosystems and plays a key role in the carbon dioxide (CO 2 ) cycle [5][6][7][8][9]. In fact, CO 2 acts as a positive feedback loop that favors fire occurrence. ...
... Given the coordinates of the events during the period 1984-2013, we evaluate the tessellation generated by the K-means when varying the number of clusters in the interval K ∈ [4,30]. Figure 1 depicts the silhouette average values, S, versus K, as well as the shape of the silhouette obtained for the optimum value K = 5, that is, the point corresponding to the maximum silhouette mean value. ...
In this paper we study the global behavior of forest fires (FFs) in the Continental United States for the period 1984–2013. The data are obtained from a public domain catalog maintained by the Monitoring Trends in Burn Severity project. First we adopt clustering analysis to reduce the information dimensionality. Then we adopt mathematical tools commonly used in the analysis of dynamical systems, namely fractal dimension, entropy and fractional Fourier transform. The fractional techniques unveil FF patterns embedded in the data.
... Herrando et al., 2005), (2) they provide cheap and easy measurements if standard methodologies are applied (e.g. Sutherland et al., 2004), (3) they are sensitive to landscape and climatic changes (e.g. Regos et al., 2015), (4) several species were studied intensively with regard to their natural variation (e.g. Martin et al., 2006), and (5) they have the capacity for population recovery in response to good management procedures in previously disturbed ecosystems (e.g. ...
... According to expert knowledge, previously reported in the scientific literature (e.g. Gil-Tena et al., 2009; Moreira et al., 2001a; Regos et al., 2015), these species were grouped into three foraging groups, namely grassland species, shrubland species and woodland species, taking into account their degree of functional specialization on open habitats (including heterogeneous open habitats with hedgerows) and habitats dominated by shrubs or forests, respectively (Appendix 1, Supplementary material). Facing the multi-scale gradient of LU/LC changes expected to occur in the study area, the selected passerine foraging groups were assumed with potential as ecological indicators. ...
... Asterisks indicate the business-as-usual scenarios. For more details, see Regos et al. (2015) 2050, inside and outside N2000. To assess the extent to which N2000 will likely be able to maintain its role to ensure the persistence of key habitats for the target species under climate and land cover change scenarios, we first calculated the percentage of squares with optimal habitats inside N2000 relative to those in the whole study area and we used this percentage as a measure of effectiveness of N2000 in 2000 (Eff 2000 ) and in 2050 (Eff 2050 ). ...
... Reducing fire suppression efforts in mild weather conditions is an alternative but hotly debated strategy that consists in using unplanned fires and associated fuel reduction to create opportunities for suppression of large fires in future adverse weather conditions (Regos et al., 2014). Our projections revealed that the negative impact of land cover change on open-habitat bird species such as the Ortolan Bunting or the Dartford Warbler Regos et al., 2015) is expected to be significantly less important when projecting species distribution changes under such a novel fire management strategy (Fig. S5.2). There are more opportunities to create new open habitats for these species through changes in fire regime below than above 800 metres elevation (Figs 3d and S5.1), where a larger number of fire events are predicted. ...
Aim
Global environmental changes challenge traditional conservation approaches based on the selection of static protected areas due to their limited ability to deal with the dynamic nature of driving forces relevant to biodiversity. The Natura 2000 network (N2000) constitutes a major milestone in biodiversity conservation in Europe, but the degree to which this static network will be able to reach its long‐term conservation objectives raises concern. We assessed the changes in the effectiveness of N2000 in a Mediterranean ecosystem between 2000 and 2050 under different combinations of climate and land cover change scenarios.
Location
Catalonia, Spain.
Methods
Potential distribution changes of several terrestrial bird species of conservation interest included in the European Union's Birds Directive were predicted within an ensemble‐forecasting framework that hierarchically integrated climate change and land cover change scenarios. Land cover changes were simulated using a spatially explicit fire‐succession model that integrates fire management strategies and vegetation encroachment after the abandonment of cultivated areas as the main drivers of landscape dynamics in Mediterranean ecosystems.
Results
Our results suggest that the amount of suitable habitats for the target species will strongly decrease both inside and outside N2000. However, the effectiveness of N2000 is expected to increase in the next decades because the amount of suitable habitats is predicted to decrease less inside than outside this network.
Main conclusions
Such predictions shed light on the key role that the current N2000 may play in the near future and emphasize the need for an integrative conservation perspective wherein agricultural, forest and fire management policies should be considered to effectively preserve key habitats for threatened birds in fire‐prone, highly dynamic Mediterranean ecosystems. Results also show the importance of considering landscape dynamics and the synergies between different driving forces when assessing the long‐term effectiveness of protected areas for biodiversity conservation.
... Wildfires are predicted to increase significantly in area and frequency in northern Eurasia (Stocks et al. 1998, Shvidenko & Schepaschenko 2013. Fire dynamics are among the strongest factors influencing the distribution of birds in the Mediterranean (Regos et al. 2015). Both fires and climate can negatively impact bird populations, potentially leading to certain species' decline or favoring others more adaptable to changing conditions. ...
The Iraq Babbler, Argya altirostris (Hartert, 1909), previously known only along the Euphrates and Tigris rivers in Iraq, Syria, and western Iran, was discovered in Türkiye at the end of the 1990s. It was observed only along the Euphrates Valley between Nizip (Gaziantep) and Birecik (Şanlıurfa) for more than 15 years. Recently, it was seen in some other parts of Gaziantep and Şanlıurfa provinces as well as Adıyaman, Hatay, Kahramanmaraş, Mersin, and Osmaniye in south Türkiye. The species was found in a few localities of Adıyaman (Gölbaşı), Hatay (Kırıkhan, Hassa, Samandağ), and Mersin (Silifke) provinces between 2020-2022 in the western and northern direction of its distribution. The six new district records are reported here for the first time. Thus, its distribution has extended to the Mediterranean and the western Türkiye (Anatolia) in the northernmost area of the species' range. Similarly, its distribution in Karbala Province expanded westwards concerning our new locality record from Iraq. To test its expansion in northern and southern Anatolia, we performed species distribution modeling for four time periods, as simulated in five General Circulation Models (GCMs), to evaluate the distributional shifts of the Iraq Babbler over the decades and to forecast its future projections. The results show that the Iraq Babbler could expand its distribution in the Mediterranean and western Türkiye and confirm our field observations. The currently unsuitable areas could become suitable by 2100, most likely expanding its potential habitat in Türkiye.
... These results are in line with previous studies that suggest that early successional species have peaks of abundance around 4-8 years after fire in Mediterranean ecosystems [40,41]. Fire creates habitat conditions to allow species such as Dartford warbler to occupy areas previously lost due to vegetation encroachment or afforestation processes driven by the longstanding rural abandonment and fire suppression (see e.g., [42]). In fact, recent studies already suggested fire as a tool to enhance bird conservation in this area, since fire could offset the negative effects of land abandonment on ecotone and open-habitat species [43,44]. ...
Fire regimes in mountain landscapes of southern Europe have been shifting from their baselines due to the accumulation of fuel fostered by long-standing rural abandonment and fire exclusion policies. Understanding the role of fire on biodiversity is paramount to implement adequate management to mitigate the impacts of altered fire regimes and land abandonment on biodiversity. Here, we explored to what extent the spatiotemporal variation in burn severity has affected bird abundance of a mountain abandoned landscape located in the Atlantic-Mediterranean transition (NW Iberia). We took advantage of: (1) satellite images of Sentinel 2 and Landsat missions to compute burn severity indicators from 2010 to 2020, and (2) standardized bird surveys carried out over 206 point-counts along the breeding season of 2021. Bird abundance models were built from burn severity metrics together with well-known fire regime attributes (% of burnt area and time since fire). Our results showed that the spatiotemporal variation of burn severity significantly correlated with the abundance of the 39% of the modeled species, supporting the role of pyro-diversity in driving bird populations in our region. The burnt area also explained abundance patterns for 28% of species. Time since fire only correlated with the abundance of 3 species. Our findings confirm the importance of incorporating burn severity indicators into the toolkit of decision makers to anticipate the response of birds to fire management.
... Birds have been proposed as ecological indicators of climatic change (Regos et al., 2015) and land use modifications (Bastos et al., 2016). Many bird species are sensitive to environmental changes (e.g., changes in forest structure) so they are considered ideal objects of study to understand the impacts produced by forest harvesting. ...
Low intensity silviculture has been used to decrease the impact of forest harvesting, for example, on bird species and structural diversity. The objective of this work was to analyse the long-term effect of thinning on bird communities of Nothofagus antarctica forests in Tierra del Fuego (Argentina), compared with unthinned forests at two different locations. Thinning was performed 15 and 50 years ago at each location (ranches), therefore we also evaluated other common forest habitat types to differentiate these effects (location and time). We sampled four habitat types associated to overstory canopy cover (CC) categories: thinned (35–65% CC), and three unthinned forests (open with <35% CC, closed with 65–85% CC, and very closed with >85% CC), totalling 32 sampling sites (2 ranches × 4 canopy cover × 4 replicates). Bird assemblages’ structure and functional traits (e.g., richness, density, trophic groups, use of strata) were surveyed during two consecutive summers (2017–2020) at each site. We also characterized habitats by: (i) forest structure and ground cover (e.g., basal area, debris, and saplings); and (ii) food availability, considering understory plants consumed by birds (e.g., plant richness, grasses and dicots cover) and arthropods (e.g., total abundance). We evaluated the effect of CC, ranch, time, habitat and food availability by Generalised Linear Mixed Models and multivariate analyses (Multiple Response Permutation Procedure, Canonical Correspondence Analysis). In thinned forests, some bird structure and functional traits remained similar to closed forests; however, thinning increased bird species richness, being more similar to open forests. Effect of time could not be detected. CC and ranch were the factors that better described bird community structure, while forest structure, ground cover and food availability (e.g., dominant height, basal area, proportion of Hymenoptera) were the main drivers of most functional traits. The whole bird assemblage was better explained by 4–6 habitat structure and food availability variables depending on location (ranch). Results suggest thinning will benefit bird conservation if thinned forests maintain characteristics of mature forests (e.g., basal area > 40 m²/ha, shrub cover > 5%).
... Birds have been proposed as ecological indicators of climatic change (Regos et al., 2015) and land use modifications (Bastos et al., 2016). Many bird species are sensitive to environmental changes (e.g., changes in forest structure) so they are considered ideal objects of study to understand the impacts produced by forest harvesting. ...
Low intensity silviculture has been used to decrease the impact of forest harvesting, for example, on bird species and structural diversity. The objective of this work was to analyse the long-term effect of thinning on bird communities of Nothofagus antarctica forests in Tierra del Fuego (Argentina), compared with unthinned forests at two different locations. Thinning was performed 15 and 50 years ago at each location (ranches), therefore we also evaluated other common forest habitat types to differentiate these effects (location and time). We sampled four habitat types associated to overstory canopy cover (CC) categories: thinned (35–65% CC), and three unthinned forests (open with <35% CC, closed with 65–85% CC, and very closed with >85% CC), totalling 32 sampling sites (2 ranches × 4 canopy cover × 4 replicates). Bird assemblages’ structure and functional traits (e. g., richness, density, trophic groups, use of strata) were surveyed during two consecutive summers (2017–2020) at each site. We also characterized habitats by: (i) forest structure and ground cover (e.g., basal area, debris, and saplings); and (ii) food availability, considering understory plants consumed by birds (e.g., plant richness, grasses and dicots cover) and arthropods (e.g., total abundance). We evaluated the effect of CC, ranch, time, habitat and food availability by Generalised Linear Mixed Models and multivariate analyses (Multiple Response Permutation
Procedure, Canonical Correspondence Analysis). In thinned forests, some bird structure and functional traits remained similar to closed forests; however, thinning increased bird species richness, being more similar to open forests. Effect of time could not be detected. CC and ranch were the factors that better described bird community structure, while forest structure, ground cover and food availability (e.g., dominant height, basal area, proportion of Hymenoptera) were the main drivers of most functional traits. The whole bird assemblage was better explained by 4–6 habitat structure and food availability variables depending on location (ranch). Results suggest thinning will benefit bird conservation if thinned forests maintain characteristics of mature forests (e.g., basal area > 40 m2/ha, shrub cover > 5%).
