Road Mitigation Research Articles

Road mitigation structures designed for Texas ocelots: Influence of structural characteristics and environmental factors on non-target wildlife usage.

Roads negatively impact wildlife through habitat fragmentation, loss of habitat connectivity, and wildlife-vehicle collisions, thus road mitigation structures, such as wildlife crossing structures (WCS), wildlife guards (WG), and fencing are commonly used to address this issue all over the world, including in the United States. In South Texas, such structures were built or modified along a State Highway in an effort to address road mortality for the endangered ocelot (Leopardus pardalis) and non-target wildlife species. The goal of this study was to examine temporal changes in wildlife interactions with WCS and WG during and after their construction and modification along a South Texas highway and to determine whether environmental factors influenced use of WCS. Using camera traps deployed to monitor the road mitigation structures, we compared crossing rates, repel rates, and species richness of all species that interacted with the structures, and we examined whether differential wildlife use of WCS and WG was affected by one or more structural dimensions, distance to nearby vegetation, and water presence. Crossings through WCS by wildlife decreased following the completion of construction of mitigation structures; however, repel interactions at WG increased. Overall, crossings decreased at WCS that had higher openness ratios and during periods of precipitation and higher daily temperatures, but distance to vegetation had minimal influence. These factors were shown to influence crossings of each of the five most frequently observed species differently. Lastly, the presence of pooled water at one WCS caused a decrease in crossings when the water level was highest but was not a barrier at lower water levels. By examining influences on wildlife interaction with road mitigation structures, we conclude that a variety of structures, including different WCS configurations, can be beneficial in facilitating movement and restricting entry into the right-of-way for a diversity of wildlife species beyond the target species.

Study of Weathering and Rock Mass Quality using the Geological Strength Index (GSI) method on the Tuntun mine road Banggai Regency Central Sulawesi Province

Abstract The mining road in the Tuntun area of Banggai Regency, Central Sulawesi Province has experienced a landslide. The mining road mitigation engineering is a concern for the sustainability of road use. The study area is composed of peridotite rocks which are included in the Ophiolite (Ku) rock formation, where these rocks undergo a very strong deformation process by showing the fractured rock conditions. The Study of Weathering and Rock Mass Quality Using the Geological Strength Index (GSI) Method on this mine road is the focus of this research. The Geological Strength Index (GSI) is a rock mass classification system developed to assist the inaccurate Rock Mass Rating System (RMR) in determining the quality of rock masses that have very poor conditions or have undergone very strong rock deformation. using the GSI value by using two quantitative parameters, namely the condition of the discontinuity plane and the density of the discontinuity plane. The value of the Geological Strength Index (GSI) at location points 1, 2, 3, 4 and 5 is 32,17,12,2, 33.4 and 23. The rock mass value indicates that the rock mass quality in the study area has poor rock mass quality. to very bad. The results of this investigation become a reference in the method of handling slopes on mining roads.

Invasion by common reed in peri-urban wetlands does not affect insectivorous bat activity, despite a negative effect on prey abundance

Common reed (Phragmites australis), an exotic invasive plant in North America, alters wetlands and thus affects the abundance, development and behavior of many animal species. We evaluated the effect of common reed invasion on 1) the abundance of nocturnal flying insects, and 2) the activity of one of their predators, insectivorous bats. As bats are highly mobile, they can be affected by parameters at a broad scale. Therefore, we considered 3) the effect of habitats and roads around invaded and non-invaded sites on bat activity. We selected 28 paired sites located in wetlands in southwestern Quebec: 14 control sites and 14 common reed-dominated sites. Nocturnal flying insects were collected in some sites, using light traps. The activity of bats was measured in all sites using acoustic detectors. Habitats and high-traffic roads around the sampled sites were characterized over several spatial scales, using ArcGISPro. Our results showed that the number of nocturnal flying insects was reduced by 53% in common reed-dominated sites, but there was no influence on the overall activity of insectivorous bats. Instead, a larger relative area of aquatic and woodland habitats, within a respective radius of 1 and 2 km in the vicinity of our study sites, favoured the overall activity of bats. Moreover, bat activity decreased with an increase in the length of high-traffic roads within a radius of 200 m around the studied wetland sites. Our results suggest that invasive plants despite reducing insect prey may not represent a major threat to insectivorous bats. They also highlight the importance of protecting forests and aquatic habitats, as well as the need to implement road mitigation measures for the conservation of insectivorous bats.

