Multiscale analysis of factors influencing herpetofaunal assemblages in early successional stages of a tropical dry forest in western Mexico

Abstract

The Tropical Dry Forest (TDF) is one of the most highly transformed and threatened neotropical systems in the world and much of its original area has been replaced by secondary forests. Therefore, it is important to understand the process of ecological succession underlying the natural regeneration of TDF, especially the role of early successional stages as drivers of the course of secondary succession. In this study, we investigated the response of herpetofaunal assemblages to vegetation and landscape attributes in areas dominated by early successional stages of TDF. Such response was evaluated in terms of assemblage's composition, richness, taxonomic diversity and functional diversity. We found a high variation in composition, richness and diversity of herpetofaunal assemblages at the initial stages of TDF succession. According to our hypothesis, in general we found the richest herpetofaunal assemblages in sites embedded in the most conserved matrix with higher levels of vegetation cover. Additionally, patch density of forest was also associated to the variation in assemblages' richness. We found high specificity on the response of frogs, lizards and snakes to the surveyed local and landscape attributes. This response involved both taxonomic and functional diversity. This study shows that composition and quality of the surrounding matrix can actually drive the maintenance of herpetofauna species in early successional stages. Considering that these stages greatly influence the course of secondary succession, the natural regeneration of the herpetofauna communities of TDF will depend not only on the local vegetation attributes but also on the initial status of the surrounding matrix. Thus, in order to preserve the resilience of the herpetofaunal assemblages it is important an adequate management of the system, maintaining high levels of the original vegetation in anthropogenic landscapes.