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We study the problem of placing wildlife crossings, such as green bridges, over human-made obstacles to challenge habitat fragmentation. The main task herein is, given a graph describing habitats or routes of wildlife animals and possibilities of building green bridges, to find a low-cost placement of green bridges that connects the habitats. We develop three problem models for this task and study them from a computational complexity and parameterized algorithmics perspective. [ABSTRACT FROM AUTHOR]

The expansion of roads into wilderness areas and biodiversity hotspots in the Global South seems inevitable and is predicted to bring about significant biodiversity loss. Even so, existing widespread strategies aiming to mitigate the direct and indirect impacts of roads on the environment have been of limited effectiveness. These tactics, including construction of fencing, wildlife crossings on paved roads, and establishment of protected areas along the roads, are unlikely to be sufficient for protecting diverse species assemblages from roadkill, habitat fragmentation, and anthropogenic activity in tropics. This indicates the need for integration of more ambitious approaches into the conservation toolkit, such as the constructing tunnels, covered ways, and elevated roads. Although these tools could significantly support conservation efforts to save tropical biodiversity, to date, they are rarely considered. Here, we discuss factors which determine the need for application of these approaches in the Global South. We highlight the often-overlooked long-term benefits associated with the application of the proposed tools. We also discuss the potential challenges and risks, and the ways to minimise them. Hopefully this article will encourage practitioners to integrate these strategies into conservation toolkits and allow policy-makers and investors to make informed decisions on sustainable road infrastructure development in the Global South. [ABSTRACT FROM AUTHOR]

Transportation and other agencies and organizations are increasingly planning and building under- and over-crossing structures for wildlife to traverse busy highways. However, if wildlife do not use these structures due to noise, light, and other factors, then the structures may have a low benefit to cost ratio. Several criteria are key for their success— sufficient safety and/or conservation need, cost, location, and anticipated use by wildlife. There is limited information in wildlife-crossing guidance on how wildlife biologists should advise designers, engineers, and architects on the use of structural and vegetation elements that could reduce noise and light disturbances. To address this problem, this study used field measurements and modeling of light and noise from traffic to inform and test the designs of two wildlife overcrossings. Wildlife-responsive designs were developed and tested for two crossings being considered or planned by California Department of Transportation in California. For the planned crossing of US 101 near the city of Agoura Hills (the Wallis-Annenberg crossing), the three designs consisted of noise/glare barriers; noise/glare barriers + berm; and noise/glare barriers + multiple berms. For the potential crossing of Interstate 15 south of Temecula, one design used noise/glare barriers of 3 different heights and the other had no barriers. Key limitations and opportunities for each design approach were identified. Creating “dark and quiet paths” using a combination of berms and noise/glare barriers could decrease disturbance in the crossing structure approach zones and increase the wildlife-responsiveness of the designs.

Road building is one of the greatest threats to biodiversity globally. This study addressed common challenges for spatially explicit ecological assessments of linear infrastructure EIAs, by first providing an overview of existing approaches and then applying a connectivity model with scenario analysis of alternative road alignments for a road bypass in Beaufort, Australia. The application included an expert-based connectivity model using a combination of least-cost paths, circuit theory, and graph theory to model five conservation targets (four species and one group) with different dispersal abilities and habitat requirements. For each of these targets, we modelled four different road alignments, then assessed mitigation options for the least impactful alignment. The results showed that each target species was dissimilarly impacted, with longer dispersers affected the most. The modelling clearly identified a single alignment with the least overall impact on connectivity and showed how wildlife crossing structures can mitigate impacts through improving overall connectivity for all target species. This real-world case-study demonstrated the potential to apply a transparent and quantitative approach to mainstreaming ecological connectivity modelling in EIAs. [ABSTRACT FROM AUTHOR]

As roads and other developed land uses proliferate, the resulting habitat fragmentation and loss of wildlife connectivity hinder animals’ ability to forage, establish new territories, and maintain genetic diversity. Wildlife crossing structures such as culverts and bridges theoretically can reduce these impacts by allowing species to effectively cross highways. However, previous research has shown that traffic presence and density can disrupt wildlife use of highway crossing structures, and that noise and light from human activities can affect animal behavior. Researchers at the University of California, Davis, Road Ecology Center measured traffic noise and light levels and placed motion- and heat-triggered cameras at 26 bridges and culverts along four interstate highways, 11 state highways and one major county road across California. The presence and behavior of animals at these highway crossing structures were compared to those detected at sites unaffected by roads to understand the effects of noise and light from a highway on wildlife behavior. This policy brief summarizes findings from that research and provides policy implications.View the NCST Project Webpage

Wildlife-vehicle conflict (WVC) occurs when traffic coincides with a place where animals decide to cross the surface of a roadway. State departments of transportation have a consistent need to understand rates and locations of WVC but inconsistent access to tools to measure statistical significance of clusters of WVC which could need mitigation. This research brief summarizes the findings from the associated project, the objective of which was to develop a standard method for analyzing WVC “hotspots” (areas of concern) that any state could use to identify potential locations for WVC mitigation.

