Roadkill Research Articles

English

Vehicle collisions with wild animals are acknowledged as a non-negligible source of death of wild birds and often affect their spatial-temporal distribution, abundance and diversity. However, data to ascertain the impact of road kills on wild birds are scarce, especially around the Serengeti Ecosystem in Tanzania. This work aims to investigate the impact of road kills on wild birds and their spatial-temporal distribution, abundance and diversity in the Serengeti ecosystem in Tanzania. Five road transects each with a length of 40 km were established within the main roads of the Serengeti ecosystem. Bird surveys were conducted in the morning and afternoon in both wet and dry seasons (March and August 2015), respectively. The study results indicated that, 1472 birds have been inventoried which belong to 42 families, 62 genera and 98 species. Mean number of individual birds was the highest in wooded grassland and species richness was also the highest in grassland habitats. In addition, more birds were observed during the wet than dry season. Birds’ mean abundance was higher during the morning than afternoon, especially in the grassland. In the ecosystem, 31 individual birds belonging to 19 species that were distributed in five families were found killed along the road networks. In the Seronera-Fort Ikoma transect, more bird species were killed in roads with higher traffic volume during the morning than afternoon compared to other transects in the area. On the contrary, the extent of the road kill was the highest in wooded grassland. This study recommends that increased road kills could be regulated within the ecosystem by placing signposts at the entrance and visitors’ centre in conjunction with educational programs to raise road users' awareness on the impact of road kills for biodiversity conservation in the area.   Key words: Birds’ roadkill, traffic volume, richness, distribution, diversity, habitat type, conservation, Serengeti ecosystem.

Wildlife Warning Reflectors' Potential to Mitigate Wildlife-Vehicle Collisions—A Review on the Evaluation Methods

Wildlife-vehicle collisions (WVC) produce considerable costs in road traffic due to human fatalities as well as ecological and economic losses. Multiple mitigation measures have been developed over the past decades to separate traffic and wildlife, to warn humans, or to prevent wildlife from entering roads. Among these, wildlife warning reflectors (WWR) have been frequently implemented, although their effectiveness remains a subject of discussion due to conflicting study results. Here we present a literature review on the effectiveness of WWR for N = 76 studies, including their methodological differences, such as the type of WWR (model and color), study conditions, and study designs. We used boosted regression trees to analyse WVC-data addressed in the literature to compare WWR effectiveness depending on the study design, study conditions, effective study duration, length of the tested sections, time period of the study, data source, reflector type, and animal species. Our analyses revealed no clear evidence for the effectiveness of WWR in preventing WVC. Instead, our meta-analysis showed that most studies indicating significant effects of WWR on the occurrence of WVC may be biased due to insufficiencies in study design and/or the approach of WVC data acquisition. Our computation of log response ratios (LRRWVC) showed that only studies applying a before-after (BA) design concluded that WWR were effective. Moreover, BRT modelling revealed that only studies of < 12 months effective study duration and < 5 km test site length indicated that WWR might lower WVC. Based on the vulnerability to confounding factors of WWR-study designs applied in the past, this review suggests the standardization of study conditions, including a before-after control-impact (BACI) or a cross-over study design with spatial and temporal control sections, a minimum test site length and a minimum study duration.

Molecular detection of fungi of public health importance in wild animals from Southern Brazil.

Some animals have an important relationship with fungal infections, and searching for pathogens in animal samples may be an opportunity for eco-epidemiological research. Since studies involving wildlife are generally restricted, using samples from road kills is an alternative. The aim of this study was to verify whether pathogenic fungi of public health importance occur in wildlife road kills from Santa Catarina State, Brazil. Organ samples (n=1063) from 297 animals were analysed according to Polymerase Chain Reaction (PCR) using universal primers to detect fungi in general and, subsequently, using primers specific to Paracoccidioides brasiliensis, Histoplasma capsulatum and Cryptococcus spp. There were 102 samples positive for fungal species. Eight samples were positive for P.brasiliensis, three samples were positive for Cryptococcus spp. and one sample had coinfection by these two fungi. No sample was positive for Histoplasma spp. according to the molecular detection. Genetic sequencing allowed the identification of Fungal sp. in 89 samples, Cryptococcus neoformans in two samples and Aspergillus penicillioides in three samples. This study shows the importance of wild animals in the epidemiology of fungal infections and assists in the mapping of pathogen occurrence in a region that was not previously evaluated.