... Las aves son consideradas buenos indicadores de cambio en las condiciones ecológicas. Han sido asociadas a cambios globales, como el climático (Regos et al. 2015), y locales, como en el uso del suelo (Bastos et al. 2016). Gran parte de sus especies son conspicuas y pueden detectarse e identificarse con métodos relativamente sencillos y suelen ser mejor conocidas que otros grupos taxonómicos. ...
El uso ganadero de los bosques de Nothofagus antarctica de Tierra del Fuego (Argentina) ha sido históricamente extensivo y poco planificado, y usualmente basado en la reducción de cobertura arbórea mediante cortas para aumentar la producción de forraje bajo su dosel. El objetivo de esta tesis fue analizar estructura y rasgos funcionales de las comunidades de aves terrestres, diurnas y residentes estivales (principalmente paseriformes), en diferentes estados del bosque de N. antarctica evaluando el efecto de variables ambientales a escala local y de paisaje, así como el potencial uso de las aves como indicadoras de impactos para mejorar las propuestas de estrategias de manejo foresto-ganadero existentes. Este trabajo se realizó en 4 Estancias (Los Cerros, Rolito, Las Hijas y Cabo San Pablo) ubicadas en el centro y este de la Isla Grande de Tierra del Fuego (Argentina). Se estudiaron 4 tipos de bosque: un tipo con raleos (Abiertos) y tres tipos sin raleos (Muy Cerrados, Cerrados y Muy Abiertos). Las aves se estudiaron en puntos de observación fijos, donde se realizaron conteos durante los meses de enero y febrero del 2017 y 2018 en Los Cerros, 2018 y 2019 en Rolito, y 2019 y 2020 en Las Hijas y Cabo San Pablo, para caracterizar estructura (composición, riqueza, densidad, biomasa e índices de diversidad) y rasgos funcionales (grupos tróficos, uso de sustratos, tipo de nidificación y estatus migratorio). En Los Cerros y Rolito también se analizó la susceptibilidad a la depredación de nidos artificiales. Los efectos analizados fueron: a escala local, la estructura forestal (altura dominante, área basal, cobertura de copas, densidad de árboles y diámetro medio), la cobertura del suelo (sotobosque, residuos leñosos, plantas no-vasculares, renovales y suelo sin vegetación), y la oferta alimenticia, vegetal (riqueza y cobertura total, de gramíneas y de dicotiledóneas consumidas por aves) y de la artropofauna (abundancia total y proporción de los órdenes más importantes); y a escala de paisaje, área, perímetro y forma del parche; área, número de parches, índice del parche más grande y conectividad de bosques y áreas abiertas; y total de bordes y densidad de bordes. Las variables fueron evaluadas mediante modelos lineales generalizados (GLM) y generalizados mixtos (GLMM), y multivariados (PCA, MRPP, IndVal, y CCA). Se pudo identificar mayor riqueza y diversidad de especies de aves en bosques Abiertos (raleados) y Muy Abiertos, dadas por la presencia de especies de áreas abiertas o de bordes de bosque. Por otro lado, se identificaron menores densidades de omnívoros y granívoras en bosques Cerrados y Muy Cerrados, respectivamente, vinculadas a los sustratos de alimentación. El uso de los sustratos difirió entre tipos de bosque, estando el uso de sustratos bajos y copas relacionado con su disponibilidad. Mientras que el uso de ramas y fustes, y la densidad de individuos volando se asociaron a la estructura forestal (cobertura de copas y área basal, entre otras). Por otro lado, la densidad de especies que nidifican en huecos y copa abierta, así como la densidad de residentes y migradoras, también difirieron entre tipos de bosque y se asociaron a la altura dominante y a la cobertura de copas. Los bosques raleados, si bien presentaron algunas diferencias con los Cerrados y Muy Cerrados (mayor riqueza de especies, diversidad, uso de sustratos bajos, densidad de aves volando y de migradoras), fueron parecidos en otros rasgos (ej. densidad de aves que utilizan ramas y copas o que nidifican en huecos), observándose en ellos incluso especies especialistas de bosque (Pygarrhichas albogularis y Aphrastura spinicauda). Si bien no se encontraron diferencias significativas en la susceptibilidad a la depredación de nidos artificiales entre tipos de bosque, los nidos que se encontraban en bosques Muy Abiertos fueron depredados más rápido. Este estudio permitió identificar especies indicadoras de bosques Cerrados y Muy Cerrados (A. spinicauda, P. albogularis), Abiertos (Spinus barbatus) y Muy Abiertos (ej. Tachycineta leucopyga). Por lo tanto, estas especies se podrían utilizar para el monitoreo de los raleos en estos bosques. Al analizar variables de diferentes escalas espaciales (local y paisaje), se pudo observar que las mismas influyeron sobre diferentes grupos de especies. Por ejemplo, la estructura forestal (área basal, cobertura de copas) y el área del parche de bosque tuvieron mayor efecto sobre P. albogularis. Se concluye que ciertas características a nivel local (ej. mayor área basal, cobertura de copas y de renovales, y proporción de himenópteros), así como a nivel de paisaje (ej. parches de bosque grandes e irregulares, alternancia con áreas abiertas), favorecen a una mayor diversidad de aves en los bosques de N. antarctica de Tierra del Fuego. El desarrollo de propuestas de manejo forestales y silvopastoriles que preserven o favorezcan la presencia de paisajes y parches de bosque con estas características contribuiría a que el manejo de estos bosques sea más sustentable.
... Fire regimes modulate vegetation composition and species population dynamics, causing range shifts (Krawchuk et al., 2009;van der Zanden et al., 2017). Climate change and ongoing land abandonment processes exacerbate the effects of fires on the landscape, and consequently, on biodiversity patterns (Amatulli et al., 2013;Regos et al., 2015). Assessments of future conservation needs, as impacted by multiple drivers, are necessary to evaluate whether existing policy and funding mechanisms can respond to future challenges. ...
Landscape dynamics pose substantial challenges to biodiversity conservation and could compromise the future effectiveness of protected areas (PAs). Multiple interacting drivers of landscape dynamics, including land-cover change, wildfire, and climate change, are usually studied separately. This limits our ability to respond effectively to conservation needs through appropriate measures.
Using Catalonia (North-east Spain) as a case study, we evaluated the future representativeness of PAs in covering the distributions of bird species of conservation interest under the effects of different global change drivers and identified priority areas for their conservation in the future. We also evaluated the role of different global change drivers in defining future conservation needs.
Under current management practices, land-cover change appears to be a more relevant driver than climate change. Forested habitats are predicted to increase at the expense of early successional habitats, and it appears that fires will not compensate for this loss by creating new early successional habitats. Consequently, early successional species are likely to suffer the greatest decline in distribution. Consequently, additional priority for future management should be given to the last available early successional habitats, mainly outside PAs, as their selection will be marginally driven by climate change or wildfires.
The conservation of early successional habitats in the European Union can benefit from existing policies, particularly the 2030 Biodiversity Strategy or the Common Agriculture Policy. However, further evaluation is needed to explore whether these policies are suitable under dynamic landscape conditions or if new policy is needed to ensure effective conservation efforts.
... Os efeitos combinados do abandono dos usos tradicionais do solo e da mudança climática das últimas décadas têm levado a regimes de incêndios que ultrapassam a capacidade de extinção, com subsequente aumento no risco para a saúde, bem-estar social e económico, bem como para a salvaguarda dos recursos materiais, assim como um forte impacto nos ecossistemas florestais e na biodiversidade (Moreira et al. 2001;Queiroz et al. 2014;Modugno et al. 2016). Compreender o que altera o regime de incêndios em termos de paisagem, assim como os seus efeitos na biodiversidade, é fundamental para qualquer política de intervenção no regime de incêndios, de ordenamento do território e de conservação da natureza (Lee et al. 2015;Regos et al. 2015). ...
Neste seminário discutiu-se um conjunto de questões relacionadas com a abrangência e eficácia da prevenção de incêndios florestais, tendo como base o conceito de “Fire Smart Territory”, que representa uma perspetiva na gestão dos incêndios florestais assente numa nova relação das comunidades, organizações e instituições com o fogo, com o objetivo de promover a segurança e o desenvolvimento sustentável. Assim, a Escola Superior Agrária do Instituto Politécnico de Castelo Branco em conjunto com a Associação Portuguesa de Ecologia da Paisagem (APEP), organizou, em Castelo Branco, o seminário “Paisagens Fire Smart Territory. Criando Territórios Resilientes”, no dia 08 de Novembro de 2019. Este seminário reuniu um conjunto de especialistas que se encontram a desenvolver uma linha de investigação relacionada com a temática do “Fire-Smart”. Nestes estudos pretendeu-se compreender o papel do ordenamento da paisagem na prevenção de incêndios florestais, conhecer modelos de gestão do espaço rural e silvicultura preventiva e, ainda ações de prevenção e mitigação de incêndios florestais.
... Os efeitos combinados do abandono dos usos tradicionais do solo e da mudança climática das últimas décadas têm levado a regimes de incêndios que ultrapassam a capacidade de extinção, com subsequente aumento no risco para a saúde, bem-estar social e económico, bem como para a salvaguarda dos recursos materiais, assim como um forte impacto nos ecossistemas florestais e na biodiversidade (Moreira et al. 2001;Queiroz et al. 2014;Modugno et al. 2016). Compreender o que altera o regime de incêndios em termos de paisagem, assim como os seus efeitos na biodiversidade, é fundamental para qualquer política de intervenção no regime de incêndios, de ordenamento do território e de conservação da natureza (Lee et al. 2015;Regos et al. 2015). ...
Os efeitos combinados do abandono dos usos tradicionais do solo e da mudança climática das últimas décadas têm levado a regimes de incêndios que ultrapassam a capacidade de extinção, com subsequente aumento no risco para a saúde, bem-estar social e económico, bem como para a salvaguarda dos recursos materiais, assim como um forte impacto nos ecossistemas florestais e na biodiversidade. Compreender o que altera o regime de incêndios em termos de paisagem, assim como os seus efeitos na biodiversidade, é fundamental para qualquer política de intervenção no regime de incêndios, de ordenamento do território e de conservação da natureza.
O presente estudo teve como principal objetivo avaliar os efeitos potenciais de opções alternativas de gestão do fogo e paisagem, visando maximizar a prevenção de incêndios rurais e ao mesmo tempo assegurar a conservação da biodiversidade para a Reserva da Biosfera Transfronteiriça Gerês-Xurés.
Foram combinadas simulações de um modelo de paisagem-fogo, com projeções de modelos de distribuição de aves, para avaliar os efeitos potenciais de opções alternativas de gestão do fogo e paisagem no regime de incêndios e na biodiversidade, entre os anos de 1990 a 2050.
Os resultados sugerem que uma combinação de políticas de gestão da paisagem focada na promoção de áreas agrícolas com áreas 'Fire-Smart' seria a estratégia mais desejável considerando a mitigação de incêndios, a conservação da avifauna e a salvaguarda das paisagens.
... In Tierra del Fuego, birds are the most abundant and diverse group of vertebrates in the terrestrial ecosystems (Lencinas et al. 2005) and they could be even more relevant because they occupy many ecological niches and key ecological roles (Díaz et al. 2005). Moreover, birds are considered good indicators of ecological changes, and have been associated with global changes, such as climate change (Regos et al. 2015), and local changes, as those motivated by land-use (Bastos et al. 2016). Many bird species are conspicuous, can be detected and identified with relatively simple methods, and are usually better known than other taxonomic groups. ...
