Road-kills were recorded at random throughout New Zealand, on 96359 km of roads, avoiding towns and busy motorways, from 1963-2018. Traffic increase from 1.04 m to 4.33 million vehicles during the ...study had little effect on mortality, even at the greater traffic density in the North Island. Seasonal changes measured on 8435 km (151 trips) between Lower Hutt and Otaki from 1985-2015 showed lowest mortality in winter. Major differences in species identification between two independent observers on the same route, from 2009-2014, resulted from one being red/green colourblind. Possum (Trichosurus vulpecula) numbers dipped briefly in the 1970s, peaked in the 1990s, and have declined since then where there has been widespread poisoning to protect trees, birds, and limit bovine TB. Rabbits (Oryctolagus cuniculus) increased steadily after control was lifted in the 1980s and now dominate the road-kills; the effect of RHD, introduced in 1997, does not register, probably because it causes short-term local oscillations. Hedgehog (Erinaceus europaeus) numbers show no clear trend and, unlike the other species, North and South Island patterns differ; the lower numbers in the South may reflect the cooler climate. Brown hares (Lepus europaeus) remain relatively stable, with a doubling in numbers since the 1980s in parallel with rabbits. The predators, cats (Felis catus) and mustelids (Mustela furo, M.erminea, M. nivalis), followed their prey increase until the 1990s when extensive predator control began; they then declined, although rabbit and rat (Rattus rattus, R. norvegicus) numbers continued to rise. In the 1950-60s, far more live mammals were being seen on and from roads, and adaptations to traffic have evolved. These historical records may be useful to assess future changes in road-kill following the adoption of silent electric cars, driverless vehicles, and public transport.
An increasing number of mammalian species worldwide have adapted to urban environments following the alteration and fragmentation of natural habitats. In recent years, the masked palm civet (Paguma ...larvata) has increased in several highly populated cities in Taiwan. Twelve‐years (2010–2021) of civet records in Taichung (the largest city in central Taiwan) from the rescue center of Taichung Wildlife Conservation Group report the population of civets has grown steadily since 2017, with the number of records in 2020 (n = 58) and 2021 (n = 55) approximately 5 times of that in 2010–2014 (mean ± SD = 5.0 ± 2.6). Our objective was to use the records from the rescue center to evaluate the potential sexual dimorphism of urban civets, explore temporal variation of civet activity and age structure, identify major threats to civets inhabiting urban areas, and investigate the environmental characteristics surrounding civet nesting sites in urban environments. The civet breeding season lasts from spring to autumn, with primary mating season in spring. The main cause of mortality in adults was dog attack followed by car accident, while the main rescue reason for young civets was because they were considered orphans following human interferences. Many civets in urban areas inhabit locations where >90% of the land cover is covered by buildings and man‐made structures, and even nest inside buildings. Our results demonstrated the need for new civet conservation and management policies to minimize dog attacks on civets to enhance co‐existence between wildlife and humans.
For individuals residing in the bustling urban centers of Asia, where population density is notably high, interactions with wildlife may seem like a distant concept. However, this paradigm is shifting. Within the past decade, masked palm civets have gradually penetrated these densely populated metropolitan areas. The most significant threat to these animals arises from fatal attacks by feral dogs, a source of conflict that requires comprehensive canine population management strategies to mitigate.
Aim
Roads impact wildlife in different ways, among which road mortality has been the most studied. Budgets in conservation biology are usually small, and macroecological approaches have been employed ...in recent years as the first steps towards guiding management. Carnivores are particularly vulnerable to mortality on roads due to their elevated ecological needs (low population density, often low fecundity and relatively large home ranges). Our aim was to develop a ranking methodology to prioritize specific areas for road‐kill mitigation.
Location
Continental Italy.
Methods
We studied 271 occurrences of live polecats (Mustela putorius) and 212 polecat road‐kill sites. We used the former to generate a species distribution model and the latter to identify the variables that determined the road‐kill risk. Habitat suitability was derived from a spatial distribution model that combined the polecat occurrence data with a set of environmental variables. Prey availability was derived from the combination of suitability maps of 26 prey species. We used generalized linear modelling to identify the set of variables that best explained the occurrence of road‐kills. The variables included in the best performing model were combined to produce the road risk map and to identify the areas with the highest densities of road sections with highest risk.
Results
Road‐kills were positively associated with the road sections with higher broad‐leaved forest coverage. The number of casualties was found to be higher than expected on the national and provincial roads and lower than expected on the local roads.
Main conclusions
This approach allowed us to identify the 10 × 10 km cells where mitigation actions to prevent road‐kills should be prioritized. As mitigation actions (wildlife passage construction, fencing) are expensive, measures should be prioritized on the specific high‐risk road sections inside these selected cells, avoiding generalized mitigation plans.
Summary
The ability to identify regions of high functional connectivity for multiple wildlife species is of conservation interest with respect to habitat management and corridor planning. We present ...a method that does not require independent, field‐collected data, is insensitive to the placement of source and destination sites (nodes) for modeling connectivity, and does not require the selection of a focal species.