An evaluation of methods used to cull invasive cane toads in tropical Australia

To identify cost-effective ways to control invasive species, we need to evaluate alternative methods. The invasion of tropical Australia by cane toads (Rhinella marina) has killed many native predators, prompting efforts to cull adult toads. We analyzed a dataset on > 17,500 toads killed by government-employed teams from 2005 to 2008, using a range of methods (incidental captures, targeted searches, traps) as well as records of toads found as road kills. The culling occurred in the northwestern part of the Northern Territory, moving west as the toad front expanded into Western Australia. Both season and method affected rates of capture and demographic attributes (sex ratio, proportion of adults) of the culled anurans, with a strong interaction between these factors. Most methods were more effective during and after the seasonal monsoons (when moist conditions facilitated anuran activity), but that seasonal variation was greater for numbers of toads found on the roads than captured in other ways. Juvenile toads and adult female toads constituted higher proportions of total captures in the Early Dry than in other times of year, reflecting seasonal breeding. Traps caught a higher proportion of adult female toads than did other methods, but overall had low capture rates. Rates of range expansion by toads were similar before, during and after the culling effort, suggesting that removing adult toads did not affect the speed of the invasion. Nonetheless, culling adult cane toads may be effective in some situations (“island” populations, extralimital translocations), and results from this program may be valuable for future toad-control efforts.

Mapping risk: Quantifying and predicting the risk of deer-vehicle collisions on major roads in England

Wildlife-vehicle collisions are increasing across both Europe and North America, with considerable implications for animal populations themselves, for human safety and in terms of economic cost. Deer are generally the primary species involved in large mammals-vehicle collisions. Classical mitigation measures have however proven to have a limited efficacy. The development of tools aimed at predicting the real-time risk of hitting deer on a particular stretch of road can improve both human and wildlife safety, particularly if such tools can be adopted on a large scale. We analysed data on deer-vehicle collisions (DVCs) occurring on the major roads in England between 2008–2014, collected on behalf of Highways England agency. Using zero-inflated regression models, we analysed the relationships between DVCs and data on environmental, bioclimatic and traffic-related factors, on different spatial scales and for different seasons. Traffic flow, average precipitation, and a combination of suburban areas and broadleaved forest were generally associated with increased frequency of DVCs. We used the results of these models to draw seasonal risk maps, which could potentially be used to target appropriate physical mitigation or measures aimed at increasing driver awareness.

Wildlife-vehicle collisions in Lanzarote Biosphere Reserve, Canary Islands.

Insular wildlife is more prone to extinction than their mainland relatives. Thus, a basic understanding of non-natural mortality sources is the first step in the development of conservation management plans. The Canary Islands are an important tourist destination due to their unique climate and rich scenery and biodiversity. During the last few decades, there has been significant development of urban areas and busy road networks. However, there have been no studies describing the effects of road mortality on wildlife in this archipelago. We describe the temporal and spatial patterns of wildlife roadkill in Lanzarote (UNESCO Biosphere Reserve), using counts from cars for an entire annual cycle. A total of 666 roadkills were recorded (monthly average of 0.09 birds/km and 0.14 mammals/km) comprising at least 37 species including native birds and introduced mammals. Seasonal abundance, richness and diversity of roadkills showed a high peak during summer months for both mammals and birds. GLMs indicated that accidents (including birds and mammals) have a higher probability of occurrence close to houses and on roads with high speed limits. When analysed separately, mammal kills occurred in sectors with high speed limits, close to houses and in areas surrounded by exotic bushes, while bird roadkills appeared in road sectors with high speed limits, close to houses and low traffic volume. Our findings highlight that roads are a potential threat to native birds in the eastern Canary Islands. Detailed studies on the local population dynamics of highly affected species, such as the Houbara Bustard, Eurasian Stone Curlew, Barn Owl or Southern Shrike, are urgently needed to determine whether these levels of road mortality are sustainable.