Existing networks of nature reserves contain a biased sample of biodiversity. In Patagonia Argentina, most nature reserves focus their protection objectives on a particular ecosystem, geoform or scenic value, and usually are located in inaccessible areas. However, unique species or assemblages could inhabit less protected ecosystems, areas or habitats, which could be threatened depending of management. In this study, we assessed the conservation value of different ecosystem types and areas (fjords) in Isla de los Estados Provincial Reserve (RPIE, Argentina), using birds as study case. We chose three fjords (east, central and west) and five ecosystems types (forests at low and high elevation, open-lands at low and high elevation, and sea coasts). Bird's assemblage richness, density, biomass, trophic level, migratory status, and use of strata per ecosystems and fjords were characterized in 75 points (3 fjords × 5 ecosystems × 5 replicates) and evaluated using ANOVA and multivariate methods. Also, Shannon (H') and Pielou (J) indices were estimated for fjords and ecosystems. Passerine was the most abundant group, being mainly residents, omnivorous and carnivorous-scavenger, and they were observed mainly flying or in the canopy. Assemblage structure and function varied with ecosystem types, with higher richness and biomass in coasts and open-lands than in other ecosystems, but with greater density in forests. Multivariate analyses showed conspicuous groups for forests and coast sampling units, with significant differences among all ecosystem types except between low and high forests. Also, east fjord significantly differed in density and biomass from the others, but west fjord also differed in structure, function and bird assemblage. We conclude that greater conservation value must be assigned to ecosystem types or areas inhabited by threatened species (as open-lands at high elevation) and highest richness and variety of use of strata (as sea coasts). However, bird assemblage patterns have particularities in less valuable ecosystems and areas, which also justify their importance for conservation, or at least, prescriptions of low impact uses and activities in the management planning. Nature reserves are opportunities to preserve endemic species, habitats or areas of special interest, as low latitude or unique isolated landscape communities, and ecosystems underrepresented in the network of local, regional or world protected areas.
... Average proportion, from the three presence/absence thresholds ('10pc', 'EqualSSS' and 'MaxSSS') is used. Regos et al., 2015). Here, excluding prescribed fire would limit the ability to break up continuous fuels across the landscape, leaving highly localised populations of the Black-eared Miner and Mallee Emu-wren vulnerable to large wildfire events (similar to findings for Sierra Nevadan old forest specialists, Tempel et al., 2015). ...
Prescribed (or “planned”) burning is used by land managers to reduce fuel-loads in order to mitigate the spread of wildfire, thereby protecting life and property, and to promote environmental heterogeneity to enhance biodiversity. Globally, many fire management agencies focus on increasing extent and frequency of prescribed burning. There is a need to assess how high levels of prescribed burning may affect the long-term, landscape-level persistence of ecological communities. We forward projected management scenarios over 21 years to explore how the operationally realistic implementation of four different prescribed burn targets, covering 5, 3, 1.5 and 0% of a large reserve per annum (p.a.) might affect provision and removal of fire-mediated habitat of 11 rare and threatened bird species. Sustained implementation of high targets (5 and 3% p.a.) homogenised the landscape toward young vegetation, substantially reducing highly suitable habitat for species requiring intermediate (20–60 years post-fire) and older (60+ years) age classes. In contrast, no prescribed burning generated insufficient habitat for species with early (<20 years) and intermediate seral requirements. Strategies reliant upon persistently high levels of prescribed burning are likely to have negative effects on a number of threatened species already considered vulnerable due to their low populations and restricted ranges. In contrast, management processes that allow for periodic evaluation and flexibility in how strategies are implemented would better enable practitioners to tailor fire management to individual ecosystems. Carefully targeting key areas for wildfire prevention, and promoting some successional changes through application of fire in other areas, will help to maintain and improve suitable habitat for species of conservation concern.
... A pesar destas limitacións, os subprodutos aquí presentados (área queimada anual, total, recorrencia e tempo dende o último incendio; Fig 4) constitúen actualmente a única fonte cartográfica dispoñible e libremente accesible para Galicia no tócante aos incendios forestais e a súa distribución, o que supón unha valiosa fonte de información espacial con múltiples aplicacións no eido da conservación da biodiversidade, da xestión forestal e do territorio. Concretamente, tanto a área queimada, como a recorrencia de incendios ou o tempo transcorrido dende o ultimo incendio son variables esenciais amplamente utilizadas para avaliar o efecto dos incendios na paisaxe e a biodiversidade, tanto a escalas amplas como máis locais (kelly et al., 2014;regos et al., 2015;dAvis et al., 2016;FerreirA et al., 2016). Está información pode ser combinada espacialmente con outras capas relativas a cubertas de usos do solo ou tipo de vexetación xerando unha información relevante para estudos de carácter ecolóxico (de cáceres et al., 2013). ...
Resumo.- O obxectivo deste traballo é obter unha cartografía actualizada das áreas afectadas por incendios forestais en Galicia (período 2001-2017), así como facilitar a súa dispoñibilidade a través dunha aplicación web mapping. A información de base é o produto de áreas queimadas do sensor MODIS (Moderate Resolution Imaging Spectrora- diometer), dos satélites Terra e Aqua da NASA. A partir desta información xeráronse os seguintes subprodutos: 1) área queimada anual, 2) total queimado para o período 2001-2017, 3) recorrencia de incendios e 4) tempo transcorrido dende o último incendio; todos eles dispoñibles a 500 m de resolución, en formato ráster e vectorial. A área queimada anual foi comparada coas estatísticas oficiais de incendios dispoñibles a nivel provincial. Os resultados amosan unha alta correlación entre a área queimada estimada a partir do produto MODIS e a obtida a partir das estatísticas oficiais (coef. de Pearson = 0.92). Porén, o produto MODIS tende a sobreestimar a área oficialmente queimada (media = 2.76%), aínda que isto depende fortemente do ano e da provincia (desv. estándar = ±103%). A pesar destas limitacións, esta cartografía constitúe unha fonte moi valiosa de información espacial con múltiples aplicacións no eido da conservación da biodiversidade, da xestión forestal e do territorio.
Abstract .- The main objective of this work is to produce an updated cartography of areas affected by wildfires in Galicia (between 2001 and 2017), as well as to ensure potential users free accessibility to this spatial dataset through a webmapping application. The baseline information is the Burned Area product derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) instruments, on-board NASA’s Terra and Aqua satellites. From this information, we generated the following secondary products: 1) annual burned area, 2) total area burned between 2001 and 2017, 3) fire recurrence and 4) time since last fire; at 500-m resolution, in raster and vectorial format. The annual burned area was compared with official fire statistics at the province level from Spanish Government. The results showed a high statistical correlation between the burned area estimated from MODIS product and official fire statistics (Pearson coef. = 0.92). However, MODIS product tends to overestimate the official burned area (mean = 2.76%), but in more or less extent depending on the year and province (SD = ±103%). Despite these limitations, these products constitute a key source of freely-available spatial information on wildfires in Galicia, with a wide range of potential applications for biodiversity conservation, forest management and land planning.
... and Pinus spp.) (Calviño-Cancela et al. 2012, Morán-Ordóñez et al. 2012, 2013, Ramil-Rego et al. 2013. In the context of ongoing land use change, the loss and fragmentation of heathlands may lead to difficult-to-reverse tipping points for species tightly linked to these habitats (Regos et al. 2015, 2016, Brambilla et al. 2017, Tapia et al. 2017. ...
The aim of this study was to assess the temporal transferability of species distribution models (SDMs) and their potential implications for bird conservation. We quantified the loss and fragmentation of Montagu’s Harrier Circus pygargus and Common Kestrel Falco tinnunculus habitats over 13 years (2001–2014) in a highly dynamic landscape in north-western Spain. For this purpose, priority habitats for the target species were modelled at four different spatial scales using an ensemble forecasting framework. To explore the temporal transferability of our ensemble predictions, the models were back-projected to the land cover conditions in 2001 and evaluated using historical occurrence data. In addition, models calibrated with historical data were projected to the land cover conditions in 2014 and evaluated using updated occurrence data. Changes in availability and connectivity of suitable habitats between both years were estimated at four spatial scales from a set of widely-used indicators. SDMs showed a good predictive accuracy but with limited temporal transferability due to changes in the species-habitat relationships between 2001 and 2014. The results showed a decrease in the avaliability of suitable habitats of 33.4% and 47.7% for Montagu’s Harrier and Common Kestrel, respectively; with the subsequent increase in their fragmentation. However, our estimates were found to be strongly dependent on the scale of analysis and model transferability. Changes in habitat availability and connectivity ranged from -48% to +54% for Montagu’s Harrier, and from +116% to +5.6% for Common Kestrel. We call for caution when using SDMs beyond the model calibration time period to guide bird conservation. This is especially important for raptors, often characterised by low population sizes and large home ranges, and particularly sensitive to unstable, highly dynamic environmental conditions. In light of these results, specific, long-standing monitoring protocols remain essential to ensure accurate modelling performance and reliable future projections.
... Because of ongoing climate change, it is also possible, now and in the future, that responses to fire by resprouting plant species (and other species) may not be in spatial or temporal synchrony with responses by their herbivores, florivores, seed dispersers, pollinators, or other interacting plant or animal species. Through climate change, the timing, frequency, and intensity of fire will have likely changed, and continue to change in the future (Bedia et al., 2015;Regos et al., 2015;Liu and Wimberly, 2016). As plant and animal species may vary in how they respond to fire-related factors, such changes to the fire regime may result in different species changing to different degrees or even in different directions. ...
The literature on fire-stimulated flowering is reviewed in terms of post-fire flowering patterns, proximal ultimate factors that affect flowering of plants post-fire, as well as application of evolutionary theory and development of evolutionary models in relation to fire-stimulated flowering. Consideration is given to the concepts involved, available empirical information, and areas that warrant further research. Understanding the factors responsible for fire-stimulated flowering is limited. Studies suggest factors involved, but confounding of variables prevents their separation. Experiments evaluate different factors, but there have been few such studies and little consideration regarding soil attributes, synergistic effects of multiple factors, and large-scale factors such as herbivory, florivory, seed dispersal, and pollination. Understanding the adaptive nature, and hence evolution, of fire-stimulated flowering is poor. Prevalence of particular fire-related responses has been related to geographical and other patterns, with deduction of adaptive nature of plant responses to fire and factors driving evolution of these responses. However, confounding of factors hinders this approach and can lead to disagreement between researchers. A better approach would be to hypothesize that evolution has resulted in plant responses to fire that are Evolutionarily Stable Strategies and to develop consequent mathematical models for such evolution, leading to predictions and tests. However, this approach requires quantitative assessment of responses to fire-related factors and influences of such responses on plant fitness, and so far few such assessments exist. This poor state of knowledge regarding plants with fire-stimulated flowering means that we cannot easily replace or enhance fire for managing species with fire-stimulated flowering, as sometimes necessary, and it also restricts their commercial cultivation. Experimental evaluation of plant responses to fire and development of evolutionary models is required. Our knowledge of the factors that trigger post-fire flowering by re-sprouting plant species remains poor, and so we cannot incorporate relationships between them and plant fitness into mathematical models of plant evolution.
... An increase in the explanatory power of models when including fire regime variables was also reported by Tucker et al. (2012): Fire variables, in addition to climate and soil variables, improved the fit of SDMs for Proteaceae species in the Cape Floristic Region of South Africa. Other work has shown that SDMs can capture the responses of birds and small mammals to fire regimes (Kelly et al. 2011, Regos et al. 2015, and recent work in our study area has demonstrated that fire influences the occurrence of birds (Robinson et al. 2014, Sitters et al. 2014a, Loyn and McNabb 2015 and, to a lesser extent, mammals , Swan et al. 2015 and plants (Cohn et al. 2015). However, predictive discrimination between a species' presence and absence remains difficult (see also Crimmins et al. 2014). ...
... An increase in the explanatory power of models when including fire regime variables was also reported by Tucker et al. (2012): Fire variables, in addition to climate and soil variables, improved the fit of SDMs for Proteaceae species in the Cape Floristic Region of South Africa. Other work has shown that SDMs can capture the responses of birds and small mammals to fire regimes (Kelly et al. 2011, Regos et al. 2015, and recent work in our study area has demonstrated that fire influences the occurrence of birds (Robinson et al. 2014, Sitters et al. 2014a, Loyn and McNabb 2015 and, to a lesser extent, mammals , Swan et al. 2015 and plants (Cohn et al. 2015). However, predictive discrimination between a species' presence and absence remains difficult (see also Crimmins et al. 2014). ...