Creating and maintaining sustainable transportation systems depends in part on understanding and mitigating ecological impacts. Wildlife crossing structures (WCS) are often used to mitigate impacts on wildlife populations. WCS and existing structures may provide passage for multiple species, depending on their sensitivity to traffic disturbance and perception of the roadway. In a previous project, the research team found that traffic conditions and traffic noise could reduce WCS effectiveness in facilitating passage of diverse and sensitive species. In the current project, they expanded the geographic scope to 26 sites throughout California, including detailed measurements of vehicle noise and lighting impacts on wildlife use of structures. They investigated individual animal behavior as the animals approached structures as a possible mechanism for reducing species diversity due to traffic disturbance. In order to inform future WCS planning, placement and construction, the team studied traffic noise and light impacts on wildlife in the vicinity of the proposed Liberty Canyon wildlife over-crossing (over US 101), the first and largest of its kind in California. They improved a preliminary statistical model of the effects of traffic on WCS use of existing structures. The authors recommend strategies for transportation agencies to use in developing and modifying WCS to improve wildlife passage.View the NCST Project Webpage

Over the past few decades, wildlife crossings have effectively reduced wildlife–vehicle collisions and improved habitat connectivity and genetic exchange for animals. However, wildlife crossings are expensive to construct, and the cost may discourage transportation agencies from implementing new wildlife crossings on public roadways. Additionally, transportation agencies and planners rarely consider the permitting and mitigation costs that wildlife crossings can require. A road profile must be raised to accommodate a wildlife underpass on many Florida roadways, particularly in low‐lying areas. Raising the road can result in new wetland impacts that would not occur but for the wildlife crossing. Consequently, new or more compensatory wetland mitigation may be required to satisfy § 404 of the Clean Water Act—a cost to the transportation agency and taxpayers. We used Florida's Uniform Mitigation Assessment Method (UMAM) to calculate the value of functions in habitats before and after planned wildlife crossings on State Road 40 in Volusia County, Florida. The results of our analysis show that wildlife crossings will enhance the functions in remnant habitats adjacent to the wildlife crossings, generating wetland mitigation credits that reduced the amount of compensatory wetland mitigation required by the U.S. Army Corps of Engineers. Our case study provides a novel application of the UMAM in valuing wildlife crossings. We believe the UMAM can be used in cost–benefit models and transportation planning to determine the functional value of new wildlife crossings, thereby producing a monetary value that can incentivize new wildlife crossing projects. [ABSTRACT FROM AUTHOR]

States increasingly maintain databases of wildlife-vehicle conflict (WVC), including locations of carcasses and crashes involving animals. Once these data are collected, a common and expensive barrier before they can be used in safety and environmental planning is identification of “hotspots” of incidents (here defined as locations of high-rates and/or statistically-significant clusters). In this project, we developed a web-based analytical environment that state DOTs can use to automate certain analyses of WVC hotspots in order to inform planning to improve driver and wildlife safety. Specifically, we coordinated with staff from 3 states: Idaho, Nevada, and Maine, and used data that we had for California to develop the pilot automated hotspots analysis tool. We tested several methods for representing both density and statistically-significant clustering of WVC events. These were implemented in the statistical package R and driven by scripts that can operate in the project web-system. Testing was conducted using California data while other states prepared/delivered their data. We developed hotspots analyses for California, Maine, Idaho, and Nevada based upon their input. We prepared a web-system to operate the tool (https://roadecology.ucdavis.edu/hotspots), that DOT staff from 13 states used so far with their own data.

Abstract Over the past few decades, wildlife crossings have effectively reduced wildlife–vehicle collisions and improved habitat connectivity and genetic exchange for animals. However, wildlife crossings are expensive to construct, and the cost may discourage transportation agencies from implementing new wildlife crossings on public roadways. Additionally, transportation agencies and planners rarely consider the permitting and mitigation costs that wildlife crossings can require. A road profile must be raised to accommodate a wildlife underpass on many Florida roadways, particularly in low‐lying areas. Raising the road can result in new wetland impacts that would not occur but for the wildlife crossing. Consequently, new or more compensatory wetland mitigation may be required to satisfy § 404 of the Clean Water Act—a cost to the transportation agency and taxpayers. We used Florida's Uniform Mitigation Assessment Method (UMAM) to calculate the value of functions in habitats before and after planned wildlife crossings on State Road 40 in Volusia County, Florida. The results of our analysis show that wildlife crossings will enhance the functions in remnant habitats adjacent to the wildlife crossings, generating wetland mitigation credits that reduced the amount of compensatory wetland mitigation required by the U.S. Army Corps of Engineers. Our case study provides a novel application of the UMAM in valuing wildlife crossings. We believe the UMAM can be used in cost–benefit models and transportation planning to determine the functional value of new wildlife crossings, thereby producing a monetary value that can incentivize new wildlife crossing projects.

