Spatial patterns of snake diversity in an urban area of north-east Brazil

Abstract

The distribution of animal populations within an assemblage includes a wide variety of patterns, which are fundamental to understanding population dynamics and aid in conservation actions. We examined a snake assemblage in an urban area to describe species distribution patterns and to identify which places are more likely to contain snakes, both venomous and non-venomous. The study was conducted in the urban area of the municipality of Rio Tinto in north-east Brazil. We used a geostatistical modelling technique called ordinary kriging to identify which places were more likely to contain snakes, and a statistical spatial method (average nearest neighbour distance) to detect distribution patterns of snake species within the study area. A total of 291 individuals distributed among 28 species were recorded. The snakes were found in streets, homes, churches, university campus, streams, and even in local supermarkets. Ordinary kriging showed that the area of distribution of individuals was concentrated at three distinct points located in the centre of the urban area. The significant results of the average nearest neighbour distance analysis showed a clustered distribution for two species and dispersed distributions for eight species. Information on urban sites where snakes are more likely to be found is important not only for conservation, but also to help local citizens better understand and live amongst snakes