Structural connectivity models provide critical insights on how movement potential varies across landscapes and can support decisions on where to prioritize land protection and restoration. Water is a common component of landscape models used to inform conservation strategies, but the impacts of water parameterization on model behavior are poorly understood. We assessed how various parameterization approaches for water bodies, such as rivers, lakes, and shorelines, in structural, omnidirectional circuit-theory connectivity models affect patterns in the primary output, cumulative current flow values, in terrestrial grid cells. We ran two structural modeling approaches with ten simulated and six real-world landscapes using three methods for assigning the resistance of water relative to terrestrial resistance values: low, high, or neutral values drawn randomly from a distribution informed by the terrestrial resistance grid cells. We then compared the cumulative current outputs from each combination. The influence of how water was parameterized was consistent across all landscapes. When resistance values for water grid cells were low, the mean values of cumulative current on land were lower, indicating a dampening effect. When water resistances were high, the means and standard deviations of current flow on land were higher, with very high values (a pattern often used to indicate key barriers related to habitat fragmentation and loss) often observed near water. Assigning neutral resistance values to water had the least impact on the current flow across land, relative to a null model. We demonstrate water parameterization has important impacts on the outputs of terrestrial structural connectivity models that can complicate model interpretation. When the modeler’s intent is to inform land protection or restoration actions in response to human modification, the choice to treat water as neutral minimizes the interaction between water and land grid cells, clarifying output interpretation and use.
Reforestation is a prominent climate change mitigation strategy, but available global maps of reforestation potential are widely criticized and highly variable, which limits their ability to provide robust estimates of both the locations and total area of opportunity. Here we develop global maps that address common critiques, build on a review of 89 reforestation maps created at multiple scales, and present eight reforestation scenarios with varying objectives, including providing ecosystem services, minimizing social conflicts, and delivering government policies. Across scenarios, we find up to 195 Mha (million hectares) are available (2225 TgCO2e (teragrams of carbon dioxide equivalent) per year total net mitigation potential), which is 71-92% smaller than previous estimates because of conservative modeling choices, incorporation of safeguards, and use of recent, high-resolution datasets. This area drops as low as 6 Mha (53 TgCO2e per year total net mitigation potential) if only statutorily protected areas are targeted. Few locations simultaneously achieve multiple objectives, suggesting that a mix of lands and restoration motivations will be needed to capitalize on the many potential benefits of reforestation.
Large-scale disturbance in peatland areas causes many wildlife species to suffer due to limited resources or habitat loss. Following the high attention to peatlands, some restoration efforts, such as canal blocking, have been undertaken to restore the hydrological condition of peatlands. Nonetheless, our understanding of peatland biodiversity post-canal blocking is still limited. Thus, we conducted a study in West Kalimantan to assess wildlife diversity in peatland rewetting areas and understand the canal blocking's impact on peatland biodiversity. Surveys were conducted during both the wet and dry seasons using line transects and point counts, along with deploying autonomous recording units in four habitat types: less disturbed peat forest, disturbed peat forest, estate crop, and disturbed wet shrub. Shannon and Simpson diversity indices suggest that habitats with complex structures (i.e., forested habitat) support higher diversity compared to those with open and uniform vegetation (i.e., non-forested habitat). This notion is also supported by acoustic indices calculations, which indicate that forested areas show higher acoustic diversity (biophony), and thus higher biodiversity compared to non-forested areas. However, our results indicate that there is insufficient evidence to suggest the effect of canal blocking on wildlife diversity in all rewetting sites. Aligning biodiversity conservation efforts with the natural climate solutions hierarchy, which is part of nature-based solutions and consists of protect, manage, and restore, could offer promising solutions for recovering the sites.
