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Four landscapes from the mid-Atlantic region (dimensions are 30.8 km and resolution 30 m): (a) Antietam, Md.; (b) Harpers Ferry at the confluence of the Susquehanna and Potomac; (c) Prince William, Va; and
Source publication
Neutral landscape models were originally developed to test the hypothesis that human-induced fragmentation produces patterns
distinctly different from those associated with random processes. Other uses for neutral models have become apparent, including
the development and testing of landscape metrics to characterize landscape pattern. Although metr...
Contexts in source publication
Context 1
... have been classified into 21 land cover types at a spatial resolution of 0.09 ha (30 m) ( Riitters et al. 2002). The four extracted landscapes were 512 · 512 pixels (786 ha) in size, located near the Antietam battleground in Maryland; Harpers Ferry on the Potomac River; Prince William Forest Park in Virginia and Rock Creek Park in Washington DC (Fig. 1). For the purposes of this analysis, the NLCD data were reclassified into four land cover types: aquatic habitat (water, wetlands); agriculture (an aggregation of seven classes including pasture, row crops, orchards and fallow lands); urban developed (residential, commercial and urban); and forest (deciduous, evergreen, mixed forests). ...
Context 2
... the constraints of the land cover mask, random forest patches are generated. This was especially evident for Antietam and Harpers Ferry where the landscape constraints and the proportion of forest cover was lowest (Fig. 3). A comparison of the cfd of the number of forest patches for the four landscapes ( Fig. 1) is illustrated in Fig. 4. The cfd of the simple random maps were not significantly different from the actual maps in three of the four cases (Table 3). The cfd for the simple random map was significantly different from the Prince William landscape due to the greater frequency of small, isolated patches in the random maps. Further ...
Citations
... Neutral landscape models are standard tools for creating fragmented landscapes (Gardner and Urban, 2007). However, the aggregation parameter constitutes only one of the many dimensions with which one can assess fragmentation (Wang et al., 2014) (some relationships between aggregation and other measures of fragmentation for our simulated landscapes can be found in Fig. 3). ...
... High-severity patch size and structure are strongly related to fire size and high-severity proportion (Cansler & McKenzie, 2014;Collins et al., 2017;Harvey et al., 2016a), exhibiting characteristic scaling relationships both within fire events and within fire regimes. Across fire size distributions, scaling behaviour arises in theory because the potential for large high-severity patches scales upward with the size of fire events (Gardner & Urban, 2007). In reality, the relative influence of broadscale drivers versus localscale constraints will dictate, to varying degrees, the occurrence of increasingly large and contiguous highseverity patches with increasing fire size (Cansler & McKenzie, 2014;Harvey et al., 2016a). ...
Increasing wildfire activity in forests worldwide has driven urgency in understanding current and future fire regimes. Spatial patterns of area burned at high severity strongly shape forest resilience and constitute a key dimension of fire regimes, yet remain difficult to predict. To characterize the range of burn severity patterns expected within contemporary fire regimes, we quantified scaling relationships relating fire size to patterns of burn severity. Using 1615 fires occurring across the Northwest United States between 1985 and 2020, we evaluated scaling relationships within fire regimes and tested whether relationships vary across space and time. Patterns of high‐severity fire demonstrate consistent scaling behaviour; as fire size increases, high‐severity patches consistently increase in size and homogeneity. Scaling relationships did not differ substantially across space or time at the scales considered here, suggesting that as fire‐size distributions potentially shift, stationarity in patch‐size scaling can be used to infer future patterns of burn severity.
... For effective multi-species management, an ideal umbrella species should have large area requirements and overlap with background species in at least one niche axis (e.g., Fleischman et al. 2000;Maslo et al. 2016;Fourcade et al. 2017). One approach to distinguishing species-area relationships from other processes that drive co-occurrence are neutral landscape models (Gardner and Urban 2007), which provide ecologically relevant null models against which to test questions of observed landscape patterns (Lancaster 2006). Neutral landscape models were developed to test landscape patterns and establish critical thresholds based on percolation theory (With and King 1997;Gardner and Urban 2007). ...
... One approach to distinguishing species-area relationships from other processes that drive co-occurrence are neutral landscape models (Gardner and Urban 2007), which provide ecologically relevant null models against which to test questions of observed landscape patterns (Lancaster 2006). Neutral landscape models were developed to test landscape patterns and establish critical thresholds based on percolation theory (With and King 1997;Gardner and Urban 2007). Using algorithms to generate plausible landscape patterns (such as species distributions), these models mimic landscapes in a manner distinct from underlying ecological processes (e.g., habitat association, competition; Turner and Gardner 2015). ...
