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Fires as agents of biodiversity: Pyrodiversity promotes biodiversity
... Many ecosystems have long evolved with fire (Pausas and Keeley, 2009), yet it remains a challenge for fire managers to identify fire regimes that enhance and maintain biodiversity (McLauchlan et al., 2020). One prominent method proposes the creation of 'pyrodiverse' landscapes-a fine scale mosaic of fire histories (Martin and Sapsis, 1992). A diversity of fire histories is thought to enhance biodiversity by increasing the diversity of niches, limiting the likelihood of large, severe fires, and, in some regions, by replicating Indigenous fire regimes (Martin and Sapsis, 1992). ...
... One prominent method proposes the creation of 'pyrodiverse' landscapes-a fine scale mosaic of fire histories (Martin and Sapsis, 1992). A diversity of fire histories is thought to enhance biodiversity by increasing the diversity of niches, limiting the likelihood of large, severe fires, and, in some regions, by replicating Indigenous fire regimes (Martin and Sapsis, 1992). Indigenous fire regimes promote pyrodiversity through burning small, frequent, low-intensity fires in regions across the world; in Australia (Bliege Bird et al., 2008), South America (Pivello, 2011), North America (Roos et al., 2021), and Africa (Sheuyange et al., 2005). ...
... One factor that might explain the context-dependence of the pyrodiversity begets biodiversity relationship is consideration of historical levels of pyrodiversity under which communities evolved (Martin and Sapsis, 1992). In many fire-prone regions, this means understanding how current patterns of pyrodiversity relate to pyrodiversity maintained under Indigenous fire stewardship. ...
... High levels of pyrodiversity have been hypothesized to give rise to a wide range of ecological niches that support higher biodiversity (i.e., "pyrodiversity begets biodiversity") [29•, 30•, 31]. The term pyrodiversity was introduced by Martin and Sapsis (1992) [32] as the "variety in interval between fires, seasonality, dimensions, and fire characteristics, producing biological diversity at the micro-site, stand, and landscape level." Indeed, the relationships between landscape diversity and biodiversity have been the focus of research since the inception of ecology as a discipline. ...
... High levels of pyrodiversity have been hypothesized to give rise to a wide range of ecological niches that support higher biodiversity (i.e., "pyrodiversity begets biodiversity") [29•, 30•, 31]. The term pyrodiversity was introduced by Martin and Sapsis (1992) [32] as the "variety in interval between fires, seasonality, dimensions, and fire characteristics, producing biological diversity at the micro-site, stand, and landscape level." Indeed, the relationships between landscape diversity and biodiversity have been the focus of research since the inception of ecology as a discipline. ...
... The conceptual introduction of pyrodiversity by Martin and Sapsis [32], while seminal, lacked empirical evidence and was sufficiently vague in definition that it left the door open for varied interpretation and application [e.g., [34][35][36][37][38]. In the following decades, numerous researchers have sought to identify pyrodiversity-biodiversity relationships and have done so using a remarkably wide range of approaches and techniques [29•]. ...
Purpose of Review
Climate change will continue to alter spatial and temporal variation in fire characteristics, or pyrodiversity. The causes of pyrodiversity and its consequences for biological communities are emerging as a promising research area with great potential for understanding and predicting global change. We reviewed the literature related to the causes and consequences of pyrodiversity over the 3-year period 2019–2021 to identify emerging themes and innovations.
Recent Findings
Key innovations include multi-scale analyses of pyrodiversity, a focus on mechanisms underlying single-species responses to pyrodiversity, investigating how pyrodiversity influences community stability and beta-diversity, and novel, integrative approaches for measuring pyrodiversity.
Summary
Pyrodiversity research is still maturing, and will benefit from exploration of multi-scale, gradient analysis of integrated (multi-measure) pyrodiversity metrics, an increased focus on how climate change may influence pyrodiversity across different systems, and a stronger framework for operational pyrodiversity within the context of land management. We suggest that research focusing on pyrodiversity could be generalized to include “turbadiversity,” or the cumulative patterns of heterogeneity produced by multiple types of disturbances (i.e., not just fire).
... mean fire return interval) and their underlying drivers [6,7], but until recently what determines the variation of fire regime characteristics, known as pyrodiversity, has received little attention. Martin & Sapsis [8] first proposed that pyrodiversity begets biodiversity by creating heterogeneous landscapes composed of dissimilar habitats and ecological niches. Since the theory was formalized, the potential importance of heterogeneity in fire regimes for ecosystem pattern and process has gained increasing attention both in research and ecosystem management [4,9]. ...
... Here, we build on Martin & Sapsis's [8] original definition of pyrodiversity and previous approaches of measuring the phenomenon (especially Hempson et al. [18] and Ponisio et al. [17]) to develop a general method for quantifying pyrodiversity using four fire regime traits within a functional diversity framework. We apply this measure of pyrodiversity broadly across all forested areas in the western United States and assess how pyrodiversity varies with climate, topography and human influence. ...
... We used four fire regime traits to calculate contemporary pyrodiversity: (i) fire return interval (frequency), (ii) burn severity, (iii) burn season and (iv) patch size (figure 1b). These traits are commonly used to define fire regime groups, are important determinants of ecosystem process in fire-adapted systems [5,6], and follow the original characteristics of pyrodiversity [8]. We mapped each of the four fire regime traits across the western United States using fire perimeter data from the national Monitoring Trends in Burn Severity database, which includes all large fires (greater than 404 ha) in the region between 1985 and 2018 [26]. ...
Pyrodiversity or variation in spatio-temporal fire patterns is increasingly recognized as an important determinant of ecological pattern and process, yet no consensus surrounds how best to quantify the phenomenon and its drivers remain largely untested. We present a generalizable functional diversity approach for measuring pyrodiversity, which incorporates multiple fire regime traits and can be applied across scales. Further, we tested the socioecological drivers of pyrodiversity among forests of the western United States. Largely mediated by burn activity, pyrodiversity was positively associated with actual evapotranspiration, climate water deficit, wilderness designation, elevation and topographic roughness but negatively with human population density. These results indicate pyrodiversity is highest in productive areas with pronounced annual dry periods and minimal fire suppression. This work can facilitate future pyrodiversity studies including whether and how it begets biodiversity among taxa, regions and fire regimes.
... Fire is a major driver of spatial pattern and is one of the few processes that land managers can manipulate to promote biodiversity (Penman et al. 2011). For example, pyrodiversity-the variation in fire regime attributes such as extent, severity, seasonality, and frequency-can increase niche space facilitating species coexistence (Martin and Sapsis 1992;Kelly et al. 2017), and provide resources for species who require multiple resource states for their survival (Law and Dickman 1998;Kelly et al. 2017). Most research into how spatial patterns in pyrodiversity affect species richness has focussed on time since fire composition (Kelly et al. , 2015Di Stefano et al. 2013;Sitters et al. 2014;Burgess and Maron 2016;McGranahan et al. 2018). ...
... An index of time since fire was also selected as a variable as it is also known to affect habitat structure and when measured at a landscape scale is hypothesised to influence mammal richness (Swan et al. 2015;Kelly et al. 2017). Further, prescribed fire can be used by land managers to manipulate pyrodiversity in the landscape (Penman et al. 2011), with the expectation that increased pyrodiversity will benefit biodiversity (Martin and Sapsis 1992). Descriptions of the rasters we used, justification for their use and their data sources are listed in Table 1. ...
... However, there are very few tools available to land managers to manipulate spatial pattern for this purpose. Prescribed fire can be used to manipulate pyrodiversity in the landscape (Penman et al. 2011), with the expectation that increased pyrodiversity will benefit biodiversity (Martin and Sapsis 1992). Our research shows that species richness is most strongly driven by factors that cannot be altered by land managers, such as NDVI and elevation. ...
ContextUnderstanding the relationships between spatial pattern, spatial scale and biodiversity can help ecologists to assess the impacts of environmental change and inform management plans. Spatial pattern research has often focussed on the effect of modified landscapes on species diversity. However, few studies have examined species responses to spatial pattern from other sources, including those which vary over time, such as fire.Objectives
We investigated the effect of composition and configuration for topographic, ecological and disturbance factors on mammal species richness. In addition, we examined whether the magnitude and predictive strength of the relationship with richness varied with spatial scale.Methods
We sampled ground-dwelling mammals at 187 sites in the Otway Ranges of south-eastern Australia. A gradient modelling approach was used to characterise landscape composition and configuration for each predictor. Relationships with mammal richness were modelled using Bayesian Networks at ten different spatial scales (7–1165 ha).ResultsComposition and configuration were both important to species richness, although the strength and presence of relationships varied across the ten scales. Patterns in NDVI, time since fire, habitat complexity and elevation had the strongest effects on mammal species richness.Conclusions
Our findings highlight the importance of measuring both the composition and configuration of environmental measures at different spatial scales to assess their effect on species richness. Further, studies focusing on just one environmental measure of spatial pattern or one spatial scale will miss important relationships between environmental variables and species richness.
... The hypothesis that "pyrodiversity begets biodiversity" still lacks in the synthesis of findings (Bowman et al., 2016) but there is an initial and contemporary theory. Fires as agents of biodiversity hypothesized that prehistoric fire regime promotes diverse biota but contemporary theory suggests that after many decades of fire suppression, we have reduced pyrodiversity which can lead to reduced biodiversity (Martin & Sapsis, 1992). ...
... One of the oldest provisioning services lasting today, and as we mentioned above, it has been hypothesized that fires are agents of biodiversity (Martin & Sapsis, 1992). Humans can modify the landscapes through fires as a powerful ecological force that can positively or negatively affect the risk of economically disruptive fires by reducing catastrophic fires (Bowman et al., 2016). ...
This chapter aims to show the phenomenon of forest fires from socioeconomic aspects to present the readers with a new perspective. We start from the assumption that fire in forest ecosystems has a positive and negative impact, which can be represented by an appropriate valuation system. The basis for such an assumption was found in the paradox of fire (in natural ecosystems), which has had human attention from the very beginning of the human population. From early views on social dependence on fire to a modern perspective, that fire is a catastrophic phenomenon in nature. Today, it can be assumed that our valuation system is set at a point where fire harms nature. This tacit acceptance has become commonplace in fire reporting where the importance of fire in removing biomass especially coniferous stands, maintaining open spaces for grazing and hunting, reducing catastrophic wildfires, in carbon balance and water regulation or scientific knowledge is almost completely omitted. Contemporary streams in nature and forest science and practice point out that fire is an ecosystem service providing many services with trade-offs between fire prevention and the provision of ecosystem services. Here, we explain why fire in natural ecosystems become relevant for science after the eighties. We present that the extent of fire damage is more than 0.012% of Worlds GDP in this decade. Major socioeconomic driving factors of forest fires are presented too. The chapter presents examples of ecosystem services and economic impacts provided by wildfires.