Aim: Several large‐mammal species in Europe have recovered and recolonized parts of their historical ranges. Knowing where suitable habitat exists, and thus where range expansions are possible, is important for proactively promoting coexistence between people and large mammals in shared landscapes. We aimed to assess the opportunities and limitations for range expansions of Europe's two largest herbivores, the European bison (Bison bonasus) and moose (Alces alces). Location: Central Europe. Methods: We used large occurrence datasets from multiple populations and species distribution models to map environmentally suitable habitats for European bison and moose across Central Europe, and to assess human pressure inside the potential habitat. We then used circuit theory modeling to identify potential recolonization corridors. Results: We found widespread suitable habitats for both European bison (>120,000 km2) and moose (>244,000 km2), suggesting substantial potential for range expansions. However, much habitat was associated with high human pressure (37% and 43% for European bison and moose, respectively), particularly in the west of Central Europe. We identified a strong east–west gradient of decreasing connectivity, with major barriers likely limiting natural recolonization in many areas. Main conclusions: We identify major potential for restoring large herbivores and their functional roles in Europe's landscapes. However, we also highlight considerable challenges for conservation planning and wildlife management, including areas where recolonization likely leads to human–wildlife conflict and where barriers to movement prevent natural range expansion. Conservation measures restoring broad‐scale connectivity are needed in order to allow European bison and moose to recolonize their historical ranges. Finally, our analyses and maps indicate suitable but isolated habitat patches that are unlikely to be colonized but are candidate locations for reintroductions to establish reservoir populations. More generally, our work emphasizes that transboundary cooperation is needed for restoring large herbivores and their ecological roles, and to foster coexistence with people in Europe's landscapes. [ABSTRACT FROM AUTHOR]

Wildlife crossing structures (WCS) over or under highways have been proposed as a solution for road-related habitat fragmentation and wildlife collisions. To assure the efficacy of WCS, road related negative impacts that could cause animals to avoid WCS, such as noise and light, need to be considered. Human-sourced noise can affect habitat occupancy, and a suite of animal behaviors such as vigilance, communication, and predation efficiency, while artificial light, especially at night, can change animal’s perception of resources, foraging, mate selection, and navigation. Furthermore, the impact of noise and light varies among wildlife species, leading to differential responses within wildlife communities. To test whether traffic noise impacts species’ use of WCS, the authors quantified overnight (afternoon to early morning) road traffic noise, measured as dB(A), at 20 WCS positioned along four central California highways (I-5, I-80, 680 and 280), as well as historical WCS mammal use for 20 recorded days during the summer of 2012, 2015, and 2016. Using species richness inclusive of all taxa as the response variable, the only significant explanatory variable was annual average daily traffic (AADT) (p 800m from the highway) were monitored over a 20-day period, to further examine the impact of noise on WCS use. Species richness was greater (p

Roads and highways act as barriers to wildlife. They disrupt movement of wildlife populations and connectivity between communities of interacting species. Transportation organizations and many wildlife agencies see highway crossing structures for wildlife as critical to mitigating highway barrier effects. These structures are optimistically assumed to be effective for most species, most of the time, but are seldom critically investigated.Wildlife use of highway crossing structures can be highly variable and dependent on structural attributes, human use, and traffic conditions. Studies of animal behavior suggest that wildlife aversion to roadways—and possibly to crossing structures—could be related to traffic noise and light. If transportation organizations and wildlife agencies can confirm this effect they may be able to design more effective wildlife crossing structures and manage existing structures to increase their use by wildlife.This policy brief discusses findings from research that measured traffic noise levels and used camera traps placed at 20 bridges and culverts in California that were known from previous work to pass at least one species.View the NCST Project Webpage

The intensive construction of road infrastructure due to urbanization and industrialization around the world carries with it negative environmental impacts, primarily due to increased emissions of gases, but also due to the separation of natural habitats and ecosystems. In order to overcome this problem, without affecting the mobility of the population, it is necessary to allow wild animals to cross over or below the roads, i.e. to create wildlife crossings, which requires knowledge of the locations where the corridors of animal movements intersect with existing or planned roads. This paper analysis the establishment of a camera system and the application of a deep learning methodology for the automatic identification of animals by species and number, in order to determine locations for the construction of crossings for large wildlife. Also, the paper presents the possibility of using geographic information systems to analyze information obtained by monitoring built wildlife crossings.