Koalas in space and time: Lessons from 20 years of vehicle‐strike trends and hot spots in South East Queensland

AbstractThe localized clustering of wildlife vehicle‐strike in space and time, often called ‘hot spots’, are commonly used to guide placement of road mitigation installations. We interrogated koala vehicle‐strike data across a 20‐year period between 1997 and 2016, examining trends in identified hot spots. We found that hot spots were not static and decline or emerge in line with the resultant pressures (e.g., from development and associated traffic increases) being exerted on koala populations within the surrounding landscape. We suggest that there is likely to be a relationship between hot spots waning over time and localized extinction of koalas. We feel strategies that solely focus on hot spot intervention will do little to halt and reverse the significant decline in the koala population across South East Queensland because they are almost always retrospective. It is imperative that regional wildlife movement solutions, around and across roads, are appropriately planned and implemented ahead of time (i.e., during initial construction/developmental expansion), if they are to serve as effective mitigation for remaining local koala population across South East Queensland. We caution against recommending mitigation based solely on historical vehicle‐strike data without considering contemporary population, movement and behavioural data.

Temporal and spatial patterns of small vertebrate roadkill in a supercity of eastern China.

An assessment of animal roadkill can help develop road mitigation measures. This article is the first to report data on animal-vehicle collisions (AVCs) in Nanjing, a supercity in eastern China. The research was conducted on a 224.27 km stretch of nine roads in Nanjing. In the period, between November 2020 and October 2021, 26 fortnightly monitoring missions were conducted to gather roadkill carcasses so that we could analyze their temporal and spatial distribution patterns. A total of 259 carcasses were collected, comprising 22 different species, of which 46.42% were mammals and 48.81% were birds. Cats and dogs are the most roadkill mammals, and blackbirds and sparrows are the most roadkill birds. The temporal analysis demonstrated that the peak of vertebrate roadkill occurred from May to July. Spatial analysis showed that the distribution patterns of vertebrate roadkill on different roads varied with a generally non-random distribution and aggregation. By mapping accidents using kernel density analysis, we were able to pinpoint locations that were at high risk for roadkill. Due to the fortnightly survey, our results would underestimate the casualties, even if, our study suggests that the problem of car accidents due to animals should be a cause for concern, and the results of the analysis of temporal and spatial patterns contribute to the establishment of mitigation measures.

Elevated road segment (ERS) passage design may provide enhanced connectivity for amphibians, reptiles, and small mammals

IntroductionDesigns for safe and effective road crossing structures for small animals are typically under-road microtunnels and culverts which have varying levels of effectiveness reported in the scientific literature. Many species, particularly migratory amphibians, may have limited ability to find and use passages if they are too far apart, resulting in substantial barrier effects.MethodsWe designed a novel open elevated passage (elevated road segment: ERS), similar to a low terrestrial bridge, that could theoretically be built to any length based upon species needs and movement characteristics. A 30 m length prototype ERS was installed along a forest road with a history of amphibian road mortality in Sierra National Forest, Fresno County, CA, USA. From 2018 to 2021, we monitored small animal activity under the ERS in relation to surrounding roadside and forest habitats using active infrared cameras.ResultsWe documented a total of 8,815 unique use events, using species specific independence criteria, across 22 species of amphibians (3), reptiles (4), and small mammals (15). Poisson regression modeling of taxonomic group activity under the ERS, roadside and forest, showed that amphibian activity was highest in the forest habitat, no differences were observed for reptiles, and small mammal activity was highest under the ERS. However, mean activity estimates under the ERS were equal to or greater than the open roadside habitat for all 22 species, suggesting that adding cover objects, such as downed logs and vegetation may further enhance passage use.DiscussionOverall, results showed that the design of the ERS crossing has potential to provide high connectivity for a wide range of amphibian, reptile, and small mammal species while reducing road mortality. ERS systems can also be used in areas with challenging terrain and other hydrological and environmental constraints. Incorporating current road ecology science, we provide supplemental ERS concept designs for secondary roads, primary roads and highways to help increase the options available for road mitigation planning for small animals.

Rapid behavioral responses of endangered tigers to major roads during COVID-19 lockdown.

