Red deer habitat selection and movements in relation to roads

Roads affect wildlife in many direct and indirect ways. For ungulates, roads may inhibit seasonal migration and may cause an effective loss of habitat due to avoidance. On the other hand, roadsides and associated agricultural lands offer high quality forage that may attract ungulates and increase the frequency of car accidents. Mitigating actions require detailed knowledge on space use in relation to roads. Using data from 67 global positioning system (GPS)-marked red deer in Norway, we quantified 1) scale of avoidance of roads, 2) crossing frequency, and 3) selection of crossing sites. Red deer avoided roads only on a very local scale and only during daytime, with minor influence of variation in road size (traffic burden). Marked red deer crossed roads, on average, 2 times per day. Females crossed more frequently than males and crossings were most frequent during autumn and winter and during night. Deer selected forested crossing sites close to agricultural pastures, reflecting that roads are crossed most often on nightly feeding excursions. Our findings imply that red deer in our study area have adjusted to exploit feeding habitat close to roads at times of low traffic burden. The high frequency of crossings suggests a limited influence on seasonal migration patterns. The frequency at which red deer cross highways suggests that mitigation measures to reduce road mortality may be effective if targeted in the right areas. © 2012 The Wildlife Society.     

Behavior of Moose Relative to a Road Network

Abstract Roads often negatively affect terrestrial wildlife, via habitat loss or fragmentation, noise, and direct mortality. We studied moose (Alces alces) behavior relative to a road network, in an area with a history of moose-vehicle accidents, to determine when moose were crossing roadways or using areas near roads and to investigate if environmental factors were involved in this behavior. We tracked 47 adult moose with Global Positioning System collars in a study area crossed by highways and forest roads. We hypothesized that moose would avoid crossing roads but would make occasional visits to roadsides to feed on sodium-rich vegetation and avoid biting insects. Further, we expected moose avoidance to be greater for highways than forest roads. We recorded 196,710 movement segments but only observed 328 highway and 1,172 forest-road crossings (16 and 10 times lower than expected by chance). Moose usually avoided road proximity up to ≥500 m on each side but 20% of collared moose made visits to areas within 50 m of highways, which might have resulted from moose searching for sodium in vegetation and roadside salt pools. In fact, vegetation along highways had higher sodium concentrations and was browsed in similar proportions to vegetation in adjacent forest, despite moose avoidance of these zones. Moose, however, did not use areas near roads more during periods of biting insect abundance. Our results supported the hypothesis of scale-dependent selection by moose; avoidance of highways at a coarse scale may confer long-term benefits, whereas selection of highway corridors at finer scales may be part of a strategy to overcome short-term limiting factors such as sodium deficiency. We found a positive relationship between home-range size and the proportion of road axes they contained, suggesting that moose either compensated for habitat loss or made specific movements along highways to gather sodium. The presence of sodium along highways likely increases moose-vehicle accident risks. Removal of salt pools or use of a de-icing salt other than sodium chloride should render highway surroundings less attractive to moose.     

Roadkills of vertebrate species on two highways through the Atlantic Forest Biosphere Reserve,southern Brazil

We assessed the magnitude, composition, and spatial and temporal patterns of road mortality of native vertebrates on two highways in southern Brazil from 18 January 2003 to 26 January 2004. The highways cross remnants of the Atlantic Rainforest, a global biodiversity hotspot, and differ in vehicle traffic and surrounding landscape. We compared the road-kill magnitude and composition of birds, mammals, and reptiles between roads and seasons. We used a modified K statistic to depict the spatial patterns of roadkills of these groups and tested the association between vehicle traffic and road mortality through linear regression. We recorded 869 kills of 92 species. The two roads differed regarding the abundance and composition of roadkills. Reptile road mortality was higher in summer than winter, but all other groups did not show significant difference in the magnitude of mortality between seasons. The composition of killed assemblages differed significantly for some of the taxonomic groups among seasons. We found only one positive association between roadkills and vehicle traffic (reptiles on one of the roads), suggesting that vehicle flow does not explain the road-kill temporal variation on these roads. Total vertebrate, bird, and mammal roadkills showed significant spatial aggregations possibly due to variation in vehicle traffic, highway design, and local landscape condition and arrangement. With expected expansion of the road network, mitigation measures for multi-species assemblages should include habitat protection, soil use regulation, road crossing structures, speed reducers, and campaigns to raise people’s awareness about road impacts on wildlife.     