Fire is a global driver of ecosystem structure, function, and change. Problems common to fire scientists and managers worldwide include a limited knowledge of how multiple taxonomic groups within a given ecosystem respond to recurrent fires, and how interactions between fire regimes and environmental gradients influence biodiversity. We tested six hypotheses relating to fire regimes and environmental gradients in forest ecosystems using data on birds (493 sites), mammals (175 sites), and vascular plants (615 sites) systematically collected in dry eucalypt forests in southeastern Australia. We addressed each of these hypotheses by fitting species distribution models which differed in the environmental variables used, the spatial extent of the data, or the type of response data. We found (1) as predicted, fire interacted with environmental gradients and shaped species distributions, but there was substantial variation between species; (2) multiple characteristics of fire regimes influenced the distribution of forest species; (3) common to vertebrates and plants was a strong influence of temperature and rainfall gradients, but contrary to predictions, inter-fire interval was the most influential component of the fire regime on both taxonomic groups; (4) mixed support for the hypothesis that fire would be a stronger influence on species occurrence at a smaller spatial extent; only for vertebrates did scale have an effect in the direction expected; (5) as predicted, vertebrates closely associated with direct measures of habitat structure were those most strongly influenced by fire regimes; and (6) the modeled fire responses for birds were sensitive to the use of either presence–absence or abundance data. These results underscore the important insights that can be gained by modeling how fire regimes, not just fire events, influence biota in forests. Our work highlights the need for management of fire regimes to be complemented by an understanding of the underlying environmental gradients and key elements of habitat structure that influence resource availability for plants and animals. We have demonstrated that there are general patterns in biotic responses to fire regimes and environmental gradients, but landscape management must continue to carefully consider species, scale, and the quality of biodiversity data to achieve biodiversity conservation in fire-prone forests.
... Forest fires (FF) are phenomena that occur in many regions of Earth [1][2][3][4] destroying vast areas and compromising ecosystems [5][6][7][8][9] . The FF space-time series exhibit complex dynamical effects that pose considerable challenges to a robust modeling and motivate their study using present-day algorithmic methods [10,11] . ...
This paper analyses forest fire (FF) patterns based on information collected by the Canadian National Fire Database. The space-time dynamics of FF reveals characteristics that require advanced mathematical and computational methods. The study adopts the perspective of dynamical analysis to process the FF data considering amplitude, space and time. Several distinct techniques, such as dimensionality reduction, clustering and computer visualization unveil the relationships embedded in the data. The results reveal long term memory effects that demonstrate the usefulness of the proposed tools and motivate collecting further data related with this complex phenomenon.
... Simulation modelling based on observed responses of plants and animals to fire is advocated and increasingly used to predict the consequences (and effectiveness) of alternative fire management strategies and climatic change on fire regimes and, in turn, biodiversity (e.g. Bradstock et al. 1998Bradstock et al. , 2005Franklin et al. 2001;Driscoll et al. 2010;Pacifici et al. 2015;Regos et al. 2015). The landscape is typically conceived of as a grid, with each cell having a fire age that either increases or returns to zero (is burnt) in each time-step, and an interfire interval across time-steps, depending on fire ignition (planned and unplanned) and spread between cells. ...
Increased incidence of landscape fire and pollinator declines with co‐extinctions of dependent plant species are both globally significant. Fire can alter species distributions, but its effects on plant–pollinator interactions are poorly understood so its present and future role in coupled plant–pollinator declines cannot be assessed.
We develop a conceptual model of fire effects on plant–pollinator interactions. We review the empirical literature in the context of this model to identify important knowledge gaps regarding the processes underlying these effects and the phenotypic traits of flowering plants and pollinators mediating these effects. Fire generates, and plant–pollinator interactions respond to, heterogeneity at multiple spatial scales. There is evidence of local‐scale fire effects on these interactions, but landscape‐scale effects are poorly understood. Nest location and floral resource utilization primarily mediate pollinator survival during and after fire. Voltinism and mobility traits are potentially important, but poorly studied. Plant traits mediating flowering responses to fire include growth form, phenology and potentially bud location, seasonal changes in bud exposure and response to bud damage.
Synthesis and applications . We suggest management actions and an agenda for future research to fill knowledge gaps currently inhibiting predictions of fire effects on plant–pollinator interactions. Fire regimes promoting floral diversity at local scales provide a surrogate means of managing pollinators and pollination while empirical research continues. Above‐ground nesting, univoltine pollinators may be particularly vulnerable under expected fire regime changes. Improved knowledge of traits mediating the exploitation of landscape heterogeneity could be used to enhance the persistence of these species. Ultimately, our conceptual framework could be used as a basis for understanding fire effects on aggregate network properties to inform fire management strategies buffering plant–pollinator networks against secondary species extinctions.
... Natural forest regeneration and succession, forest disasters (fires, pests, and diseases), and human disturbance may cause numerous changes in forestland, leading to direct effects of forest vegetation dynamics on the balance and health of terrestrial ecosystems (Webster et al. 2003;Alongi 2015). The research in forest dynamics can help us to learn the quantity and quality of forest resources (Regos et al. 2015), monitor their variations (Lamers and Junginger 2013), analyze the effects of the natural, economic and social conditions on forest growth (Houghton 2013;Law 2014), establish or update the forest resource files (Ernst et al. 2013), and plan the vegetation configuration for restoration and reconstruction of forests due to climate change (Campbell 2004). ...
To learn the forest dynamics and evaluate the ecosystem services of forest effectively, a timely acquisition of spatial and quantitative information of forestland is very necessary. Here, a new method was proposed for mapping forest cover changes by combining multi-scale satellite remote-sensing imagery with time series data. Using time series Normalized Difference Vegetation Index products derived from the Moderate Resolution Imaging Spectroradiometer images (MODIS-NDVI) and Landsat Thematic Mapper/Enhanced Thematic Mapper Plus (TM/ETM+) images as data source, a hierarchy stepwise analysis from coarse scale to fine scale was developed for detecting the forest change area. At the coarse scale, MODIS-NDVI data with 1-km resolution were used to detect the changes in land cover types and a land cover change map was constructed using NDVI values at vegetation growing seasons. At the fine scale, based on the results at the coarse scale, Landsat TM/ETM+ data with 30-m resolution were used to precisely detect the forest change location and forest change trend by analyzing time series forest vegetation indices (IFZ). The method was tested using the data for Hubei Province, China. The MODIS-NDVI data from 2001 to 2012 were used to detect the land cover changes, and the overall accuracy was 94.02 % at the coarse scale. At the fine scale, the available TM/ETM+ images at vegetation growing seasons between 2001 and 2012 were used to locate and verify forest changes in the Three Gorges Reservoir Area, and the overall accuracy was 94.53 %. The accuracy of the two layer hierarchical monitoring results indicated that the multi-scale monitoring method is feasible and reliable.
Understanding habitat selection patterns in congeneric species has raised special interest due to its importance when designing conservation strategies for the species. We analysed reproductive habitat selection of three coexisting warbler species in the eastern Iberian Peninsula. We detected the individuals by their vocalizations at 40 listening points in two study areas (Carcaixent and Alcoy). We used satellite images to identify different vegetation types and their availability. Reproductive habitat selection was analysed by the Ivlev selectivity index and a compositional analysis. In addition, we determined the effect of different habitat variables (dominant vegetation, vegetation height, cover and site) on the presence of the species fitting a binomial GLM with logistic linking function. We found that the Sardinian Warbler ( Curruca Melanocephala) selected scrub-dominated areas; while the Dartford Warbler ( C. undata) preferred areas with low (<50%) vegetation cover; and the Subalpine Warbler ( C. cantillans) was present in areas with scrubs and low (<50%) vegetation cover, avoiding crops. The compositional analysis showed that the species used different vegetation types, in relation to their availability and that the selection differed between species. The Sardinian Warbler was the only species which showed spatial variation in reproductive habitat selection. Our results evidence that the studied warbler species select and avoid different types of vegetation in relation to their specific requirements and the present habitat structure. This represents valuable information to understand the composition of local communities and the reproductive habitat selection of the studied species.
Fire regimes in mountain landscapes of southern Europe have been shifting from their baselines due to rural abandonment and fire exclusion policies. Understanding the effects of fire on biodiversity is paramount to implement adequate management. Herein, we evaluated the relative role of burn severity and heterogeneity on bird abundance in an abandoned mountain range located in the biogeographic transition between the Eurosiberian and Mediterranean region (the Natural Park ‘Baixa Limia–Serra do Xurés’). We surveyed the bird community in 206 census plots distributed across the Natural Park, both inside and outside areas affected by wildfires over the last 11 years (from 2010 to 2020). We used satellite images of Sentinel 2 and Landsat missions to quantify the burn severity and heterogeneity of each fire within each surveyed plot. We also accounted for the past land use (forestry or agropastoral use) by using a land cover information for year 2010 derived from satellite image classification. We recorded 1735 contacts from 28 bird species. Our models, fitted by using GLMs with Poisson error distribution (pseudo-R2-average of 0.22 ± 0.13), showed that up to 71% of the modeled species were linearly correlated with at least one attribute of the fire regime. The spatiotemporal variation in burnt area and severity were relevant factors for explaining the local abundance of our target species (39% of the species; Akaike weights >0.75). We also found a quadratic effect of at least one fire regime attribute on bird abundance for 60% of the modeled species. The past land use, and its legacy after 10 years, was critical to understand the role of fire (Akaike weights >0.75). Our findings confirm the importance of incorporating remotely sensed indicators of burn severity into the toolkit of decision makers to accurately anticipate the response of birds to fire management.
Semi-natural open habitats have drastically changed in the last few decades due to agricultural intensification and rural depopulation. Steppe-birds, and especially those adapted to primary stages of vegetation succession, are threatened by an increase in scrub cover, and management actions are being applied to reverse scrub encroachment and restore habitat suitability in semi-natural open habitats. In this paper we evaluated for the first time, the long-term effects of a wildfire on habitat structure, vegetation productivity, and the associated response of an endangered scrub-steppe specialist bird, the Dupont’s Lark Chersophilus duponti. Wildfire occurred in a Mediterranean steppe of central Spain dominated by permanent community of dwarf cushions scrubs. Bird abundance was evaluated by line transects in the burnt and unburnt areas 3 years prior to the fire and 4 and 7 years after the fire. We quantified changes in habitat structure at fine scale level through vegetation sampling points and in vegetation productivity by estimating the Normalized Difference Vegetation Index (NDVI). Fire had strong effects for at least up to 4 years after the fire, when lower NDVI values, less scrub cover and fewer, but not significant, number of males were detected in the burnt area with respect to the pre-fire conditions. Seven years after fire most vegetation variables measured did not differ between areas, number of males detected within the burnt area was recovered and NDVI values in burnt area were slightly recovered but were significantly lower than in control area. Slow regeneration of the scrub cover after fire explained the unsuccessful occupation of the burnt area by the Dupont’s Lark up to several years after fire. The more dispersed and shorter habitat created by fire 7 years after the fire seems to be more suitable for the species than that in control areas. The large number of males around the burnt area may have played a role in the recolonization process. In sum, vegetation recovery and the presence of a low scrub-steppe specialist, as the Dupont’s lark, suggests that fire management could be integrated into conservation plans to effectively manage scrub encroachment processes in Mediterranean scrub-steppes.
1.The combined effects of climate change and other factors, such as land use change or fire disturbance, pose daunting challenges for biodiversity conservation worldwide.
2.We predicted the future effectiveness of the Natura 2000 (N2000), the current network of protected areas (PA) in Europe, at maintaining and representing suitable environmental conditions for a set of 79 bird species between 2000 and 2050 in a fire‐prone area, strongly affected by land abandonment processes in North East Spain. We then compared PA performance with a set of alternative priority areas for conservation, which consider fire‐vegetation dynamics, selected by using a conservation planning tool (Marxan). Fire‐vegetation dynamics were modelled using a process‐based model (Medfire Model) under alternative fire management and climate change scenarios. Bird assemblage distributions were predicted using the spatially‐explicit species assemblage modelling framework (SESAM) using distribution models from individual species that hierarchically integrate climate change and wildfire‐vegetation dynamics.
3.The amount of suitable environmental conditions within the N2000 network was predicted to fall by around 15%, on average, over the next decades in relation to the initial conditions but could be partially modulated by fire management policies in future. The efficiency of the current PA system was predicted to decrease from 17.4 to 15% over the next decades. However, a more efficient PA system could be achieved with a conservation planning approach that explicitly considers fire‐vegetation dynamics and their management.