... Fire is an important agent of spatial and temporal disturbance in terrestrial ecosystems of the Pacific Northwest which Native American communities have harnessed to maintain resources essential to livelihood and cultural continuity (Lewis, 1973;Martin and Sapsis, 1992;Kimmerer and Lake, 2001;Storm and Shebitz, 2006;Miller and Davidson-Hunt, 2010;Taylor et al., 2016;Marks-Block et al., 2019). The use of fire in the management of pre-colonial forests by Native Peoples provided sustenance to human and animal populations, shaped local and regional patterns of diversity, and created spatially and temporally heterogeneous terrestrial communities (Lewis, 1973;Martin and Sapsis, 1992;Stephens et al., 2007;Smith, 2011;Lightfoot et al., 2013;Lightfoot and Cuthrell, 2015;Taylor et al., 2016). ...
... Fire is an important agent of spatial and temporal disturbance in terrestrial ecosystems of the Pacific Northwest which Native American communities have harnessed to maintain resources essential to livelihood and cultural continuity (Lewis, 1973;Martin and Sapsis, 1992;Kimmerer and Lake, 2001;Storm and Shebitz, 2006;Miller and Davidson-Hunt, 2010;Taylor et al., 2016;Marks-Block et al., 2019). The use of fire in the management of pre-colonial forests by Native Peoples provided sustenance to human and animal populations, shaped local and regional patterns of diversity, and created spatially and temporally heterogeneous terrestrial communities (Lewis, 1973;Martin and Sapsis, 1992;Stephens et al., 2007;Smith, 2011;Lightfoot et al., 2013;Lightfoot and Cuthrell, 2015;Taylor et al., 2016). Acorns produced by trees of the genera Quercus and Notholithocarpus are used ubiquitously as a food source by Native Californian peoples (Schenck and Gifford, 1952;Hendryx and Davis, 1991;Anderson, 2005Anderson, , 2007. ...
Prescribed fire is used extensively as a management tool in fire-adapted landscapes of the American West to maintain ecosystem structure and function while reducing wildfire risk. Seasonally specific prescribed fire is used by many Indigenous groups to increase the quality and quantity of cultural resources and promote desired patterns of habitat diversity. Traditionally, the Karuk and Yurok Tribes of California applied fire in tanoak (Notholithocarpus densiflorus, Fagaceae) acorn gathering areas during the fall to reduce infestation in acorns by larvae of the filbertworm (Cydia latiferreana, Tortricidae) and filbert weevil (Curculio occidentalis, Curculionidae). It has become increasingly difficult to select culturally appropriate times in which to apply fire as a resource management tool due to changing environmental conditions and associated political considerations. To assess the effect of non-traditional management on tribal acorn resource systems, we investigated the effects of early summer burning on rates of larval infestation in tanoak acorns. We also studied how competing frugivores affected the availability of edible acorns to human consumers. We found that non-traditional early summer prescribed fire significantly reduced rates of larval infestation during the burn year (36.7%) but no difference between treatments was detected one year-post fire. Selective vertebrate frugivory significantly reduced the density of edible acorns by 39%. Our results highlight the importance of seasonally-specific prescribed fire in managing Karuk and Yurok resource systems and supporting tribal eco-cultural revitalization.
... Furthermore, variation in characteristics of the fire regime (e.g. fire history and severity) are hypothesized to increase the variability within ecosystems resulting in subsequent increases in diversity within the landscape-the pyrodiversity-biodiversity hypothesis that posits that pyrodiversity begets biodiversity (Martin and Sapsis 1992). ...
... Fire severity-in grasslands, severe fires can result from an accumulation of woody biomass fuel from shrub encroachment. With less-frequent fires, sporadically distributed downed wood can generate a mosaic of different fire severities in the landscape (Brown et al. 2019) resulting in so called 'pyrodiversity' (Martin and Sapsis 1992;Jones and Tingley 2021). Fires of different intensities and severities differ in their impacts on biotic and abiotic soil attributes (Certini et al. 2021). ...
Fire can impact terrestrial ecosystems by changing abiotic and biotic conditions. Short fire intervals maintain grasslands and communities adapted to frequent, low-severity fires. Shrub encroachment that follows longer fire intervals accumulates fuel and can increase fire severity. This patchily distributed biomass creates mosaics of burn severities in the landscape—pyrodiversity. Afforded by a scheduled burn of a watershed protected from fires for 27 years, we investigated effects of woody encroachment and burn severity on soil chemistry and soil-inhabiting bacteria and fungi. We compared soils before and after fire within the fire-protected, shrub-encroached watershed and soils in an adjacent, annually burned, non-encroached watershed. Organic matter and nutrients accumulated in the fire-protected watershed but responded less to woody encroachment within the encroached watershed. Bioavailable nitrogen and phosphorus and fungal and bacterial communities responded to high severity burn regardless of encroachment. Low severity fire effects on soil nutrients differed, increased bacterial but decreased fungal diversity, and effects of woody encroachment within the encroached watershed were minimal. High severity burns in the fire-protected watershed led to a novel soil system state distinct from non-encroached and encroached soil systems. We conclude that severe fires may open grassland restoration opportunities to manipulate soil chemistry and microbial communities in shrub-encroached habitats.
... One of the difficult aspects of characterizing species responses across landscapes with intact fire regimes is the complexity associated with varying fire extent, frequency, seasonality, and severity over time, collectively known as pyrodiversity. Martin and Sapsis (1992) explored the concept of pyrodiversity and hypothesized that pyrodiversity across a given landscape increases biodiversity. This hypothesis was based on the idea that fire creates unique niches in space and time and alters competition and resource availability; this increase in environmental heterogeneity increases the number of species that can coexist (Martin and Sapsis 1992;Bond and Keeley 2005). ...
... Martin and Sapsis (1992) explored the concept of pyrodiversity and hypothesized that pyrodiversity across a given landscape increases biodiversity. This hypothesis was based on the idea that fire creates unique niches in space and time and alters competition and resource availability; this increase in environmental heterogeneity increases the number of species that can coexist (Martin and Sapsis 1992;Bond and Keeley 2005). The biodiversity fostered by pyrodiversity may in turn also make future fires more diverse by altering fuels and increase future biodiversity. ...
Background
Fire suppression in western North America increased and homogenized overstory cover in conifer forests, which likely affected understory plant communities. We sought to characterize understory plant communities and their drivers using plot-based observations from two contemporary reference sites in the Sierra Nevada, USA. These sites had long-established natural fire programs, which have resulted in restored natural fire regimes. In this study, we investigated how pyrodiversity—the diversity of fire size, severity, season, and frequency—and other environment factors influenced species composition and cover of forest understory plant communities.
Results
Understory plant communities were influenced by a combination of environmental, plot-scale recent fire history, and plot-neighborhood pyrodiversity within 50 m. Canopy cover was inversely proportional to understory plant cover, Simpson’s diversity, and evenness. Species richness was strongly influenced by the interaction of plot-based fire experience and plot-neighborhood pyrodiversity within 50 m.
Conclusions
Pyrodiversity appears to contribute both directly and indirectly to diverse understory plant communities in Sierra Nevada mixed conifer forests. The indirect influence is mediated through variability in tree canopy cover, which is partially related to variation in fire severity, while direct influence is an interaction between local and neighborhood fire activity.
... We review historical and expected future trends in wildfire and projected shifts in vegetation under future climate/fire conditions. For terrestrial fauna, we review effects of wildfire regimes, including evidence for the "pyrodiversity" hypothesis (Martin & Sapsis, 1991), which suggests that a mosaic of patches with varied burn histories and characteristics (e.g., soil characteristics, fire residuals, successional stages) will promote higher biodiversity (He et al., 2019;Minnich & Chou, 1997;Winford et al., 2015). Next, we review the effects of wildfire on aquatic habitat. ...
... Pyrodiverse landscapes should support higher species diversity by facilitating coexistence of species with different preferences for wildfire disturbance (He et al., 2019;Martin & Sapsis, 1991). Habitat complementation is therefore an important mechanism to promote diversity. ...
Wildfires in many western North American forests are becoming more frequent, larger, and severe, with changed seasonal patterns. In response, coniferous forest ecosystems will transition toward dominance by fire-adapted hardwoods, shrubs, meadows, and grasslands, which may benefit some faunal communities, but not others. We describe factors that limit and promote faunal resilience to shifting wildfire regimes for terrestrial and aquatic ecosystems. We highlight the potential value of interspersed nonforest patches to terrestrial wildlife. Similarly, we review watershed thresholds and factors that control the resilience of aquatic ecosystems to wildfire, mediated by thermal changes and chemical, debris, and sediment loadings. We present a 2-dimensional life history framework to describe temporal and spatial life history traits that species use to resist wildfire effects or to recover after wildfire disturbance at a metapopulation scale. The role of fire refuge is explored for metapopulations of species. In aquatic systems, recovery of assemblages postfire may be faster for smaller fires where unburned tributary basins or instream structures provide refuge from debris and sediment flows. We envision that more-frequent, lower-severity fires will favor opportunistic species and that less-frequent high-severity fires will favor better competitors. Along the spatial dimension, we hypothesize that fire regimes that are predictable and generate burned patches in close proximity to refuge will favor species that move to refuges and later recolonize, whereas fire regimes that tend to generate less-severely burned patches may favor species that shelter in place. Looking beyond the trees to forest fauna, we consider mitigation options to enhance resilience and buy time for species facing a no-analog future.
... Local environmental heterogeneity, in turn, is a fundamental driver of the richness of communities (e.g., diversity begets diversity; Rosenzweig, 1995;Stein, Gerstner, & Kreft, 2014). Previous investigations have found that high pyrodiversity-variation in the fire history of a landscape, such as fire extent, severity, and frequency (Martin & Sapsis, 1992)-promotes landscape heterogeneity and therefore helps to promote biodiversity (Ponisio, Wilkin, et al., 2016). Spatial variation in fire history generates successional and structural habitat diversity, allowing a greater number of species to coexist across the landscape (Bowman et al., 2016;Brown & York, 2017;Burrows, 2008;Kelly & Brotons, 2017;Martin & Sapsis, 1992;Parr & Brockett, 1999;Ponisio, Wilkin, et al., 2016;Tingley et al., 2016). ...
... Previous investigations have found that high pyrodiversity-variation in the fire history of a landscape, such as fire extent, severity, and frequency (Martin & Sapsis, 1992)-promotes landscape heterogeneity and therefore helps to promote biodiversity (Ponisio, Wilkin, et al., 2016). Spatial variation in fire history generates successional and structural habitat diversity, allowing a greater number of species to coexist across the landscape (Bowman et al., 2016;Brown & York, 2017;Burrows, 2008;Kelly & Brotons, 2017;Martin & Sapsis, 1992;Parr & Brockett, 1999;Ponisio, Wilkin, et al., 2016;Tingley et al., 2016). Depending on the accumulation of functional redundancy versus complementarity and species rich- (Ollerton, Winfree, & Tarrant, 2011), and severe droughts are known to affect both plants and pollinators (Alarcón, Waser, & Ollerton, 2008;Minckley et al., 2013). ...
