Seasonal variation in the composition of ground-dwelling anuran (Amphibia) assemblages in southern Brazil

Abstract

Climate seasonality may differently influence habitat quality and heterogeneity depending on habitat type. We examined whether the taxonomic, functional and phylogenetic composition of ground-dwelling anuran assemblages from grassland and forest habitats vary seasonally. We tested the hypothesis that the forest anuran assemblage varies less seasonally than the grassland assemblage. We monitored anurans using pitfall trap arrays in two areas, sampled across four seasons over a two-year period. For the functional composition, we acquired information on species morphology, reproduction, and habitat use to represent the anuran niche. For the phylogenetic composition, we used the most comprehensive anuran phylogeny. We used Principal Coordinate Analysis and Analysis of Variance to evaluate seasonal variations in assemblage composition along the study period. Our data revealed significant seasonal variation in the taxonomic and phylogenetic composition of anuran assemblages. Variation in taxonomic composition was higher in the grassland than in the forest assemblage, while variation in phylogenetic composition was higher in the spring-summer than in the autumn-winter seasons. We did not identify seasonal variation in functional composition. Seasonal variations in taxonomic and phylogenetic composition, but not in functional composition, indicate that the species with a fluctuating seasonal abundance have similar life-history traits, but belong to different lineages.

Keywords: anuran traits, Brazilian highland grasslands, habitat variability, temporal beta diversity, temporal turnover.