4.Synthesis and applications. Our findings show: (1) how the current Natura 2000 could still hold an important bird conservation value by 2050; (2) how the relocation of some protected areas should be considered in order to substantially increase bird conservation effectiveness; and (3) how the integration of fire‐vegetation dynamics, fire management policies and their objectives within conservation planning provide ‘win‐win’ solutions for bird conservation and fire prevention in fire‐prone abandoned landscapes.
Climate change is considered one of the greatest challenges that current biodiversity is facing. Successful adaptation of different species to climate-related changes depends on their ability to follow the habitat shift by modifying their range. We assessed the projected future range changes for a grassland specialist bird using two available climate scenarios. The model subject, the Lesser Grey Shrike (Lanius minor), is a vulnerable grassland specialist, distributed in southeastern Europe, with its European population concentrated in Romania. We created a distribution model for the species using data provided by the national Common Bird Monitoring Programme for the years 2002–2005. Several different statistical models, based on the generalised linear model and multivariate adaptive regression splines, were tested with use of the available habitat and climate data. The final working model was selected by means of the lowest root mean square error from the cross-validation process. The model was tested against two climate scenarios—A1 (integrated world, rapid economic growth) and B2 (regional development, environmentally friendly scenario)—on a long-term (2050) scale. To assess the efficiency of site-based conservation (Natura 2000 sites) as the only tool currently in place for the preservation of Lesser Grey Shrike populations in Romania, we evaluated the mean changes in suitable habitats inside the national protected area network. The projected changes show large-scale reduction of suitable habitats, both inside protected areas and at the national level, due to the forecasted shifts in grassland belts. Our results show that under both scenarios, two thirds of the seminatural grasslands will be out of the recent protected area system by 2050. Small protected areas will lose more habitats than larger ones, irrespective of the Lesser Grey Shrike populations breeding therein. These results suggest that current site-based protection measures will become largely insufficient for the conservation of seminatural grasslands and the associated flora and fauna in the long term in Romania.
Quantifying species distributions using species distribution models (SDMs) has emerged as a central method in modern biogeography. These empirical models link species occurrence data with spatial environmental information. Since their emergence in the 1990s, thousands of scientific papers have used SDMs to study organisms across the entire tree of life, with birds commanding considerable attention. Here, we review the current state of avian SDMs and point to challenges and future opportunities for specific applications, ranging from conservation biology, invasive species and predicting seabird distributions, to more general topics such as modeling avian diversity, niche evolution and seasonal distributions at a biogeographic scale. While SDMs have been criticized for being phenomenological in nature, and for their inability to explicitly account for a variety of processes affecting populations, we conclude that they remain a powerful tool to learn about past, current, and future species distributions – at least when their limitations and assumptions are recognized and addressed. We close our review by providing an outlook on prospects and synergies with other disciplines in which avian SDMs can play an important role.
Wildfires play a determining role in the composition and structure of many plant and animal communities. On the other hand, climate change is considered to be a major driver of current and future fire regime changes. Despite increases in drought in many areas of the world, the effects of aridity on post-fire colonization by animals have been rarely addressed. This study aims to analyse how a regional aridity gradient affects post-fire recovery of vegetation , bird species richness and the numbers of four early to middle-successional warbler species associated with the shrub cover. The database contains bird relative abundance and environmental variables from 3072 censuses in 695 transects located in 70 recently burnt areas (1 to 11 years after wildfire) in Catalonia (Spain), which were sampled between 2006 and 2013. Generalized linear mixed models (GLMMs) showed that plant cover was affected by time since fire, aridity and forest management. However, only the highest vegetation height layer (>100 cm) recovered slower in arid areas after fire. Time since fire positively influenced bird species richness and the relative abundance of the four focal species. The post-fire recovery of Melodious (Hippolais polyglotta) and Subalpine warblers (Sylvia cantillans) was hampered by aridity. Although this was not demonstrated for Dartford (S. undata) and Sardinian warblers (S. melanocephala), their occurrence was low in the driest areas during the first three years after fire. Overall, this study suggests that future increases in aridity can affect plant regeneration after fire and slow down the recovery of animal populations that depend on understorey and shrublands. Given the recently highlighted increases in aridity and fire frequency in Mediterranean-climate regions, improved knowledge on how aridity affects ecological succession is especially necessary.
Increases in fire impacts over many regions of the world have led to large-scale investments in fire-suppression efforts. There is increasing recognition that biomass extraction for energy purposes may become an important forest-management practice in fire-prone ecosystems. However, at present, very few studies have explicitly assessed biomass extraction as a fuel treatment at landscape scale. Here, we use a landscape fire-succession model in Catalonia (NE Spain) to quantitatively evaluate the potential effects of a biomass extraction-based strategy on essential fire-regime attributes after considering different levels of fire suppression, biomass extraction intensity, and spatial allocation of such efforts. Our simulations indicated that the effectiveness (area suppressed in relation to expected area to burn) at suppressing wildfires was determined by extraction intensity, spatial allocation of the extraction effort, and the fire-suppression levels involved. Indeed, the highest suppressed-area values were found with lower harvesting intensities, especially under high fire-suppression capabilities and strategies focused on bioenergy goals (figures close to 0.7). However, the leverage (area suppressed in relation to managed area) was higher when the treatments were based on the fire-prevention strategy and focused on high-fire-risk areas (up to 0.45) than with treatment designed for energy reasons (lower than 0.15). We conclude that biomass extraction for energy purposes has the potential to induce changes in fire regimes and can therefore be considered a cost-effective landscape-level fuel-reduction treatment. However, our results suggest that large-scale biomass extraction may be needed if significant changes in fire regimes are to be expected.
Based on phylogenetic research, this complete study of the genus Sylvia describes two new species and establishes identification criteria for all members of the family.
A lengthy introduction explains the background to the research and outlines the main features of the genus. The 25 species are then treated in detail, including the African parisomas, which are here included in the Sylva group. The species accounts include sections on every aspect of identification, with colour illustrations showing age, sex and racial differences, distribution maps, sonograms, moult and wing diagrams and tables.
Exploring the role of fire in each of the five Mediterranean-type climate ecosystems, this book offers a unique view of the evolution of fire-adapted traits and the role of fire in shaping Earth's ecosystems. Analyzing these geographically separate but ecologically convergent ecosystems provides key tools for understanding fire regime diversity and its role in the assembly and evolutionary convergence of ecosystems. Topics covered include regional patterns, the ecological role of wildfires, the evolution of species within those systems, and the ways in which societies have adapted to living in fire-prone environments. Outlining complex processes clearly and methodically, the discussion challenges the belief that climate and soils alone can explain the global distribution and assembly of plant communities. An ideal research tool for graduates and researchers, this study provides valuable insights into fire management and the requirements for regionally tailored approaches to fire management across the globe. © J. E. Keeley, W. J. Bond, R. A. Bradstock, J. G. Pausas and P. W. Rundel 2012.
A major wildfire burned 228 400 ha of forest in East Gippsland (Victoria, Australia) in February and March 1983, including Cooaggalah forest block where flora and fauna studies had just commenced. Bird abundance was assessed on 13 sites immediately before and after the fire, and annually for three years to 1986. The sites represented a range of habitats including rainforest, heaths and eucalypt forest, all of which burned. Total bird abundance was reduced to 60% of initial levels by the fire, but recovered within three years. These changes differed significantly between habitats. Initial decreases were greatest and subsequent recovery least in heaths where most above-ground vegetation had been killed. Post-fire increases were greatest in rainforest and on granite ridges, and in each case bird abundance rose to levels substantially higher than before fire. Some changes may have involved recovery from drought as well as fire. Changes over time were highly significant for many groups of birds (e.g., honeyeaters), while others showed little change (e.g., bark-foragers and insectivores that inhabit dense understorey or damp ground below shrubs). Honeyeaters and seed-eaters suffered the greatest initial declines, and some species in these groups were slow to recover (e.g., New Holland and Crescent Honeyeaters and Beautiful Firetail). Some species that feed from open ground increased quickly to levels greater than before fire (Flame and Scarlet Robins, Buff-rumped Thornbill and Superb Fairy-wren), but all except the latter then declined as shrubs regenerated. The main loss of birds immediately after the fire was of highly mobile species, and the composition of the remaining bird fauna appeared to depend on resource availability rather than the capacity of species to survive the fire front. Initial responses of species to fire were poor predictors of their responses after three years. Hence, the effects of fire should be considered in terms of habitat changes over several years. Many forest types including rainforest can provide continuing habitat even when they burn, but populations of mobile birds such as honeyeaters depend on access to alternative habitats on a broad regional scale.
We studied the post-fire dynamics of two Mediterranean warblers (the Sardinian (Sylvia melanocephala) and the Dartford Warbler (Sylvia undata)) to determine whether these were influenced by local habitat recovery or by external population trends unrelated to the occurrence of fire. We used the point-count method to survey warblers from the first to the sixth breeding seasons after fire in burnt and unburnt control zones of the Iberian Peninsula. Both species increased similarly in the burnt zone until the fourth year after fire, but the Dartford Warbler increased faster than the Sardinian Warbler from then on. Six years after fire, the abundance of the Dartford Warbler was even higher in the burnt zone than in the control, where the population of this species remained constant during the study period. In contrast, a parallel increase in the populations of Sardinian Warbler in both zones was observed, thus suggesting that processes other than fire were pro-foundly involved in the dynamics of this species in the burnt zone. Our results indicate that the post-fire dynamics of these two species greatly differ, the Dartford Warbler being highly influenced by local habitat changes in the burnt zone and the Sardinian Warbler by population trend on a larger scale than the disturbed habitat.
We analyse the observed climate-driven changes in summer wildfires and their future evolution in a typical Mediterranean environment (NE Spain). By analysing observed climate and fire data from 1970 to 2007, we estimate the response of fire number (NF) and burned area (BA) to climate trends, disentangling the drivers responsible for long-term and interannual changes by means of a parsimonious Multi Linear Regression model (MLR). In the last forty years, the observed NF trend was negative. Here we show that, if improvements in fire management were not taken into account, the warming climate forcing alone would have led to a positive trend in NF. On the other hand, for BA, higher fuel flammability is counterbalanced by the indirect climate effects on fuel structure (i.e. less favourable conditions for fine-fuel availability and fuel connectivity), leading to a slightly negative trend. Driving the fire model with A1B climate change scenarios based on a set of Regional Climate Models from the ENSEMBLES project indicates that increasing temperatures promote a positive trend in NF if no further improvements in fire management are introduced.
The 21st century is projected to witness unprecedented climatic changes, with greater warming often reported for high latitudes.
Yet, climate change can be measured in a variety of ways, reflecting distinct dimensions of change with unequal spatial patterns
across the world. Polar climates are projected to not only warm, but also to shrink in area. By contrast, today’s hot and
arid climates are expected to expand worldwide and to reach climate states with no current analog. Although rarely appreciated
in combination, these multiple dimensions of change convey complementary information. We review existing climate change metrics
and discuss how they relate to threats and opportunities for biodiversity. Interpreting climate change metrics is particularly
useful for unknown or poorly described species, which represent most of Earth’s biodiversity.
Despite the huge resources invested in fire suppression, the impact of wildfires has considerably increased across the Mediterranean region since the second half of the 20th century. Modulating fire suppression efforts in mild weather conditions is an appealing but hotly-debated strategy to use unplanned fires and associated fuel reduction to create opportunities for suppression of large fires in future adverse weather conditions. Using a spatially-explicit fire-succession model developed for Catalonia (Spain), we assessed this opportunistic policy by using two fire suppression strategies that reproduce how firefighters in extreme weather conditions exploit previous fire scars as firefighting opportunities. We designed scenarios by combining different levels of fire suppression efficiency and climatic severity for a 50-year period (2000-2050). An opportunistic fire suppression policy induced large-scale changes in fire regimes and decreased the area burnt under extreme climate conditions, but only accounted for up to 18-22% of the area to be burnt in reference scenarios. The area suppressed in adverse years tended to increase in scenarios with increasing amounts of area burnt during years dominated by mild weather. Climate change had counterintuitive effects on opportunistic fire suppression strategies. Climate warming increased the incidence of large fires under uncontrolled conditions but also indirectly increased opportunities for enhanced fire suppression. Therefore, to shift fire suppression opportunities from adverse to mild years, we would require a disproportionately large amount of area burnt in mild years. We conclude that the strategic planning of fire suppression resources has the potential to become an important cost-effective fuel-reduction strategy at large spatial scale. We do however suggest that this strategy should probably be accompanied by other fuel-reduction treatments applied at broad scales if large-scale changes in fire regimes are to be achieved, especially in the wider context of climate change.