In the first step of our approach, we created a cost surface that represented permeability of the landscape to movement for a suite of species. We randomly selected nodes around the perimeter of the buffered study area and used circuit theory to connect pairs of nodes. When the buffer was removed, the resulting current density map represented, for each grid cell, the probability of use by moving animals.
We found that using nodes that were randomly located around the perimeter of the buffered study area was less biased by node placement than randomly selecting nodes within the study area. We also found that a buffer of ≥ 20% of the study area width was sufficient to remove the effects of node placement on current density. We tested our method by creating a map of connectivity in the Algonquin to Adirondack region in eastern North America, and we validated the map with independently collected data. We found that amphibians and reptiles were more likely to cross roads in areas of high current density, and fishers (Pekania Martes pennanti) used areas with high current density within their home ranges.
Our approach provides an efficient and cost effective method of predicting areas with relatively high landscape connectivity for multiple species..
Understanding road-kill patterns is the first step to assess the potential effects of road mortality on wildlife populations, as well as to define the need for mitigation and support its planning. ...Reptiles are one of the vertebrate groups most affected by roads through vehicle collisions, both because they are intentionally killed by drivers, and due to their biological needs, such as thermoregulation, which make them more prone to collisions. We conducted monthly road surveys (33months), searching for carcasses of freshwater turtles, lizards, and snakes on a 277-km stretch of BR-101 road in Southernmost Brazil to estimate road-kill composition and magnitude and to describe the main periods and locations of road-kills. We modeled the distribution of road-kills in space according to land cover classes and local traffic volume. Considering the detection capacity of our method and carcass persistence probability, we estimated that 15,377 reptiles are road-killed per year (55reptiles/km/year). Road-kills, especially lizards and snakes, were concentrated during summer, probably due to their higher activity in this period. Road-kill hotspots were coincident among freshwater turtles, lizards, and snakes. Road-kill distribution was negatively related to pine plantations, and positively related to rice plantations and traffic volume. A cost-benefit analysis highlighted that if mitigation measures were installed at road-kill hotspots, which correspond to 21% of the road, they could have avoided up to 45% of recorded reptile fatalities, assuming a 100% mitigation effectiveness. Given the congruent patterns found for all three taxa, the same mitigation measures could be used to minimize the impacts of collision on local herpetofauna.
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•Estimate of 15,377 freshwater turtles, lizards, and snakes road-killed per year•Road-kill hot moments in summer, especially in December for lizards and snakes•Road-kill hotspots highly coincident among freshwater turtles, lizards, and snakes•Positive effects of traffic and rice plantation, and negative of pine plantation•Hotspots (21% of the road extent) included 45% of reptile fatalities.
•We built a stochastic model of road kill with realistic animal and vehicle movements.•Speed and recursion of animals increase collisions more than traffic speed or volume.•Collision risks increase ...positively with traffic but plateaued to an asymptotic value.•Wildlife managers should focus on animal movement for efficient road kill mitigation.
Road networks have major ecological impacts on living organisms consequent to habitat loss and fragmentation, chemical and acoustic pollution, and direct mortality when wildlife-vehicle collisions are involved (WVC). The many past empirical studies revealed major variables accounting for WVC incidence (e.g., population density). Similarly, spatial locations of WVC hot-spots are associated to landscape features at large spatial scales, and to road characteristics at small spatial scales. Yet, we currently lack a comprehensive theoretical framework for WVC. Animal movement in relation to habitats is likely an essential driver of encounters with roads, but this remains largely ignored in most studies. Movement ecology now provides the necessary tools to investigate the impact of animal movement on WVC. We built a general individual-based model incorporating recent knowledge in movement ecology (movement typology: roaming, migratory route crossing a road, active attraction and active repulsion of roads) to estimate WVC risks. We explored the relative effects of animal and vehicle movement parameters (speed, abundance, road sinuosity and animal movement pattern) on collision probability. We show that animal behavior toward roads has major impacts on the number and risks of WVC, but also modulate the effects of other factors (animal speed, species local abundance, road traffic volume) on WVC. Sensitivity analyses show that the movement and behavior of the animal has more influence on WVC risks than any of the characteristics of roads and vehicles we tested. Our results suggest that empirical studies of WVC should incorporate knowledge about the behavioral habits of the focal species in relation to roads.
Collisions with vehicles represent the main conflict between infrastructures and wildlife, causing damages to both humans and animals. As to the latter, road mortality is a growing phenomenon and the ...largest single cause of death for many vertebrates. When focusing on endangered species, the Eurasian otter (Lutra lutra) is among the most vulnerable to road-kills, which represent the predominant cause of deaths recorded in Europe. We propose a large scale spatially-explicit assessment of road-kill risk for the Eurasian otter in Italy as a tool to identify road stretches at high collision risk, thus optimizing the location of mitigation measures. The modelling approach was produced for South Central Italy, hosting the only remnant viable population of otters in Italy. We used a maximum entropy approach including 56 road collision events recorded between 2004 and 2016 through a citizen science initiative, along with seven environmental predictors measured on 1 km grid cells. Four predictors were selected to describe roads characteristics, i.e. density of highways, and of state, regional and local roads. The remaining three variables referred to the quality of otter habitat in the surrounding of the collision sites, i.e. elevation, density of freshwater bodies, and a measure of landscape heterogeneity calculated on land-cover categories. The model achieved a good predictive accuracy (AUC > 0.8; Boyce index > 0.8). The collision probability was mostly affected by elevation, density of state roads, and density of freshwater bodies. Specifically, collision risk was higher in areas at low elevation and medium density of state roads located near rivers and wetlands. In addition, model predictions evidenced that implementing mitigation measures along 10% of road network in the study area could have potentially hampered ca. 50% of otter casualties recorded during the study period.