Roads pose a major, and growing, challenge for the conservation of endangered species. However, very little is known about how endangered species behaviorally respond to roads and what that means for road mitigation strategies. We used the nation-wide lockdown in Nepal during the COVID-19 pandemic as a natural experiment to investigate how dramatic reductions in traffic volume along the national highway affected movements of two GPS-collared tigers (Panthera tigris)-a globally endangered species. This work is the first systematic research on tigers in Nepal using radiotelemetry or GPS tracking data since the 1980s. We found that the highway more strongly constrained the space use and habitat selection of the male in Parsa National Park than the female in Bardia National Park. Over the entire study period, the female on average crossed 10 times more often per week than the male, and when he was near the highway, he was over 11 times more probable to not cross it than to cross during the day. However, we also found that the cessation of traffic during the pandemic lockdown relaxed tiger avoidance of roads and made the highway more permeable for both animals. They were 2-3 times more probable to cross the highway during the lockdown than before the lockdown. In the month following the lockdown, the space use area of the male tiger tripled in size (160-550km2), whereas the female's shrunk to half its previous size (33-15km2). These divergent patterns likely reflect differences between the two parks in their highway traffic volumes and regulations as well as ecological conditions. Our results provide clear evidence that vehicle traffic on major roads impede tiger movements, but also that tigers can respond quickly to reductions in human pressures. We conclude by identifying various actions to mitigate road impacts on tigers and other endangered species.

Pollutant accumulation in road mitigation tunnels for amphibians: A multisite comparison on an ignored but important issue

Underpasses or road tunnels are increasingly installed to reconnect habitats and ensure safe wildlife passage, thus preventing habitat fragmentation caused by roads and mortality from collisions with vehicles. In the UK, such underpasses are regularly implemented for amphibians and especially the protected great crested newt, Triturus cristatus. However, roads are also a key source of environmental pollutants including trace metals, road salt, petroleum and diesel hydrocarbons and these might impact road mitigation structures where amphibians are funnelled to, yet the extent and implications of such pollutants are almost never quantified in relation to this aspect, despite the recognised sensitivity of amphibians to chemical pollutants. Sediments were analysed from four amphibian road mitigation tunnel sites across the UK and compared to natural soil formations at local reference sites to determine whether contaminants were indeed accumulating within the tunnels. Three potential contaminants (copper, lead, and total petroleum hydrocarbons) were found in greater concentrations in the underpass sediments than respective reference sites at three of four locations, while one (zinc) was found in greater concentrations at all four studied underpasses compared to reference sites. Aggregated sediment pH value was significantly greater in the underpass sediment than the respective reference sites at all four study sites and in several instances the contaminants reached values that exceeded the thresholds of environmental concern. Despite the large geographic area covered and the significant site differences the absolute values of potential pollutants in tunnels were similar across sites, thus suggesting similar pollution sources and pathways. These results suggest road tunnels installed for ecological mitigation could be a significant pathway for pollutants from road surfaces to amphibians and it is recommended that focussed monitoring and maintenance of the underpasses is enacted given that their short or long-term impacts on amphibians are currently unknown. Potential management options could include regular jet-washing of the underpasses, or alternatively, pre- or post-implementation modifications of mitigation designs should aim to minimise the pollution pathway from road surfaces.

Prioritizing road mitigation using ecologically based land‐use planning

AbstractWildlife–vehicle collisions (WVCs) are a critical threat to biodiversity and human safety. To implement WVC mitigation measures where most needed, we need to link models predicting the probability of the presence of species, at large spatial scales, with the likelihood of occurring collisions along roads. Here, we propose a framework for the prioritization of road sections for implementing mitigation measures using ecologically based information. Within this framework, we first model the likelihood of WVC occurrence for focal species in road vicinity areas. We then use spatial prioritization tools to select road sections that entail a higher probability of WVC across the focal species using user‐defined criteria for weighting species records. We applied this framework to Mato Grosso do Sul state (Brazil), using systematic information on WVC collected over 3 years along ca. 2000 km of roads. We focused on the WVC involving three large mammals commonly road‐killed therein, which represent a threat to humans when involved in WVC: the lowland tapir Tapirus terrestris, giant anteater Myrmecophaga tridactyla and capybara Hydrochoerus hydrochaeris. We were able to identify road sections (<10% of the road network) that should be prioritized for implementing mitigation actions, which could significantly reduce the number of WVCs. However, the large extent of the road network classified as a priority for mitigation suggests the need to engage the public and private sectors in the early stages of the decision‐making process, in order to reach a consensus on the prioritization. Our framework may improve the environmental licensing process, namely by guiding where mitigation measures should be implemented first.