Fire is a major agent involved in landscape transformation and an indirect cause of changes in species composition. Responses to fire may vary greatly depending on life histories and functional traits of species. We have examined the taxonomic and functional responses to fire of eight taxonomic animal groups displaying a gradient of dietary and mobility patterns: Gastropoda, Heteroptera, Formicidae, Coleoptera, Araneae, Orthoptera, Reptilia and Aves. The fieldwork was conducted in a Mediterranean protected area on 3 sites (one unburnt and two burnt with different postfire management practices) with five replicates per site. We collected information from 4606 specimens from 274 animal species. Similarity in species composition and abundance between areas was measured by the Bray-Curtis index and ANOSIM, and comparisons between animal and plant responses by Mantel tests. We analyze whether groups with the highest percentage of omnivorous species, these species being more generalist in their dietary habits, show weak responses to fire (i.e. more similarity between burnt and unburnt areas), and independent responses to changes in vegetation. We also explore how mobility, i.e. dispersal ability, influences responses to fire. Our results demonstrate that differences in species composition and abundance between burnt and unburnt areas differed among groups. We found a tendency towards presenting lower differences between areas for groups with higher percentages of omnivorous species. Moreover, taxa with a higher percentage of omnivorous species had significantly more independent responses of changes in vegetation. High- (e.g. Aves) and low-mobility (e.g. Gastropoda) groups had the strongest responses to fire (higher R scores of the ANOSIM); however, we failed to find a significant general pattern with all the groups according to their mobility. Our results partially support the idea that functional traits underlie the response of organisms to environmental changes caused by fire.
Mediterranean landscapes are suffering two opposing forces leading to large-scale changes in species distribution: land abandonment of less productive areas and an increase in wildfire impact. Here, we test the hypothesis that fires occurred in recent decades drive the pattern of expansion of early-successional, open-habitat bird species by aiding in the process of colonisation of newly burnt areas. The study was carried out in Catalonia (NE Spain). We selected 44 burnt sites occurring between 2000 and 2005 to model colonisation patterns under different assumptions of potential colonisers’ sources and evaluated the colonisation estimates with empirical data on six bird species especially collected for this purpose. We first defined three landscape scenarios serving as surrogates of potential colonisers’ sources: open-habitats created by fire, shrublands and farmlands. Then, we used a parameter derived from a functional connectivity metric to estimate species colonization dynamics on the selected sites by each particular scenario. Finally, we evaluated our colonisation estimates with the species occurrence in the studied locations by using generalized linear mixed models. The occurrence of the focal species on the newly burnt sites was significantly related to the connectivity patterns described by both the recent fire history and the other open-habitat types generated by a different type of disturbance. We suggest that land use changes in recent decades have produced a shift in the relative importance of habitats acting as reservoirs for open-habitat bird species dynamics in Mediterranean areas. Before the middle of the twentieth century species’ reservoirs were probably constituted by relatively static open habitats (grassland and farmland), whereas afterwards they likely consist of a shifting mosaic of habitat patches where fire plays a key role as connectivity provider and largely contributes to the maintenance of species persistence.
A new computation framework (BIOMOD: BIOdiversity MODelling) is presented, which aims to maximize the predictive accuracy of current species distributions and the reliability of future potential distributions using different types of statistical modelling methods. BIOMOD capitalizes on the different techniques used in static modelling to provide spatial predictions. It computes, for each species and in the same package, the four most widely used modelling techniques in species predictions, namely Generalized Linear Models (GLM), Generalized Additive Models (GAM), Classification and Regression Tree analysis (CART) and Artificial Neural Networks (ANN). BIOMOD was applied to 61 species of trees in Europe using climatic quantities as explanatory variables of current distributions. On average, all the different modelling methods yielded very good agreement between observed and predicted distributions. However, the relative performance of different techniques was idiosyncratic across species, suggesting that the most accurate model varies between species. The results of this evaluation also highlight that slight differences between current predictions from different modelling techniques are exacerbated in future projections. Therefore, it is difficult to assess the reliability of alternative projections without validation techniques or expert opinion. It is concluded that rather than using a single modelling technique to predict the distribution of several species, it would be more reliable to use a framework assessing different models for each species and selecting the most accurate one using both evaluation methods and expert knowledge.
Environmental factors controlling the distribution and abundance of boreal avifauna are not fully understood, limiting our ability to predict the consequences of a changing climate and industrial development activities underway. We used a compilation of avian point-count data, collected over 1990–2008 from nearly 36 000 locations, to model the abundance of individual forest songbird species within the Canadian boreal forest. We evaluated 30 vegetation and 101 climatic variables, representing most of the widely-used dimensions of climate space, along with less usual measures of inter-annual variability. Regression tree models allowed us to calculate the relative importance of climate and vegetation variable classes according to avian migration strategy without the need for a priori variable selection or dimension reduction. We tested for hierarchical habitat selection by formulating hypotheses on the locations of variables within the model tree structures. Climate variables explained the majority (77%) of deviance explained over 98 species modelled. As may be expected at high latitudes, we found energy availability (temperature, 65%) to be more important than moisture availability (precipitation, 12%). The contributions of inter- and intra-annual climate variability (28%) were about half that of mean conditions. The relatively large contribution of remotely-sensed vegetation metrics (23%) highlighted the importance of local vegetation heterogeneity controlled by non-climatic factors. The two most important vegetation variables were landcover type and April leaf area index. When selected, these generally occurred in a model's right subtree, consistent with predictions from hierarchical habitat selection theory. When occupying the root node, landcover effectively delineated the historical forest-prairie ecotone, reflecting the current disequilibrium between climate and vegetation due to human land use. Our findings suggest a large potential for avian distributional shifts in response to climate change, but also demonstrate the importance of finer scale vegetation heterogeneity in the spatial distribution of boreal birds.
Available data show that future changes in global change drivers may lead to an increasing impact of fires on terrestrial ecosystems worldwide. Yet, fire regime changes in highly humanised fire-prone regions are difficult to predict because fire effects may be heavily mediated by human activities We investigated the role of fire suppression strategies in synergy with climate change on the resulting fire regimes in Catalonia (north-eastern Spain). We used a spatially-explicit fire-succession model at the landscape level to test whether the use of different firefighting opportunities related to observed reductions in fire spread rates and effective fire sizes, and hence changes in the fire regime. We calibrated this model with data from a period with weak firefighting and later assess the potential for suppression strategies to modify fire regimes expected under different levels of climate change. When comparing simulations with observed fire statistics from an eleven-year period with firefighting strategies in place, our results showed that, at least in two of the three sub-regions analysed, the observed fire regime could not be reproduced unless taking into account the effects of fire suppression. Fire regime descriptors were highly dependent on climate change scenarios, with a general trend, under baseline scenarios without fire suppression, to large-scale increases in area burnt. Fire suppression strategies had a strong capacity to compensate for climate change effects. However, strong active fire suppression was necessary to accomplish such compensation, while more opportunistic fire suppression strategies derived from recent fire history only had a variable, but generally weak, potential for compensation of enhanced fire impacts under climate change. The concept of fire regime in the Mediterranean is probably better interpreted as a highly dynamic process in which the main determinants of fire are rapidly modified by changes in landscape, climate and socioeconomic factors such as fire suppression strategies.
Where a legacy of aggressive wildland fire suppression has left forests in need of fuel reduction, allowing wildland fire to burn may provide fuel treatment benefits, thereby reducing suppression costs from subsequent fires. The least-cost-plus-net-value-change model of wildland fire economics includes benefits of wildfire in a framework for evaluating suppression options. In this study, we estimated one component of that benefit - the expected present value of the reduction in suppression costs for subsequent fires arising from the fuel treatment effect of a current fire. To that end, we employed Monte Carlo methods to generate a set of scenarios for subsequent fire ignition and weather events, which are referred to as sample paths, for a study area in central Oregon. We simulated fire on the landscape over a 100-year time horizon using existing models of fire behaviour, vegetation and fuels development, and suppression effectiveness, and we estimated suppression costs using an existing suppression cost model. Our estimates suggest that the potential cost savings may be substantial. Further research is needed to estimate the full least-cost-plus-net-value-change model. This line of research will extend the set of tools available for developing wildfire management plans for forested landscapes.
Postfire salvage logging is currently a controversial issue because of the impact that the removal of snags
has on ecosystem structure and function. Although it is a common practice worldwide, the absence of
comparisons across regions hinders the development of broad generalizations. Here we compare bird
response to postfire salvage logging in two regions with significant differences in landscape and bird
communities, the Mediterranean Basin and the Rocky Mountains. The Mediterranean Basin features a
landscape dominated by a mosaic of small-sized forests, farmland and shrublands, while the Rocky
Mountains have large extensions of continuous forests. Bird conservation priorities are also different.
In the Mediterranean Basin, priorities are oriented toward farmland birds, while they are oriented toward
fire-specialists in the Rocky Mountains. We used databases describing bird species occurrence in burned
forests from both regions and defined three groups of species based on their level of association with
snags. We then compared the richness of each group among logged and unlogged sites, and also between
regions. We found a higher proportion of species that showed some degree of association with snags in
burned forests of the Rocky Mountains than in the Mediterranean Basin. Highly snag-associated birds
from both regions showed a common negative response to salvage logging. Not snag-associated species
increased in salvaged areas, but only in the Mediterranean Basin. The general negative effect of salvage
logging on forest-dwelling species that are associated with trees or snags is a noteworthy pattern given
the big differences between regions. Nevertheless, in the Mediterranean, some threatened farmland species
benefit from logging, so the overall effect of the removal of snags appears to be relatively more detrimental
to birds in the Rocky Mountains.
Protected areas play a key role in the preservation of biodiversity, but their implementation at sea is lagged behind terrestrial environments, especially in offshore areas. Here we describe the identification of foraging hotspots off the Mediterranean Iberian coast using three Procellariiform species as examples, and assess the stability of these sites. Then, we show how these foraging hotspots contributed to the delimitation of marine Important Bird Areas (IBAs). The whole process consisted of: (1) seabird data col-lection (extensive boat-based surveys and seabird tracking, conducted in 1999–2010) and compilation of relevant spatial descriptors of the marine environment; (2) species distribution modeling (SDM) aimed at identifying areas with high habitat quality for the different seabird species (3); identification and delin-eation of the main seabird hotspots, based on models, supported by direct seabird data, and mediated by expert opinion; (4) application of BirdLife International IBA criteria for hotspot validation; and (5) com-bination of hotspots from different species to set the final limits of the marine IBAs. This approach allowed to identify a series of hotspots for pelagic species in the study area, and provided nice examples of stability assessment, which slightly differed in performance between seabird species. They contributed to the Spanish marine IBA inventory, which is in the process of receiving legal protection. Future work should be directed at confirming the stability of the marine IBAs in the long term, and to address the development of management plans to make effective the protection of these sites.
Processes derived from global change such as land-use changes, climate warming or modifications in the perturbation regime may have opposite effects on forest extent and structure with still unknown consequences on forest biodiversity at large spatial scales. In the present study, we aimed at determining forest dynamics associated with global change processes (forest spread, maturation and fire) that have driven the variation in forest bird distributions in Mediterranean forest ecosystems in recent years. The study was located in Catalonia (NE Spain) and used changes in richness of specialist and generalist forest bird species in the last 20 years of the 20th century as indicators of forest biodiversity change. Forest bird distribution changes showed strong spatial patterns and appeared to be related to population processes occurring beyond sampling units (10 km × 10 km squares). Forest maturation appeared as the most important driver of such changes because most of the studied species have a non-Mediterranean origin and are associated with more mature forests. To a lower degree, forest spread also contributed to forest bird distribution changes whereas the impact of forest fires was not associated to a decrease in the richness of either group of forest species. Given the relatively coarse scale at which our study was conducted, caution should be taken when extrapolating our results to the possible future impacts of climate change on fire regime and forest bird distribution. Our results indicate that large-scale forest maturation and spread due mainly to land abandonment in Catalonia has overridden the potentially negative effects of fires on forest bird distributions and are currently driving changes in forest biodiversity patterns across the region.