Context Ecological corridors are one of the most recommended ways to mitigate biodiversity loss. With growing recognition of corridor importance, robust, quantitative validation methods lag behind the use of corridor modeling. Objective We propose a post-hoc corridor validation framework, considering the range of methods across data needs and statistical intensity. We aim to demonstrate the importance of post-hoc corridor validation by testing several validation methods on different corridor model outputs, using the same input data. Methods We used three different transformations on a Florida black bear (Ursus americanus floidanus) habitat suitability model to create different resistance grids, independent GPS collar data from a Florida black bear study population, and Circuitscape to create corridor models. We used several validation methods, including a novel method, to compare resulting corridors with management objectives. Results Transformed resistance grids were all correlated, yet differing validation and resistance grids resulted in different corridor recommendations. The use of one resistance surface and one validation category can result in the selection of inefficient or ineffective corridors. At a minimum, modelers should determine what proportion of an independent population falls within resulting corridors and should move towards more robust, documented methods as resources allow. The use of multiple validation methods can ensure greater confidence of modeling results. Conclusions We encourage the addition and development of the framework presented here to create more robust, effective corridors. If validation methods are not improved, the ecological and economic cost of poor corridor science will continue to increase with increasing biodiversity loss.
Nature-based solutions (NBS) can deliver many benefits to human wellbeing, including some crucial to climate adaptation. We quantitatively assess the global potential of NBS strategies of protection, restoration, and agroforestry by modeling global climate change mitigation and local ecosystem services (water availability, sediment retention, runoff, pollination, nitrogen retention, green water storage, and coastal protection). The strategies with the most potential to help people do not necessarily deliver the most climate change mitigation: per area of conservation action, agroforestry provides substantial benefits (>20% increase in at least one local ecosystem service) to three times more people on average than reforestation while providing less than one tenth the carbon sequestration per unit area. Each strategy delivers a different suite of ecosystem service benefits; for instance, avoided forest conversion provides a strong increase in nitrogen retention (100% increase to 72 million people if fully implemented globally) while agroforestry increases pollination services (100% increase to 3.0 billion people if fully implemented globally). One common disservice shared by all the NBS strategies modeled here is that increased woody biomass increases transpiration, reducing annual runoff and in some watersheds negatively impacting local water availability. In addition, the places with the greatest potential for climate change mitigation are not necessarily the ones with the most people. For instance, reforestation in Latin America has the greatest climate change mitigation potential, but the greatest ecosystem service benefits are in Africa. Focusing on nations with high climate mitigation potential as well as high local ecosystem service potential, such as Nigeria in the case of reforestation, India for agroforestry, and the Republic of Congo for avoided forest conversion, can help identify win-win sites for implementation. We find that concentrating implementation of these three conservation strategies in critical places, covering 5.8 million km2, could benefit 2.0 billion people with increased local ecosystem services provision. These critical places cover only 35% of the possible area of implementation but would provide 80% of the benefits that are possible globally for the selected set of ecosystem services under the NBS scenarios examined here. We conclude that targeting these critical places for protection, restoration, and agroforestry interventions will be key to achieving adaptation and human wellbeing goals while also increasing nature-based carbon mitigation.
Ecological corridors are one of the most recommended ways to mitigate biodiversity loss. With growing recognition of corridor importance, corridor modeling lags others in the development of robust, quantitative validation methods. We propose a post-hoc corridor validation framework, considering the range of methods across data needs and statistical intensity. We demonstrate the importance of post-hoc corridor validation by testing several validation methods on different corridor model outputs. We used three different transformations on a Florida black bear (Ursus americanus floidanus) habitat suitability model to create different resistance grids, independent GPS collar data from a case study population, and Circuitscape to create corridor models. We used several validation methods, including a novel method, to compare resulting corridors. Transformed resistance grids were all correlated, yet differing validation and resistance grids resulted in different recommended corridors. The use of one resistance surface and one validation type can result in the selection of inefficient or ineffective corridors. At a minimum, modelers should determine what proportion of an independent population falls within resulting corridors and should move towards more robust, documented methods as resources allow. The use of multiple validation methods can ensure greater confidence of modeling results. We encourage the use and further development of the framework presented here to drive the corridor modeling field towards more effective corridor creation and improved conservation outcomes. If validation methods are not improved, the ecological and economic cost of poor corridor science will continue to increase with increasing biodiversity loss.