Where to invest in road mitigation? A comparison of multiscale wildlife data to inform roadway prioritization

Roads and associated traffic have significant impacts on wildlife, from direct mortality caused by vehicle collisions to indirect effects when wildlife avoid roads, restricting access to important resources. Road mitigation measures such as constructing wildlife passages over or under the road with directional fencing have proven effective at reducing wildlife vehicle collisions while also enabling wildlife to safely cross the road. Highway mitigation projects are led by transportation agencies with a primary purpose of improving motorist safety. More recently, through the discipline of road ecology, considerations have included safe wildlife passage through transportation corridors. To prioritize road sections for mitigation, data sources include animal vehicle collision data collected by transportation agencies and connectivity models generated by wildlife professionals. We used a third data source, pronghorn observations collected by citizen scientists, and demonstrated its value to prioritize potential wildlife mitigation sites. Our results clearly demonstrate a misalignment of road mitigation sites using animal-vehicle collision data and those of rarer species of interest.

Landscape connectivity for an endangered carnivore: habitat conservation and road mitigation for ocelots in the US

Landscape connectivity for an endangered carnivore: habitat conservation and road mitigation for ocelots in the US

A before-after-control-impact study of wildlife fencing along a highway in the Canadian Rocky Mountains

Wildlife exclusion fencing has become a standard component of highway mitigation systems designed to reduce collisions with large mammals. Past work on the effectiveness of exclusion fencing has relied heavily on control–impact (i.e., space-for-time substitutions) and before–after study designs. These designs limit inference and may confound the effectiveness of mitigation with co-occurring process that also changes the rate of collisions. We used a replicated (n = 2 sites monitored for over 1000 km years combined) before-after-control-impact study design to assess fencing effectiveness along the Trans-Canada Highway in the Rocky Mountains of Canada. We found that collisions declined for common ungulates species (elk, mule deer, and white-tailed deer) by up to 96% but not for large carnivores. The weak response of carnivores is likely due to the combination of fence intrusions and low sample sizes. We calculated realized fencing effectiveness by applying the same change in collision rates observed at control (unfenced) sites as the expected change for adjacent fenced sections. Compared with the apparent fencing effectiveness (i.e., the difference in WVCs rates before and after fencing was installed), the realized estimates of fencing effectiveness declined by 6% at one site and increased by 10% at another site. When factoring in the cost of ungulate collisions to society, fencing provided a net economic gain within 1 year of construction. Over a 10-year period, fencing would provide a net economic gain of > $500,000 per km in reduced collisions. Our study highlights the benefits of long-term monitoring of road mitigation projects and provides evidence of fencing effectiveness for reducing wildlife–vehicle collisions involving large mammals.

Road mitigation structures reduce the number of reported wildlife‐vehicle collisions in the Bow Valley, Alberta, Canada

AbstractHuman population and economic growth have resulted in roads transecting much of the North American landscape and this has negatively affected wildlife populations by fragmenting habitat, impeding movement between populations and increasing the chance of wildlife‐vehicle collisions. A common conservation tool to counteract these effects is the incorporation of road mitigation structures (RMS, i.e., jumpouts and overpasses/underpasses/fencing) into highway systems. However, gaps remain in our knowledge on RMS efficacy due to a lack of long‐term multispecies studies that can assess temporal and species‐specific variation in use. We investigate the efficacy of the Alberta Environment and Parks and Alberta Transportation RMS on the Trans‐Canada Highway (TCH) in the Bow Valley by analyzing annual reported wildlife‐vehicle collisions over a 23‐year period and wildlife use of the underpasses over a ten‐year period. We found that the incorporation of multiple underpasses and jumpouts, along with fencing, reduced the number of reported wildlife‐vehicle collisions on the TCH. We also found that wildlife use of the RMS exhibited variation with regards to month and location. Overall, our results add to the research supporting RMS effectiveness and suggest that incorporating additional similar infrastructure has the potential to further reduce wildlife‐vehicle collisions on the TCH.