The use of a brunt Mediterranean shrubland by birds was investigated during the first three years following a summer fire. Birds were censused by point counts, and vegetation cover was estimated. The results show an early and continuous use of the burnt area by birds. During this period, the variation in avifauna composition relate first to the season, and secondarily to the time elapsed since fire, as shown by Correspondence Analysis of the birds x samples matrix. The main effect of fire is to induce a rapid transition from a shrubland breeding avifauna (dominated by insectivorous species). After fire, the overall abundance of birds at the breeding season is positively correlated with the foliage volume, which seems to be the main limiting factor. Examples of positive specific responses (colonisation, dispersion, or site tenacity) are shown. Site tenacity of birds, favoured both by the presence of rocky patches and by the persistence of very small unburnt remnants, may explain the relatively moderate effect of fire on this community.
Wildfires are the most extensive and severe disturbance affecting the shrublands where Sardinian and Dartford Warblers (Sylvia melanocephala and S. undata) abound. Estimating the long-term use of burned habitats by these species (i.e. their time-window of occurrence) is fundamental to understanding their regional distribution and to plan possible conservation measures for the near-threatened Dartford Warbler. In this study, we describe the post-fire time-window of occurrence and cover preferences of the two warblers using an abundance dataset, gathered by point counts over 22 consecutive years, and a density dataset, resulting from territory mapping of four different plots for up to 8 years. Both datasets span before and after fire. The two species colonized burned areas as soon as the second year after fire. The Dartford Warbler showed its highest abundance between 4 and 9 years after fire and disappeared after 16 years or more. The Sardinian Warbler had a peak of abundance at 9 years, but the study was not long enough to record its local extinction. Partial least squares regression showed that abundance at points and plot density of the Dartford Warbler were positively related to the plant cover between 0.25 and 1 m, whereas vegetation between 0.5 and 4 m was important for the Sardinian Warbler. The Dartford Warbler, therefore, depends on the existence of dense and low shrublands, that are often the result of past fires.
Boosting is one of the most important recent developments in classi-fication methodology. Boosting works by sequentially applying a classifica-tion algorithm to reweighted versions of the training data and then taking a weighted majority vote of the sequence of classifiers thus produced. For many classification algorithms, this simple strategy results in dramatic improvements in performance. We show that this seemingly mysterious phenomenon can be understood in terms of well-known statistical princi-ples, namely additive modeling and maximum likelihood. For the two-class problem, boosting can be viewed as an approximation to additive modeling on the logistic scale using maximum Bernoulli likelihood as a criterion. We develop more direct approximations and show that they exhibit nearly identical results to boosting. Direct multiclass generalizations based on multinomial likelihood are derived that exhibit performance comparable to other recently proposed multiclass generalizations of boosting in most situations, and far superior in some. We suggest a minor modification to boosting that can reduce computation, often by factors of 10 to 50. Finally, we apply these insights to produce an alternative formulation of boosting decision trees. This approach, based on best-first truncated tree induction, often leads to better performance, and can provide interpretable descrip-tions of the aggregate decision rule. It is also much faster computationally, making it more suitable to large-scale data mining applications.
The effects of prescribed fire on understory vegetation structure and bird populations of Pinus pinaster stands in northern Portugal were assessed by using a synchronic sampling approach. During the spring of 1998 and 1999, 49 plots (of which 40 had been burned from 0.5 to 5 years ago) were characterised in terms of vegetation structure, surrounding landscape composition and breeding bird populations. Linear regression analysis and ANOVA were used to evaluate the effects of prescribed fire on vegetation and birds. Herbaceous vegetation showed a modal growth with a maximum development ca. 3 years after fire. Shrub development increased linearly with time since fire. Understory vegetation structure 5 years after fire was similar to control plots. Bird abundance and richness were influenced by plot variables (increased with stand age) and landscape variables (decreased with the amount of shrublands and eucalyptus stands surrounding the plot). After controlling for the effect of these variables, time since fire affected bird abundance, particularly for shrub/ground nesters. Minimum abundance occurred in the second or third breeding season after fire, possibly due to site tenacity or increased food availability. Prescribed burns did not affect bird richness. The size of the burned plots did not affect bird abundance or richness, probably because most burns were very small. Measures to increase bird diversity in these forests include maintaining other tree species and snags, avoiding the use of eucalyptus, and keeping a 5-year interval between consecutive prescribed burns in a given stand. The average size of burns could probably be increased without detrimental effects on bird populations.
For climate change projections to be useful, the magnitude of change must be understood relative to the magnitude of uncertainty in model predictions. We quantified the signal-to-noise ratio in projected distributional responses of boreal birds to climate change, and compared sources of uncertainty. Boosted regression tree models of abundance were generated for 80 boreal-breeding bird species using a comprehensive data set of standardized avian point counts (349 629 surveys at 122 202 unique locations) and 4-km climate, land use, and topographic data. For projected changes in abundance, we calculated signal-to-noise ratios and examined variance components related to choice of global climatemodel (GCM) and two sources of species distribution model (SDM) uncertainty: sampling error and variable selection. We also evaluated spatial, temporal, and interspecific variation in these sources of uncertainty. The mean signal-to-noise ratio across species increased over time to 2.87 by the end of the 21st century, with the signal greater than the noise for 88% of species. Across species, climate change represented the largest component (0.44) of variance in projected abundance change. Among sources of uncertainty evaluated, choice of GCM (mean variance component = 0.17) was most important for 66% of species, sampling error (mean = 0.12) for 29% of species, and variable selection (mean = 0.05) for 5% of species. Increasing the number of GCMs from four to 19 had minor effects on these results. The range of projected changes and uncertainty characteristics across species differed markedly, reinforcing the individuality of species' responses to climate change and the challenges of one-size-fits-all approaches to climate change adaptation. We discuss the usefulness of different conservation approaches depending on the strength of the climate change signal relative to the noise, as well as the dominant source of prediction uncertainty.
Fire is used as a management tool for biodiversity conservation worldwide. A common objective is to avoid population extinctions due to inappropriate fire regimes. However, in many ecosystems, it is unclear what mix of fire histories will achieve this goal. We determined the optimal fire history of a given area for biological conservation with a method that links tools from 3 fields of research: species distribution modeling, composite indices of biodiversity, and decision science. We based our case study on extensive field surveys of birds, reptiles, and mammals in fire‐prone semi‐arid Australia. First, we developed statistical models of species’ responses to fire history. Second, we determined the optimal allocation of successional states in a given area, based on the geometric mean of species relative abundance. Finally, we showed how conservation targets based on this index can be incorporated into a decision‐making framework for fire management. Pyrodiversity per se did not necessarily promote vertebrate biodiversity. Maximizing pyrodiversity by having an even allocation of successional states did not maximize the geometric mean abundance of bird species. Older vegetation was disproportionately important for the conservation of birds, reptiles, and small mammals. Because our method defines fire management objectives based on the habitat requirements of multiple species in the community, it could be used widely to maximize biodiversity in fire‐prone ecosystems.
Historiales de Incendios Óptimos para la Conservación de la Biodiversidad
Advanced warning of potential new opportunities and threats related to biodiversity allows decision-makers to act strategically to maximize benefits or minimize costs. Strategic foresight explores possible futures, their consequences for decisions, and the actions that promote more desirable futures. Foresight tools, such as horizon scanning and scenario planning, are increasingly used by governments and business for long-term strategic planning and capacity building. These tools are now being applied in ecology, although generally not as part of a comprehensive foresight strategy. We highlight several ways foresight could play a more significant role in environmental decisions by: monitoring existing problems, highlighting emerging threats, identifying promising new opportunities, testing the resilience of policies, and defining a research agenda.
Aim
To quantify bird responses to a large unplanned fire, taking into consideration landscape‐level fire severity and extent, pre‐fire site detection frequency and environmental gradients.
Location
South‐eastern A ustralia.
Methods
A major wildfire in 2009 coincided with a long‐term study of birds and provided a rare opportunity to quantify bird responses to wildfire. Using hierarchical B ayesian analysis, we modelled bird species richness and the detection frequency of individual species in response to a suite of explanatory variables, including (1) landscape‐level fire severity and extent (2) pre‐fire detection frequency, (3) site‐level vegetation density and (4) environmental variables (e.g. elevation and topography).
Results
Landscape‐level fire severity had strong effects on bird species richness and the detection frequency of the majority of bird species. These effects varied markedly between species; most responded negatively to amount of severely burned forest in the landscape, one negatively to the amount of moderately burned forest and one responded negatively to the total area of burned forest. Only one species – the F lame R obin – responded positively to the amount of burned forest. Relationships with landscape‐scale fire extent changed over time for one species – the B rown T hornbill – with initially depressed rates of detection recovering after just 2 years. The majority of species were significantly more likely to be detected in burned areas if they have been recorded there prior to the fire.
Main conclusions
Birds responded strongly to the severity and spatial extent of fire. They also exhibited strong site fidelity even after severe wildfire which causes profound changes in vegetation cover – a response likely influenced by environmental features such as elevation and topography.
Random forests are a combination of tree predictors such that each tree depends on the values of a random vector sampled independently and with the same distribution for all trees in the forest. The generalization error for forests converges a.s. to a limit as the number of trees in the forest becomes large. The generalization error of a forest of tree classifiers depends on the strength of the individual trees in the forest and the correlation between them. Using a random selection of features to split each node yields error rates that compare favorably to Adaboost (Y. Freund & R. Schapire, Machine Learning: Proceedings of the Thirteenth International conference, ***, 148–156), but are more robust with respect to noise. Internal estimates monitor error, strength, and correlation and these are used to show the response to increasing the number of features used in the splitting. Internal estimates are also used to measure variable importance. These ideas are also applicable to regression.
We investigate first whether fire regimes resulting from the combination of climate change and fire-fighting policy may affect species distributions in Mediterranean landscapes, and second to what extent distributional dynamics may be constrained by the spatial legacy of historical land use.
Catalonia (north-eastern Spain).
We modelled the distributional responses of 64 forest and open-habitat bird species to nine fire-regime scenarios, defined by combining different levels of climate change and fire suppression efficiency. A fire-succession model was used to stochastically simulate land-cover changes between 2000 and 2050 under these scenarios. We used species distribution models to predict habitat suitability and occupancy dynamics under either no dispersal or full dispersal assumptions.
Under many simulated scenarios, the succession from shrubland to forest dominated over the creation of new low-vegetation areas derived from wildfires. Consequently, open-habitat specialists were the group most affected by losses of suitable habitat. Fire regimes obtained under scenarios including high fire suppression efficiency resulted in a larger number of bird species experiencing reductions in their distribution area.
Anthropogenic factors, such as historical land-use change and fire suppression, can drive regional distribution dynamics in directions opposite to those expected from climatic trends. This raises the question of what drivers and interactions should be given priority in the prediction of biodiversity responses to global change at the regional scale.
It is widely accepted that the postfire recovery in Mediterranean plant com- munities is carried out by direct regeneration, i.e., the fast recovery of a plant community with the same species pool that it had immediately prior to disturbance. However, there is evidence that not all plant species in the Mediterranean basin survive fire in all situations, suggesting that the direct regeneration process might not apply to all situations. We analyze whether the main combinations of forest tree species (up to 16) of the western Mediterranean basin exhibit a postfire direct regeneration process. Based on data from field surveys, we have developed a stochastic model to predict the medium-term forest dynamics. In general, Quercus species (resprouters) and the pines Pinus halepensis and P. pinaster (seeders that produce abundant seedlings) showed direct regeneration patterns. In contrast, forests of P. nigra, P. sylvestris, and P. pinea (seeders that produce few seedlings) changed to other situations after fire. This outcome was validated by additional data from plots with known fire history. These results did not support completely the direct regeneration model, since only half of the combinations of tree species analyzed exhibited a .50% probability of recovering the original prefire situation after fire. This partial failure of direct regeneration evidences the need for reconsidering restoration and conservation plans for Mediterranean ecosystems after fire.