The Alapahoochee watershed microgeographic structure and its potential influence on metal concentrations and genetic structure in the Florida cottonmouth, Agkistrodon piscivorus conanti, within the watershed.

This study examines the microgeographic structure of the Alapahoochee watershed, part of the Suwannee River basin, south-central GA, USA, and relates it to variations in liver metal concentrations and genetic structure of the Florida cottonmouth, Agkistrodon piscivorus conanti. One objective was to determine if liver metal concentrations in A. piscivorus differ between Grand Bay and Mud creeks, which form the watershed's upper portion. Grand Bay Creek is relatively pristine, whereas Mud Creek is polluted with various metals. Genetic analyses were used to assess possible migration patterns between the creeks indicating whether the basin possesses a single population or two populations. Collections occurred in 2008 and 2009. Specimens were captured, euthanized, or collected as road kills, and liver metal concentrations were analyzed and DNA extracted. No differences in metal concentrations were detected between the creeks, except for nickel in females. Metal concentrations in A. piscivorus were not significantly different between males and females nor show a relationship to body size. Genetic analyses were limited to three primer sets, which amplified informative loci. Locus, CH4B, was highly divergent between the putative populations and particularly informative. Genetic structure indicates potential population isolation within the two creeks. Results suggest that two distinct A. piscivorus populations were present and those populations did not differ in their liver metal concentrations (exception being nickel), despite the differences in environmental metal concentrations in the areas. These findings provide new insight into metal accumulation and detoxification in these animals.

Wildlife warning reflectors and white canvas reduce deer–vehicle collisions and risky road‐crossing behavior

ABSTRACTCollisions between wildlife and vehicles are detrimental to both wildlife and human safety. A variety of mitigation methods have been deployed with the intent of increasing ungulate awareness of approaching vehicles. Wildlife warning reflectors are one such method. Roadside reflectors are designed to reflect headlights into the right‐of‐way and alert ungulates to approaching vehicles. Studies of the effectiveness of these reflectors have yielded mixed results. We conducted a robust test of reflectors in central Wyoming, USA, during 2013 and 2014, and unexpectedly discovered a potentially more effective method than the reflectors for reducing collisions between vehicles and mule deer (Odocoileus hemionus). In our initial experiment, we manipulated 10 1.6‐km segments of highway by leaving their reflectors exposed or covering them with a white canvas bag with the intention of neutralizing the reflector. The treatment configuration was swapped monthly. We counted deer carcasses under each treatment for 1 year and observed deer road‐crossing behavior using thermal video cameras. Carcass rates were 33% less in the white canvas treatment relative to uncovered reflectors. Deer in the white canvas treatment also stopped before entering the road 20% more often, ran into the road from the right‐of‐way 11% less often, and fled from the road 12% more often than when reflectors were uncovered. In a follow‐up experiment, we found that deer carcass rates were 32% less when reflectors were exposed versus covered with black canvas. We further found that deer road‐crossing behavior was least risky in a white canvas treatment, intermediate in a reflectors treatment, and most risky when reflectors were removed from posts. Taken together, these results indicate that, although reflectors were moderately effective, white canvas was substantially more effective in reducing deer–vehicle collisions. This unexpected finding suggests that new vigilance‐enhancing mitigation methods should be explored as a way to reduce wildlife–vehicle collisions. © 2018 The Wildlife Society.

Road expansion: A challenge to conservation of mammals, with particular emphasis on the endangered Asiatic cheetah in Iran

