How did the animal come to cross the road? Drawing insights on animal movement from existing roadkill data and expert knowledge

Abstract

Context Animal movement through the landscape is essential to several ecological processes, assuring genetic flow, reproductive success and population dynamics. In fragmented landscapes, species change their movement patterns according to their sensitivity to landscape cover and configuration. Increased landscape habitat loss and fragmentation affects resource distribution and habitat availability, compelling species to move more frequently through anthropized matrices. Objectives Our aim was to provide a new prospect for what is known about animal movement through the landscape anthropogenic matrix in the Atlantic Forest biodiversity hotspot, by analyzing the potential movement distances of several mammal, bird, reptile, and amphibian species. Methods We used recorded roadkills within the Brazilian Atlantic Forest as a source of information of species’ occurrence. We assumed the euclidean distance from the roadkill spot to the nearest forest fragment as the potential movement distance by different species through the anthropogenic matrix. Experts’ classification of species’ forest dependence degree, and animal movement information from the literature survey was used to analyze the variation in potential animal movement distance in these matrices. Results We analyzed 90 species, the majority of them being non-forest dependent (n = 64; 71%). The potential movement distances ranged from 0 to > 1500 m, and forest-dependent species presented lower mean distances (between 772 and 978 m) than non-forest dependent species (between 673 and 1015 m). The literature survey resulted in 44 articles regarding animal movement in the matrix, referred only to 22 species. No articles were found for 20 species, mainly reptiles and amphibians. Conclusions By comparing these values to the average distance between forest remnants in the Atlantic Forest, we expect that the distance to be traveled through the matrix to reach forest fragments may be restrictive, mainly for species with higher degree of forest dependence. Despite being descriptive, our results provide important insights on animal movement through the matrix, especially for less studied species, such as amphibians and reptiles.

The Atlantic Forest of South America: spatiotemporal dynamics of remaining vegetation and implications for conservation

“…The effect of roads and railways was more pronounced in FV than in NV, due to their greater density in large forest fragments located in Serra do Mar, southern Bahia in Brazil, and in the region of Misiones in Argentina. Roads and railways have a huge impact on biodiversity, modifying the movement pattern, reducing connectivity, and causing roadkill, which leads to population declines and local extinction (Cassimiro et al, 2023; Martinez Pardo et al, 2023).…”

“…Finally, although connectivity and isolation were not apparently sensitive to the roads and railways effect, this lack of sensitivity may be due to short-distance divisions into FV or NV fragments, as the additional cost that these linear structures cause, preventing animals from crossing short distances (Martinez Pardo et al, 2023), were not considered. Thus, it is essential to propose fauna passages for improving landscape permeability to maintain wildlife gene flow and reduce roadkill (Cassimiro et al, 2023; Teixeira et al, 2022; Zimmermann Teixeira et al, 2017).…”

“…We used roads and railways to trim their overlapping FV and NV (henceforth called "trimmed" and "not trimmed" scenarios). This procedure enabled us to avoid overestimating large fragments of vegetation and check the metrics' sensitivity to linear infrastructure, since these structures decrease landscape connectivity and threaten multiple taxonomic groups (Cassimiro et al, 2023). Thus, we analyzed four vegetation maps: "FV not trimmed", "FV trimmed", "NV not trimmed", and "NV trimmed".…”

“…In addition, the AF has a high density of linear infrastructure since it hosts a high (and increasing) human population. This severely impacts natural vegetation and biodiversity and must be considered in landscape structure analyses (Cassimiro et al, 2023).…”

Environmental and anthropogenic factors mediating the functional connectivity of the mesquite lizard along the eastern Trans‐Mexican Volcanic Belt

“…The fact that agricultural cover can facilitate connectivity at both scales highlights the importance of this landscape for S. grammicus. Moreover, movement distance in terrestrial reptiles has been recorded to be >1000 m in some species and even increasing in disturbed landscapes, mainly in organisms with smaller body sizes (Cassimiro et al, 2023;Doherty et al, 2021), suggesting that the interaction between body size and thermoregulation has important implications in their response (Garland & Albuquerque, 2017). Therefore, landscapes with good thermal quality (Díaz de la Vega-Pérez, Barrios-Montiel, et al, 2019) and facilitating connectivity are important, like the LAMOS and CEGRI low-elevation sites.…”