One of the challenges in ecological research is to integrate data from different spatial scales to assess ecological and evolutionary processes that influence the community assembly rules. Here, we use a broad approach to analyze the association between environmental filtering, traits, and evolutionary history in amphibian communities sampled at 14 protected areas in the Brazilian Atlantic Forest. Our questions were: i) which reproductive modes are filtered by the environment? ii) reproductive modes have a phylogenetic signal (i.e., closely related species are expected to have similar trait states, while distantly related species are likely to have distinct trait states)? iii) which lineages are affected by these filters? For that, we recorded amphibian species in the 14 protected areas between December 2014 and February 2016. As traits, we used the reproductive modes (i.e., the oviposition site, ovum and clutch characteristics, the rate and duration of development, the stage and size of hatchlings, and the type of parental care, if any) of the amphibian species. We built a regional phylogeny by pruning the most recent amphibian phylogeny published and species not sampled in the phylogeny were added as intrageneric polytomies. We used WorldClim database at a resolution of 5.0’ to obtain climatic variables for each community.
Results/Conclusions
Overall, 21 reproductive modes were found among the 89 amphibian species recorded for the 14 Atlantic Forest sites. All environmental variables were spatially autocorrelated. We observed that sites from eastern region have mild temperatures and constant precipitation throughout the year while sites from western region have high temperatures and marked seasonality in precipitation. The first axis of the ordination, applied to both space and environment, and both reproductive modes and phylogeny, explains 92% of the total variation. We found that reproductive modes have a phylogenetic signal. The species that occurred in areas with high humidity levels and mild temperatures have reproductive modes specialized for streams, bromeliads and soil, while species that occurred in the regions with high temperatures and marked seasonality in precipitation showed reproductive modes specialized to be more resistant to desiccation. Thus, environmental harshness in the western sites might prevent the colonization of new species from eastern region that is recognized by its high rates of speciation and endemism. Therefore, our results suggest that niche conservatism (i.e., tendency of lineages to retain their niche-related traits through speciation events) and environmental filters are important processes organizing amphibian communities in the Brazilian Atlantic Forest.