Theory predicts that network characteristics may help anticipate how populations and communities respond to extreme climatic events, but local environmental context may also influence responses to extreme events. For example, altered fire regimes in many ecosystems may significantly affect the context for how species and communities respond to changing climate. In this study, I tested whether the responses of a pollinator community to extreme drought were influenced by the surrounding diversity of fire histories (pyrodiversity) which can influence their interaction networks via changing partner availability. I found that at the community level, pyrodiverse landscapes promote functional complementarity and generalization, but did not consistently enhance functional redundancy or resistance to simulated co‐extinction cascades. Pyrodiversity instead supported flexible behaviors that enable populations to resist perturbations. Specifically, pollinators that can shift partners and network niches are better able to take advantage of the heterogeneity generated by pyrodiversity, thereby buffering pollinator populations against changes in plant abundances. These findings suggest that pyrodiversity is unlikely to improve community‐level resistance to droughts, but instead promotes population resistance and community functionality. This study provides unique evidence that resistance to extreme climatic events depends on both network properties and historical environmental context.
... Incorrectly applying or excluding fire can have undesirable results such as bush encroachment, soil loss and shifts in species composition. Therefore, the decision on when and how to burn grassland should be based on an assessment of the veld condition and fuel load at the time, rather than recipe-based management [45]. In general, the lower the grazing pressure, the more fire is needed, especially in mesic and coastal grasslands. ...
... Some actions have already been taken. In 2011, the recreation of the Bureau of Development of the Center-West (SUDECO) autarchy of the Ministry of National Integration was announced to face the pressure already existent on arable land, energy and water resources which are abundantly available in the Cerrado [45]. Aiming at the reduction of regional inequalities, increment of regional economy competitiveness linked to social inclusion and environment conservation, SUDECO's strategies also observe the fundamental role of green science and technology. ...
In Africa large areas of savannah, grass- and cropland are burned every year, mostly for agricultural management purposes. These fires influence nutrient cycling patterns and are still a controversial issue. Most importantly, biomass burning causes a loss in soil organic matter and nutrients by particulate dispersal or volatilization. In this chapter, the effects of fires on the physical, chemical and biological properties of the soil are evaluated. The question whether controlled biomass burning promotes or destroys biodiversity is also addressed. We show that in the long term, if not managed correctly, the environmental impact of crop residue burning will be detrimental, causing loss of nutrients, soil biota, total N and C in the topsoil layer and soil erosion. The sustainable utilization of residues should therefore be promoted by ensuring the correct management of low-intensity fires.
... In forest ecosystems, the occurrence of fire regulates the main influences on biodiversity, i.e., environmental heterogeneity and resource availability (Stein et al. 2014). Vegetation and topographic conditions during a fire create spatial variation in fire-related patches, resulting in higher environmental heterogeneity, highly variable resource availability and an increase in diverse ecological niches, thus promoting biodiversity (Dantas et al. 2013;Martin and Sapsis 1992). For example, fire has strongly favored functional diversity in open savanna ecosystems (Teixeira et al. 2022). ...
Aim
Biodiversity plays an important role in regulating understory biomass. Aboveground and belowground biodiversity changes in response to fire-induced changes in environmental factors. However, little is known about the relationship between biodiversity and understory biomass after prescribed burning.
Methods
We selected Pinus koraiensis plantation and Quercus mongolica plantation in Northeast China, which have different regeneration strategies in response to fire. We analyzed the effects of prescribed burning on understory plant diversity (species diversity, functional diversity, trait efficiency and trait quantity) and soil microbial diversity (fungi and bacteria), and assessed the relationship between biodiversity and understory biomass after prescribed burning.
Results
Prescribed burning significantly increased functional diversity, trait efficiency, trait quantity and soil fungal diversity in P. koraiensis plantation, but significantly decreased functional diversity, trait efficiency and trait quantity in Q. mongolica plantation. Prescribed burning had no direct effect on understory biomass in either forest type, but had indirect positive effects on understory biomass in P. koraiensis plantation through trait quantity (i.e. total leaf phosphorus per unit area) and functional diversity (i.e. functional dispersion diversity based on leaf dry matter content); and indirect negative and positive effects on the understory biomass in Q. mongolica plantation through trait quantity (i.e. total leaf nitrogen per unit area) and soil fungal diversity (i.e. Chao index), respectively.
Conclusions
The responses of understory plant diversity and soil microbial diversity to prescribed burning depended on post-fire regeneration strategies of forest dominant species. This study improves understanding of the ecological mechanisms that influence understory biomass after prescribed burning.
... analysis, and each scenario allowed for climatic, lightning-caused fire, with the number of potential lightning strikes scaled linearly with climate. Earlier state-wide fire history research indicated that 6-16% of pre-Columbian California burned annually (Kilgore and Taylor, 1979;Martin and Sapsis, 1992). Because the southern Sierra Nevada were considered to have had low population densities given that the Foothill Yokuts and Tubatulabal were mobile, scenarios that tested cultural burning allowed up to 6% area cumulatively burned, inclusive of climatic, lightning-caused fires. ...
Paleoecology and paleolandscape modeling have the potential to differentiate cultural burning from climatic fires, improving interpretations of past fire histories and vegetation resource management practices. People have conducted variations of traditional fire management to increase terrestrial resources for hundreds of millennia, commonly in fire-prone areas where vegetation is adapted to frequent fire events. Over time, these cultural fires influenced regrowth and led to an anthropogenically-modified landscape. For some non-agrarian, semi-nomadic societies, such as the pre-Colonial groups within what is now known as California, identifying anthropogenic landscapes is difficult because of a lack of domesticated plant remains in the environmental record to indicate where human impacts occurred. This paper uses case studies from the central and southern Sierra Nevada range in California to explore the potential of paleoecology, specifically pollen and sedimentary charcoal, and spatially-explicit paleolandscape modeling to identify and distinguish periods of cultural burning in mountainous forests to improve archaeological interpretations of human-fire dynamics. Specifically, I use climate-vegetation dynamics and cluster analysis to look at temporal relationships of change between sites. These case studies are ideal because (1) the region is naturally fire-prone, (2) study sites are typically well-dated and analyzed at a sub-centennial resolution, (3) study sites are associated with archaeological sites, and (4) indigenous groups were proto-agricultural, balanophagy societies known to practice cultural burning. These case study sites show a strong potential to identify periods of cultural burning that help better inform archaeological interpretations and show synchronous evidence for cultural burning during the Little Ice Age (1250-1850). Furthermore, these studies provide better dated timelines of human influence at each site than nearby archaeological studies, indicating that in certain locales, paleoecological studies with high temporal resolutions could be used to inform the timing of archaeological activities and shifts.
... Nonetheless, we found that distinct fungal community assemblages and distinct assemblages of ectomycorrhizal, saprotrophic and pathogenic species can arise under different post-fire successional stages and fire frequency classes (Anderson et al., 2007;Berglund et al., 2011). Importantly, this suggests that pyrodiverse landscapes, which have a diversity of temporal and spatial fire histories, could be important in maintaining diverse fungal communities, by creating a higher diversity of niches to suit a higher diversity of species needs (Fox et al., 2022;Martin & Sapsis, 1992). ...
Fire has shaped global ecosystems for millennia by directly killing organisms and indirectly altering habitats and resources. All terrestrial ecosystems, including fire-prone ecosystems, rely on soil-inhabiting fungi, where they play vital roles in ecological processes. Yet our understanding of how fire regimes influence soil fungi remains limited and our knowledge of these interactions in semiarid landscapes is virtually absent. We collected soil samples and vegetation measurements from sites across a gradient in time-since-fire ages (0-75 years-since-fire) and fire frequency (burnt 0-5 times during the recent 29-year period) in a semiarid heathland of south-eastern Australia. We characterized fungal communities using ITS amplicon-sequencing and assigned fungi taxonomically to trophic guilds. We used structural equation models to examine direct, indirect and total effects of time-since-fire and fire frequency on total fungal, ectomycorrhizal, saprotrophic and pathogenic richness. We used multivariate analyses to investigate how total fungal, ectomycorrhizal, saprotrophic and pathogenic species composition differed between post-fire successional stages and fire frequency classes. Time-since-fire was an important driver of saprotrophic richness; directly, saprotrophic richness increased with time-since-fire, and indirectly, saprotrophic richness declined with time-since-fire (resulting in a positive total effect), mediated through the impact of fire on substrates. Frequently burnt sites had lower numbers of saprotrophic and pathogenic species. Post-fire successional stages and fire frequency classes were characterized by distinct fungal communities, with large differences in ectomycorrhizal species composition. Understanding the complex responses of fungal communities to fire can be improved by exploring how the effects of fire flow through ecosystems. Diverse fire histories may be important for maintaining the functional diversity of fungi in semiarid regions.
... At the landscape scale, local variations in disturbance regimes increase habitat heterogeneity [134] and should consequently promote local and regional biodiversity, according to the habitat heterogeneity hypothesis [225]. In this regard, landscapes with a high diversity of fire histories (i.e., a high pyrodiversity sensu [226]) support a greater abundance and diversity of pollinators [131•, 227]. The total amount of habitat over a landscape can also modulate communities at a local scale, according to the habitat amount hypothesis [228]. ...
Purpose of Review
The increasing impact of droughts, wildfires and windstorms in temperate areas poses a significant challenge to the adaptation capacity of forests and their associated arthropod communities. Organisms, organic material, and environmental conditions occurring after disturbances, i.e. the disturbance legacies, shape arthropod communities during their transition from pre- to post-disturbance conditions. We describe the contribution of disturbance legacies to the organization of forest arthropod communities following droughts, wildfires, or windstorms. We also highlight how forest conditions, arthropod traits and post-disturbance management influence disturbance legacies and their impact on arthropod communities.
Recent Findings
Key disturbance legacies include surviving arthropods, micro-environmental legacies, and tree- and ground-related resources. Most of these are driven by canopy openness and tree condition. For arthropods, dispersal ability and other biological and demographic traits determine their vulnerability to disturbances, but also their capacity to colonize post-disturbance microhabitats, and withstand micro-environmental legacies. Dominant tree species and management strategies influence disturbance regimes and mediate the pattern of their legacies. Droughts, wildfires and windstorms have idiosyncratic effects on disturbance legacies, and arthropod taxa can have specific responses to legacies, making it difficult to predict the likely composition of post-disturbance arthropod communities.
Summary
This review highlights a particular gap in our understanding of the effects of drought on forest arthropod communities and the need for more research in this area. In addition, a better understanding of how forest arthropod communities are altered by changes in disturbance regimes is urgently needed. Our goal is to foster an improved understanding of the role of disturbance legacies for forest arthropod communities in order to improve management decisions and promote the conservation of forest arthropod species.
... The difficulties associated with elucidating fire-biodiversity relationships may explain the scarcity of examples where fire management is specifically designed to meet the requirements of target species. An alternative approach is to base fire management on the assumption that a spatiotemporally diverse fire regime will conserve biodiversity by creating a greater variety of ecological niches: that pyrodiversity promotes biodiversity (henceforth referred to as the 'pyrodiversity hypothesis') (Martin and Sapsis, 1992). There is evidence that pyrodiversity promotes biodiversity in some systems (Tingley et al., 2016;Ponisio et al., 2016), but not others (Taylor et al., 2012;Farnsworth et al., 2014). ...