Individual Spatial Responses towards Roads: Implications for Mortality Risk

Background

Understanding the ecological consequences of roads and developing ways to mitigate their negative effects has become an important goal for many conservation biologists. Most mitigation measures are based on road mortality and barrier effects data. However, studying fine-scale individual spatial responses in roaded landscapes may help develop more cohesive road planning strategies for wildlife conservation.

Methodology/Principal Findings

We investigated how individuals respond in their spatial behavior toward a highway and its traffic intensity by radio-tracking two common species particularly vulnerable to road mortality (barn owl Tyto alba and stone marten Martes foina). We addressed the following questions: 1) how highways affected home-range location and size in the immediate vicinity of these structures, 2) which road-related features influenced habitat selection, 3) what was the role of different road-related features on movement properties, and 4) which characteristics were associated with crossing events and road-kills. The main findings were: 1) if there was available habitat, barn owls and stone martens may not avoid highways and may even include highways within their home-ranges; 2) both species avoided using areas near the highway when traffic was high, but tended to move toward the highway when streams were in close proximity and where verges offered suitable habitat; and 3) barn owls tended to cross above-grade highway sections while stone martens tended to avoid crossing at leveled highway sections.

Conclusions

Mortality may be the main road-mediated mechanism that affects barn owl and stone marten populations. Fine-scale movements strongly indicated that a decrease in road mortality risk can be realized by reducing sources of attraction, and by increasing road permeability through measures that promote safe crossings.     

Spatial,road geometric and biotic factors associated with Barn Owl mortality along an interstate highway

Highway programmes typically focus on reducing vehicle collisions with large mammals because of economic or safety reasons, while overlooking the millions of birds that die annually from traffic. We studied wildlife–vehicle collisions along an interstate highway in southern Idaho, USA, with among the highest reported rates of American Barn Owl Tyto furcata road mortality. Carcass data from systematic and ad hoc surveys conducted in 2004–2006 and 2013–2015 were used to explore the extent to which spatial, road geometric and biotic factors explained Barn Owl–vehicle collisions. Barn Owls outnumbered all other identified vertebrate species of roadkill and represented > 25% of individuals and 73.6% of road‐killed birds. At a 1‐km highway segment scale, the number of dead Barn Owls decreased with increasing numbers of human structures, cumulative length of secondary roads near the highway and width of the highway median. The number of dead Barn Owls increased with higher commercial average annual daily traffic (CAADT), small mammal abundance index and grass rather than shrubs in the roadside verge. The small mammal abundance index was also greater in roadsides with grass vs. mixed shrubs, suggesting that Barn Owls may be attracted to grassy portions of the highway with more abundant small mammals for hunting prey. When assessed at a 3‐km highway segment scale, the number of dead Barn Owls again increased, with higher CAADT as well as with greater numbers of dairy farms. At a 5‐km scale, the number of dead Barn Owls increased with a greater percentage of cropland near the highway. Although human conversion of the environment from natural shrub‐steppe to irrigated agriculture in this region of Idaho has probably enhanced habitat for Barns Owls, it simultaneously has increased risk for owl–vehicle collisions where an interstate highway traverses the altered landscape. We review some approaches for highway mitigation and suggest that reducing wildlife–vehicle collisions involving Barn Owls may contribute to the persistence of this species.     

Inter-Individual Variability of Stone Marten Behavioral Responses to a Highway

Efforts to reduce the negative impacts of roads on wildlife may be hindered if individuals within the population vary widely in their responses to roads and mitigation strategies ignore this variability. This knowledge is particularly important for medium-sized carnivores as they are vulnerable to road mortality, while also known to use available road passages (e.g., drainage culverts) for safely crossing highways. Our goal in this study was to assess whether this apparently contradictory pattern of high road-kill numbers associated with a regular use of road passages is attributable to the variation in behavioral responses toward the highway between individuals. We investigated the responses of seven radio-tracked stone martens (Martes foina) to a highway by measuring their utilization distribution, response turning angles and highway crossing patterns. We compared the observed responses to simulated movement parameterized by the observed space use and movement characteristics of each individual, but naïve to the presence of the highway. Our results suggested that martens demonstrate a diversity of responses to the highway, including attraction, indifference, or avoidance. Martens also varied in their highway crossing patterns, with some crossing repeatedly at the same location (often coincident with highway passages). We suspect that the response variability derives from the individual''s familiarity of the landscape, including their awareness of highway passage locations. Because of these variable yet potentially attributable responses, we support the use of exclusionary fencing to guide transient (e.g., dispersers) individuals to existing passages to reduce the road-kill risk.     