Natural climate solutions (NCS) play a critical role in climate change mitigation. NCS can generate win–win co-benefits for biodiversity and human well-being, but they can also involve trade-offs (co-impacts). However, the massive evidence base on NCS co-benefits and possible trade-offs is poorly understood. We employ large language models to assess over 2 million published journal articles, primarily written in English, finding 257,266 relevant studies on NCS co-impacts. Using machine learning methods to extract data (for example, study location, species and other key variables), we create a global evidence map on NCS co-impacts. We find that global evidence on NCS co-impacts has grown approximately tenfold in three decades, and some of the most abundant evidence relates to NCS that have lower mitigation potential. Studies often examine multiple NCS, indicating some natural complementarities. Finally, we identify countries with high carbon mitigation potential but a relatively weak body of evidence on NCS co-impacts. Through effective methods and systematic and representative data on NCS co-impacts, we provide timely insights to inform NCS-related research and action globally. Rich evidence of the potential co-benefits and trade-offs of natural climate solutions is available but remains poorly understood. Assessing the literature with machine learning methods, this study maps and analyses the growing evidence of trade-offs in natural climate solutions globally.
IntroductionGiven the different life histories and movement behaviors of diverse species, reconciling conservation measures to benefit all species is a critical concern for landscape conservation planning. Understanding land cover composition and finding multispecies movement routes across heterogeneous landscapes are crucial to maintaining many target species. The primary objectives of this study were to determine the optimal environment in Florida that promotes multispecies connectivity in landscapes increasingly threatened by rapid suburban development and to enhance methods for delineating the state’s ecological networks.MethodsPotential functional connectivity of the focal species with statewide distributions and are considered priorities because of the historical and current threats to their population viability, such as the Florida black bear (Ursus americanus floridanus), Florida panther (Puma concolor coryi), eastern indigo snake (Drymarchon couperi), and southern fox squirrel (Sciurus niger niger), were modeled using Linkage Mapper, Omniscape, and resistant kernels. We combined quantiles from each method for a single species combination approach to leverage the results from the three models for planning purposes. Subsequently, we integrated the results into a novel multiple species, multi-model connectivity mapping approach. Following the corridor analysis, a comparison was made between multispecies connectivity maps, current managed conservation lands, and the main priority areas for the Florida Wildlife Corridor, a previously developed planning network of natural hubs and corridors. Finally, we used the spatial prioritization software Zonation to identify areas of conservation priority, while also illustrating the impacts of infrastructure (built infrastructure, roadways, mining, and future development 2040 and 2070 projections) and threats from human activity (landscape fragmentation, recreation, pollution, contamination, and clean-up sites).ResultsThe study identified priority areas for all four species, with a particular focus on areas not currently protected. The connectivity models showed significant overlap with current managed conservation lands and the main priority areas for the Florida Wildlife Corridor. Pinchpoint areas or bottlenecks were identified as needing fine-scale incorporation into spatial planning. Using the spatial prioritization software Zonation, we identified areas of conservation priority and illustrated the impacts of infrastructure and threats.DiscussionThe results indicate that species-relevant connectivity models incorporating a group of focal species with both complementary and opposing habitat requirements can better inform biodiversity conservation and landscape design decisions. This multi-model approach provides a robust framework for identifying and prioritizing areas for conservation, particularly in landscapes facing rapid suburban development. Integrating multispecies connectivity models into conservation planning can enhance the effectiveness of ecological networks and contribute to the long-term viability of diverse species in Florida.
