Are Road-Kill Hotspots Coincident Among Different Vertebrate Groups?

Abstract

The evaluation of road-kill spatial patterns is an important tool to identify the priority of locations for mitigation measures aiming to reduce wildlife mortality on roads. Single-target or multi-species approaches are usually adopted on the implementation of such measures, although their success must be assessed. We aim to test if road-kill hotspots are coincident among different vertebrate groups. If this proves to be right, data on accidents from one group could be used to plan measures applicable to other groups. We identified hotspots using five different grouping criteria: vertebrate Classes (reptiles, birds or mammals), body size (large or small), species commonness (common or rare), type of locomotion (flying or non-flying), and time of activity (nocturnal/crepuscular or diurnal). We analyzed data from road-kill surveys on four roads in southern Brazil, each with at least one year of monitoring. We performed a modified Ripley's K-statistic to recognize scales of road-kill aggregation, and we carried out a hotspot analyses to identify the location of road-kill aggregations for each group described above on each road. To test for similarity in hotspot location among different groups we performed an association test using correlation as the resemblance measure. Hotspot analyses and association tests were done using different spatial scales to evaluate the effect of scales on similarities. Correlation results between groups presented low values at small scales although they had a tendency to increase with raising scales. Our results show that road-kill hotspots are different among groups, especially when analyzed on small scales. We suggest that, for a successful biodiversity approach to mitigation, one should first select general hotspots on large scales and then identify specific hotspots on small scales to implement specific measures. These findings are relevant in a context of existing road networks, where mitigation measures are being planned to reduce impact on wildlife.

Comparative spatial ecology of sympatric adult muskellunge and northern pike during a one-year period in an urban reach of the Rideau River, Canada

“…Following the methods of Teixeira et al (2013) and Coelho et al (2014), 2D HotSpot Identification analysis was performed using SIRIEMA (version 1.1, Laboratory of Ecology of Populations and Communities, Porto Alegre, RS, Brazil). Esocid positions were plotted on a geo-referenced map of the Rideau River centre line in SIRIEMA.…”

Wild vertebrates roadkill aggregations on the BR-050 highway, state of Minas Gerais, Brazil

“…Recent studies have showed wild vertebrates roadkill aggregations in Brazil and worldwide (CLEVENGER et al, 2003;COELHO et al, 2008;CÁCERES et al, 2012;TEIXEIRA et al, 2013). Coelho and colleagues (2008) showed that roadkill of vertebrates, mammals and birds occurs in aggregated form in the Atlantic Forest.…”

“…An initial radius of 100 meters, a radius increase of 500 meters, confidence level of 95% and a thousand simulations were used. The values of initial radius and radius increment corresponded to the scale at which mitigation measures can be effective (TEIXEIRA et al, 2013). The program tests the existence or not of roadkill aggregations in different scales (COELHO et al, 2011).…”

Effects of Road Density and Pattern on the Conservation of Species and Biodiversity

“…Another study determined that variations in carcass persistence could also bias survey results, as persistence was much lower in small animals and easily influenced weather conditions [129]. Other studies flagged up survey interval [130], scavenger removal [131] and species detectability [132,133] as factors that would influence survey results. Such biased surveys are particularly concerning if mortality estimates are used to determine the impact of roads and road networks on a species, and particularly when species of concern are involved.…”