Distributional patterns and conservation planning for a snake assemblage from temperate South America

Abstract

We analyzed the spatial distribution of a snake assemblage from the Sierras de Ventania mountain range, a rich endemism area in east-central Argentina. We used field-collected and museum specimens combined with high-resolution environmental variables to identify common distributional patterns, estimate the suitable habitat for each species, and develop a conservation proposal related to the Protected Natural Areas (PNAs) system. Distributional models diverged into two opposite patterns: suitable habitats for most species at relatively high altitude in the hills, and suitable habitats for Bothrops ammodytoides and Lygophis anomalus at relatively low altitude in the surrounding hill plain. We assessed two proposals based on different conservation algorithms: the additive benefit function (ABF), which favours hilly environments, prioritizing areas with high specific richness, and the core-area zonation (CAZ), which prioritizes the distribution of all species, further indicating areas with low richness in the surrounding plain. Regardless of the algorithm used, our results indicated that the existing PNAs are not effective in protecting the snake assemblage. Protecting at least 5% of the highest species richness areas (ABF) or 5% of the distribution core areas of all species (CAZ), the existing PNAs only represented 2.2% of these priority areas. Our findings are largely consistent with previous work, highlighting that a widespread area needs to be assigned for conservation purposes. Thus, protection of the snake assemblage should take place both inside and outside the PNAs.