Maximising the spatiotemporal variability of prescribed fire (i.e. pyrodiversity) is often thought to benefit biodiversity. However, given mixed empirical support, the generality of the pyrodiversity hypothesis remains questionable. Here, we use a simulation experiment to explore the effects of spatiotemporal fire patterns on the population trajectories of four mammal species in a northern Australian savanna: northern brown bandicoot (Isoodon macrourus), northern brushtail possum (Trichosurus vulpecula arnhemensis), grassland melomys (Melomys burtoni), and northern quoll (Dasyurus hallucatus). Underpinned by data from a landscape-scale fire experiment, we simulated mammal population trajectories under three scenarios of fire size (ambient, small/dispersed fires, large/clumped fires) and three levels of dispersal ability (low, moderate, high) over a 21-year period across the Kapalga area of Kakadu National Park. The simulated population size of all four species declined markedly, regardless of fire spatial pattern and dispersal ability. However, the predicted final population size (i.e. number of individuals in the final timestep of the simulation) for the northern brown bandicoot, northern brushtail possum and grassland melomys were significantly influenced by fire size, with declines most severe under the small/dispersed fire scenario. Our results suggest that maximising the dispersion of small fires at the expense of disturbance refugia (such as less-frequently burnt areas) may exacerbate the severity of mammal decline. This highlights the importance of considering trade-offs between spatial (i.e. fire dispersion) and temporal (i.e. fire frequency) aspects of pyrodiversity, and the potential risks when applying fire management for biodiversity conservation without a firm understanding of the requirements of the target species.
... We know that fire typically triggers shifts in plant communities and that fire in the short-term promotes plant diversity (Kelly et al. 2020). We also know that at larger spatio-temporal scales, fire creates landscape heterogeneity: pyrodiversity (Jones and Tingley 2022;Martin and Sapsis 1992) (Fig. 1). However, we still lag far behind in our understanding of how fire affects soil biota involved in PSF, and there are very few studies on the impact of fire on PSF in any ecosystem . ...
Aims
Plant–soil feedback (PSF) is an important mechanism controlling plant growth, vegetation dynamics, and longer-term and larger-scale patterns of plant community diversity. We know that feedback between plants and soil biota depends on several external factors, such as nutrient and water availability, and interactions with neighbouring plants. We argue that in the ‘real world’, PSF are not working in isolation but instead proceed within a complex context of multiple interacting factors. Fire is one of those complex external factors which could greatly alter PSF by re-setting or re-directing plant-soil biota interactions.
Methods
We reviewed key literature on the effects of fire on soil biota and soil physicochemical properties with soil depth, to generate predictions on the complex effects of fire on PSF.
Results
We highlight that fire has strong potential to directly and indirectly affect the strength of PSF. To what extent this influences longer-term plant community trajectories depends on the interactions between fire characteristics and ecosystem type. Here, we conceptualized these effects of fire on soil properties and biota, and then discuss the main pathways through which fire should alter PSF.
Conclusions
We think that PSF processes should be nullified under and after fire. Average neutral PSF responses are expected to be more common in the short-term or within the timeframe required for major soil microbial players to regain their pre-fire abundances and diversity. We conclude by providing directions for future research and possible methods to study fire effects on PSF both in the field and under controlled conditions.
... This view prevailed in the early 20th century and prompted the development of large-scale fire management programs with the initial goal of complete fire exclusion (Arno andAllison-Bunnell, 2002, Stocks andMartell, 2016). Now, after nearly a century of extensive fire suppression, there is a growing consensus that fire is essential for sustaining many ecosystems, and that the complete exclusion of fire can have unintended consequences in these ecosystems (Martin and Sapsis, 1992, Arno and Allison-Bunnell, 2002, Pausus and Keeley, 2009, Driscoll et al., 2010. ...
The concurrent impacts of fire suppression, climate-warming, and industrial forestry have dramatically altered the spatio-temporal patterns of fire across the globe. Pyrophilic insects are among the species most threatened by these changes due to their dependence on recurring fire, and the extent to which they are adapted for exploiting the post-burn environment. Here, I review our current understanding of pyrophilic insects and the life-history adaptations that facilitate this highly specialized mode of life. I begin with an evaluation of three lines of evidence commonly used to characterize species’ associations with fire, including pyrophilic behaviour (i.e., attraction to fire), possession of pyrophilic adaptations (e.g., infrared sensors), and abundance patterns in burnt and unburnt habitats. This evaluation shows a general incongruence between the resulting lists of pyrophilic species that may explain, in part, the varying approaches to defining pyrophily in the literature. Many insects, including non-pyrophilic species, are opportunistically drawn to fire, suggesting that attraction to fire alone is not a good indicator of pyrophily. Although the relative abundance of species considered to be pyrophilic was generally higher in burnt habitats, data limitations restricted this evaluation to a small subset of species. Evidence of pyrophilic adaptations was the best single indicator of pyrophily given that these traits reflect longstanding, co-evolution with fire. Whereas much of our limited knowledge of these species stems from studies of individual taxa, there is growing consensus that these insects are part of a larger community that have evolved to exploit reproductive advantages in the post-burn environment.
... Fire clearly has negative effects as well, especially at high frequencies and for some vulnerable taxa. As predicted by the pyrodiversity hypothesis [109,110], landscapes with a diversity of fire histories may support a greater abundance and diversity of pollinators than those that burn more homogeneously [111]. Ulyshen et al. [97 •] found pyrodiversity to be a positive predictor of bee and butterfly abundance in Florida. ...
Purpose of Review: Fire and insects are major disturbances in North American forests. We reviewed literature on the effects of fire on bark beetles, defoliators, and pollinators, as well as on the effects of bark beetle and defoliator epidemics on fuels and wildfires.
Recent Findings: Fire has direct and indirect effects on insects, but our understanding of these effects is confounded by sev- eral factors identified in this review. Direct effects are expressed through insect mortality due to exposure to fire, with few studies published on this topic. Indirect effects are expressed through changes in insect hosts and forest conditions, with bark beetle responses to fire-injured trees following prescribed fires and low-severity wildfires being the most studied. Although fire effects on pollinators are an emerging field of research, it is clear that fire can benefit pollinators by creating more open forest conditions, which, in turn, enhance floral resource availability. Bark beetle and defoliator epidemics can exert large effects on fuels, but their effects on wildfires are mixed. Differences in the severity, extent, and timing of epidemics, fire regimes, fire weather, topography, and the metrics and models used to assess wildfires, among other factors, confound our understanding of the effects of bark beetle and defoliator epidemics on wildfires.
Summary: Fire has both positive and negative effects on insects. Bark beetle and defoliator epidemics have positive and negative effects on wildfires. Additional study of these relationships is warranted given the effects of climate change on forests and forest disturbances, recent declines in some pollinator species in North America, and interests in restoring fire-adapted forest ecosystems.
... The "pyrodiversity begets biodiversity" hypothesis (He et al., 2019;Jones & Tingley, 2021;Martin & Sapsis, 1992;Parr & Andersen, 2006) predicts that habitat mosaics, produced by an array of vegetation conditions resulting from varying attributes of fire effects in space and time, can enhance landscape-scale biodiversity. The strength of the relationship between diversity in fire and biodiversity depends strongly on fire regime attributes (i.e., frequency, severity, patch size and seasonality, among others; e.g., Agee, 1996). ...
Background
Historically, wildfire regimes produced important landscape‐scale disturbances in many regions globally. The “pyrodiversity begets biodiversity” hypothesis suggests that wildfires that generate temporally and spatially heterogeneous mosaics of wildfire severity and post‐burn recovery enhance biodiversity at landscape scales. However, river management has often led to channel incision that disconnects rivers from their floodplains, desiccating floodplain habitats and depleting groundwater. In conjunction with predicted increases in frequency, intensity and extent of wildfires under climate change, this increases the likelihood of deep, uniform burns that reduce biodiversity.
Predicted synergy of river restoration and biodiversity increase
Recent focus on floodplain re‐wetting and restoration of successional floodplain habitat mosaics, developed for river management and flood prevention, could reduce wildfire intensity in restored floodplains and make the burns less uniform, increasing climate‐change resilience; an important synergy. According to theory, this would also enhance biodiversity. However, this possibility is yet to be tested empirically. We suggest potential research avenues.
Illustration and future directions
We illustrate the interaction between wildfire and river restoration using a restoration project in Oregon, USA. A project to reconnect the South Fork McKenzie River and its floodplain suffered a major burn (“Holiday Farm” wildfire, 2020), offering a rare opportunity to study the interaction between this type of river restoration and wildfire; specifically, the predicted increases in pyrodiversity and biodiversity. Given the importance of river and wetland ecosystems for biodiversity globally, a research priority should be to increase our understanding of potential mechanisms for a “triple win” of flood reduction, wildfire alleviation and biodiversity promotion.
... The 'pyrodiversity begets biodiversity' hypothesis (Martin and Sapsis 1992;Parr and Andersen 2006;Davies et al. 2012), suggests pyrodiversity, or the diversity of post-fire conditions (i.e., age, seasonality, severity, or scale) promotes biodiversity (Tingley et al. 2016;He et al. 2019). The proposed mechanism driving biodiversity as a function of pyrodiversity is that variation in fire history results in variation in post-fire vegetation conditions with patches at variable stages and trajectories of succession. ...
Context
Fire influences the distribution of ecosystems on Earth, but the link between pyrodiversity, the heterogeneity in post-fire conditions, and biodiversity is just emerging.
Objectives
We tested the pyrodiversity begets biodiversity theory, which was developed at broader scales, to a scale where land management decisions are commonly made.
Methods
To assess the effects of landscape attributes on avian species richness, we deployed programmable acoustic recorders at 34 sites in a frequently burned longleaf pine (Pinus palustris) ecosystem which were set to record three, five–minute sessions per day for six days for two years. We identified avian species by their vocalizations and grouped them by nesting and forging guilds to assess the effects of land cover type, soil productivity, forest structure and fire history characteristics including, pyrodiversity on species richness and occupancy at the community, guild, and species levels using hierarchical Bayesian multispecies occupancy models. We defined pyrodiversity as the richness in time since fire values around a site.
Results
We found support for the pyrodiversity begets biodiversity hypothesis at the community level, as avian species richness increased with pyrodiversity (β = 0.136, 95% CrI 0.009–0.260). Species richness of cavity nesting species decreased with increasing time since fire, suggesting frequent fire increases diversity of this guild (β = − 0.334, 95% CrI − 0.713 to − 0.003).
Conclusions
Our work highlights the importance of pyrodiversity as a driver for biodiversity, and links theory to practices by examining this phenomenon at a scale readily translated into conservation action.
... Despite support for the IDH for fire, other studies have detected neutral, linear positive, and negative relationships between species diversity and fire severity (He et al., 2019;Miller & Safford, 2020). Martin and Sapsis (1992) coined the term "pyrodiversity" to capture a growing awareness of the ecological importance of variation across landscapes in fire severity, frequency, size, and other attributes (see also Bowman et al., 2016;He et al., 2019;Krawchuk & Moritz, 2011;Perry et al., 2011). They argued that pyrodiversity promotes variation in plant assemblages among sites (i.e., β) because, as with the underlying assumption of the IDH, different sets of species thrive under different conditions related to fire, a phenomenon observed for decades in fire-prone ecosystems (Bond et al., 2005;Pausas & Ribeiro, 2017;Romme, 1982). ...