... We also created a binary mask based on "not available" (NA) values in songbird data. Because our focal region was not a rectangular raster (Fig. 1), we used the masking feature to ensure the algorithm worked within the same spatial extent and coverage as our data (Gardner and Urban 2007;Etherington et al. 2015). Previously, areas were masked in the grassland bird layers to avoid predictions beyond available data (Monroe et al. 2021), whereas masks were applied to sage-grouse predictions to avoid predicting in areas where sage-grouse do not occur (Fedy et al. 2014). ...
Context
Steep declines in North American rangeland biodiversity have prompted researchers and managers to use umbrella species as a tool to manage diverse suites of co-occurring wildlife, but efficacy of this method has been variable. Evaluation of prairie and shrubland grouse as umbrellas is typically restricted to observed overlap between umbrella and background species, but this approach does not distinguish between overlap due to ubiquity or niche overlap.
Objectives
We demonstrate a novel application of neutral landscape models (NLMs) to test the effectiveness of greater sage-grouse (Centrocercus urophasianus) as an umbrella species for grassland songbirds at a grassland-sagebrush ecotone in northeastern Wyoming, USA.
Methods
We leveraged existing spatial data representing sage-grouse habitat in two distinct seasons (nesting and late brood-rearing) and density and distribution of eight grassland songbirds. We applied a permutation-based analysis using NLMs to determine whether overlap between background species and greater sage-grouse was greater than expected by chance.
Results
Three species (western meadowlark Sturnella neglecta, loggerhead shrike Lanius ludovicianus, and lark bunting Calamospiza melanocorys) had greater overlap than expected with at least one type of greater sage-grouse habitat, while western kingbirds (Tyrannus verticalis) indicated avoidance of all sage-grouse habitat assessed.
Conclusions
NLMs provided a more nuanced evaluation of the umbrella species concept than previously available and allowed us to differentiate between overlap due to ubiquity (e.g., vesper sparrow; Pooecetes gramineus) rather than overlap in habitat use. All grassland passerine species with greater than expected overlap with sage-grouse habitat either nest in sagebrush (loggerhead shrike) or often select nest locations underneath small shrubs (western meadowlark, lark bunting). These results indicate that nesting substrate is a potential niche axis to consider when evaluating the umbrella species concept, especially within sagebrush-grassland ecotones.
... Building on the work of Saura and Pascual-Hortal (2007) and Jaeger (2000), we present a list of criteria to evaluate desirable properties of metrics (Table 1). Bounded values (property A in Table 1) between 0.0 and 1.0 are needed for unambiguous calculation of indicators (Gardner & Urban, 2007;Schultz, 2001). Decreases in connectivity values with increases in interpatch distance (Property B), increased fragmentation (Property C), loss of an isolated patch (Property D), loss of patch area (Property E), and an increased number of clusters (Property F) are consistent with the theory of island biogeography (MacArthur & Wilson, 1967;Saura & Pascual-Hortal, 2007). ...
Abstract Measuring connectivity is key to track progress toward broad conservation goals, such as the United Nations Convention on Biological Diversity's proposed Post‐2020 Global Biodiversity Framework. The framework includes an area‐based target for the protection of 30% of lands and seas globally—through well‐connected systems of protected areas. Although the field of connectivity science has grown rapidly, limited progress has been made in tracking conservation connectivity in practice. This is in part due to the lack of a standardizing framework to clarify different purposes, approaches, and datasets—particularly in differentiating a metric from its application within a broader connectivity framework—as well as a benchmark to quantitatively compare alternative approaches. To address this science‐practice gap, we developed a novel metric of connectivity called the Protected Network metric (ProNet). ProNet is designed to assess the structural connectivity of a protected area network in a way that can be easily described, clearly communicated, and rapidly computed at high resolution. We evaluated how ProNet adheres to fundamental conservation science principles using a library of hypothetical landscapes, compared it to two commonly used existing connectivity metrics, and demonstrated its performance in assessing connectivity for a set of real‐world landscapes selected across the gradient of human modification. More broadly, ProNet is a powerful tool to galvanize emerging connectivity conservation as a countermeasure to increasing fragmentation of global ecosystems.
... Perhaps because of a paucity of options for producing NLMs for human-dominated landscapes, NLMs that incorporate human processes such as urbanisation may use patterns of existing urban areas (Bierwagen 2007;Gardner and Urban 2007;Smets et al. 2019). This is not a problem when modelling focuses on issues of relevance to a specific location. ...
Context
Neutral landscape models are useful and popular tools for exploring effects of spatial patterns on ecological processes. Most neutral landscape models mimic natural landscape patterns that often consist of curved, complex, and sometimes fractal shapes. However, human-dominated landscapes often have a spatial rectilinear pattern that is highly aligned and dominated by straight lines and right angles.