Integrating recent scientific knowledge into management decisions supports effective natural resource management and can lead to better resource outcomes. However, finding and accessing scientific knowledge can be time consuming and costly. To assist in this process, the U.S. Geological Survey (USGS) is creating a series of annotated bibliographies on topics of management concern for western lands. Previously published reports introduced a methodology for preparing annotated bibliographies to facilitate the integration of recent, peer-reviewed science into resource management decisions. Therefore, relevant text from those efforts is reproduced here to frame the presentation. Sagebrush ecosystems throughout North America face management challenges including habitat loss and fragmentation. Brachylagus idahoensis (pygmy rabbits) are a sagebrush-obligate species that has experienced population declines and range contraction in recent decades. A disjunct population of pygmy rabbits in the Columbia Basin in Washington was listed as federally endangered in 2003. Due to their specialized habitat requirements and low dispersal ability, pygmy rabbits are a high priority for managers throughout their range. We compiled and summarized peerreviewed journal articles, data products, and formal technical reports (such as U.S. Forest Service General Technical Reports and U.S. Geological Survey Open-File Reports) on pygmy rabbits published between January 1, 1990 and December 31, 2020. We first conducted a structured search of three reference databases and three government databases using the phrase “pygmy rabbit” or “Brachylagus idahoensis.” We refined the initial list of products by removing (1) duplicates, (2) products not written in English, (3) publications that were not focused on North America, (4) publications that were not published as research, data products, or scientific review articles in peer-reviewed journals or as formal technical reports, and (5) products for which pygmy rabbits were not a research focus or for which the study did not present new data or findings about pygmy rabbits. We summarized each product using a consistent structure (background, objectives, methods, location, findings, and implications) and identified the management topics (for example, captive breeding, habitat characteristics, and population estimates) addressed by each product. We also noted which publications included new publicly available geospatial data. The review process for this annotated bibliography included an initial internal colleague review of each summary, requesting input on each summary from an author of the original publication, and a formal peer review. Our initial searches resulted in 2,285 total products, of which 105 met our criteria for inclusion. Sensitive/rare wildlife, behavior or demographics, site-scale habitat characteristics, habitat selection, and effects distances or spatial scale were the management topics most commonly addressed. The online version of this bibliography, Science for Resource Managers, will be searchable by topic, location, and year; it will include links to each original publication, where available. The studies compiled and summarized here may inform planning and management actions that seek to maintain and restore sagebrush landscapes and associated native species across the western United States.
Indonesia offers a dramatic opportunity to contribute to tackling climate change by deploying natural climate solutions (NCS), increasing carbon sequestration and storage through the protection, improved management, and restoration of drylands, peatlands, and mangrove ecosystems. Here, we estimate Indonesia’s NCS mitigation opportunity for the first time using national datasets. We calculated the maximum NCS mitigation potential extent using datasets of annual national land cover, peat soil, and critical lands. We collated a national emissions factor database for each pathway, calculated from a meta-analysis, recent publications from our team, and available literature. The maximum NCS mitigation potential in 2030 is 1.3 ± 0.04 GtCO 2 e yr −1 , based on the historical baseline period from 2009–2019. This maximum NCS potential is double Indonesia’s nationally determined contribution (NDC) target from the forestry and other land use sector. Of this potential opportunity, 77% comes from wetland ecosystems. Peatlands have the largest NCS mitigation potential (960 ± 15.4 MtCO 2 e yr −1 or 71.5 MgCO 2 e ha −1 yr −1 ) among all other ecosystems. Mangroves provide a smaller total potential (41.1 ± 1.4 MtCO 2 e yr −1 ) but have a much higher mitigation density (12.2 MgCO 2 e ha −1 yr −1 ) compared to dryland ecosystems (2.9 MgCO 2 e ha −1 yr −1 ). Therefore, protecting, managing, and restoring Indonesia’s wetlands is key to achieving the country’s emissions reduction target by 2030. The results of this study can be used to inform conservation programs and national climate policy to prioritize wetlands and other land sector initiatives to fulfill Indonesia’s NDC by 2030, while simultaneously providing additional co-benefits and contributing to COVID-19 recovery and economic sustainability.