Highways can fragment habitat and be a significant mortality source for mammals. Wildlife exclusion fencing has been shown to reduce wildlife-vehicle collisions, but can also prevent animals from escaping the highway corridor if they enter at access roads or at fence ends. Earthen escape ramps, or “jumpouts,” have been proposed as a possible solution but remain relatively untested. From 2012-2014, we used wildlife cameras to continuously document wildlife use of four jumpout ramps constructed as part of a 2.5-mile wildlife exclusion fence project along Highway 101 near San Luis Obispo, California. Mule deer occasionally used the jumpouts, but quantifying the rate of utilization was confounded by repeated visits by the same individuals. Male and female deer appeared to have different responses to the jumpouts, which warrants deeper investigation using additional data collected from further monitoring through mid-2017. The longer dataset will also better document how individual deer learn to use the jumpouts. Fenced highways can also reduce connectivity unless there is sufficient use of crossing structures. We documented mountain lion, bobcat, black bear, and mule deer used culverts and underpasses in and adjacent to the wildlife fence zone from 2012-2014. Mule deer used the large underpasses almost exclusively, and rarely if ever used culverts. Bear used a wider variety of structures, and bobcats were detected at almost every site and at a higher rate than the other taxa. Mountain lion detections were quite rare, likely due to lower population density in the study area. We propose a deeper multivariate analysis of the factors influencing these species’ use of culverts including culvert dimensionality, nearby habitat, and proximity to cover, based on an expanded dataset of up to five years of continual monitoring at certain sites. The goal of these analyses is to provide information that will help reduce wildlife-vehicle collisions while facilitating regional wildlife connectivity.

Roads can have unintended effects on wildlife populations, such as causing direct mortality through animal collisions with cars, changing animal behaviors or distributions from traffic disturbance (e.g., noise, lighting), and fragmenting habitat. Roads may also act as barriers to wildlife movements, which prevents populations on either side from exchanging genes. Over time, wildlife populations isolated by barriers will lose genetic diversity, a process associated with an increased risk of extinction.To better understand this dynamic in Northern California, a studywas completed examining whether State Route 49 (SR 49), a road initially constructed during the Gold Rush era, acts as a barrier to movements of two similar species with different tolerances to human activity, the coyote and gray fox. This policy brief summarizes findings from that study and discusses the policy implications.View the NCST Project Webpage

Roads networks may have profound impacts on the viability of wildlife populations. In particular, highways can be barriers to wildlife movement, leading to genetic diversity loss, inbreeding, and increased extinction risk for small, isolated populations on either side. The effects that highways have on wildlife movement can be variable, dependent on the unique dispersal behaviors of individual species. In this study, we test the hypothesis that highways will pose less of a barrier to coyotes, a species tolerant of human disturbance, than to gray fox, a species more sensitive to disturbance. We used landscape genetic tools to determine whether State Route 49, part of the California Essential Habitat Connectivity Project, was a barrier to coyote or gray fox movements. Genetic diversity among both coyotes and gray foxes was high and comparable to other studies. We found little evidence of contemporary genetic structure across State Route 49 for either species. All genetic differentiation that we observed was driven by family structure and relatives were found on both sides of the highway. Coyotes exhibited a significant signal of isolation by distance and a positive association between traffic volume and genetic distance. There are two possible explanations for these findings. State Route 49 may be permeable to coyote and gray fox movement due to successful road crossings. Alternatively, State Route 49 is a barrier to coyote and gray fox movement but there may be a time lag between initial reduction of gene flow and detection of population structure.View the NCST Project Webpage

Roads have the potential to fragment wildlife populations, leading to genetic diversity loss, inbreeding, and increased extinction risk for small, isolated populations. In this study, the authors used coyote as a model to investigate how four Northern California highways affect gene flow of ground-dwelling mammals. The authors collected coyote scat samples from opposite sides of a stretch of I-580 and I-680 in the Bay Area and I-80 and US 50 in the Sierra Nevada foothills. The authors extracted DNA and genotyped each coyote at 13 microsatellite loci. The authors estimated genetic diversity and determined how that diversity was partitioned across the landscape in each region. Genetic diversity levels in coyotes were high and comparable to other studies. The authors found significant genetic structure in both the Bay Area and Sierra Nevada foothills, although it didn’t always correspond to highway presence. In the Bay Area, two populations were identified and although some evidence suggested I-580 was a significant barrier to gene flow, the authors identified migrants across the highway. One of the two populations in the Bay Area contained many second order relatives, suggesting limited gene flow into that population. There was evidence of dispersal out of that population, however. In the Sierra Nevada foothills, the authors identified three populations. Individuals from one population were sampled across highway I-80 suggesting it was not a significant barrier to movement. The most genetically divergent population in the Sierra Nevada foothills was also the most geographically distant and therefore it was difficult to determine whether gene flow into that population was limited by highway presence or simply geographic distance from other populations. The conclusions drawn in their pilot study are limited by the small number of samples they were able to genotype completely in the timeframe of this project. The authors are going to continue analyzing samples that currently have only partial genotypes and add those to their regional datasets. Genetic analysis with these larger samples will allow them to better understand the role of highways in structuring coyote populations in the Bay Area and Sierra Nevada foothills.View the NCST Project Webpage

