Environmental, spatial and biotic factors affect the tadpole distribution in Brazilian savannas

Abstract

Multiple factors contribute to explaining the composition and structure of communities, and the niche is still the most used theory to describe how organisms interact with such factors to generate biological communities’ patterns. Both biotic and abiotic aspects of the environment along with the geographic space interact in complex ways with the behavior and physiological tolerance of organisms to structure a community. In this study, we tested the potential effects of the environment, space and competition and assess how the may determine the distribution of tadpoles in aquatic habitats located at Emas National Park. To this end, we sampled 23 aquatic habitats, described their environmental characteristics, recorded their geographic location, and carried out a survey of the tadpoles found. Later, we evaluated the effect of environmental and spatial variables on the distribution of species, through a Partial Redundancy analysis, using matrices of environmental descriptors and geographic location. We found that both environmental and spatial factors drive the distribution and the species composition of the studied assemblages. Also, when we analyzed the pattern of co-occurrence, we observed that the number of co-occurrence pairs of species in the Emas National Park is less frequent than expected by chance, suggesting that besides the effect of abiotic components (environmental and spatial factors), competition is a co-structuring factor in the assemblages of tadpoles.