Radio‐tracking three Sugar Gliders using forested highway median strips at Bongil Bongil National Park,north‐east New South Wales

Major roads and highways disrupt ecological flows and create barriers or filters to the movement of many species of wildlife, including gliding mammals. Mitigating these impacts presents major challenges for road authorities. One approach has been the retention of forest vegetation in median strips to serve as ‘stepping stones’ for gliding mammals to cross road gaps otherwise beyond their glide capacity. A recently upgraded section of the Pacific Highway through tall open forest near Bonville in north‐east New South Wales retained forest within two 10‐ to 45‐m‐wide median strips separating each carriageway and a service road. We investigated whether Sugar Gliders (Petaurus breviceps) used these median strips to cross an 85 to 135 m‐wide road corridor. Three radio‐collared Sugar Gliders (one male and two females) moved between both highway medians and forest on either side of the road corridor during 32 days of radio‐tracking. Although the sample size is small, these results suggest that highway median strips, featuring mature vegetation with a major den tree, can provide ‘stepping stones’ for gliding mammals to cross a highway that would otherwise function as a movement barrier or filter. Longer‐term research with greater numbers of animals at this and other sites is required to determine whether such strips would be commonly used when den trees are absent and whether gliding via median strips may also increase road mortality of the species.     

Road effects on demographic traits of small mammal populations

Recent studies have highlighted the positive effects of road verges on the abundance of small mammals. However, most of these studies occurred in intensively grazed or cultivated areas, where verges were the last remnants of suitable habitats, which could mask the true effects of roads on population traits. We analysed the effects of roads on small mammal populations living in a well-preserved Mediterranean forest. We used the wood mouse (Apodemus sylvaticus) as a model of forest-dwelling small mammals that probably are among the species most affected by road clearings. Our study compared populations in similar habitat areas with and without road influence. We assessed abundance, survival and temporary emigration using extended Pollock’s robust design capture-recapture models. Moreover, we analysed population turnover, sex ratio, age structure and body condition. We found that wood mouse abundance and body condition were lower at the road bisected area, whereas the remaining population traits were similar. This suggests that the reduced habitat availability and quality due to the physical presence of the road and verge vegetation clearing are the main drivers of demographic differences in wood mouse populations between areas. Nevertheless, our results also suggest that in high-quality habitats surrounding national roads, wood mouse populations present similar dynamics to others living in undisturbed areas, despite the decrease in abundance and body condition. Overall, the often-reported increased small mammal abundance in road surroundings should not be generalized independently of habitat quality or to other population traits.     

Can the barrier effect of highways cause genetic subdivision in small mammals?

Roads and highways contribute enormously to habitat fragmentation, because they can inhibit or even block animal movement across them, which may result in the ultimate division of the populations adjacent to the roads into smaller isolated subpopulations. The isolation reduces gene flow and increases risk of extinction due to a decrease in the genetic diversity of the isolated population. The aim of the present study is to determine whether highways can cause genetic subdivision of the bank vole Myodes glareolus (Schreber, 1780) and yellow-necked mouse Apodemus flavicollis (Melchior, 1834). The study was carried out at three sites in the Highway D1 (Prague-Brno) in the Czech Republic, where a previous study demonstrated a barrier effect of the highway avoiding the interchange of individuals of both species. The genetic structure was determined from the analysis of six DNA microsatellites loci in M. glareolus and five in A. flavicollis. We found only weak genetic differences between populations living at opposite sides of the highway in either of the species and a low degree of subdivision, but significant positive correlation between genetic and geographical distance, which suggests isolation by distance in both species.     

The Loss of Efficiency Caused by Agents’ Uncoordinated Routing in Transport Networks

Large-scale daily commuting data were combined with detailed geographical information system (GIS) data to analyze the loss of transport efficiency caused by drivers’ uncoordinated routing in urban road networks. We used Price of Anarchy (POA) to quantify the loss of transport efficiency and found that both volume and distribution of human mobility demand determine the POA. In order to reduce POA, a small number of highways require considerable decreases in traffic, and their neighboring arterial roads need to attract more traffic. The magnitude of the adjustment in traffic flow can be estimated using the fundamental measure traffic flow only, which is widely available and easy to collect. Surprisingly, the most congested roads or the roads with largest traffic flow were not those requiring the most reduction of traffic. This study can offer guidance for the optimal control of urban traffic and facilitate improvements in the efficiency of transport networks.     