Aim
Drastic changes in fire regimes are altering plant communities, inspiring ecologists to better understand the relationship between fire and plant species diversity. We examined the impact of a 90,000-ha wildfire on woody plant species diversity in an arid mountain range in southern Arizona, USA. We tested recent fire-diversity hypotheses by addressing the impacts on diversity of fire severity, fire variability, historical fire regimes, and topography.
Location
Chiricahua National Monument, Chiricahua Mountains, Arizona, USA, part of the Sky Islands of the US–Mexico borderlands.
Taxon
Woody plant species.
Methods
We sampled woody plant diversity in 138 plots before (2002–2003) and after (2017–2018) the 2011 Horseshoe Two Fire in three vegetation types and across fire severity and topographic gradients. We calculated gamma, alpha, and beta diversity and examined changes over time in burned versus unburned plots and the shapes of the relationships of diversity with fire severity and topography.
Results
Alpha species richness declined, and beta and gamma diversity increased in burned but not unburned plots. Fire-induced enhancement of gamma diversity was confined to low fire severity plots. Alpha diversity did not exhibit a clear continuous relationship with fire severity. Beta diversity was enhanced by variation in fire severity among plots and increased with fire severity up to very high severity, where it declined slightly.
Main Conclusions
The results reject the intermediate disturbance hypothesis for alpha diversity but weakly support it for gamma diversity. Spatial variation in fire severity promoted variation among plant assemblages, supporting the pyrodiversity hypothesis. Long-term drought probably amplified fire-driven diversity changes. Despite the apparent benign impact of the fire on diversity, the replacement of two large conifer species with a suite of drought-tolerant shrubs signals the potential loss of functional diversity, a pattern that may warrant restoration efforts to retain these important compositional elements.
... Thus, the lack of response to vegetation characteristics we observed likely reflects these species' tendency to forage above the canopy, where they are less affected by variation in fine-scale forest structure. In agreement with previous work investigating relationships between pyrodiversity and biodiversity (Kelly et al., 2017;Martin and Sapsis, 1992;Tingley et al., 2016), these varied responses among bat species suggest that a shifting mosaic approach to fire management may serve to most effectively promote bat diversity. Our analysis of feeding buzzes and early-evening activity suggests that variation in bat activity across fire regimes is in part related to roosting/emergence and foraging. ...
Disturbances such as fire play an important role in shaping forests and the wildlife they support. As such, forest managers employ prescribed fire to restore ecosystem function, promote forest biodiversity, and maintain wildlife habitat. To better understand how bats respond to variation in fire regime, we used acoustic recorders to quantify bat activity in forests maintained by frequent fire in southern Florida, USA and modelled this variation as a function of both fire regime and vegetation characteristics. Next, to better understand the mechanisms underlying these responses, we quantified variation in bat foraging efficiency and activity during the important early evening period. We found that even in regions historically maintained by frequent fire, bat activity was more closely associated with vegetation conditions, such as canopy cover and woody understory volume, than fire regime. When vegetation and fire frequency were considered together, the bat activity response was nuanced. Activity across the bat community was greater in forests that had burned more frequently in the previous two decades, but bats appeared more likely to encounter prey in forests that burned less frequently. Species-specific responses added additional complexity, potentially related to size and wing morphology, with larger bats responding more strongly to fire, whereas activity of smaller bats was primarily related to vegetation characteristics. Similarly, activity during the early-evening shifted as a function of fire frequency, but in different directions for different species. Our results suggest that investigations of occurrence or overall bat activity may provide an incomplete understanding of the complex responses to fire regimes that become more apparent when activity is partitioned into more refined metrics. These nuances have implications for management of fire-maintained forests. Though frequent burning may best promote the ecosystem services associated with insec-tivorous bat activity, a more heterogenous approach to fire management that considers bat species diversity, bat behavior, and vegetation conditions may provide additional benefits to bats.
... Thirty years ago, ecologists introduced the concept of pyrodiversity and posited that managing landscapes for a mosaic of fire return intervals, sizes and severities would increase biodiversity (Martin & Sapsis, 1992). Practitioners of this approach have compared species richness to diversity indices (e.g. ...
Aim
Fire can strongly influence ecosystem function, and human activities are disrupting fire activity at the global scale. Ecological theory and a growing body of literature suggest that a mixed severity fire regime promotes biodiversity in western North America. Some researchers advocate the use of pyrodiversity (i.e. heterogeneity in aspects of the fire regime such as time since fire or severity) as a conservation index to be maximized. Others caution against this approach arguing that the index oversimplifies fire–biodiversity interactions across trophic, spatial and temporal scales. We evaluated the effects of several landscape-scale pyrodiversity indices, and their severity and time-since-fire components, on species richness of forest carnivores.
Location
Northern California, United States.
Methods
We gathered data on fire history and mammal occurrence from camera trap surveys at 1,451 sites across Northern California public and private forestlands during 2009–2018. We used these data to model the effects of fire severity diversity, and its components (i.e. low, moderate and high severity wildfires), on carnivore richness at short (10 years) and longer (25 years) timeframes. We repeated the modelling using a measure of time-since-fire diversity and its components (<10 years, 10–20 years, 20–30 years, 30–40 years, 40–100 years). We used Bayesian multispecies occupancy modelling to correct for imperfect measurement of species richness.
Results
We found that carnivore richness was highest at locations with intermediate fire severity diversity (0.46, 90%CI: 0.40–0.52) calculated using Simpson's Measure of Evenness (range: 0–1) for the 10-year timeframe, and the results were almost identical yet less precise for the longer timeframe. When we separated fire severity diversity into its components, we found that carnivore richness was highest at locations where 17% (90%CI: 4–20) of the landscape had experienced low severity burns over the past decade. In contrast, we found no association between time-since-fire diversity and carnivore richness, however, an intermediate amount of one of the components (e.g., the total amount of fire in the past 10 years) was positively associated with carnivore richness. Our results are consistent with a mixed severity fire regime wherein there is a greater extent of low severity than high severity fire.
Main conclusions
Overall our results suggest that carnivores would benefit from landscapes managed for greater, but not maximal, fire severity diversity. Our results also suggest that prescribed, low severity burns may provide ecological services to wildlife not otherwise provided by silviculture in a managed forest landscape.
... Over a century of widespread fire suppression related to colonization and land-use change has shifted human relationships with and reliance on fire. Not surprisingly, this has resulted in changes in community structure and composition and declines in pyrodiversity (the diversity and characteristics of fires in a region) (15,16). New and fundamentally different human-environment interactions are rapidly displacing human-fire linkages that have existed for millennia, and contemporary changes in human-fire Significance Large and severe wildfires are becoming increasingly common worldwide and are having extraordinary impacts on people and the species and ecosystems on which they depend. ...
Significance
Large and severe wildfires are becoming increasingly common worldwide and are having extraordinary impacts on people and the species and ecosystems on which they depend. Indigenous peoples comprise only 5% of the world’s population but protect approximately 85% of the world’s biodiversity through stewardship of Indigenous-managed lands. Much of this is attributed to long-term and widespread relationships with and dependence on fire, which has been applied as a tool for managing landscapes for millennia. Fortunately, the revitalization of Indigenous fire stewardship is demonstrating the value of routinely applying controlled fire to adapt to changing environments while promoting desired landscapes, habitats, and species and supporting subsistence practices and livelihoods.
... This may be explained by the rain (started in February in our study area) that stimulated the growth of the plants during the rainy. The season remains an important factor as it characterizes the bush fire regime and its impact on the environment as demonstrated by [32]. The number varies respectively from 3 to 35, from 5 to 43 and from 4 to 32 species in the sites CSF, CAF and witness for the tree savanna. ...
Few studies were carried out on the impact of wood cutting and bush fires on the dynamics of the herbal strata in savannahs of Adamawa, Cameroon. This study has as objectives to evaluate: 1. the recovery of the vegetation of shrub and grass savanna, 2. the evolution of the number of herbs with regards to time, 3. the floristic and specific contribution of the herbal specie. The inventories of herbaceous plants were carried out through quadra method in 9 sub-plots of 10 m × 10 m for each vegetal formation. The experimental design was split-plot with two (02) factors (savanna trees and shrubs), three (3) treatments (felling without fire, with fire and witness) and three (3) rehearsals/repetitions (portions). The analysis of variance (ANOVA) was used to compare means between treatments by using STATGRAPHIC XVII, and XLSAT to obtain result shown that 103 herbaceous plants divided in 73 genres and 23 families. The rate of recovery of savanna vegetation the herbs are more numerous 60% in the CSF, 50% in the CAF and 45% in witness site (wood savanna), Adversely, 30% in a witness site, 40% in the CSF and 50% in the CAF (shrub savanna). The number the species have grown from 3 to 45 in the tree’s savanna and 2 to 34 for the shrub savanna. The specific contribution of herbaceous varies according to the sites and the species.
... The concept of pyrodiversity combines variation in spatial and temporal dimensions of fire regimes (Martin and Sapsis, 1992). While much work to date has framed animal relationships with pyrodiversity by asking the question 'does pyrodiversity promote biodiversity?' a more nuanced approach is emerging that recognises that there are many different forms of pyrodiversity (Parr and Andersen, 2006;Kelly et al., 2017). ...
Fire has shaped Australia's diverse mammal fauna for millennia. However, ongoing changes to fire regimes threaten native mammal populations, and a significant conservation challenge is to understand and promote desirable forms of pyrodiversity (variation in fire regimes). A way forward is to quantify how different aspects of pyrodiversity influence whole mammal assemblages and produce dynamic maps of species distributions to inform conservation. We aimed to determine and map how spatial and temporal variation in fire regimes correlates with a diverse mammal assemblage comprising macropods, microbats, rodents, small marsupials and a monotreme. We built species distribution models for 17 species against fire, climate and environmental covariates in fire-prone woodlands of semi-arid Australia. Spatial measures of fire included the area, diversity and configuration of landscape elements, and temporal measures included time since fire and fire frequency. Native mammals showed a variety of responses to pyrodiversity. Microbats were more likely to occur as time since fire increased, whereas rodents were correlated with recently burned areas. Small dasyurid marsupials were correlated with the area of older post-fire age-classes, while western grey kangaroo occurrence was positively associated with high diversity of post-fire ages. Our new approach, using predictive models to map mammal distributions in relation to spatial and temporal variation in fire regimes, provides outputs that managers can use to improve conservation planning. This enables the positive and negative effects of fire to be better understood and will assist in achieving desirable forms of pyrodiversity that meet the needs of whole mammal assemblages.
