Inventário das espécies de serpentes da mata de cocais em áreas semiurbanizadas no município de Bacabal – Maranhão

Abstract

Snakes are essential for ecological balance, controlling prey populations and connecting different levels in food chains. Even though they are a highly important group, knowledge about their diversity in the Cocais Forest region is still limited, especially in semi-urban areas of the state of Maranhão. With that in mind, this study aimed to make an inventory of snake species, looking at their richness, abundance, diversity, similarity between sampled areas, and the effectiveness of the collection methods used. The collections took place in three areas that are representative of the municipality, using techniques like Time-Constrained Searching (TCS), Pitfall and Interception Traps (PIT), Opportunistic Encounters (OE), and Records from Third Parties (RTP). A total of 62 snakes were found, belonging to 17 species, 13 genera, and four families, with Dipsadidae being the most represented. The species Erythrolamprus poecilogyrus, Oxyrhopus trigeminus, and Leptodeira annulata were the most abundant. Richness estimators suggested that more species occur in the region, as the accumulation curves did not level off. Area 1 had the highest diversity indices, Area 2 had the highest evenness index, and Area 3 had the lowest richness and abundance indices. The similarity comparison showed that Areas 1 and 2 were the most similar, indicating that environmental characteristics play an important role in shaping snake community composition. Among the methods used, Time-Constrained Search was the most effective in documenting the species. The data obtained show that, despite human influence, the remaining Cocais Forest in Bacabal harbors considerable snake diversity and that this study is the first systematic survey of these reptiles in the city, contributing to the knowledge of the herpetofauna of Maranhão and serving as a basis for future research, conservation measures, and educational actions.