Road crossing in bank voles and yellow-necked mice

Roads and highways represent one of the most important anthropogenic impacts on natural areas and contribute to habitat fragmentation, because they are linear features that can inhibit animal movement, thereby causing barrier effects subdividing the populations adjacent to the roads. The paper examines to what extent a narrow (2-lane) and a wide (4-lane) highways represent barriers for two small mammal species: bank volesClethrionomys glareolus Schreber, 1780 and yellow-necked miceApodemus flavicollis Melchior, 1834, and whether displaced rodents are able to return across roads of different widths. The study was performed at four sites in the Czech Republic. The capture-mark-recapture method was used to determine crossing rates. At two sites, the animals captured close to the road were transferred to the other side and released, to compare return movements across the roads with the movements made by the non-transferred animals. We found that the narrow highway did not prevent movement of neither of the species, although voles crossed only after they had been transferred. Wide highways, on the other hand, completely prevened crossing of both species. While the narrow highways acted at individuals level, the wide highways affected the population subvision.     

The genetic effects of roads: A review of empirical evidence

Roads exert various effects of conservation concern. They cause road mortality of wildlife, change the behaviour of animals and lead to habitat fragmentation. Roads also have genetic effects, as they restrict animal movement and increase the functional isolation of populations. We first formulate theoretical expectations on the genetic effects of roads with respect to a decrease in genetic diversity and an increase in genetic differentiation or distance of populations or individuals. We then review the empirical evidence on the genetic effects of roads based on the available literature. We found that roads often, but not always, decrease the genetic diversity of affected populations due to reduced population size and genetic drift. Whether the reduction in genetic diversity influences the long-term fitness of affected populations is, however, not yet clear. Roads, especially fenced highways, also act as barriers to movement, migration and gene flow. Roads therefore often decrease functional connectivity and increase the genetic differentiation of populations or the genetic distance among individuals. Nevertheless, roads and highways rarely act as complete barriers as shown by genetic studies assessing contemporary migration across roads (by using assignment tests). Some studies also showed that road verges act as dispersal corridors for native and exotic plants and animals. Genetic methods are well suited to retrospectively trace such migration pathways. Most roads and highways have only recently been built. Although only few generations might thus have passed since road construction, our literature survey showed that many studies found negative effects of roads on genetic diversity and genetic differentiation in animal species, especially for larger mammals and amphibians. Roads may thus rapidly cause genetic effects. This result stresses the importance of defragmentation measures such as over- and underpasses or wildlife bridges across roads.     

Why are some animal populations unaffected or positively affected by roads?

In reviews on effects of roads on animal population abundance we found that most effects are negative; however, there are also many neutral and positive responses [Fahrig and Rytwinski (Ecol Soc 14:21, 2009; Rytwinski and Fahrig (Biol Conserv 147:87–98, 2012)]. Here we use an individual-based simulation model to: (1) confirm predictions from the existing literature of the combinations of species traits and behavioural responses to roads that lead to negative effects of roads on animal population abundance, and (2) improve prediction of the combinations of species traits and behavioural responses to roads that lead to neutral and positive effects of roads on animal population abundance. Simulations represented a typical situation in which road mitigation is contemplated, i.e. rural landscapes containing a relatively low density (up to 1.86 km/km²) of high-traffic roads, with continuous habitat between the roads. In these landscapes, the simulations predict that populations of species with small territories and movement ranges, and high reproductive rates, i.e. many small mammals and birds, should not be reduced by roads. Contrary to previous suggestions, the results also predict that populations of species that obtain a resource from roads (e.g. vultures) do not increase with increasing road density. In addition, our simulations support the predation release hypothesis for positive road effects on prey (both small- and large-bodied prey), whereby abundance of a prey species increased with increasing road density due to reduced predation by generalist road-affected predators. The simulations also predict an optimal road density for the large-bodied prey species if it avoids roads or traffic emissions. Overall, the simulation results suggest that in rural landscapes containing high-traffic roads, there are many species for which road mitigation may not be necessary; mitigation efforts should be tailored to the species that show negative population responses to roads.     

