Habitat and microhabitat use by Crossodactylus schmidti (Anura: Hylodidae) in Atlantic Rainforest streams

Abstract

A combination of biotic and abiotic factors influences the habitat and microhabitat selection by anurans. To analyze the habitat and microhabitat use by adults of Crossodactylus schmidti, we sampled 13 streams in the Atlantic Rainforest of Iguaçu National Park, Southern Brazil, between November 2014 and August 2015. We recorded abundance data and measured structural environmental variables of the streams related to habitat selection on three occasions in each stream. Data collection occurred along a 50-meter transect in each stream. Additionally, two samplings were conducted specifically to obtain microhabitat usage data, sampling only the same three streams on each sampling. We employed Generalized Least Squares analysis to assess spatial variation in abundance as a function of environmental structural variables, considering models with and without spatial structuring. We applied the Multinomial Goodness-of-Fit Test to elucidate the types of microhabitats most utilized by the frogs. Our analysis revealed that considering or not the spatial autocorrelation in the variation in C. schmidti abundance, none of the predictor variables was significant. The results obtained demonstrate that the analyzed environmental variables are not important for habitat selection of C. schmidti, and the spatial configuration and distance among streams are not determinants for abundance distribution. At the habitat scale, this species exhibits a random distribution independent of spatial and environmental features. Regarding microhabitats, individuals were predominantly found inhabiting streams in pool areas characterized by rocky substrate or organic matter accumulation. Conservation strategies for this species should encompass the scale-dependent relationships.