... Cultural burning increases stem production for basketweavers, but also increases quality forage for ungulates (Lawrence and Biswell 1972;Kie 1984;Long et al. 2008, Williamson andWeckerly 2020), and may also improve nut production for humans and wildlife (Lake 2007;Fine et al. 2013;Armstrong et al. 2018). Cultural burns may also increase wildlife habitat, supporting biodiversity (Martin and Sapsis 1992;Hankins 2009) and endangered species such as the California Condor (Gymnogyps californianus [Shaw, 1797]) and Spotted Owl (Strix occidentalis [Xántus de Vésey, 1860]) that feed in edge habitats and clearings (Cowles 1967;Franklin et al. 2000;Roberts et al. 2011;Nabhan and Martinez 2012;Eyes et al. 2017). The improvements in habitat and biodiversity that emerge from understory burning (Webster and Halpern 2010;Knapp et al. 2013;Wynecoop et al. 2019) have cascading effects on a wide range of other plant and animal species, which in turn sustain the cultural traditions, economic livelihoods, and social and physical well-being of the firedependent cultures that rely on these species and processes in their ancestral territories (Heffner 1984;Ortiz 1993;Mathewson 2007;Eriksen and Hankins 2015;Smith 2016). ...
Background
Karuk and Yurok tribes in northwestern California, USA, are revitalizing the practice of cultural burning, which is the use of prescribed burns to enhance culturally important species. These cultural burns are critical to the livelihoods of indigenous peoples, and were widespread prior to the establishment of fire exclusion policies. One of the major objectives of cultural burning is to enhance California hazelnut ( Corylus cornuta Marsh var. californica ) basketry stem production for Karuk and Yurok basketweavers. To evaluate cultural burning as a form of human ecosystem engineering, we monitored hazelnut basketry stem production, qualities, and shrub density in 48 plots (400 m ² ) within two prescribed and 19 cultural burn sites. Socio-ecological variables that were analyzed included burn frequency, burn season, overstory tree (≥10 cm diameter at breast height) basal area, ungulate browse, and aspect. We also observed basketry stem gathering to compare travel distances, gathering rates, and basketweaver preferences across sites with different fire histories and land tenure.
Results
Hazelnut shrubs, one growing season post burn, produced a 13-fold increase in basketry stems compared with shrubs growing at least three seasons post burn ( P < 0.0001). Basketry stem production and stem length displayed negative relationships with overstory tree basal area ( P < 0.01) and ungulate browse ( P < 0.0001). Plots burned at high frequency (at least three burn events from 1989 to 2019) had 1.86-fold greater hazelnut shrubs than plots experiencing less than three burn events ( P < 0.0001), and were all located on the Yurok Reservation where land tenure of indigenous people is comparatively stronger. Basketweavers travelled 3.8-fold greater distance to reach gathering sites burned by wildfires compared with those that were culturally burned ( P < 0.01). At cultural burn sites, wildfire sites, and fire-excluded sites, mean gathering rates were 4.9, 1.6, and 0.5 stems per minute per individual, respectively.
Conclusions
Karuk and Yurok cultural fire regimes with high burn frequencies ( e.g., three to five years) promote high densities of hazelnut shrubs and increase hazelnut basketry stem production. This improves gathering efficiency and lowers travel costs to support the revitalization of a vital cultural practice. Our findings provide evidence of positive human ecosystem engineering, and show that increasing tribal sovereignty over fire management improves socio-economic well-being while at the same time supports measures of ecosystem structure and function.
... Suppression of disturbance events such as fires have fundamentally altered landscapes and reliant wildlife communities (Parsons and DeBenedetti, 1979, Pyne et al., 1996, Pasch and Koprowski, 2011, Harper et al., 2016. Disturbance is a critical process in ecosystems (Pickett andWhite, 2013, White andJentsch, 2001) generating spatial and temporal heterogeneity in vegetation communities and credited with increasing biodiversity (Martin and Sapsis, 1992). Through immediate redistribution of resources, disturbances alter competition dynamics among species and disturbances at various trophic levels can cascade through the ecosystem producing variable outcomes (Bowman et al., 2016, Lugo, 2020. ...
Suppression of historic fire regimes in North America has altered successional stages and shifted vegetation communities, negatively impacting wildlife diversity in forests. Prescribed fire is often used to increase habitat for wildlife populations and diversity but monitoring of responses does not always capture nuanced differences in habitat that influence wildlife communities over a range of ecological conditions and processes. We matched avian point count data with extensive vegetation sampling of unburned plots and plots that burned 12–16 months prior to evaluate the effects of coarse- and fine-scale habitat variables on the abundance of a suite of avian indicator species and nesting guilds. We estimated abundance conditional on detection probability based on repeated sampling over time intervals using N-mixture models and assessed support for coarse- and fine-scale habitat variables using multimodel inference and AIC. Six of 10 species demonstrated different abundances on burned and unburned plots. Abundances of three species were influenced solely by coarse variables, one species by fine-scale vegetation, and five species were dependent on a mix of coarse- and fine-scale variables. Even fine-scale vegetation characteristics did not fully capture the ecological processes stimulated by fire and compensatory community differences including interactions among species such as competition and predator avoidance should be considered in predicting species responses to prescribed fire. Shrub nester abundance was much higher on plots that burned the year prior, but the effect sizes of other variables were small for ground, tree, and cavity nesters, even though there were strong differences in abundances of individual species within those guilds. Detection probability was most often affected by conditions during the count including start time, temperature and wind, but also burn status and observer, suggesting potential bias in findings that do not account for heterogeneity in detection probability. We suggest variable responses of individual species within nesting guilds may obscure identification of responses in the avian community and inhibit assessment of management and restoration actions. Understanding species-specific responses to fine-scale habitat variables in the context of coarse ecological typology and the associated vegetative and wildlife community will provide the greatest insight to how prescribed fire characteristics interact to produce wildlife responses, and thus enhance its use as a restoration tool.
... Although spatial scale may be a major factor determining overall biodiversity contained within the fire island, heterogeneity within the fire regime likely augments the slope of change. This concept, referred to as pyrodiversity, is defined by diversifying attributes within fire regimes, such as fire-return interval, fire intensity, and fire season, to promote a mosaic of community structure across patches with different fire histories (Martin and Sapsis 1992;Ponisio et al. 2016;Tingley et al. 2016;Kelly and Brotons 2017;Beale et al. 2018). Similarly, firing techniques that promote heterogeneity in fire spread can accomplish the same goal within a burn unit. ...
The idea that not all fire regimes are created equal is a central theme in fire research and conservation. Fire frequency ( i.e., temporal scale) is likely the most studied fire regime attribute as it relates to conservation of fire-adapted ecosystems. Generally, research converges on fire frequency as the primary filter in plant community assembly and structure, which is often critical to conservation goals. Thus, conservation success is commonly linked to fire frequency in fire regimes.
The spatial scale of fire may also be vital to conservation outcomes, but this attribute is underrepresented in the primary literature. In our global, contemporary literature search, we found 37 published syntheses concerning the effects of prescribed fire in conservation over the last decade. In those syntheses, only 16% included studies that reported data-based inferences related to the spatial scale of the fire, whereas 73% included discussion of empirical studies on the temporal scale. Only one of the syntheses discussed studies that explicitly tested the effects of spatial extent, and none of those studies were experiments manipulating spatial scale. Further, understanding spatial-scale-dependent patterns may be relevant because two databases of fire-occurrence data from the United States indicated that spatial scale among lightning-ignited and prescribed fires may have been mismatched over the past few decades.
Based on a rich ecological literature base that demonstrates pervasive scale-dependent effects in ecology, spatial-scale-dependent relationships among prescribed fire regimes and conservation outcomes are likely. Using examples from the southeastern United States, we explored the potential for scale-dependent ecological effects of fire. In particular, we highlighted the potential for spatial scale to (a) influence wildlife populations by manipulating the dispersion of habitat components, and (b) modulate plant community assembly and structure by affecting seed dispersal mechanics and spatial patterns in herbivory. Because spatial-scale-dependent outcomes are understudied but likely occurring, we encourage researchers to address the ecological effects of spatial scale in prescribed-fire regimes using comparative and manipulative approaches.
... At a landscape scale, the presence of fires can increase biodiversity by creating mosaic habitats with high spatial heterogeneity (Malkinson and Wittenberg 2011). The pyrodiversity begets biodiversity hypothesis suggests that fires drive a diversification of habitats which allows species with different niches to coexist, therefore increasing global ecosystem biodiversity (Martin and Sapsis 1992;He et al. 2019). For instance, fires allow and foster the survival of many plants, mostly by inducing seed germination of many species (Moreira and Pausas 2012) which strongly affects species composition and regeneration of plant communities (Trabaud and Oustric 1989;Vilà-Cabrera et al. 2008). ...
The pyrodiversity begets biodiversity hypothesis suggests that wildfires drive habitat diversification, allowing species with different niches to coexist and increasing biodiversity. However, despite numerous wildfires studies, limited research has addressed species-specific effects of fire recurrence. We radio-tracked grey long-eared bats (Plecotus austriacus) from the largest maternity roost (a historical monastery) in an area of the Mediterranean coastal belt with one of the highest fire recurrence rates. Although shrublands cover over 80% of the surroundings and P. austriacus is known to forage in a wide range of habitats, the tracked bats barely used this habitat. They spent 92% of their flight time in scattered small Aleppo pine forest fragments, and never visited any habitat patches that burnt more than three times in the last 30 years. We also report some of the longest foraging and commuting distances (9.95 and 10.5 km) from the roost described for the species in the literature. These results showcase how P. austriacus essentially forage in small forest fragments avoiding recurrently burnt areas, and highlight the colonies’ dependence on the monastery, probably due to limited alternative roost availability. This knowledge needs to be built on and accounted for in biodiversity conservation policies to ensure that species-specific responses to recurring fires in the Mediterranean are addressed.
... Variation in the frequency, space and intensity (high, medium or low) of fires draw different kinds of patterns in the landscape. Martin and Sapsis (1991) argued that diverse fire regimes (pyrodiversity) promote biodiversity in environments where fire is a key disturbance. According to this hypothesis, higher spatial and temporal variation in fires produces a greater variety of ecological niches and therefore favours the coexistence of more species and especially favours different combustibility and age classes. ...
El fuego como componente del sistema de los bosques de pino laricio.
Experiencia acumulada en el uso de las quemas prescritas para la conservación de los bosques de pino laricio.
Integración del fuego en la conservación del hábitat.
Disponible en español, catalán e inglés.
... Pyrodiversity, or the heterogeneity in fire characteristics (e.g. age, extent, severity, and frequency), can have important implications for wildlife populations and communities (Martin and Sapsis, 1992;He et al., 2019). To characterize pyrodiversity around a given survey site, we created at multiple buffers (500 m, 1000 m, and 1500 m) around each survey site and identified the number of unique times since fire values within each buffer. ...