Road Permeability Index as a tool for mitigation planning of road impacts on wildlife in Colombia: a case study using mammals

Mitigation planning for road projects in Colombia has been largely based on actions aimed at reducing wildlife roadkills. Nonetheless, the efficiency of these actions is compromised because of the absence of robust empirical studies supporting their implementation. In this work, I used the Road Permeability Index (RPI) in conjunction with expert knowledge information to estimate the strength of the barrier effect imposed by an under-construction road (Yuma road, Santander department, Colombia) on nine functional groups of medium and large-sized mammals. The influence of 12 landscape variables on the permeability of each functional group was assessed at 30 locations along the road. The RPI was calculated for each functional group, and the whole studied mammal assemblage at each location. The relative influence of each variable on overall permeability was also estimated. I found that functional groups including terrestrial and semiarboreal species present higher contribution values to overall road permeability, indicating that they represent priority targets for mitigation actions. The RPI identified six highly permeable locations for animal movement—where higher roadkill rates are expected—which are key for implementing mitigation strategies aimed at reducing wildlife road mortality. Forest cover had the strongest influence on road permeability, therefore is crucial for landscape conectivity. Overall, the results of this work show that RPI constitutes a reliable and easily adaptable alternative for identifying priority species, or faunal groups, and locations for road mitigation planning.

Road Flooding in Kigali City, Rwanda: Causes, Effects on Road Transportation and Mitigation Measures

Road Flooding in Kigali City, Rwanda: Causes, Effects on Road Transportation and Mitigation Measures

Responses of migratory amphibians to barrier fencing inform the spacing of road underpasses: a case study with California tiger salamanders (Ambystoma californiense) in Stanford, CA, USA

Migratory amphibians are at high risk of negative impacts when roads intersect their upland and breeding habitats. Road mortality can reduce population abundance, survivorship, breeding, recruitment, and probability of long-term persistence. Increasingly, environmental planners recommend installation of under-road tunnels with barrier fencing to reduce mortality and direct amphibians towards the passages. Often, the permeability of these barrier and passage systems to amphibian population movements are unknown. We studied the movements of California tiger salamanders (CTS: Ambystoma californiense) in relation to solid and mesh barrier fencing attached to a 3-tunnel system between upland and breeding habitats in Stanford, California. We deployed active-trigger cameras along the fencing, used pattern recognition software to identify individuals by their unique spot patterns, and calculated individual salamander movement distances, speed, direction changes, and “success” at reaching the tunnel system. We found that migrating adult CTS moved an average of 40 m along barrier fencing before turning back into the habitat or “giving-up”. This short distance, in comparison to long migratory movements, may be explained by the orientation mechanisms salamanders use to reach their breeding sites. The probability CTS found a passage decreased rapidly with increasing distance from the tunnel system, particularly if individuals turned the “wrong” way after encountering the fence. Salamanders changed directions more often and spent more time along mesh fencing. Our results suggest that a maximum of 12.5 m between passages along CTS migration routes should allow approximately 90% of adult salamanders to encounter road crossings. Additionally, use of solid fencing or a visual barrier on mesh fencing may help to lead salamanders to passages most efficiently. These considerations can assist those seeking to design effective road mitigation for CTS and other migratory amphibians.

Contrasting wolf responses to different paved roads and traffic volume levels

In some regions of the world, large carnivores, such as wolves, persist in landscapes with dense networks of paved roads. However, beyond the general impacts of roads on wildlife, we still lack information on carnivore responses to different types of roads and traffic volume levels. Using wolves in NW Spain as a case study, we show how wolves respond differently to paved road classes depending on road size, speed limit and traffic volume. All wolves evaluated (25 GPS collared wolves) crossed paved roads. Overall, during 3,915 sampling days, we recorded 29,859 wolf crossings. Wolf crossings of all paved road classes were recorded at a mean rate of 0.022 crossings/day/km (95% CI 0.016–0.027). Wolves crossed low speed and low traffic volume roads more frequently, and more often during the night, in order to lessen the chances of encountering traffic. We found mortality to be highest on roads with high speed and high traffic volume. How wolves interact with paved roads should be considered in landscape planning strategies in order to guarantee wolf long-term persistence in human-dominated landscapes. In our case, our results support an increasing focus on primary roads (class II) to identify segments of these roads where road mitigation efforts should be prioritised. Our study also highlights the importance of considering paved road classes when studying the impact of roads on wildlife.

