Seasonal variation and patterns in the land snail community along a fine-scale humidity gradient in an Atlantic Rainforest remnant, Southeastern Brazil.

Abstract

In this study, we provide the first data regarding seasonal variation and patterns along a fine-scale humidity gradient on the land snail community, including parameters such as richness and abundance, in the Sooretama Biological Reserve, Espírito Santo, Brazil. Our study was conducted from January 2017 to December 2018, covering all four seasons (summer, autumn, winter and spring). We used 24 plots of 250 m each, combined with subplots of 25 x 75 cm (to sample leaf-litter), following the RAPELD methodology. We collected 440 live specimens belonging to 35 species from 11 families. The snail species richness varied among seasons, with the highest mean values in summer and spring. The highest variation of richness occurred between summer and autumn, and the smallest variation occurred between spring and summer. Soil temperature, relative air moisture and soil moisture affected significantly the overall land snail abundance. The rainy season was hotter and wetter than the dry season and showed highest richness and abundance of species. Our results showed a clear compositional change along the moisture gradient, suggesting differences in species preference for moisture conditions even at a fine-scale.