Understanding the link between environmental factors such as disturbance events, land cover, and soil productivity to spatial variation in animal abundance is fundamental to population ecology and wildlife management. The Longleaf pine (Pinus palustris) ecosystem is an archetypal fire-mediated ecosystem, which has seen drastic reductions in land area due to fire suppression. Current restoration utilizes prescribed fire and hardwood removal, but little is known regarding how these restoration efforts influence predator spatial distributions and predator-prey interactions. We conducted a study to investigate how fire, land cover, and soil productivity influence spatial distributions of predators in a fire-mediated ecosystem. We conducted a 34-camera survey across Camp Blanding Joint Training Center, a military installation in northern Florida, and utilized N-mixture models to estimate relative abundances of mammalian predators. To conceptualize our results relative to managed prey species, we categorized predators into white-tailed deer fawn predators [i.e. coyote (Canis la-trans), bobcat (Felis rufus), and Florida black bear (Ursus americanus floridanus)] and nest predators [i.e. raccoon (Procyon lotor), Virginia opossum (Didelphis virginiana), and nine-banded armadillo (Dasypus novemcinctus)]. Coyote (P = < 0.001) and bobcat (P = 0.01), increased relative abundance with decreasing pyrodiversity, the number of unique time since fire values. Raccoon relative abundance increased with distance from recent burns (P = 0.02). Coyote (P = < 0.001) and bobcat (P = < 0.001) relative abundance also increased with proximity to hardwoods, while raccoon relative abundance decreased with proximity to pine (P = 0.02). Interestingly, there was a lack of detections of mesopredators [i.e. red fox (Vulpes Vulpes), grey fox (Urocyon cinereoargenteus), spotted skunk (Mephitis mephitis) and striped skunk (Spilogale putorius)] that were historically considered common throughout the Southeastern United States and longleaf pine ecosystems. Our results indicate that predator space use was altered by fire conditions and distances to pine and hardwood stands, which supports a predator management strategy that utilizes management tools commonly used in restoration and conservation of the LLP ecosystem to indirectly alter predator distributions, which has the potential to positively affect the management of important species within this ecosystem.
... Beyond mean burn severity, pyrodiversity may increase biodiversity by diversifying available ecological niches 5 . We found some evidence of a positive relationship between pyrodiversity and bat diversity with approximately one additional species (6% of the community) predicted to occur on average when moving from areas of low to high pyrodiversity (Fig. 6), and greater community dissimilarity between points with increasingly different burn severities ( Figure S3a). ...
Wildfire is an important ecological process that influences species’ occurrence and biodiversity generally. Its effect on bats is understudied, creating challenges for habitat management and species conservation as threats to the taxa worsen globally and within fire-prone ecosystems. We conducted acoustic surveys of wildfire areas during 2014–2017 in conifer forests of California’s Sierra Nevada Mountains. We tested effects of burn severity and its variation, or pyrodiversity, on occupancy and diversity for the 17-species bat community while accounting for imperfect detection. Occupancy rates increased with severity for at least 6 species and with pyrodiversity for at least 3. Two other species responded negatively to pyrodiversity. Individual species models predicted maximum occupancy rates across burn severity levels but only one species occurred most often in undisturbed areas. Species richness increased from approximately 8 species in unburned forests to 11 in pyrodiverse areas with moderate- to high-severity. Greater accessibility of foraging habitats, as well as increased habitat heterogeneity may explain positive responses to wildfire. Many bat species appear well adapted to wildfire, while a century of fire suppression and forest densification likely reduced habitat quality for the community generally. Relative to other taxa, bats may be somewhat resilient to increases in fire severity and size; trends which are expected to continue with accelerating climate change.
... This change in perspective concerning fire emerges along with a scenario that combines not only the frustrated attempts of environmental managers to supress increasingly sever and frequent wildfires, but also transformations in the scientific paradigms themselves. For sure, the ecological debates surrounding the concept of 'pyrodiversity,' which seeks to analyse various effects of the diversity of fire regimes, are still heated and controversial (Martin and Sapsis 1992, Parr and Andersen 2006, Bowman et al. 2016). However, it is increasingly certain that the 'zero fire' paradigm, hegemonic until the start of the twenty-first century, has demonstrated its failure in the face of the increasing recurrence of large forest fires. ...
The article seeks to shift away from the centrality attributed to the idea of ‘control’ in the debate on participatory fire management. To do so, it addresses three modes of existence of the phenomenon in the Brazilian savannah - queimada (burned place), fogos gerais (fire that spreads or general fires) and fogo fora do tempo (fire out of time) - aiming to explore the perceptual disparities between wanted and unwanted fires with quilombolas and environmental managers in the Jalapão region (Tocantins, Brazil). This problem is discussed in light of the concept of normativity formulated by the epistemologist George Canguilhem in dialogue with the anthropology of techniques. The goal is to contribute to a research agenda in which the distinction between ‘good fire’ and ‘bad fire’ is thematized in specific ethnographic contexts rather than from pre-given normative criteria. I conclude by arguing that the current fire management policies concern not only the legal protocol of fire authorization, but also the modulation of technical and vital processes.
... In fire prone ecosystems it has been suggested that increasing the variability in the application of prescribed fire will increase habitat diversity and thus biological diversity (Martin & Sapsis, 1992;Brockett, Biggs & van Wilgen, 2001;Fuhlendorf & Engle, 2001, 2004. Specifically, Fuhlendorf & Engle (2001, 2004 suggested the fire-grazing feedback or pyric-herbivory, in which recently burned patches are preferentially grazed, could be used to create a shifting mosaic of habitat types when fire is patchily distributed on the landscape in contrast to the traditional homogeneous application of fire. ...
Background:
Patch-burn management approaches attempt to increase overall landscape biodiversity by creating a mosaic of habitats using a patchy application of fire and grazing. We tested two assumptions of the patch-burn approach, namely that: (1) fire and grazing drive spatial patch differentiation in community structure and (2) species composition of patches change through time in response to disturbance.
Methods:
We analyzed species cover data on 100 m2 square quadrats from 128 sites located on a 1 × 1 km UTM grid in the grassland habitats of the Tallgrass Prairie Preserve. A total of 20 of these sites were annually sampled for 12 years. We examined how strongly changes in species richness and species composition correlated with changes in management variables relative to independent spatial and temporal drivers using multiple regression and direct ordination, respectively.
Results:
Site effects, probably due to edaphic differences, explained the majority of variation in richness and composition. Interannual variation in fire and grazing management was relatively unimportant relative to inherent site and year drivers with respect to both richness and composition; however, the effects of fire and grazing variables were statistically significant and interpretable, and bison management was positively correlated with plant richness.
Conclusions:
There was some support for the two assumptions of patch-burn management we examined; however, in situ spatial and temporal environmental heterogeneity played a much larger role than management in shaping both plant richness and composition. Our results suggest that fine-tuning the application of fire and grazing may not be critical for maintaining landscape scale plant diversity in disturbance-prone ecosystems.
... The capacity for unburned patches to promote longleaf pine regeneration and thereafter increase fuel loads and fire severity should also reduce concerns about increased woody plant cover in temporarily unburned areas. Results of this study provide a concrete example of the application of "pyrodiversity" (sensu [89]) and patch mosaic burning [90] for accomplishing conservation and forest management goals, in light of criticism of their application in the absence of demonstrated efficacy [91]. ...
Research Highlights: Spatial patterns of fire spread and severity influence survival of juvenile pines in longleaf pine savannas. Small areas that do not burn during frequent fires facilitate formation of patches of even-aged longleaf pine juveniles. These regeneration patches are especially associated with inner portions of openings (gaps) and where canopy trees have died in recent decades. Patterns of prescribed fire can thus have an important influence on stand dynamics of the dominant tree in pine savannas. Background and Objectives: Savannas are characterized by bottlenecks to tree regeneration. In pine savannas, longleaf pine is noted for recruitment in discrete clusters located within gaps away from canopy trees. Various mechanisms promoting this pattern have been hypothesized: light limitations, soil moisture, soil nutrients, pine needle mulching, competition with canopy tree roots, and fire severity associated with pine needle litter. We tested the hypothesis that regeneration patches are associated with areas that remain unburned during some prescribed fires, as mediated by gaps in the canopy, especially inner portions of gaps, and areas re-opened by death of canopy trees. Materials and Methods: We mapped areas that were unburned during prescribed fires applied at 1–2 year intervals from 2005–2018 in an old-growth pine savanna in Georgia, USA. We compared the maps to locations of longleaf pine juveniles (<1.5 m height) measured in 2018 and canopy cover and canopy tree deaths using a long-term (40 year) tree census. Results: Logistic regression analysis showed juveniles to be associated with unburned areas, gaps, inner gaps, and areas where canopy trees died. Conclusions: Patterns of fire spread and severity limit survival of longleaf pine juveniles to patches away from canopy trees, especially where canopy trees have died in recent decades. These processes contribute to a buffering mechanism that maintains the savanna structure and prevents transition to closed canopy forest or open grassland communities.
... It has been suggested that it is the variability in fire events (different fire sizes, fire intensities, fire return times) that is key for maintaining high biodiversity (Martin et al., 1992), and there is evidence in Africa that bird and mammal species richness responds positively to "pyrodiversity" (Hempson The fi re season appears as a distinct wave as it spreads through Africa. It peaks in January in West Africa (the northern hemisphere dry season), and in southern Africa in August (southern hemisphere dry season). ...
... Methodology for determining the historic fire regime in the project area is commonly referred to as a point frequency analysis (Maruoka and Agee 1994;Agee 1996). Point frequencies are used to determine fire regime statistics for fairly small areas of the landscape and in ecosystems characterized by short-interval fire regimes (Martin and Sapsis 1991). These fire regimes typically contain tree species such as ponderosa pine, Douglas-fir (Pseudotsuga menziesii [Mirb.] ...
Global environmental and social change are pushing wildfire activity and impact beyond known trajectories. Here, we conducted a targeted review to distill five wildfire challenges that we argue form opportunities for their governance (research aim 1). We exemplified our arguments by drawing from the case of Cyprus (research aim 2), a small island country in the south-east European Mediterranean Basin at risk of extreme wildfire impact. Findings indicate that burning for social and ecological resource benefits, innovative management paradigms and anticipatory governance systems offer actionable solutions to the wildfire paradox and the limits of suppression. Local adaptive institutions and a reconceptualisation of wildfire as a risk and process beyond technocratic interpretations are necessary to account for broader social conditions shaping wildfire regimes and community impact. Governance systems that accommodate collective action have proven suitable to address multiple wildfire complexities linked with different socio-economic systems and values. A systematic literature review, policy review, and qualitative data collection on wildfire management in Cyprus track back to the initial framing. Our case study offers insights for tackling wildfires with actionable steps through overarching governance systems, and illustrates the potential for change in thinking of and acting on wildfire in flammable landscapes globally.
Background
Understanding pre-1850s fire history and its effect on forest structure can provide insights useful for fire managers in developing plans to moderate fire hazards in the face of forecasted climate change. While climate clearly plays a substantial role in California wildfires, traditional use of fire by Indigenous people also affected fire history and forest structure in the Sierra Nevada. Disentangling the effects of human versus climatically-induced fire on Sierran forests from paleoecological records has historically proved challenging, but here we use pollen-based forest structure reconstructions and comparative paleoclimatic-vegetation response modeling to identify periods of human impact over the last 1300 years at Markwood Meadow, Sierra National Forest.