Roads reduce amphibian abundance in ponds across a fragmented landscape

Roads threaten animal species through habitat loss, fragmentation and degradation, and direct mortality. It is crucial to understand how species respond to linear infrastructure for effective conservation of animal communities in fragmented landscapes. We assessed relationships between amphibian abundance and roads/ railways and habitat fragmentation. We examined whether the combined effects of habitat loss and roads or railways (accessible habitat) was a better predictor of amphibian abundance than (1) the total amount of habitat surrounding ponds, (2) distance to a highway or railway, or (3) surrounding road cover. Aquatic surveys for amphibian larvae were conducted at 30 freshwater ponds over the breeding season in a mixed peri-urban/ agricultural landscape in Hungary. Landscape variables were quantified within a 1000-m radius surrounding ponds and habitat variables were measured at the local (pond) scale. The larvae of seven amphibian species were detected. There were strong relationships between the abundance of amphibian larvae and the distance to a highway and the proportion of road cover within 1000 m of ponds. Relationships with accessible habitat and total habitat amount were uncertain, while there were no clear relationships with a major railway. Larval abundance increased with pond size, but there were mixed relationships with the presence of fish. Our results suggest that road effects were having a stronger impact on amphibian abundance than the combined effects of roads and habitat amount in the study area. Highways appeared to be negatively impacting amphibian communities within a wide road-effect zone up to 1 km from ponds. However, our results were obtained from a single-season snap-shot study and multi-season surveys are likely required to reduce uncertainty in the model predictions. Our analysis suggests that road mitigation projects for amphibians should create large ponds in areas with no highways and low road density, and with connectivity to surrounding habitats.

Pairing long-term population monitoring and wildlife crossing structure interaction data to evaluate road mitigation effectiveness

Roads negatively affect wildlife populations directly as a source of mortality and indirectly through habitat fragmentation, restricted movement, and altered habitat use. Wildlife crossing structures and roadside fencing are two common road mitigation strategies implemented to reduce wildlife road mortalities and maintain population connectivity. Metrics quantifying use of crossing structures by wildlife are often used to determine their effectiveness, but interpreting these metrics can be challenging when local population processes and individual variation in use are not considered. We used over six years of remote camera data, including two years of post-construction data, from a road improvement project in south Texas to evaluate mitigation efforts in the context of long-term felid abundance. Variation in seasonal felid abundance was tied to precipitation in the preceding 12 months, highlighting the importance of accounting for baseline wildlife abundance when measuring structure efficacy. Crossing structure use by felids was positively correlated with abundance estimates, though frequency and consistency of use varied among individuals. Probability of use was related to roadside fencing, canopy cover, time since crossing construction, and presence of water in the structure. Our results suggest that conventional indices of crossing structure effectiveness, such as crossing rates, are more informative when ongoing population processes are considered. By interpreting structure use in the context of long-term abundance trends and individual variation, managers can compare use across sites to better determine factors that influence crossing structure effectiveness and take steps to site, construct, and maintain structures that enable safe wildlife road crossing and promote connectivity.

Potential Movement Corridors and High Road-Kill Likelihood do not Spatially Coincide for Felids in Brazil: Implications for Road Mitigation.

The negative effects of roads on wildlife populations are a growing concern. Movement corridors and road-kill data are typically used to prioritize road segments for mitigation measures. Some research suggests that locations where animals move across roads following corridors coincide with locations where they are often killed by vehicles. Other research indicates that corridors and road-kill rarely occur in the same locations. We compared movement corridor and road mortality models as means of prioritizing road segments for mitigation for five species of felids in Brazil: tiger cats (Leopardus tigrinus and Leopardus guttulus were analyzed together), ocelot (Leopardus pardalis), jaguarundi (Herpailurus yagouaroundi), and puma (Puma concolor). We used occurrence data for each species and applied circuit theory to identify potential movement corridors crossed by roads. We used road-kill records for each species and applied maximum entropy to determine where mortality was most likely to occur on roads. Our findings suggest that movement corridors and high road mortality are not spatially associated. We suggest that differences in the behavioral state of the individuals in the species occurrence and road-kill data may explain these results. We recommend that the road segments for which the results from the two methods agree (~5300 km for all studied species combined at 95th percentile) should be high-priority candidates for mitigation together with road segments identified by at least one method in areas where felids occur in low population densities or are threatened by isolation effects.