The principle of sustainable transportation suggests that impacts to environmental processes and patterns will be limited as much as possible during construction and operation of the transportation system. Wildlife populations are affected by transportation in various ways, including individual animal deaths due to collisions with vehicles, animal aversion to roads due to light and noise, habitat fragmentation, and human access for recreation and hunting. If individual animals of a species have limited movement in part or all of their range, then divided populations can become genetically different from each other, which can jeopardize survival of populations and even whole species. This population subdivision can happen even in the relatively short time since California highways were constructed.This policy brief summarizes findings from a research that examined the potential population division effect of highways on coyote populations in the Bay Area and Sierra Nevada foothills.View the NCST Project Webpage

Planning and policy are best done through integrated approaches that holistically address multiple sustainability issues. Climate change and biodiversity loss are two of the most significant issues facing our planet. Accordingly, advancements in integrated sustainability planning and policy require a means for examining how certain strategies and actions may align or conflict with these sustainability imperatives. Here, we enhance the knowledge of integrated approaches for addressing sustainability challenges by developing and applying a framework for examining different planning and policy areas in the context of climate action and biodiversity conservation. As a case study, we used wildlife crossing planning and landscape connectivity policy in Canada, which is currently piecemeal, fragmented, and could benefit from an integrated approach. The study was conducted in two stages. First, we developed an analytical framework for examining issues in the context of climate action and biodiversity conservation co-benefits and trade-offs. Then, we applied the framework to wildlife crossing and landscape connectivity issues to elucidate opportunities and challenges for integrated planning and policy. We used a literature review to develop an integrated climate-biodiversity framework (ICBF). ICBF was subsequently applied to wildlife crossing and landscape connectivity planning and policies in Canada. ICBF maps relationships between climate action and biodiversity conservation co-benefits and trade-offs and is organized into six themes: green space, transportation, green infrastructure, food and agriculture, energy, and land management. Applying ICBF to participant interview data produced insights into opportunities and challenges for integrated approaches to wildlife crossing and landscape connectivity by elucidating potential co-benefits and trade-offs such as alignments between stormwater management and aquatic crossings (i.e., co-benefits) and potential issues related to energy development and habitat fragmentation (i.e., trade-offs). ICBF has application beyond wildlife crossings, and its continual use and refinement will result in a better understanding of how to effectively implement integrated approaches and transition toward sustainable development paths. [ABSTRACT FROM AUTHOR]

Natural and artificial canopy bridges can be used to mitigate the effects of habitat fragmentation. Understanding the ecological factors that influence bridge use is imperative to the effective design and placement of this potential conservation intervention. Moonlight, seasonality and weather may influence the cost and risk of using bridges, potentially reducing their effectiveness. We installed five artificial waterline bridges and, between 2017 and 2019, monitored via camera trapping their use by Javan palm civets Paradoxurus musanga javanicus and Javan slow lorises Nycticebus javanicus. We used a weather station to record microclimate data (temperature and relative humidity) and calculated the illumination percentage of the moon. We tested the influence of moon luminosity, relative humidity, seasonality (Julian day) and temperature on the frequency of bridge use via Generalised Additive Models. Camera traps captured 938 instances of bridge use by civets, which was significantly lower than the reference value at moon luminosity > 90%, temperatures > 20 °C, humidity > 90%, and during the drier period (May–July). Camera traps captured 1036 instances of bridge use by lorises, which was significantly lower than the reference value during the drier period and higher than the reference value at temperatures > 20 °C. Lorises showed peaks in bridge use close to sunset and sunrise whereas civets showed peaks around 2 h after sunset and 2 h before sunrise. Our study illustrates the utility of simple-to-construct bridges by two sympatric nocturnal mammals facing severe habitat loss, with bridge use differing between those species according to abiotic factors. In particular, less use by both taxa during the drier season could suggest modifying placement of bridges or providing another intervention during that time. Camera traps were an excellent mechanism to record these differences and to validate the importance of the bridges, including during inclement weather and dark nights, when observations would be more difficult for human observers. By understanding the influence that abiotic factors have on the use of artificial bridges, we can improve bridge placement and construction to encourage use by a variety of species, particularly those threatened by habitat fragmentation. [ABSTRACT FROM AUTHOR]