First posted June 25, 2021 For additional information, contact: Director, Fort Collins Science CenterU.S. Geological Survey2150 Centre Ave., Building CFort Collins, CO 80526-8118 Integrating recent science into management decisions supports effective natural resource management and can lead to better resource outcomes. However, finding and accessing science information can be time consuming and costly. To assist in this process, the U.S. Geological Survey (USGS) is creating a series of annotated bibliographies on topics of management concern for western lands. Previously published reports introduced a methodology for preparing annotated bibliographies to facilitate the integration of recent, peer-reviewed science into resource management decisions. Therefore, relevant text from those efforts is reproduced here to frame the presentation. Invasive annual grasses are widely distributed throughout the western United States and threaten native ecosystems by altering fire regimes, replacing native plants, and altering grazing patterns, often with tremendous associated costs. One invasive annual grass, Ventenata dubia (hereafter, ventenata), was first introduced to the United States in the 1950s and has recently been identified as a management concern. Ventenata has a wide native geographic range, from Africa to northern Europe, and could thus potentially spread widely in the United States if left unmanaged. We compiled and summarized peer-reviewed journal articles, government reports, and data products on ventenata published between January 1, 2010, and August 27, 2020. We first conducted a systematic search of three reference databases and three government databases using the search phrase: “ventenata” OR “Ventenata dubia.” We refined the initial list of products by removing (1) duplicates, (2) products not written in English, (3) publications that were not focused in North America, (4) publications that were not published as research, data products, or scientific review articles in peer-reviewed journals or as formal technical reports, and (5) products for which ventenata was not a research focus or for which the study did not present new data or findings about ventenata. We summarized each product using a consistent structure (background, objectives, methods, location, findings, and implications) and identified the management topics (for example, species and population characteristics, habitat, control and management efforts) addressed by each product. We also noted which publications included new geospatial data. The review process for this annotated bibliography included an initial internal colleague review of each summary, requesting input on each summary from an author of the original publication, and a formal peer review. Our initial searches resulted in 505 total products, of which 29 met our criteria for inclusion. Nonnative invasive plants; weed management; behavior or demographics; dispersal, spread, vectors and pathways; site-scale habitat characteristics; survival; and weed management subtopic: herbicides were the management topics most commonly addressed. The online version of this annotated bibliography will be searchable by topic, location, and year; it will also include links to each original publication, where available. The studies compiled and summarized here may inform planning and management actions that seek to maintain and restore landscapes and control nonnative invasive species across the western United States.
Abstract Indonesia is one of the most biodiverse countries in the world yet suffers from the highest global deforestation rate. Having more diverse voices in conservation science contributing innovative ideas and solutions could benefit the country's biodiversity. However, some aspects of conservation work in Indonesia remain male‐dominated, particularly fieldwork. Understanding motivations and challenges for women pursuing a conservation career is critical to diversifying the workforce. We present some of the motivations and challenges of women conservation scientists attending a field skills and networking workshop in Sumatra, Indonesia, in September 2019. We conducted semistructured surveys in a preliminary study with female conservation scientists at the beginning of their careers and those with established careers of at least 3 years. Early‐career women predominantly cited a love of nature as their main motivator and cultural‐based gender norms as their primary challenge. Established career women discussed slowly improving gender norms and the importance of mentors throughout their careers. Without active engagement in career training and support over the long‐term for underrepresented groups in conservation, we could lose out on novel perspectives that could help solve the world's most daunting ecological problems.
Globally, wide-ranging carnivore populations are imperiled due to human-caused habitat fragmentation. Where populations are fragmented, habitat quantification is often the first step in conservation. Presence-only species distribution models can provide robust results when proper scales and data are considered. We aimed to identify habitat for a fragmented carnivore population at two scales and aid conservation prioritization by identifying potential future habitat fragmentation. We used location data and environmental variables to develop a consensus model using Maxent and Mahalanobis distance to identify black bear ( Ursus americanus floridanus ) habitat across Florida, USA. We compared areas of habitat to areas of predicted sea level rise, development, and protected areas. Local-scale models performed better than state-scale models. We identified 23,798 km 2 of habitat at the local-scale and 45,703 km 2 at the state-scale. Approximately 10% of state- and 14% of local-scale habitat may be inundated by 2100, 16% of state- and 7% of local-scale habitat may be developed, and 54% of state- and 15% of local-scale habitat is unprotected. Results suggest habitat is at risk of fragmentation. Lack of focused conservation and connectivity among bear subpopulations could further fragmentation, and ultimately threaten population stability as seen in other fragmented carnivore populations globally.
