Road and Landscape Features That Affect Bat Roadkills in Southeastern Brazil

Abstract

The most studied impact on road ecology is roadkill, however, there is little information about the relations between highways and specific groups like bats. This study intended to identify the species of bats roadkilled and to evaluate the existence of temporal fluctuation between the roadkill rates, specific stretches of the road with higher rates, and characteristics of the road/landscape that may influence those rates. We encountered at least nine bat species among 65 roadkills (most Phyllostomidae), which comprise a subgroup of the local fauna that presents ecologic features that make them susceptible to being hit, especially Artibeus lituratus. The medium roadkill rate was of 0.01 individuals/km/day of monitoring, and there was no significant temporal variation. We identified five hotspots through special 2D HotSpot Identification Analysis. The selection of theoretical models through Generalized Linear Models showed that roadkill occurrence has a positive relation with vehicular traffic and negative relation with presence of marginal pasture and forests. As the major part of records was of species that are tolerant to human-disturbances, the increase in traffic consequently affected a higher number of bats capable to explore the area occupied by the road. The presence of native forest close to the road can lead to a decrease of animals hit by vehicles, once it offers more resources and favorable habitats, which reduces the need for bats to cross the roads for foraging. On the other hand, many species that necessarily depend on areas sheltered by trees for shelter, and do not possess the ability to fly long distances do not occur in open areas such as pastures. In this context, we suggest that the main measure of mitigation regard bat species would be the traffic control through speed limit, especially on the roadkill hotspots areas.

Road effects on bat activity depend on surrounding habitat type

“…Several studies have shown that bats suffer frequent road kills (Gaisler et al, 2009;Lesiński, 2007;Lesiński et al, 2010;Medinas et al, 2013;Russell et al, 2009;Secco et al, 2017), have reduced foraging activity near roads with street lighting (Hale et al, 2015;Stone et al, 2009;Stone et al, 2012) or intense traffic noise (Luo et al, 2015;Schaub et al, 2008;Siemers and Schaub, 2011) and have restricted access to some habitats when these areas are dissected by roads (i.e., barrier effect) (Kerth and Melber, 2009). Other studies have shown that gleaning species are less active and that species richness decreases, when approaching the major roads (Zurcher et al, 2010;Berthinussen and Altringham, 2012;Kitzes and Merenlender, 2014).…”

Effects of land‐use changes on Brazilian bats: a review of current knowledge

“…A first step in a landscape study is to define the size of the landscape unit, and options are as follows: 1) to choose the size corresponding to the ecology of the focal taxon (Jackson & Fahrig 2012), or 2) to use a multi‐scale approach (Martin & Fahrig 2012). The studies included in this review used landscape unit sizes that ranged from 0.008 to 200 km 2 (Mendes et al 2017, Secco et al 2017), and five studies opted for a multi‐scale approach (Ferreira et al 2017, Mendes et al 2017, Rocha et al 2017a,b, Secco et al 2017). The choice of landscape unit size was based on the absolute home‐range size (Ferreira et al 2017, Rocha et al 2017a) or the dispersal abilities (Mendes et al 2017) of species.…”

Seasonal and Spatial Variation of Road-Killed Vertebrates on Br330, Southwest Bahia, Brazil

“…According to Novaes et al (2018), most publications on wildlife road-kill in Brazil do not report bats, which could give the false idea that roads pose no risk to this group. These same authors believe that, because bats are road-killed during flight, most individuals can be projected off the road, leading to an underestimation of the number of road-killed bats (Secco et al 2017).…”