The impact of wildlife--vehicle collisions on drivers and wildlife populations has been gaining attention in the United States. Given the established success of wildlife crossings with fencing in reducing wildlife crashes and connecting habitat, information is needed on cost-effective means of implementation for departments of transportation. When wildlife crossings are constructed, they are often built into new road projects as a series of 2 or more underpasses and/or overpass structures connected by exclusionary fencing. Given limited transportation budgets and the prevalence of maintenance activities more so than new construction in many states, enhancing existing underpasses on previously constructed roads has been recognized as a cost-effective mitigation opportunity. More research is needed, however, on the effects of adding fencing to existing underpasses, particularly those that are too far from one another to be connected with contiguous fencing. In this study, we evaluated the effectiveness of this measure when applied to isolated underpasses. Approximately 1.6 km of 2.4-m-high wildlife fencing was added to each of 2 existing underpasses, a large bridge underpass and a large box culvert, situated approximately 8 km apart from one another on Interstate 64 in Virginia, USA. We conducted a 2-year post-fencing camera monitoring study and compared the findings from a 2-year pre-fencing study with regard to collision frequencies with white-tailed deer (Odocoileus virginianus) and black bears (Ursus americanus); the use of the underpasses by wildlife; and roadside deer activity. We also evaluated deer activity data to compare different fence end designs applied at the study sites. After fencing installation, deer--vehicle collisions (DVCs) were reduced by 96.5% and 88% at the box culvert and bridge underpass, respectively, and there were no increases in DVCs within 1.6 km of the fence ends. Deer crossings increased 410% at the box culvert and 71% at the bridge underpass. Use of the culvert and bridge underpasses by other mammals increased 81% and 165%, respectively. Although deer use of the underpasses was much greater than their activity at any of the fence ends, there was relatively high deer activity at the fence ends that did not tie into a feature such as right-of-way fencing. Our study found that the addition of wildlife fencing to certain existing isolated underpasses can be a highly cost-effective means of increasing driver safety and enhancing habitat connectivity for wildlife. The benefits from crash reduction exceeded the fencing costs in 1.8 years, and fencing resulted in an average saving of >$2.3 million per site over the 25-year lifetime of the fencing. The results add to the growing body of knowledge about effective ways we can use existing infrastructure to connect wildlife habitat and increase driver safety. [ABSTRACT FROM AUTHOR]

Planning and policy are best done through integrated approaches that holistically address multiple sustainability issues. Climate change and biodiversity loss are two of the most significant issues facing our planet. Accordingly, advancements in integrated sustainability planning and policy require a means for examining how certain strategies and actions may align or conflict with these sustainability imperatives. Here, we enhance the knowledge of integrated approaches for addressing sustainability challenges by developing and applying a framework for examining different planning and policy areas in the context of climate action and biodiversity conservation. As a case study, we used wildlife crossing planning and landscape connectivity policy in Canada, which is currently piecemeal, fragmented, and could benefit from an integrated approach. The study was conducted in two stages. First, we developed an analytical framework for examining issues in the context of climate action and biodiversity conservation co-benefits and trade-offs. Then, we applied the framework to wildlife crossing and landscape connectivity issues to elucidate opportunities and challenges for integrated planning and policy. We used a literature review to develop an integrated climate-biodiversity framework (ICBF). ICBF was subsequently applied to wildlife crossing and landscape connectivity planning and policies in Canada. ICBF maps relationships between climate action and biodiversity conservation co-benefits and trade-offs and is organized into six themes: green space, transportation, green infrastructure, food and agriculture, energy, and land management. Applying ICBF to participant interview data produced insights into opportunities and challenges for integrated approaches to wildlife crossing and landscape connectivity by elucidating potential co-benefits and trade-offs such as alignments between stormwater management and aquatic crossings (i.e., co-benefits) and potential issues related to energy development and habitat fragmentation (i.e., trade-offs). ICBF has application beyond wildlife crossings, and its continual use and refinement will result in a better understanding of how to effectively implement integrated approaches and transition toward sustainable development paths.