Moose Movement Rates Along Highways and Crossing Probability Models

ABSTRACT We developed and validated a density-adjusted spatial model to predict moose (Alces alces) highway-crossing probability to see if the model could be used as an index of moose-vehicle collision risk. We installed Global Positioning System telemetry collars on 47 moose in the north of the Laurentides Wildlife Reserve, Québec, for 2–36 months. We recorded only 84 highway crossings in spring (0.29% of 28,967 2-hr steps) and 122 crossings in summer (0.18% of 68,337 2-hr steps), despite a high sampling effort and having captured moose close to highways. Moose movement rates during movement steps crossing a highway were on average 3 times higher than during the steps preceding or following highway crossing. Paths used by moose when crossing a highway were characterized by a high proportion of food stands, low proportion of lakes and rivers, and topography typical of a valley. Highway-crossing sites were located in valleys with brackish pools and forest stands providing coniferous cover but a low proportion of lakes and rivers. We adjusted moose crossing probability for local variation in moose density using aerial survey data and assessed crossing probability along the highways in the entire Laurentides Wildlife Reserve. We tested the model using moose-vehicle accident data from 1990 to 2002. The relationship between the density-adjusted crossing probability and number of accidents was relatively loose at the 1-km scale but improved markedly when using longer highway sections (5–15 km; r > 0.80). Our results demonstrate that roads and their surroundings are perceived as low-quality habitat by moose. We also conclude that road segments installed along secondary valleys could be a highly strategic site to deploy mitigation measures such as fences and that it could be desirable to increase the width of road shoulders to reduce forest cover and to eliminate brackish pools to reduce cervid-vehicle collisions. We suggest using empirical data such as location of vehicle-wildlife collisions to plan mitigation measures at a fine scale.     

Interchange as the main factor determining wildlife–vehicle collision hotspots on the fenced highways: spatial analysis and applications

Despite the fact that all highways in Hungary are built with fencing, there are still 5 % of traffic accidents that involve wildlife. Therefore, this study focused on the incidence of collisions along fenced roads. Wildlife–vehicle collision (WVC) hotspots were mapped, and the spatial frequencies were analysed with Poisson regression. In general, most WVCs and almost all of the roe deer fatalities occurred at highway intersections, or at interchanges. Red fox casualties also occurred at interchanges as well as at passages. Wild boar fatalities were not particularly frequent at interchanges but were recorded near railways that are parallel to highways; otter–vehicle collision hotspots were found near their habitats and migration corridors such as streams. For otter, badger and wild boar, we were able to examine the role of local population density; most WVCs happened in areas of high population density. The badger model predicted that badger kills were more likely where the fence was not buried in the soil. Most WVCs occur at interchanges because wildlife enters the right-of-way (ROW) at fence ends; or it enters at a fence gap and runs along the outside of fence and becomes funnelled onto the ROW at the interchanges. Interruption in the continuity and linearity are important factors in both cases. We concluded that the number of WVCs can be reduced significantly if animals were prevented from entering highway interchanges and proposals for mitigation were made. We also propose a tool to assist in alleviating WVCs, by mapping them in Google Maps and integrating hotspots into a car navigation system.     

利用红外相机技术监测道路对野生动物丰富度的影响——以观音山国家级自然保护区道路为例

2014年7月至2018年10月,利用20台红外相机监测陕西观音山国家级自然保护区一条内部道路对兽类和鸟类活动的影响.监测期间获得照片16168张,共鉴定到13种兽类和14种鸟类,包括4种国家Ⅰ级重点保护野生动物和7种国家Ⅱ级重点保护野生动物.结果 显示,距道路的距离越远,出现的物种种类越多.有2种兽类只活动于距离道路...     

Effects of narrow roads on the movement of carabid beetles (Coleoptera,Carabidae) in Nopporo Forest Park,Hokkaido

Forest-dwelling carabid beetles that have no flight ability were studied using mark-recapture methods in late-June to mid-October 2007. This study was done to determine the effects of narrow roads in Nopporo Forest Park, Hokkaido on carabid beetle movement and habitat use. The investigation was conducted at four sites: one site was an abandoned grassy road with a width of 3.5 m, two sites were gravel roads with widths of 3.5 and 4.5 m, and another site was an asphalt-paved road with a width of 4.5 m. A total of 3,580 individuals from six species of carabid beetles were collected using dry pit-fall traps, and recapture rates ranged from 6.1 to 36.2%. All examined roads acted as barriers against the movement of Leptocarabus arboreus ishikarinus. All roads, except the abandoned grassy road, acted as a barrier against Carabus granulatus yezoensis movement. Forest–roadside verge comparisons demonstrated that some carabid beetles avoid even narrow roadside verges. Harmful effects increase with increasing road width and both paved roads and narrow roads negatively affect the movement of carabid beetles inhabiting the bordering forest. Therefore, forest specialist beetles are influenced by a barrier effect that starts at the forest road verge, and this barrier effect may be exacerbated by vehicular traffic. Therefore, these barrier effects on carabid beetles should be considered when planning and implementing road construction and maintenance in forests.     