Anthropogenic activities, including road expansion, are one of the main drivers of biodiversity loss in Iran. Central and northeastern Iran have been among the most vulnerable areas where expanding anthropogenic activities (in particular construction of road networks) have come into conflict with conservation and management of the endangered Asiatic cheetah (Acinonyx jubatus venaticus), along with other large mammals. The present study aimed to determine hotspot locations along an extremely high-risk road for mammals in northeast Iran (Touran Biosphere Reserve [TBR]) and propose mitigation measures for mammals such as the Asiatic cheetah. Using a spatially-explicit algorithm to estimate collision incidences, we adopted the kernel density estimation (KDE) and the distance method with respect to EDGE (evolutionarily distinct and globally endangered) and home range values for all locations. Also, a habitat suitability map was prepared to create habitat patches and applied to corridor modeling for the Asiatic cheetah. We investigated locations of 73 wildlife–vehicle collisions (WVCs) and crossing data from 2005–2016, that included Persian gazelles (Gazella subgutturosa), Asiatic cheetahs, striped hyenas (Hyaena hyaena), golden jackals (Canis auerus), red fox (Vulpes vulpes), European hare (Lepus europaeus), caracal (Caracal caracal), and grey wolves (Canis lupus). Our results showed that, based on the two methods, hotspot locations and the Asiatic cheetah corridor coincided. The corridor between TBR and Miandasht Wildlife Refuge was illustrated. This corridor is about 55 km length and 656 km2 area, which connects two population patches within these protected areas. Asiatic cheetah vehicle collisions mostly occurred where a road crossed this corridor at the border of the TBR. The mitigation strategies proposed in this study for large mammals, particularly the Asiatic cheetah, are as follows: retrofit and installation of culverts in hotspots; installation of fences for crossing carnivores; and, roadside vegetation clearance in critical seasons for the Persian gazelles along the Semnan-Mashhad road.

Testing the Value of Citizen Science for Roadkill Studies: A Case Study from South Africa

Roads impact wildlife through a range of mechanisms from habitat loss and decreased landscape connectivity to direct mortality through wildlife-vehicle collisions (roadkill). These collisions have been rated amongst the highest modern risks to wildlife. With the development of ‘citizen science’ projects, in which members of the public participate in data collection, it is now possible to monitor the impacts of roads over scales far beyond the limit of traditional studies. However, the reliability of data provided by citizen scientists for roadkill studies remains largely untested. This study used a dataset of 2 666 roadkill reports on national and regional roads in South Africa (total length ~170 000 km) over three years. We first compared roadkill data collected from trained road patrols operating on a major highway with data submitted by citizen scientists on the same road section (431 km). We found that despite minor differences, the broad spatial and taxonomic patterns were similar between trained reporters and untrained citizen scientists. We then compared data provided by two groups of citizen scientists across South Africa: 1) those working in the zoology/conservation sector (that we have termed ‘regular observers’, whose reports were considered to be more accurate due to their knowledge and experience), and 2) occasional observers, whose reports required verification by an expert. Again, there were few differences between the type of roadkill report provided by regular and occasional reporters; both types identified the same area (or cluster) where roadkill was reported most frequently. However, occasional observers tended to report charismatic and easily identifiable species more often than road patrols or regular observers. We conclude that citizen scientists can provide reliable data for roadkill studies when it comes to identifying general patterns and high-risk areas. Thus, citizen science has the potential to be a valuable tool for identifying potential roadkill hotspots and at-risk species across large spatial and temporal scales that are otherwise impractical and expensive when using standard data collection methodologies. This tool allows researchers to extract data and focus their efforts on potential areas and species of concern, with the ultimate goal of implementing effective roadkill-reduction measures.

Seasonal Variation in Wildlife Roadkills in Plantations and Tropical Rainforest in the Anamalai Hills, Western Ghats, India

