Microhabitat features determine the tadpole diversity in mountainous streams

Abstract

The study on the mechanism driving the spatial patterns of biological diversity along elevational gradients is a main focus in ecology, biogeography, and conservation biology. Based on the intraspecific variability of tadpole communities in 18 mountainous streams, the present study quantified the spatial patterns of taxonomic and functional diversity, and the environmental factors underlying the process of spatial distribution and diversity. First, our results illustrated that both elevation and microhabitat features (e.g., water pH, dissolve oxygen, current velocity, chlorophyll a, and ammonium nitrogen) determined tadpole community compositions. Second, the richness of functional entities showed a hump-shape response to the change of elevation. However, no significant relationships were detected between other diversity indices at both taxonomic and functional levels and site elevation. Finally, microhabitat environmental variables were the primary drivers of the taxonomic variation and functional diversity in tadpole communities. However, the relative contribution to the variation of specific diversity indices differed among microhabitat environmental variables. Our results supported the claim that the assembly of montane communities is determined by both spatial processes and environmental filtering. Importantly, tadpole taxonomic and functional diversities were strongly determined by microhabitat features in mountainous streams, providing evidence that microhabitat should be a priority in this study of tadpole diversity conservation. This study suggests that tadpole diversity should be considered in the long-time monitoring of species conservation, as the tadpole is part of the life history in amphibians.

Keywords

• Intraspecific variability
• Spatial patterns
• Functional diversity
• Microhabitat features
• Community assembly