The spatial, climatic and temporal factors influencing roadkill change according to the taxonomic level.

Roads are the second largest anthropogenic cause of mortality for most vertebrates. Previous research has analyzed the factors influencing roadkill either by species or by group of species based on some species-specific characteristics. However, to gain a comprehensive understanding on the consistency of findings within and between taxa, it is necessary to conduct an analysis that encompasses both individual species and group of species. This study aims to assess the role of taxonomic level in determining the spatial, climatic and temporal drivers using roadkill data for 70 species. We used generalized linear models to examine the association between roadkill and land cover and climate across 26 individual species and groups of reptiles, birds and mammals. Temporal patterns were evaluated using circular statistics. Our study revealed variations in spatial, climatic and temporal factors among taxa. For reptiles, spatial patterns differed between the class/order and species level, while climatic and temporal patterns remained consistent among these taxonomic levels. Spatial and climatic patterns were not consistent between class, order and associated species for birds and mammals. Temporal patterns, on the other hand, were consistent between each order and its associated species. In general, we found that roadkill incidence was positively associated with silviculture and agriculture cover as well as proximity of rivers. Accumulated insolation and mean minimum temperature were positively associated with roadkill, while mean temperature exhibited a negative association. Our study emphasizes the importance of analyzing roadkill variables on a species-specific basis. In the case of endangered species with low roadkill rates, it is essential to consider their assessment alongside other species exhibiting similar behavior and ecological needs.

Do roadkill aggregations of wild and domestic mammals overlap? / ¿Se traslapan las agregaciones de atropellos de mamíferos silvestres y domésticos?

Abstract Domestic animals are involved in a large number of traffic accidents and they represent danger to humans due to their size. Despite this, few studies consider domestic animals. That is why we evaluate mammals' roadkill aggregations in order to locate them and to determine if wild and domestic mammals' roadkills overlap. In addition, we investigate the influence of the landscape on the location of the aggregations. This study was carried out on the BR-050 highway, an area of Cerrado biome, in Southeastern Brazil. The monitoring was executed from April 2012 to March 2013, by car, at an average speed of 60 km/h, with two observers looking for roadkills on the highway. We found 482 mammals' roadkills, including 260 (54 %) wild mammals, 164 (34 %) domestic and 58 (12.0 %) undetermined specimens. Of the 21 recorded mammal species, five were domestic. The wild mammals' roadkill rate was 0.03 (± 0.02) individuals/km/day and the domestic roadkill rate was 0.02 (± 0.01). We detected roadkill aggregations for wild and domestic mammals. Roadkill hotspots of domestic mammals and wild mammals did not overlap. The variables that had the highest influence on wild mammals' roadkill probability were: agriculture and silviculture cover as positive effects and distance to the nearest river, to the urban perimeter and to a natural fragment as negative effects. For domestic mammals these variables were: area of the smallest fragment and distance to a natural fragment as positive effects and silviculture cover as a negative effect. The explanation for the wild and domestic mammals' roadkill hotspot non overlapping seems to be the effect of each variable in determining the roadkill hotspot since their effect is different for wild and domestic mammals. On the other hand, this non overlapping can be a result of domestic mammals' scavenging habits. We propose different kinds of mitigation measures in order to reduce domestic and wild mammals' roadkill.(AU)

Resumen Los animales domésticos están involucrados en una gran cantidad de accidentes de tránsito y representan un peligro para los humanos debido a su tamaño. A pesar de esto, pocos estudios consideran a los animales domésticos. Es por eso que evaluamos agregaciones de atropellos de mamíferos, con el fin de ubicarlas y determinar si los atropellos de los mamíferos silvestres y domésticos se traslapan. Además, investigamos la influencia del paisaje en la ubicación de las agregaciones. Este estudio se realizó en la carretera BR-050, un área del bioma Cerrado, en el sureste de Brasil. El muestreo se ejecutó entre abril 2012 y marzo 2013, en automóvil, a una velocidad promedio de 60 km/h, y dos observadores buscaron animales atropellados en la carretera. Encontramos 482 mamíferos atropellados, incluidos 260 (54 %) mamíferos silvestres, 164 (34 %) ejemplares domésticos y 58 (12 %) especímenes indeterminados. De las 21 especies de mamíferos registradas, cinco fueron de origen doméstico. La tasa de mortalidad de mamíferos silvestres fue de 0.033 (± 0.018) individuos/km/día y la de domésticos de 0.020 (± 0.008). Detectamos agregaciones de atropellos para mamíferos silvestres y domésticos. Los "hotspots" de atropellos de mamíferos domésticos y silvestres no se traslapan. Las variables que tuvieron la mayor influencia positiva en la probabilidad de atropello de mamíferos silvestres fueron: cobertura de la agricultura y la silvicultura; mientras que distancia al río más cercano, al perímetro urbano y al fragmento natural tuvieron un efecto negativo. Para los mamíferos domésticos estas variables con un efecto positivo fueron: área del fragmento más pequeño y distancia al fragmento natural; en tanto que la cobertura de silvicultura tuvo un efecto negativo. El que no haya un traslape de los atropellos de mamíferos silvestres y domésticos se podría explicar por el efecto de cada variable en la determinación de los "hotspots" de atropellos, ya que su efecto es diferente para los mamíferos silvestres y domésticos. Por otro lado, el no traslape puede ser el resultado de los hábitos carroñeros de los mamíferos domésticos. Proponemos diferentes tipos de medidas de mitigación con el fin de reducir los atropellos de los mamíferos domésticos y salvajes.(AU)