Roads as barriers to animal movement in fragmented landscapes

Roads can act as barriers to animal movement through mortality during crossing attempts or behavioral avoidance. This barrier effect has negative demographic and genetic consequences that can ultimately result in local or regional extinction. Here we use radio-telemetry data on three terrestrial vertebrates (eastern massasauga Sistrurus catenatus , eastern box turtle Terrapene carolina and ornate box turtle Terrapene ornata ) to test whether roads acted as barriers to movement. Specifically, we test whether individuals avoided crossing roads by comparing the number of observed crossings with the number of road crossings predicted by randomizations of individual movement paths. All species crossed roads significantly less often than predicted by chance, indicating strong road avoidance. Results of this study showing behavioral avoidance and previous studies on road mortality indicate that roads are strong barriers to these species. High mortality during crossing attempts would select for road avoidance, reducing the number of individuals killed on roads over time but leading to genetically partitioned subpopulations due to a lack of gene flow. In species that are long-lived and late-maturing, negative genetic effects might not be observable over short time-scales, thus placing populations at high risk of extinction because of a failure to detect an incrementally worsening problem. Formulating successful management strategies for many species in decline will require integrating data on road mortality, animal behavior and population genetics in order to understand more clearly the barrier effect of roads.     

Vehicle–wild vertebrate collision mortality on the highways of Tigray,Ethiopia, implications for conservation

In view of the upcoming road network improvement and expansion in Ethiopia, specifically in Tigray, it is also necessary to understand the potential impacts of road accidents with wildlife vertebrate animals. Road mortality detection surveys were conducted from March 2013 to June 2014. We surveyed around 530 km using vehicle with special emphasis given to roads surrounded by wetlands, forests, rocky areas and rivers each month. Additional information was also collected using a standardized questionnaire. A total of twenty species, 143 individuals of amphibians, reptiles, birds and mammals were recorded as road vehicular accidents in the surveyed area. Of all, mammals showed the highest species richness (80 individuals belonging to ten species) followed by birds (49 individuals belonging to eight species). The survey revealed most accidents happened during the early morning and late evening. This might be due to relatively high traffic and continued activity of wild animals at that time, besides the driver's inability to avoid accidents when it is dark. Wildlife underpasses during road construction, location of crossing structures, rules of wildlife conservation, improving driver's awareness are relevant in this context and may be the most important mitigation measures to reduce mortality of wildlife on the roads.     

Road mortality in freshwater turtles: identifying causes of spatial patterns to optimize road planning and mitigation

Road mortality of freshwater turtles can be high enough to imperil populations near roads, thus there is a need to efficiently and accurately locate regions of excessive road-kill along road networks for mitigation. Weekly over 2?years, we drove a 160?km highway circuit in northeastern New York State, USA and recorded the location of all detected road-kill of three freshwater turtle species (Chelydra serpentina, Chrysemys picta, Emydoidea blandingii). We then analyzed the spatial dispersion of road-kill and the road and landscape features associated with road-kill locations. Road-kill was most prevalent at a limited number of short road segments, termed ‘hotspots’. The locations of hotspots, as indicated by kernel density analysis, and the peak spatial extent of hotspots (250?m), as indicated by Ripley’s?K, corresponded to the locations and average lengths of causeways (road segments with wetlands within 100?m on both sides). Hotspots were located at causeways that were greater than 200?m length and characterized by high traffic volumes, close proximity to water, and high forest coverage. We conclude that freshwater turtle road mortality is spatially aggregated at short, severe hotspots, and hotspot locations can be predicted when the locations of wetlands, traffic volumes, and the land-uses bordering roads are known. Hotspot models using these predictors can locate sites along a road network that are the most promising for mitigation to reduce excessive road mortality and maintain connectivity.