As the human population grows and wildlife habitat is lost, managers are increasingly reliant on hands-on management strategies such as translocation. Without much evidence suggesting success, moving a species or population from one location to another has been controversial for some taxa, especially for wildlife in urban areas. Here, in an ad hoc translocation of Terrapene carolina carolina (Eastern Box Turtle) in Washington, DC, we describe movements of 10 translocated turtles from 2011 to 2014, with 4 settling into apparent short-term home ranges and 6 requiring repeated relocation. Our study population was small, but results suggested that home-range establishment may occur with repositioning individuals post-release. Translocations should not proceed without sufficient investment from managers to carry out long-term monitoring of released individuals.
Despite the establishment of a national protected area system at the beginning of the 20th century to protect some of the world's most biodiverse forests, Indonesia has one of the highest deforestation rates in the world, due in part to the expansion of the global palm oil industry. The unique ecosystems of Sumatra, Indonesia provide habitat for critically endangered Sumatran tigers (Panthera tigris sumatrae), Sumatran elephants (Elephas maximus swnatrensis), and two species of orangutans (Pongo abelii and Pongo tapanuliensis). In this study, we use a matching method with generalized boosted models to determine the effectiveness of three nationally protected areas in preventing deforestation from 2002 to 2016. We also examine leakage - an increase in deforestation directly outside of protected areas relative to the wider landscape - to provide a clearer picture of the effects of agricultural expansion in this landscape. We found that Tesso Nilo National Park, with its lowland rain forest and conditions suitable for oil palm, offered the least protection from deforestation (avoided deforestation rate = 4.18%, p < 0.05 95% CI [1.97% - 6.45%]). Bukit Tigapuluh National Park, which may experience some de facto protection (i.e. protection due to factors independent of policy) with its mountainous terrain and difficult access, had the highest avoided deforestation rate (26.36%, p < 0.05 95% CI [24.17-28.55]), but had relatively high leakage (10.21%, p < 0.05 95% CI [7.51-12.98]). The low avoided deforestation rate in Tesso Nilo could be due to high localized human population and/or other socio-economic factors we were unable to control for in this study. The quantitative evidence of deforestation and effectiveness of protected areas in this heavily modified landscape supports the need for increased enforcement around protected areas locally, and globally in other oil palm production regions. These actions are critical in the preservation of global, tropical endemic flora and fauna.
Worldwide, roads are a main driver of deforestation and degradation as they increase forest access along the forest edge. In many tropical areas, unofficial roads go unreported and unrecorded, resulting in inaccurate estimates of intact forested areas. This is the case in central Sumatra, which boasts populations of critically endangered Sumatran elephants (Elephas maximus sumatrensis), tigers (Panthera tigris sumatrae) and other endemic flora and fauna that make the area globally unique. However, maps do not reflect the reality of forest loss in the area. Here we present new maps from 2002 and 2016 of digitized and ground-truthed roads in one of Sumatra's unique lowland tropical protected areas, Tesso Nilo National Park. Using our newly created roads dataset, we examine the distribution of forest with respect to distance to roads. Our data show >2,400 km of roads within the national park in 2016 -nearly a 10-fold increase from roads known in 2002. Most forest (82-99%) within Tesso Nilo falls within 100 m, 500 m, and 1000 m of road edges. Length of road increased 157% and road density increased from 1.06 km/km2 to 2.63 km/km2 from 2002-2016. Our results suggest that this endemic ecosystem is facing substantial threat from roads and their associated impacts. Without swift management action, such as road closures and increased enforcements by park management, this ecosystem, and its endemic wildlife, could be lost. It is imperative that protected areas worldwide more rigorously consider roads and road effects on ecosystem fragmentation in their conservation plans.
