Factors Affecting Roadkills of Semi-Aquatic Mammals

Abstract

We previously showed that registration efforts and traffic intensity explain 90% of variation in mammal roadkill numbers, 70% of variation in the numbers of recorded species and 40% of diversity variation. Here we analyze semiaquatic mammal roadkill in Lithuania in 2002–2021, relating these to the monitoring effort. From 39,936 analyzed roadkill, the European beaver (Castor fiber) was registered 60 times, American mink (Neovison vison) 26 times, otter (Lutra lutra) 22 times and muskrat (Ondatra zibethica) 3 times. The average roadkill indexes were 0.000065, 0.00076, 0.00061 and 0.00010 ind./km/day, and the extrapolated annual roadkill for the country was 44–357, 36–456, 49–464 and 89–144 individuals, respectively. Beaver roadkill numbers correlated with the registration effort and traffic intensity, otter roadkill with registration effort only and mink with hunting bag (number of hunted individuals per year). Roadkill was not always related to proximity to water, with 38–54% of roadkill occurring over 200 m from the nearest water source. With American mink and muskrat being invasive species in the EU and otter protected in many countries, it is valuable to enhance the registrations of their roadkill (using targeted efforts by drivers, hunters or other citizen scientists) to obtain the extrapolated amount of roadkill and to use this knowledge in species management.

Ninja Turtles: high mobility and successful passage through common barriers to movement in a semi-terrestrial freshwater turtle

“…For species averse to urbanisation, the negative population-level impacts of roads and fences are more pronounced, often further endangering already threatened species (Taylor and Goldingay 2004;Seidler et al 2015;Jakes et al 2018). Species that disperse or migrate, such as semi-aquatic species using a complex of wetlands, are particularly sensitive to barriers (Roe et al 2006; Glista et al 2007; Balčiauskas et al 2022). In particular, freshwater turtles often travel frequently between water bodies and are negatively impacted by these arti cial barriers (Aresco 2005a Many freshwater turtles have large home ranges (Slavenko et al 2016) and use water-adjacent land for nesting (Bodie 2001;Petrov et al 2018;Van Dyke et al 2018), thermoregulation (Chessman 2020), and to travel between water bodies (Graham et al 1996;Serrano et al 2020).…”