•Road-kill risk for otters is highest at low elevation.•Road-kill risk was directly related with water presence and state roads density.•The distribution modelling approach proved accurate in predicting road-kill risk.•Mitigation measures on 10% of the roads could have hampered 50% of the recorded kills.
Sandy beaches are not roads, but they have been used as such worldwide, threatening endemic fauna such as ghost crabs (Crustacea: Ocypodidae). The objective of the present study was to identify the ...spatial factors influencing the incidence of ghost crabs (Ocypode quadrata) killed by vehicles. This study included a systematic study of carcasses with clear signals of crushing by cars on beaches with distinct urbanization levels and on dirt roads crossing low-urbanized beach stretches. Predictive variables (e.g., tyre tracks on the sand, proxies of urbanization, distance from coastal lagoons and beach width) were obtained for the kill points and random points. Generalized linear models with binomial distributions showed that the number of tyre tracks nearby (positive correlation) and indicators of urbanization in the environment (negative correlation) were the main variables explaining ghost crab kills on the beach. Similarly, the likelihood of finding crabs killed by vehicles on the dirt road was associated with the areas with the densest ghost crab populations (higher beach width and low-urbanized areas). Therefore, as an important conservation strategy and mitigation action, vehicle traffic must be severely controlled mainly on low-urbanized beaches, both on the sand and dirt roads crossing natural beach vegetation.
•We applied the road ecology approach to investigate vehicle-ghost-crab collisions.•Ghost crabs killed by vehicles were found on the beach and on the dirt road.•Ghost crabs deaths were related with higher vehicle traffic and lower urbanization.•Surveillance of beach driving is essential for coastal biodiversity conservation.
Roads and traffic impacts on wildlife populations are well documented. Three major mechanisms can cause them: reduced connectivity, increased mortality and reduced habitat quality. Researchers ...commonly recommend mitigation based on the mechanism they deem responsible. We reviewed the 2012-2016 literature to evaluate authors' inferences, to determine whether they explicitly acknowledge all possible mechanisms that are consistent with their results. We found 327 negative responses of wildlife to roads, from 307 studies. While most (84%) of these responses were consistent with multiple mechanisms, 60% of authors invoked a single mechanism. This indicates that many authors are over-confident in their inferences, and that the literature does not allow estimation of the relative importance of the mechanisms. We found preferences in authors' discussion of mechanisms. When all three mechanisms were consistent with the response measured, authors were 2.4 and 2.9 times as likely to infer reduced habitat quality compared to reduced connectivity or increased mortality, respectively. When both reduced connectivity and increased mortality were consistent with the response measured, authors were 5.2 times as likely to infer reduced connectivity compared to increased mortality. Given these results, road ecologists and managers are likely over-recommending mitigation for improving habitat quality and connectivity, and under-recommending measures to reduce road-kill.
Transportation infrastructures are directly responsible for killing billions of animals worldwide. Although the understanding about road impacts have recently increased, the impact of railroads on ...wildlife has received less attention. The current knowledge concerning the impacts of railroads focuses mainly on large mammals although amphibians might be affected. Our study aims to unravel temporal and spatial patterns of Rhinella toad fatalities on a Brazilian Amazonian railroad, to comprehend how toads are killed and to estimate the magnitude of toad fatalities. Data collection was carried out on foot on an 871-km stretch of the Estrada de Ferro Carajás from 2013 to 2017. We identified different potential causes for fatalities: being run over, desiccated or with barotrauma signs. We estimated a surprisingly high carcass persistence probability of about 38 days. After correcting for the bias from carcass detection and removal, we estimated that approximately 10,000 toads are killed per year (≈ 11 fatalities/km/year). A GLM model showed that toads were more likely to be killed in the dry to wet transition. We identified critical zones of fatalities and prioritized them according to their intensity. The highly critical segments encompass >10% of all fatalities although they cover only 1.5% of the railroad. Our study is the first one to address carcass detection and persistence on railroads and to unravel patterns of fatalities of an amphibian species in a tropical climate. A better understanding of the patterns of animal fatality on railroads is of fundamental importance to manage and mitigate this impact.
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•Causes of fatalities on railroads can differ from those of roads.•Toad carcass persistence was surprisingly high (>30 days).•More than 10,000 toad fatalities estimated per year•Toad fatalities were more abundant in wet and transition to wet seasons.•16.7% of the railroad encompassed 58.4% of fatalities in critical zones.
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