Context: Road infrastructure construction is integral to economic development, but negatively affects biodiversity. To mitigate the negative impacts of infrastructure, various types of wildlife crossings are realized worldwide, but little is known about their effectiveness, and cost-effectiveness. Objective: The paper contributes to the methodological and empirical discussion on the effectiveness of wildlife crossings for enhancing the quality of surrounding nature and its cost-effectiveness by analyzing a large-scale wildlife-crossings program in the Netherlands. Method: A multi-criteria cost–benefit analysis is applied, comprised of monetary and non-monetary measures, and a mixed-method approach is used to determine ecological effects. Ecological effects are expressed in the standardized weighted hectare measurement of threat-weighted ecological quality area (1 T-EQA = 1 ha of 100% ecological quality, averagely threatened). Cost-effectiveness is calculated comparing the monetary costs of intervention with ecological benefits (Euro costs/T-EQA), for different types of wildlife crossings and for two other nature policies. Results: The Dutch habitat defragmentation program has induced an increase in nature value of 1734 T-EQA at a cost of Euro 283 million. Ecological gains per hierarchically ordered groups of measures differ strongly: The most effective are ecoducts (wildlife crossing bridges) followed by shared-use viaducts and large fauna tunnels. Ecoducts generated the largest gain in nature value, but were also the most costly measures. In terms of cost-effectiveness, both large fauna tunnels and shared-use viaducts for traffic and animals outperformed ecoducts. Conclusions: Ecoducts deliver ecologically, but their cost-effectiveness appears modest. Purchasing agricultural land for restoration of nature appears more cost-effective than building wildlife crossings. Yet, reducing environmental pressures or their effects on existing nature areas is likely to be most cost-effective. [ABSTRACT FROM AUTHOR]

Canopy bridges are increasingly used to reduce fragmentation in tropical habitats yet monitoring of their impact on the behavior of primates remains limited. The Javan slow loris (Nycticebus javanicus) is endemic to Java, Indonesia, where the species most often occurs in human‐dominated, highly patchy landscapes. Slow lorises cannot leap, are highly arboreally adapted, and are vulnerable on the ground. To increase arboreal connectivity, as part of a long‐term conservation project in Cipaganti, West Java, we built and monitored seven slow lorises bridges of two types—waterline or rubber—and monitored their use by seven adult individuals from 2016 to 2017. Motion triggered camera traps collected data for 195 ± standard deviation (SD) 85 days on each bridge. We collected 341.76 hr (179.67 hr before and 162.09 hr after the installation of bridges) of behavioral and home range data via instantaneous sampling every 5 min, and terrestrial behavior (distance and duration of time spent on the ground) via all occurrences sampling. We found that slow lorises used bridges on average 12.9 ± SD 9.7 days after their installment mainly for traveling. Slow lorises showed a trend toward an increase in their home range size (2.57 ha before, 4.11 ha after; p = 0.063) and reduced ground use (5.98 s/hr before, 0.43 s/hr; p = 0.063) after implementation of bridges. Although the number of feeding trees did not change, new feeding trees were included in the home range, and the proportion of data points spent traveling and exploring significantly decreased (p = 0.018). Waterline bridges serve a purpose to irrigate the crops of local farmers who thus help to maintain the bridges, and also ascribe value to the presence of slow lorises. Other endemic mammal species also used the bridges. We advocate the use and monitoring of artificial canopy bridges as an important supplement for habitat connectivity in conservation interventions. Research Highlights: We integrated artificial canopy bridges into the home range of Javan slow lorises allowing them to save energy and access new areas.Bridges made of water pipes supplied irrigation to farmers' crops providing additional benefits for local communities. [ABSTRACT FROM AUTHOR]

Globally, human activities impact from one-third to one-half of the earth’s land surface; a major component of development involves the construction of roads. In the US and Europe, road networks fragment normal animal movement patterns, reduce landscape permeability, and increase wildlife-vehicle collisions, often with serious wildlife population and human health consequences. Critically, the placement of wildlife crossing structures to restore landscape connectivity and reduce the number of wildlife-vehicle collisions has been a hit-or-miss proposition with little ecological underpinning, however recent important developments in allometric scaling laws can be used to guide their placement. In this paper, we used cluster analysis to develop domains of scale for mammalian species groups having similar vagility and developed metrics that reflect realistic species movement dynamics. We identified six home range area domains; three quarters of 102 species clustered in the three smallest domains. We used HR0.5 to represent a daily movement metric; when individual species movements were plotted against road mile markers, 71.2% of 72 species found in North America were included at distances of less-than-or-equals, slant1 mi. The placement of wildlife crossings based on the HR0.5 metric, along with appropriate auxiliary mitigation, will re-establish landscape permeability by facilitating wildlife movement across the roaded landscape and significantly improve road safety by reducing wildlife vehicle collisions.

Many agencies are contemplating building wildlife crossings to reduce wildlife mortality, to improve habitat connectivity, and to reduce vehicle collisions. For this to occur without problems and interagency disagreements, relationships between agencies and key individuals must be well-developed. Once relationships are in-place highway improvements and wildlife habitat objectives are more easily integrated. The second step in coordinating wildlife issues with transportation is development of interagency statewide, regional or highway specific wildlife habitat linkage plans. These determine a number of critical factors necessary to locate wildlife crossings, prioritize opportunities and focus funding and personnel. To be effective, transportation, wildlife management and land management agencies must be involved in these plans. The third step involves choosing the appropriate location, structure type and structure size for target species. This process must take into consideration more than biological criteria and includes cost factors and construction feasibility issues born by highway agencies. Last, monitoring will help improve future wildlife crossing efforts and help all agencies and the public gain confidence in their effectiveness.