Riau Province in central Sumatra, with its peatland, lowland, and montane forest habitats, was once a stronghold for Sumatran tiger (Panthera tigris sumatrae) populations. Today, Riau may have one of the highest deforestation rates in the world and wildlife populations are dwindling, with natural forest now comprising approximately only 18% of the province, mostly contained within protected areas. Agriculture (acacia, rubber, and oil palm) makes up the majority of Riau's land cover and deforestation for the creation of new plantations is rampant. Natural forest and tigers still remain in Bukit Tigapuluh National Park and Rimbang Baling Wildlife Reserve, which remain connected to tiger populations in montane forest on the western edge of Sumatra. In this study, using freely available Landsat imagery and a maximum likelihood classification algorithm, we create land cover maps for central Sumatra from 2002 to 2016. We then use current land cover, elevation, and slope variables to predict changes from forest to plantation from 2016 to 2050 at five year intervals using a multilayer perceptron neural network. Finally, we compare connectivity based on a 100 km distance threshold (based on potential tiger dispersal) across the landscape and across years. Land cover maps had 80-90% accuracy, and we predict forest in Tesso Nilo and the western edge of the study area to be lost by 2050 given current rates of deforestation. Our connectivity analysis shows that Tesso Nilo and the area between Rimbang Baling and Bukit Tigapuluh are important components for maintaining connectivity throughout the study area. Focusing conservation and rehabilitation efforts on forests close to plantations in flat areas, including Tesso Nilo, is necessary to maintain forests and increase connectivity in Riau to ensure future habitat connectivity for survival of tigers and Sumatra's other diverse endemic species.
Barbed and woven wire fences, common structures across western North America, act as impediments to wildlife movements. In particular, fencing influences pronghorn (Antilocapra americana) daily and seasonal movements, as well as modifying habitat selection. Because of fencing's impacts to pronghorn and other wildlife, it is a potentially important factor in both wildlife movement and habitat selection models. At this time, no geospatial fencing data is available at regional scales. Consequently, we constructed a regional fence model using a series of land tenure assumptions for the Hi-Line region of northern Montana - an area consisting of 13 counties over 103,400 km(2). Randomized 3.2 km long transects (n = 738) on both paved and unpaved roads were driven to collect information on habitat, fence densities and fence type. Using GIS, we constructed a fence location and a density model incorporating ownership, size, neighboring parcels, township boundaries and roads. Local knowledge of land ownership and land use assisted in improving the final models. We predict there is greater than 263,300 km of fencing in the Hi-Line region, with a maximum density of 6.8 km of fencing per km(2) and mean density of 2.4 km of fencing per km(2). Using field data to assess model accuracy, Cohen's Kappa was measured at 0.40. On-the-ground fence modification or removal could be prioritized by identifying high fence densities in critical wildlife areas such as pronghorn migratory pathways or sage grouse lekking habitat. Such novel fence data can assist wildlife and land managers to assess effects of anthropogenic features to wildlife at various scales; which in turn may help conserve declining grassland species and overall ecological functionality.
Terrestrial long-distance migrations are declining globally: in North America, nearly 75% have been lost. Yet there has been limited research comparing habitat suitability and connectivity models to identify migration corridors across increasingly fragmented landscapes. Here we use pronghorn (Antilocapra americana) migrations in prairie habitat to compare two types of models that identify habitat suitability: maximum entropy (Maxent) and expert-based (Analytic Hierarchy Process). We used distance to wells, distance to water, NDVI, land cover, distance to roads, terrain shape and fence presence to parameterize the models. We then used the output of these models as cost surfaces to compare two common connectivity models, least-cost modeling (LCM) and circuit theory. Using pronghorn movement data from spring and fall migrations, we identified potential migration corridors by combining each habitat suitability model with each connectivity model. The best performing model combination was Maxent with LCM corridors across both seasons. Maxent out-performed expert-based habitat suitability models for both spring and fall migrations. However, expert-based corridors can perform relatively well and are a cost-effective alternative if species location data are unavailable. Corridors created using LCM out-performed circuit theory, as measured by the number of pronghorn GPS locations present within the corridors. We suggest the use of a tiered approach using different corridor widths for prioritizing conservation and mitigation actions, such as fence removal or conservation easements.