Wildlife–vehicle collisions on the roads lead to mortality of a range of animal taxa both within and around wildlife reserves. Quantifying and understanding impacts of roads on wildlife mortality are essential for identifying vulnerable taxa and suitable mitigation measures. We studied animal mortality on roads in relation to habitat and season in the Anamalai Tiger Reserve and adjoining Valparai plateau in the Western Ghats, India. Habitats were broadly classified as forest, monoculture plantations (tea, coffee, eucalyptus) and mixed. Eleven road transects of 3–12 km length were surveyed between 9 and 12 times each during monsoon (2011) and summer (2012). We recorded 2969 roadkills (mean = 2.01/km) during the 1473.4 km of road surveys carried out. The overall roadkill rate was 21.2 (± 3.87 SE) individual kills/10 km. Amphibians were most frequent in roadkills (overall roadkill rate of 9.3 ± 2.17 SE kills/10 km, n = 1307), followed by invertebrates and unidentified taxa (7.6 ± 1.81 SE kills/10 km, n = 1066). Roadkill rate was 2.4 times higher in monsoon than summer, with amphibians particularly averaging higher kill rate during monsoon. Frequency of roadkills of various animal groups differed between seasons in different habitats. In both the seasons, most roadkills were recorded mainly in tea, forest, and forest–tea habitats. Relative to length of roads through forest, a disproportionately large number of roadkills of herpetofauna and mammals were recorded in forest habitat. Higher vehicular movements, including tourist traffic, road widening, removal of native plants along roads and construction of sidewalls without breaks obstruct animal movements and may be responsible for roadkills. Designing roads to be more permeable for safe animal movement, particularly where roads pass through forest, and sensitizing highways authorities are essential to reduce animal mortality and make roads more wildlife-friendly in this region.

Regional‐based mitigation to reduce wildlife–vehicle collisions

ABSTRACTVehicular collisions with large ungulates pose serious challenges for managing and conserving large ungulates throughout the world. Despite the global frequency, mitigation efforts are mostly limited to localized hotspots and not effective on broad scales. Our goal was to determine whether dynamic, regional attributes could inform broader focus for mitigation efforts. We applied a spatiotemporal dynamic model to examine the regional influences on white‐tailed deer (Odocoileus virginianus)–vehicle collisions (DVCs) throughout the Midwest United States from traffic, abundance of deer, and composition and configuration of the landscape during 2000–2011. The regions included eco‐zones representing landscape dominated by shelter‐forage habitats with ubiquitous and abundant distribution of deer (i.e., forest‐agriculture matrix), landscape dominated by agriculture with sparse refugia (i.e., agriculture), and landscape dominated by forests with seasonal migration for deer (i.e., northern forest). We found little fluctuation in the factors affecting collisions through time but substantial differences among regions. In the forest‐agriculture matrix eco‐zone, fragmentation of the landscape was the most important predictor of collisions. In the agriculture eco‐zone, traffic and abundance of deer best predicted collisions. In the northern forest eco‐zone, the predictors of collisions were variable and likely related to winter severity and deer migration. This research provides new justification for broadening the focus of current mitigation measures to regional extents. In regions dominated by forest and agriculture, new policies that reduce habitat fragmentation should be the primary focus for reducing collisions. Reducing abundance of ungulates will have the most direct effect in regions dominated by agriculture. Finally, a variety of seasonal and local mitigation measures will be most effective in northern forests where large ungulates migrate. © 2018 The Wildlife Society.

The influence of time factors on the dynamics of roe deer collisions with vehicles

Environmentalists and authorities responsible for road safety are trying to reduce the number of wildlife collisions with vehicles (WCV) worldwide. Roe deer are the most common large animal involved in WCV in Europe. This article discusses the distribution of 2010 wildlife-vehicle collisions involving roe deer (WVRD) in Lithuania in 2013 and 2014. The collisions were analyzed in terms of monthly and daily data for each month separately, and the results are compared with the time of sunrise and sunset in Lithuania. By analyzing trends of natural factors that influence the number of collisions we show that the frequency of WVRD is strongly correlated with seasonal and yearly changes in sunrise and sunset. This research shows that these natural factors are extremely important for the dynamics of WVRD. Future analysis of these factors and application of appropriate preventative measures should significantly reduce the risk of collision between vehicles and roe deer.

Spatial ecology of an urban eastern grey kangaroo (Macropus giganteus) population: local decline driven by kangaroo–vehicle collisions