Abstract In the current context of biodiversity loss through habitat fragmentation, the effectiveness of wildlife crossings, installed at great expense as compensatory measures, is of vital importance for ecological and socio‐economic actors. The evaluation of these structures is directly impacted by the efficiency of monitoring tools (camera traps…), which are used to assess the effectiveness of these crossings by observing the animals that use them. The aim of this study was to quantify the efficiency of camera traps in a wildlife crossing evaluation. Six permanent recording video systems sharing the same field of view as six Reconyx HC600 camera traps installed in three wildlife underpasses were used to assess the exact proportion of missed events (event being the presence of an animal within the field of view), and the error rate concerning underpass crossing behavior (defined as either Entry or Refusal). A sequence of photographs was triggered by either animals (true trigger) or artefacts (false trigger). We quantified the number of false triggers that had actually been caused by animals that were not visible on the images (“false” false triggers). Camera traps failed to record 43.6% of small mammal events (voles, mice, shrews, etc.) and 17% of medium‐sized mammal events. The type of crossing behavior (Entry or Refusal) was incorrectly assessed in 40.1% of events, with a higher error rate for entries than for refusals. Among the 3.8% of false triggers, 85% of them were “false” false triggers. This study indicates a global underestimation of the effectiveness of wildlife crossings for small mammals. Means to improve the efficiency are discussed.

Highlights • We propose the Road Permeability Index (RPI) based on expert knowledge. • RPI measures potential restrictions to wildlife movement across roads. • The index varies from −1 to 1, indicating low to high chance of road crossing. • A case study compared the influences of road and landscape attributes on five taxa. • The RPI can assist on rapid assessments of road impacts on wildlife. Abstract Roads impede ecological flows through landscapes, mainly by acting as barriers to animal movement, reducing habitat connectivity and increasing animal mortality. Road permeability is not homogeneous, and animals perceive traffic and road structures differently. There is a lack of information about how species behave when they face a road. Expert knowledge is an alternative source of information when empirical data are not available. We propose the Road Permeability Index (RPI) as a formal method to incorporate expert knowledge into quantitative assessments of road permeability. We used a multi-taxon, expert-based approach that combines landscape structure and road infrastructure effects on fauna throughout landscapes. All codes are in R language, which are freely available at a GitHub repository. As a study case, we applied the RPI to 28 sampling sites along two highways in the north of São Paulo Metropolitan Region-Brazil. We used expert knowledge information on five taxa: primates, bats, medium- and large-sized terrestrial mammals, birds, and amphibians. We also propose a method to rank taxa according to their relative contribution to RPI , which enables prioritization in environmental impact assessments related to roads. For our study case, landscape and road attributes were both important for predicting road permeability, though landscape variables showed a slightly stronger average influence. RPI constitutes a replicable and easily adaptable alternative to evaluate road permeability, particularly in the absence of empirical data. RPI outcomes can inform road impact mitigation strategies and location. [ABSTRACT FROM AUTHOR]

Wildlife crossings are designed to mitigate barrier effects of transportation infrastructure on wildlife movement. Most efforts in evaluating crossing efficiency focus on counting animal use. However, crossings placed at suboptimal locations may alter animals’ natural movement pattern and decrease population fitness, which cannot be reflected solely by counts of animal use. The long-distance migration of Tibetan antelope (Pantholops hodgsonii) is directly affected by the Qinghai-Tibet Railway (QTR). Using the Wubei wildlife underpass along the QTR, we evaluated how underpass placement affects migration routes and decreases movement efficiency. We calculated the net-squared displacement of each animal to identify migration segments (wintering, calving, and migrating) based on Argos tracking data. We used two corridor modeling methods to identify optimal routes that theoretically require less energy to travel between seasonal habitats. We calculated the distance from actual migration routes recorded by Argos to the modelled optimal routes. We found that antelopes stray farther away from the optimal routes as they approach Wubei, indicating that animals have to deviate from their optimal migration pathway to access the railway underpass. On average, antelopes prolong their migration distance by 86.19 km (SEM = 17.29 km) in order to access the underpass. Our study suggests crossing location can affect animal migrations even if structures facilitate animal crossing. To better conserve long-distance migrations, long-term studies using tracking data which evaluate optimal migration routes are needed. We suggest considering the location and structural characteristics in designing and improving wildlife crossings, which do not only facilitate utilization, but also optimize animal movement processes such as migration. [ABSTRACT FROM AUTHOR]