Influence of environmental heterogeneity on spatio-temporal structuring of cave invertebrate communities

Abstract

This dissertation aimed to understand how environmental heterogeneity shapes the spatial and temporal structuring of terrestrial cave invertebrates. To do so, we analyzed the effects of substrate components, as well as microclimatic and trophic resource variables on biological communities. The study included a total of 31 caves distributed throughout the karst region of Iuiú and Malhada, in the southwest of the state of Bahia. In the first chapter, written following the guidelines of the "Journal of Applied Ecology" journal, we sought to understand if the structuring of communities associated with different zones of the caves (photic and aphotic zones) respond similarly. We used a multiscale approach, where we considered variables at different scales (micro and mesoscale), seeking greater robustness in our results. As hypothesized, the communities present in different regions responded differently to the tested substrate components and other variables. We also highlighted the strong relationship between the surface environment and communities closely associated with the more distant regions from the entrance. In the second chapter, written following the guidelines of the "Community Ecology" journal, we addressed the temporal relationship between community structuring and environmental heterogeneity. Our goal was to evaluate whether the relationship between species richness of invertebrates and habitat structuring remained over time, in this case, with a five-year period between samplings. We used a multimodal statistical approach, which considers the average of the best predictive models constructed, and evaluated the variation in richness between sampling events. We concluded that there was no significant difference in the species richness collected between samplings. Furthermore, our models show that bare cave soil rock brings greater homogeneity to the environment, negatively affecting species richness. On the other hand, the presence of boulders and their overlap provides greater availability of potential habitats for fauna, reflecting positively on richness. Finally, we found that the fauna's response to the presence of boulders remained between sampling periods. The results of this study have implications for the conservation and management of underground ecosystems, as they provide useful information about the ecological processes that govern these ecosystems. Additionally, the results can be beneficial to improve the understanding of underground ecosystem ecology in general, contributing to advances in the field.