Context As urban landscapes proliferate globally, the need for research into urban wildlife interactions is magnified. The eastern grey kangaroo (Macropus giganteus) is a widespread species commonly involved in wildlife–vehicle collisions in urban areas in Australia. Despite the many urban kangaroo populations and associated conflicts with human activities, few studies have examined how eastern grey kangaroos interact with, and are affected by, the urban matrix. Aims The present study aimed to quantify kangaroo demography, movements, habitat utilisation and exposure to risks during a period of intensive urban development in a rapidly changing suburb located in a region undergoing high urban growth rates. Methods We utilised foot-based census surveys, global positioning system (GPS) collars, direct observations and reports of wildlife mortality between 2014 and 2016. Geographical information systems (GIS) were used to integrate GPS-tracking data with spatial layers, to quantify kangaroo movements and habitat utilisation. Key results The kangaroo population underwent a steep decline and kangaroo–vehicle collisions were the main source of mortality (73%) during the study period. Kangaroos were regularly exposed to the risk of injury, with roads intersecting many parts of their home range. Kangaroos showed positive habitat selection both for lawn and forest habitats and kangaroo movement and presence at the study site were influenced by high-quality forage and cover. Conclusions The present research has highlighted that despite areas of suitable habitat remaining, road-kill was a major contributor to localised kangaroo-population decline. We showed that habitat preferences of eastern grey kangaroos in this urban area were consistent with those in natural landscapes. Implications The present study is the first to implicate kangaroo–vehicle collisions as the major factor in population decline in kangaroos. These findings can be utilised to guide design and placement of kangaroo–vehicle collision mitigation and assist in planning of urban areas, particularly where kangaroo populations are in decline. Local extirpation of urban kangaroo populations would be greatly reduced by incorporating site-specific kangaroo habitat preferences and existing patterns of kangaroo habitat use in infrastructure planning. The study has contributed to our understanding of the effects of roads on urban wildlife in general and highlighted the importance of landscape permeability.

A Proposed Analysis of Deer Use of Jumpout Ramps and Wildlife Use of Culverts along a Highway with Wildlife Exclusion Fencing

Author(s): Jensen, Alex J.; Perrine, John D.; Siepel, Nancy; Robertson, Morgan | Abstract: 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.

FOLLOWING THE “WHY? WHAT? AND HOW?” SCHEMA TO IMPROVE ROAD-KILL EVALUATION IN ENVIRONMENTAL IMPACT ASSESSMENTS OF SOUTHERN BRAZIL

Environmental licensing is one of the most important tools of environmental policies in any country, as it allows to adopt preventive and mitigation measures on predicted or observed environmental impacts. However, Environmental Impact Assessments are recurrently criticized due to their low quality and effectiveness to support decisions for project viability or mitigation planning. One way to counteract those limitations is by strengthening terms of reference. Here we present the results of a collaborative initiative carried out in southernmost state of Brazil to improve terms of reference for assessmentsof vertebrate road mortality in a context of road widening. This initiative integrated contributions from stakeholders involved in road planning, construction, operation and road environmental assessments and licensing through a series of workshops undertaken during two years. Using the Why, What and How schema, we first briefly present the reasons to evaluate wildlifevehicle collisions in environmental assessments, and then we comment some limitations of current legal regulations and environmental impact assessments in Brazil and identify the improvements needed. We describe the approach and principles used to develop a sampling protocol for what and how to sample and how to analyze vertebrate road mortality data in Brazilian roads. Finally, we present the result of this effort, the guidelines itself. Although focused on a single road impact (road-kill), we expect that our approach could be replicated to produce guidelines to improve assessments of other road impacts and even other types of infrastructures or activities for which environmental licensing is a pre-requisite.

Performance of Arch-Style Road Crossing Structures from Relative Movement Rates of Large Mammals

In recent decades, an increasing number of highway construction and reconstruction projects have included mitigation measures aimed at reducing wildlife-vehicle collisions and maintaining habitat connectivity for wildlife. The most effective and robust measures include wildlife fences combined with wildlife underpasses and overpasses. The 39 wildlife crossing structures included along a 90 km stretch of US Highway 93 on the Flathead Indian Reservation in western Montana represent one of the most extensive of such projects. We measured movements of large mammal species at 15 elliptical arch-style wildlife underpasses and adjacent habitat between April and November 2015. We investigated if the movements of large mammals through the underpasses were similar to large mammal movements in the adjacent habitat. Across all structures, large mammals (all species combined) were more likely to move through the structures than pass at a random location in the surrounding habitat. At the species level, white-tailed deer (Odocoileus virginianus) and mule deer (O. hemionus) used the underpasses significantly more than could be expected based on their movement through the surrounding habitat. However, carnivorous species such as bear (Ursus americanus) and coyote (Canis latrans) moved through the underpasses in similar numbers compared to the surrounding habitat.