Results
We find strong evidence for anthropogenic fires at Markwood Meadow ca. 1550 – 1750 C.E., contemporaneous with archaeological evidence for fundamental shifts in Indigenous lifeways. When we compare our findings to five other paleoecological sites in the central and southern Sierra Nevada, we find evidence for contemporaneous anthropogenic effects on forest structure across a broad swath of cismontane central California. This is significant because it implies that late 19th and early twentieth century forest structure – the structure that land managers most often seek to emulate – was in part the result anthropogenic fire and precolonial resource management.
Conclusion
We consequently suggest that modern management strategies consider (1) further incorporating traditional ecological knowledge fire practices in consultation with local tribal groups, and (2) using pollen-based reconstructions to track how forest composition compares to pre-1850 C.E. conditions rather than the novel forest states encountered in the late 20th and early twenty-first centuries. These strategies could help mitigate the effects of forecast climate change and associated megafires on forests and on socio-ecological systems in a more comprehensive manner.
Background and aims
In many systems, postfire vegetation recovery is characterised by temporal changes in plant species composition and richness. We attribute this to changes in resource availability with time since fire, with the magnitude of species turnover determined by the degree of resource limitation. Here we test the hypothesis that postfire species turnover in South African fynbos heathland is powered by fire-modulated changes in nutrient availability, with the magnitude of turnover in nutrient-constrained fynbos being greater than in fertile renosterveld shrubland. We also test the hypothesis that floristic overlaps between fynbos and renosterveld are attributable nutritional augmentation of fynbos soils immediately after fire.
Methods
We use vegetation survey data from two sites on the Cape Peninsula to compare changes in species richness and composition with time since fire.
Key results
Whereas fynbos communities display a clear decline in species richness with time since fire, no such decline is apparent in renosterveld. In fynbos, declining species richness is associated with declines in the richness of plant families having high foliar concentrations of nitrogen, phosphorus, and potassium, and possessing attributes which are nutritionally costly. By contrast, families which dominate late-succession fynbos possess adaptations for the acquisition and retention of sparse nutrients. At the family level, recently burnt fynbos is compositionally more similar to renosterveld than is mature fynbos.
Conclusions
Our data suggest that nutritionally driven species turnover contributes significantly to fynbos community richness. We propose that the extremely low baseline fertility of fynbos soils serves to lengthen the nutritional resource axis along which species can differentiate and coexist, thereby providing the opportunity for low-nutrient extremophiles to coexist spatially with more fertile adapted species. This mechanism has the potential to operate in any resource-constrained system in which episodic disturbance affects resource availability.
Many fire‐prone forests are experiencing wildfires that burn outside the historical range of variation in extent and severity. These fires impact pollinators and the ecosystem services they provide, but how the effects of fire are mediated by burn severity in different habitats is not well understood. We used generalized linear mixed models in a Bayesian framework to model the abundance of pollinators as a function of burn severity, habitat, and floral resources in post‐fire, mid‐elevation, conifer forest, and meadow in the Sierra Nevada, California. Although most species‐level effects were not significant, we found highly consistent negative impacts of burn severity in meadows where pollinators were most abundant, with only hummingbirds and some butterfly families responding positively to burn severity in meadows. Moderate‐severity fire tended to increase the abundance of most pollinator taxa in upland forest habitat, indicating that even in large fires that burn primarily at high‐ and moderate‐severity patches may be associated with improved habitat conditions for pollinator species in upland forest. Nearly all pollinator taxa responded positively to floral richness but not necessarily to floral abundance. Given that much of the Sierra Nevada is predicted to burn at high severity, limiting high‐severity effects in meadow and upland habitats may help conserve pollinator communities whereas low‐ to moderate‐severity fire may be needed in both systems.
Background
Late dry-season wildfires in sub-Saharan Africa’s savanna-protected areas are intensifying, increasing carbon emissions, and threatening ecosystem functioning. Addressing these challenges requires active local community engagement and support for wildfire policy. Savanna burning emissions abatement schemes first implemented in Northern Australia have been proposed as a community-based fire management strategy for East and Southern Africa’s protected areas to deliver win–win-win climate, social, and biodiversity benefits. Here, we review and critically examine the literature exploring the design and application of savanna burning emissions abatement schemes in this region, characterizing their contextual and implementation challenges.
Results
We show that the application of Northern Australian savanna burning methodologies in East and Southern Africa tends to adopt centrally determined objectives and market-based approaches that prioritize carbon revenue generation at the national level. The exclusive prescription of early-dry season burns in African mesic savannas prone to woody thickening can compromise savanna burning objectives to mitigate late-dry season wildfires and their greenhouse gas emissions in the long-term, as well as present multiple biodiversity trade-offs in the absence of formal metrics monitoring species’ responses to changes in fire regime. These features restrict indigenous participation and leadership in fire management, creating uncertainties over the opportunities for local income generation through carbon trading. Findings suggest that future savanna burning applications will need to address asymmetries between formal institutions and local land governance systems, explicitly acknowledging colonial legacies in institutional arrangements across protected areas and hierarchies in agrarian politics that threaten processes of equitable decentralization in natural resource management.
Conclusion
We argue that the effective transfer of the Northern Australian fire management model is limited by a lack of long-term ecological and emissions data and political and institutional barriers, and is hindered by the region’s recent colonial history, population growth, and consequences of rapid climatic change. To provide a community-based strategy, savanna burning schemes need to establish context-specific legal frameworks and implement Free, Prior, and Informed Consent to safeguard the roles and responsibilities of indigenous and local people and their distribution of carbon benefits.
To date, most studies of fire severity, which is the ecological damage produced by a fire across all vegetation layers in an ecosystem, using remote sensing have focused on wildfires and forests, with less attention given to prescribed burns and treeless vegetation. Our research analyses a multi-decadal satellite record of fire severity in wildfires and prescribed burns, across forested and treeless vegetation, in western Tasmania, a wet region of frequent clouds. We used Landsat satellite images, fire history mapping and environmental predictor variables to understand what drives fire severity. Remotely-sensed fire severity was estimated by the Delta Normalised Burn Ratio (ΔNBR) for 57 wildfires and 70 prescribed burns spanning 25 years. Then, we used Random Forests to identify important predictors of fire severity, followed by generalised additive mixed models to test the statistical association between the predictors and fire severity. In the Random Forests analyses, mean summer precipitation, mean minimum monthly soil moisture and time since previous fire were important predictors in both forested and treeless vegetation, whereas mean annual precipitation was important in forests and temperature seasonality was important in treeless vegetation. Modelled ΔNBR (predicted ΔNBRs from the best-performing generalised additive mixed model) of wildfire forests was higher than modelled ΔNBR of prescribed burns. This study confirms that western Tasmania is a valuable pyrogeographical model for studying fire severity of wet ecosystems under climate change, and provides a framework to better understand the interactions between climate, fire severity and prescribed burning.
ContextIn many regions of the world, Indigenous people continue to shape landscape patterns using fire. Some studies show that Indigenous fire regimes create a diverse “visible mosaic” of time-since-fire ages. Less is known about the underlying, cumulative spatiotemporal patterns of fires that are hidden beneath visible fire scars—termed the “invisible fire mosaic”—despite its role in shaping biota in fire-prone landscapes.Objectives
We investigated how distance from Indigenous communities affects landscape patterns, focusing on aspects of the visible (i.e., time-since-fire diversity and maximum landscape area burnt) and invisible (i.e., number of years burnt, diversity of fire frequency patches, and number of unique fire histories) fire mosaic.Methods
We quantified fire histories for 450 landscapes across Western Australia. We calculated the distance of each landscape to the nearest Indigenous community (a proxy for the intensity of human landscape use) and used regression models to investigate how distance influenced the properties of the visible and invisible fire mosaic.ResultsLandscapes near Indigenous communities experienced more frequent fire, had higher time-since-fire diversity, higher diversity of fire frequency patches, and a greater number of unique combinations of fire histories (seasons, interval lengths, and time-since-fire ages). Pyrodiversity was negatively related to the maximum area burnt, supporting the notion that Indigenous burning limits fire size.Conclusions
Indigenous burning creates distinctive visible and invisible fire mosaics which dwarf the pyrodiversity of more distant areas, thereby potentially crafting ecosystem states that profoundly differ from those without human presence.
Context
Spatial patterns of vegetation change and fire severity are influenced by fire exclusion, topography and weather conditions during a fire. Since the late nineteenth century, fire exclusion has increased vegetation cover which could influence fire severity and post-fire vegetation composition.
Objectives
We use field measurements and remote sensing of a 2011 wildfire to answer the following questions: (1) How did twentieth century vegetation change influence fire severity patterns? (2) What were the key drivers of wildfire severity? (3) Did initial post-fire development indicate stability or a shift in woody plant composition.
Methods
Repeat aerial photography and pre and post fire field measurements were used to quantify twentieth century vegetation change and measure wildfire effects. Spatial controls on 2011 fire severity were determined using geospatial layers of vegetation type and change, topography, fire weather, daily fire extent, and fire severity.
Results
Vegetation changes since 1935 increased area of closed woodlands and shrublands and the 2011 fire reversed this trend and increased heterogeneity of vegetation types. Vegetation in plots experienced a post-fire shift towards resprouting species. At the landscape scale, terrain and weather were the main variables controlling fire severity with modest contribution by vegetation type and areas with vegetation change since 1935.
Conclusions
Our findings indicate that wildfire severity in this landscape is strongly influenced by weather and terrain and wildfires reverse the effects of fire exclusion. Using terrain based landscape compartments for prescribed and wildfire management would help maintain the heterogeneous effects of the 2011 fire into future.
Aim
Wildfires increasingly create large high‐severity patches with interior areas far from less disturbed habitats. We evaluated how these trends impact bird communities by investigating the effect of internal distance from lower‐severity areas, high‐severity patch size, and years since fire on avian alpha and beta diversity.
Location
Sierra Nevada, California, USA.
Methods
Bird occurrence data were collected during 2009–2017 within high‐severity patches of 27 wildfires representing 1–30 years since disturbance. A two‐step multispecies occupancy method was used to account for imperfect detection of 94 species and estimate effects of patch characteristics on community richness and dissimilarity.
Results
Community richness decreased with distance from patch edge and with patch size. Richness increased with years since fire, but this pattern was dependent on distance from edge with higher peak richness (23 species) near edges than interiors (18 species). Community dissimilarity was not associated with distance, indicating that large high‐severity patch interiors contain subsets of, rather than complements to, edge communities. Dissimilarity peaked later with increasing patch size. Guild richness of tree and primary cavity nesters was negatively associated with distance and patch size. Richness of ground and shrub nesters was insensitive to distance, while shrub nester richness increased somewhat with patch size. Due to declines among other species, ground and shrub nesters made up a greater percentage of the avian community within the interiors of large high‐severity patches.
Main conclusions
As fire activity increases due to accumulating forest fuels and accelerating climate change, high‐severity patches and their resulting early‐seral habitats are becoming more extensive with less edge and more interior area. Such changes are likely to decrease avian diversity locally and shift community composition away from forest‐associated species. Management actions that promote the full range of fire effects but limit high‐severity patch size may best conserve bird diversity within fire‐adapted ecosystems.
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