Objectives
As existing rectilinear neutral landscape models lack controls over either the size, position, orientation, and shape of the rectilinear patches, or do not recognise the hierarchical structure of patch formation in human-dominated landscapes, our objective was to create a neutral landscape model capable of meeting these requirements.
Methods
We present binary space partitioning as a method that generates hierarchical and rectilinear neutral landscape models. In doing so we explain how to control the size, position, orientation, and shape of the rectilinear patches, as well as generate a tree that records the hierarchical patch structure.
Results
Binary space partitioning succeeds in providing a simple, repeatable, process to generate a range of neutral landscape models for human-dominated landscapes. A large variety of landscape patterns can be efficiently produced from only a very small number of parameters.
Conclusions
Binary space partitioning based neutral landscape models would be useful in representing many human-dominated landscapes. Their implementation is straightforward and should be easily understood, used, and developed by landscape ecologists.
... Virtual landscape simulations allow a systematic understanding through a quasi-experimental approach. Neutral landscape models have been applied for understanding effects of landscape pattern on movements of single and interacting biota (With 1997;Etherington 2016), or on lateral processes like fire spread (Plotnick and Gardner 2002;Gardner and Urban 2007). Virtual landscapes offer an important approach to complement real landscape scenarios, which address potential changes in landscape composition (Ausseil et al. 2013;Lamarque et al. 2014;Mitchell et al. 2015a;Qiu et al. 2018;Schirpke et al. 2020) and configuration (Cordingley et al. 2015;Richards et al. 2018;van Strien et al. 2016;With Fig. 5 Multifunctionality indicators for the six ecosystem services considered at landscape (top row) or pixel (bottom row) scale depending on landscape mean patch size. ...
Context
In climate-smart landscapes people manage land use for integrating sustainable production, climate change adaptation and mitigation. The spatial dimension of this multifunctionality remains to be formalised to increase effectiveness of nature-based solutions.
Objectives
We aimed to systematically analyse effects of fragmentation on multifunctionality and their interactions with land-use intensity responses.
Methods
We generated virtual landscapes to model interactions among six ecosystem services (ES) of different spatial sensitivities. We simulated land-use patterns on topographies from plains to mountains. Four land-use intensity treatments departed from hypothesised optimal composition for biodiversity and ES with > 30% intensive, < 30% extensive or protected and > 40% intermediate intensity use. For each composition we generated landscapes with differing fragmentation.
Results
Pixel- and landscape-level multifunctionality emerge from sensitivities of the six ES to landscape composition, fragmentation and their interactions. In heterogeneous landscapes of intermediate land-use intensity extensive grasslands and spatial complementarity supported multiple ES provision. Increasing land use intensity decreased multifunctionality by reducing all ES. However, greater fragmentation mitigated some of these effects because its benefits to nitrogen retention and pollination exceeded losses for recreation, especially in finer-grained landscapes. The five regulating ES were synergistic and showed trade-offs with recreation. Although interactions were most sensitive to intensity given its dominant effects on individual ES, fragmentation mediated interaction strength.
Conclusions
Virtual simulations allow a systematic understanding of how interactions between land-use intensity and fragmentation modulate multifunctionality. This constitutes an essential step to designing templates for climate smart-landscapes tailored to regional geographies, land-use allocation and ES priorities.
... Perhaps because of a paucity of options for producing NLMs for human-dominated landscapes, NLMs that incorporate human processes such as urbanisation may use patterns of existing urban areas (Bierwagen 2007;Gardner and Urban 2007;Smets et al. 2019). This is not a problem when 70 modelling focuses on issues of relevance to a specific location. ...
Context Neutral landscape models are useful and popular tools for exploring effects of spatial patterns on ecological processes. Most neutral landscape models mimic natural landscape patterns that often consist of curved, complex, and sometimes fractal shapes. However, human-dominated landscapes often have a spatial rectilinear pattern that is highly aligned and dominated by straight lines and right angles. Objectives As existing rectilinear neutral landscape models lack controls over either the size, position, orientation, and shape of the rectilinear patches, or do not recognise the hierarchical structure of patch formation in human-dominated landscapes, our objective was to create a neutral landscape model capable of meeting these requirements. Methods We present binary space partitioning as a method that generates hierarchical and rectilinear neutral landscape models. In doing so we explain how to control the size, position, orientation, and shape of the rectilinear patches, as well as generate a tree that records the hierarchical patch structure. Results Binary space partitioning succeeds in providing a simple, repeatable, process to generate a range of neutral landscape models for human-dominated landscapes. A large variety of landscape patterns can be efficiently produced from only a very small number of parameters. Conclusions Binary space partitioning based neutral landscape models would be useful in representing many human-dominated landscapes. Their implementation is straightforward and does not require any cognitive or computational requirements that would be beyond landscape ecologists.