Modelling potential wildlife-vehicle collisions (WVC) locations using environmental factors and human population density: A case-study from 3 state highways in Central California

Roads can exert direct and indirect impacts on ecosystems and organisms. In particular, wildlife-vehicle collisions (WVC) may be a considerable threat for populations of certain wildlife species. Despite such threat, there is still incomplete understanding of the factors responsible for high road mortality. Only a few empirical studies have tested the idea that spatial variation of roadkill is affected by environmental characteristics and socio-demographic factors. This study examines the relationships between WVC involving different taxonomic groups (i.e. ungulate, avian, medium mammal, small mammal) and physical and human population characteristics of landscapes by adapting the ecological model, Maxent, to distribution modelling of carcasses resulting from WVC. We used observations from the California Roadkill Observation System of four taxonomic groups recorded along highways in northern California. Our results indicated that current carcass-observation locations were explained primarily by total forest area (cells) within 500m buffer and road density within a 500m neighborhood. Our results found that current carcass-observation locations are modelled well using environmental variables and human population density together. Moreover, a comparison of projected potential roadkill locations based on environmental factors and human population density among different taxonomic groups revealed substantially different distributions. These results indicate potential areas where wildlife populations are at increased risk of coming into contact with traffic and the potential utility of this methodology for modelling current and future distributions of wildlife across landscapes using the Maxent approach.

Reducing the threat of wildlife-vehicle collisions during peak tourism periods using a Roadside Animal Detection System

Roadside Animal Detection Systems (RADS) aim to reduce the frequency of wildlife-vehicle collisions. Unlike fencing and wildlife passages, RADS do not attempt to keep animals off the road; rather, they attempt to modify driver behavior by detecting animals near the road and warning drivers with flashing signs. A RADS was installed in Big Cypress National Park (Florida, USA) in 2012 in response to an increased number of Florida panther mortalities. To assess driver response, we measured the speed of individual cars on the road when the RADS was active (flashing) and inactive (not flashing) during the tourist season (November–March) and the off-season (April–October), which vary dramatically in traffic volume. We also used track beds and camera traps to assess whether roadside activity of large mammal species varied between seasons. In the tourist season, the activation of the RADS caused a significant reduction in vehicle speed. However, this effect was not observed in the off-season. Track and camera data showed that the tourist season coincided with peak periods of activity for several large mammals of conservation interest. Drivers in the tourist season generally drove faster than those in the off-season, so a reduction in speed in response to the RADS is more beneficial in the tourist season. Because traffic volume and roadside activity of several species of conservation interest both peak during the tourist season, our study indicates that the RADS has the potential to reduce the number of accidents during this period of heightened risk.

An evaluation of odor repellent effectiveness in prevention of wildlife-vehicle collisions

Wildlife-vehicle collisions (WVC) amount to 11% of all registered traffic crashes in the Czech Republic causing, apart from numerous deaths and serious injuries to animals, property damage and injuries to car passengers. Odor repellents have the potential to lower the overall number of WVC and allow animals to cross roads at the same time.We tested the effectiveness of odor repellent preparation in prevention of WVC. 18 places were selected on the Czech road network where WVC were concentrated on the basis of traffic crash data. Control sections on the same road segments were also delimited in order to keep the traffic intensities constant.We applied a Before-After-Control-Impact (BACI) study design to control not only the effect of the measures but also the expected natural variations in wildlife populations over time. Data were compared before and after odor repellent installations. Wildlife carcass gathering was carried out during the spring and autumn. We also used the police crash database to supplement carcass data when no field works were carried out. 201 killed mammals (roe deer and wild boars) were identified in total over 47 months.We applied a Bayesian approach as only a limited numbers of WVC were available. A WVC decrease between 26 – 43% can be expected on the treated road sections. These numbers are, however, up to three-times lower than those claimed by producers of odor preparations.