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. RESUMO OS HOTSPOSTS DE ATROPELAMENTOS NAS ESTRADAS SÃO COINCIDENTES ENTRE DIFERENTES GRUPOS DE VERTEBRADOS? A avaliação de padrões espaciais de atropelamento em estradas é uma ferramenta importante para identificar locais prioritários para medidas de mitigação voltadas à redução da mortalidade da vida silvestre nas estradas. Abordagens voltadas a uma ou várias espécies são geralmente adotadas para a implantação de tais medidas, apesar de seu sucesso dever ser avaliado. Nosso