The goal of this article is to address the question: can the production and sale of biomass for energy help reduce the costs of conventional mechanical pile and burn forest fuel treatments? To address this question, this study analyzes data from six forest fuel reduction treatment units that combined biomass-harvesting trials in the Superior National Forest located in the state of Minnesota, USA. Machine operating and ownership costs are assessed. Costs for conventional mechanical treatment costs (pile and burn) are compared with those for a biomass-harvesting option (harvesting and delivery costs less income from the sale of recovered biomass for energy or pulp). In study trials, conventional treatment costs were found to be less than the biomass energy option costs, indicating that the conventional treatment is a cheaper option. A sensitivity analysis of different transport distance and operating conditions scenarios is carried out. Findings show that under certain operational conditions these operations could be cost effective. Conditions determining cost effectiveness are site specific and depend on-site conditions, harvesting prescriptions, biomass stocking, forwarding distance, distance to end users, equipment hauling costs, the number of operations using the same machine, the operator’s skill, and truck payload.
Fire is a key mechanism creating and maintaining habitat heterogeneity in Mediter- ranean landscapes by turning continuous woody landscapes into mosaics of forests and shrublands. Due to the long historical role of fires in the Mediterranean, we hypothesised a moderate negative effect of this type of perturbation on forest bird distribution at a landscape level. We conducted point bird censuses in Aleppo pine forest patches surrounded by burnt shrublands and studied the relationships between three ecological groups of bird species (forest canopy species, forest understorey species, and ubiquitous species) and the features of local habitat, whole patch and surrounding landscape. We used a multi-scale approach to assess the effects of landscape variables at increasing spatial scales on point bird richness. Regarding local habitat components, canopy species were positively associated with tall pines while understorey species with the cover of shrubs and plants from holm-oak forests. Forest birds were positively related to patch size and irregular forest shapes, that is, with high perimeter/size ratios. Thus, these species did not seem to perceive edges as low quality but rather favourable microhabitats. We did not detect any negative effect of isolation or cover of woodlands in the landscape on the presence of forest species after local habitat factors had been accounted for. Finally, only local habitat factors entered the model for ubiquitous species. We suggest that mosaic-like landscapes shaped by fires in the Mediterranean basin are not strongly associated with negative effects fragmentation on forest birds other than those related with habitat loss.
Aim Spatial modelling techniques are increasingly used in species distribution modelling. However, the implemented techniques differ in their modelling performance, and some consensus methods are needed to reduce the uncertainty of predictions. In this study, we tested the predictive accuracies of five consensus methods, namely Weighted Average (WA), Mean(All), Median(All), Median(PCA), and Best, for 28 threatened plant species.
Location North-eastern Finland, Europe.
Methods The spatial distributions of the plant species were forecasted using eight state-of-the-art single-modelling techniques providing an ensemble of predictions. The probability values of occurrence were then combined using five consensus algorithms. The predictive accuracies of the single-model and consensus methods were assessed by computing the area under the curve (AUC) of the receiver-operating characteristic plot.
Results The mean AUC values varied between 0.697 (classification tree analysis) and 0.813 (random forest) for the single-models, and from 0.757 to 0.850 for the consensus methods. WA and Mean(All) consensus methods provided significantly more robust predictions than all the single-models and the other consensus methods.
Main conclusions Consensus methods based on average function algorithms may increase significantly the accuracy of species distribution forecasts, and thus they show considerable promise for different conservation biological and biogeographical applications.
Managing fire regimes for conservation of biodiversity is a global challenge. We examined the responses of birds to fire mosaics (4-km diameter landscapes) comprising different compositions of fire age-classes, and used these results to evaluate the relative value of four contemporary strategies for fire management. These were: (1) promoting a diverse range of age-classes; (2) promoting particular age-classes for fire-sensitive species; (3) preventing reserve-scale wildfire; and (4) burning a fixed percentage (e.g. 5%) of the landscape annually. None of the 28 species examined was positively associated with landscapes with extensive recently burned (<10 years) vegetation. One species was associated with landscapes with a greater diversity of age-classes while two species, including the endangered Black-eared Miner (Manorina melanotis), were associated with less diverse landscapes. Landscapes with extensive older (>35 years since fire) vegetation were favoured by three species; while two species preferred those with extensive mid-age (11–35 years since fire) vegetation. Our findings suggest that in semi-arid mallee ecosystems, management that results in large proportions of recently burned vegetation (e.g. by burning 5% of the landscape annually or permitting reserve-scale wildfires), or a high local diversity of age-classes, will negatively affect more bird species than they would aid. Management strategies that promote particular age-classes (i.e. mid-age and older vegetation) are likely to benefit bird species. Species-specific knowledge from a landscape perspective can refine management strategies to assist in defining the characteristics of ‘desirable’ fire mosaics for maintaining biodiversity.
Aim We examined the century-long post-fire responses of reptiles to (1) determine the time-scales over which fauna – fire relationships occur, (2) assess the capacity of a conceptual model to predict faunal response to fire, and (3) investigate the degree to which models of fauna – fire relationships can predict species occurrence and are transferable across space.
Location A 104,000 km2 area in the semi-arid Murray Mallee region of south-eastern Australia.
Methods We surveyed reptiles at 280 sites across a century-long post-fire chronosequence. We developed generalized additive mixed models (GAMMs) of the relationship between time since fire and the occurrence of 17 species in two subregions, and compared modelled responses with predictions derived from the conceptual model. The predictive capacity of GAMMs was then assessed (1) within the subregion the model was developed and (2) when transferred into a novel subregion.
Results Eleven species displayed a significant relationship with time-since-fire, with changes in species probability of occurrence continuing up to 100 years post-fire. Predictions of the timing of species post-fire peak in occurrence were accurate for 9 of 13 species models for which a significant fire response was detected, but little success was achieved in predicting the shape of a species' response. GAMMs predicted species occurrence more accurately when applied within the subregion in which they were developed than when transferred into a novel subregion, primarily due to some species responding to fire more strongly in one part of their geographic range.
Main conclusions Fire influences the occurrence of reptiles in semi-arid ecosystems over century-long time frames. Habitat-use conceptual models have value in predicting the peak occurrence of species following fire, particularly for species with distributions strongly shaped by fire. Species relationships with fire can differ across their geographic range, probably associated with variation in climatic influences on post-fire succession and the consequent provision of habitat resources.
The volatile costs of fossil fuels, concerns about the associated greenhouse gas emissions from these fuels, and the threat of catastrophic wildfires in western North America have resulted in increased interest and activity in the removal and use of woody biomass from forests. However, significant economic and logistical challenges lie between the forests and the consumers of woody biomass. In this study, we provide a current snapshot of how biomass is being removed from forests and used across the United States to demonstrate the wide variety of successful strategies, funding sources, harvesting operations, utilization outlets, and silvicultural prescriptions. Through an analysis of 45 case studies, we identified three themes that consistently frame each biomass removal and utilization operation: management objectives, ecology, and economics. The variety and combination of project objectives exemplified by the case studies means biomass removals are complex and difficult to categorize for analysis. However, the combination of objectives allows projects to take advantage of unique opportunities such as multiple funding sources and multiparty collaboration. The case studies also provide insight into the importance of ecological considerations in biomass removal both because of the opportunity for forest restoration and the risk of site degradation. The national view of the economic aspects of biomass removal provided by this wide variety of case studies includes price and cost ranges. This study is an important first step that helps define woody biomass removals which are becoming an essential part of forestry in the 21st century.
The Dartford warbler Sylvia undata is a rare bird of lowland heaths in southern England. Based on the results from a recent study, the present essay aims to describe the practical steps conservationists might take to promote its future in the British avifauna. There is a need for greater safeguarding of sites by acquisition or protection from undesirable developments, while on surviving heaths encroachment of birch, bracken and pines will have to be resisted or even reversed. The maintenance of an ideal age range of vegetation is considered and selective propagation of gorse is suggested as a way to improve some sites for Dartford warblers. Consideration is given to translocating birds and to providing food artificially in winter, though both these possibilities are not considered to be ideal. Recommendations are made for the maintenance and development of sufficient knowledge on the Dartford warbler to aid its conservation.
1. Postfire salvage logging is the most commonly applied forestry practice in burned forests world-wide, mainly for economic reasons. However, it strongly affects bird communities and is generally considered to be detrimental for bird conservation. In Europe, many open-habitat species are currently declining owing to land use changes. Wildfires, which are common disturbances in the Mediterranean Basin, can create suitable habitat for these species but the effect of postfire salvage logging on bird communities is unknown.
2. We surveyed breeding birds in two burned secondary pine forests from the western Mediterranean Basin and analysed the effect of salvage logging and vegetation regeneration as determinants of individual species and community parameters. We used a pseudoexperimental before-after-control-impact approach to study the changes in the bird community during the first three springs after fire.
3. Most bird species were affected by salvage logging (measured by snag density), a relationship that was positive for forest birds and negative for open-habitat species. Species linked to shrub and edge habitats were positively affected by vegetation regrowth. Bird communities in logged areas held more species of conservation concern than those in unlogged areas. Species richness and overall density tended to decrease from the first to the second year after fire and to increase from the second to the third.
4. Salvage logging benefits a number of open-habitat species, although its effect on bird conservation depends strongly on the specific threats that birds face in each region or ecosystem.
5. Synthesis and applications. In the Mediterranean Basin, some postfire salvage logging of pine forests can be compatible with bird conservation. We recommend that managers retain some standing dead trees during logging operations and that logged forest is interspersed with unlogged stands. This will provide suitable habitat for the widest range of species.
Aim Two main mechanisms may explain post‐disturbance species colonization patterns of early successional habitats such as those originated by wildfires. First, post‐disturbance colonization is not limited by the dispersal ability of the species to reach the newly created open areas and, secondly, colonization is limited by dispersal. Under the first hypothesis, we expect, at a regional scale, to find similar post‐disturbance communities to develop on recently burned sites. However, colonization limited by dispersal will lead to strong between‐site variations in species composition.
Location To test these hypotheses, we studied the post‐fire colonization patterns of nine open‐habitat bird species in eight distantly located wildfires in the north‐eastern Iberian Peninsula.
Methods We censused post‐fire bird composition by means of field transects and identified potential colonization sources from species–habitat suitability maps derived from atlas data.
Results Our results showed strong significant differences in post‐fire species composition between burnt areas. Burnt areas located in areas with low probability of species presence before the fire event showed lower species occurrence and richness after the fire.
Main conclusions These results do not support the idea that early successional stages and open habitats have a homogeneous community structure at regional scales and suggest that dispersal is a key constraint determining bird colonization of post‐fire habitats. Further attention should be paid to landscape heterogeneity as a key factor in determining population dynamics of open‐habitat species in the light of current and future land‐use changes in Mediterranean regions.
Broom matorrals are subjected to extensive burning in the Pyrenees to improve grazing value, despite being a habitat of conservation interest in Europe. Our aim here is to evaluate the impact of such management practices over the long term, and of fire severity over the short term, on avifauna. Bird-habitat stations were distributed in broom shrublands from a few months to 51 years after fire, at 1400–2100 m a.s.l. Overall, shrub cover was the main habitat variable affecting the bird community composition. The abundance trends of bird species for half a century after fire were varied, but population recovery seemed slower (especially in the Dartford warbler Sylvia undata) than it had been reported at a lower altitude. Three species of European conservation concern (Alauda arvensis, Lullula arborea and Lanius collurio) showed abundance peaks at 10–19 years after fire. This time interval showed the highest species richness, abundance and conservation value, whereas shrub cover continued to increase afterwards. The bird assemblage tended to impoverish with increasing fire severity in the first year after a fire. Our results emphasize: (1) the slow recovery of bird community of burnt mountain shrublands; (2) the need for long-term biodiversity assessments to help improve planning of fire intervals at different altitudes; (3) the relevance of reducing fire severity due to its impact on fauna.