... Multifractal maps with autocorrelation parameter of 0.9 (H=0.9) were the most realistic landscapes generated by QRULE in this study because the effects of autocorrelation among sites affect the spatial patterns produced by the process of landscape fragmentation. Therefore, high H parameter well represents highly clump of forest habitat within landscapes in this study (Gardner et al. 1987;Gardner & Urban 2007). ...
... Also, testing whether landscape pattern indices differ significantly and understanding spatial pattern and ecological process are challenging. Although neutral models, which are one of the approaches for comparison between the outcome of a spatial stochastic process and a real landscape, have provided insight to the comparison of landscape pattern indices or significant testing of differences among landscapes, landscape pattern indices need to be compared with care because composition and configuration influence landscape pattern indices (Gardner & Urban 2007). ...
Preserving wildlife and their environment from anthropogenic activities requires identification and establishment of protected areas, and monitoring of their long-term effects on wildlife and habitat. Tropical forests are one of the most at-risk habitats and many tropical species have become extinct recently due to human activity. It is imperative to monitor habitat in protected areas and without in order to identify strategies and legislative policies that optimize conservation outcomes. To this end, I quantified habitat fragmentation for the great hornbill ( Buceros bicornis ) in Om Koi Wildlife Sanctuary, Thailand, pre- and post-establishment, within and outside the protected area, from 1973, 1985, and 1992, to assess the effectiveness of the protected area status, established in 1978, and a national logging ban, established in 1989, in preserving and restoring hornbill habitat. The results demonstrate that the establishment of Om Koi Wildlife Sanctuary did not decrease the rate of hornbill habitat fragmentation relative to areas outside the protected area. While the protected area had less fragmentation to begin with, protection status did not affect the rate of loss. Fragmentation increased significantly both inside and outside the protected area between the first and second time points (p < 0.05), after the protected area was first established. However, the national logging ban policy implemented in 1985 seems to have successfully halted the fragmentation of habitat within the protected area and surrounding unprotected areas, with all areas showing no significant change ( p > 0.05 ). While not significant, the rate of fragmentation outside the protected area was greater. This suggests that the establishment of a protected area alone may not be sufficient to stop or reverse anthropogenic damage to endangered habitat and the species that utilize these environments. The incorporation of multiple strategies for management is likely needed to increase the ability of protected areas to preserve tropical forest species and habitats. The assessment of protected areas via satellite and ground-level data is an essential tool for evaluating the effectiveness of conservation strategies and improving outcomes.
... Generative models are widely applied in landscape ecology for simulating virtual landscapes (i.e., a mosaic of fields having shapes and properties that vary in space and time and provide a support for biotic and abiotic processes) to systematically study the effects and impacts of landscape heterogeneity on ecosystem processes; see the recent reviews of Langhammer et al. (2019), Poggi et al. (2018). The purpose of such models is to generate a high number of virtual but structurally realistic maps of land-cover (Gardner (1999), Gardner and Urban (2007), Saura and Martinez-Millan (2000), Sciaini et al. (2018)), and, often, parameters related to landscape features, such as the percentage of land-cover, the habitat fragmentation or spatial autocorrelation (Langhammer et al. (2019)) can be controlled. In this paper we focus on modeling agricultural landscapes, and we consider neutral landscape models where the model does not directly interact with the biotic or abiotic processes (Gardner et al. (1987), With and King (1997)). ...
... No reuse allowed without permission. Fragmented prey habitat in our model is generated using 4 neutral landscape models (1). More specifically, we generate 5 lattices with periodic boundary conditions from an underly-6 ing fractional Brownian motion (fBm) characterized by the 7 Hurst exponent H ∈ (0, 1) that controls the spatial corre-8 lation between adjacent sites (2). ...
Increased fragmentation caused by habitat loss represents a major threat to the persistence of animal populations. How fragmentation affects populations depends on the rate at which individuals move between spatially separated patches. Whereas negative effects of habitat loss on biodiversity are well-known, effects of fragmentation per se on population dynamics and ecosystem stability remain less understood. Here, we use a spatially explicit predator-prey model to investigate how the interplay between fragmentation and optimal foraging behavior affects predator-prey interactions and, subsequently, ecosystem stability. We study systems wherein prey occupies isolated patches and are consumed by predators that disperse following Lévy random walks. Our results show that the Lévy exponent and the degree of fragmentation jointly determine coexistence probabilities. In highly fragmented landscapes, Brownian and ballistic predators go extinct and only scale-free predators can coexist with prey. Furthermore, our results confirm that predation causes irreversible habitat loss in fragmented landscapes due to overexploitation of smaller patches of prey. Moreover, we show that predator dispersal can reduce, but not prevent nor minimize, the amount of lost habitat. Our results suggest that integrating optimal foraging theory into population- and landscape ecology is crucial to assessing the impact of fragmentation on biodiversity and ecosystem stability.
