Ecological communities are complex entities that can be maintained and structured by niche-based processes such as environmental conditions, and spatial processes such as dispersal. Thus, diversity patterns may be shaped simultaneously at different spatial scales by very distinct processes. Herein we assess whether and how functional, taxonomic, and phylogenetic beta diversities of frog tadpoles are explained by environmental and/or spatial predictors. We implemented a distance–based redundancy analysis to explore variation in components of beta diversity explained by pure environmental and pure spatial predictors, as well as their interactions, at both fine and broad spatial scales. Our results indicated important but complex roles of spatial and environmental predictors in structuring phylogenetic, taxonomic and functional beta diversities. The pure fine-scales spatial fraction was more important in structuring all beta diversity components, especially to functional and taxonomical spatial turnover. Environmental variables such as canopy cover and vegetation structure were important predictors of all components, but especially to functional and taxonomic beta diversity. We emphasize that distinct factors related to environment and space are affecting distinct components of beta diversity in different ways. Although weaker, phylogenetic beta diversity, which is structured more on biogeographical scales, and thus can be represented by spatially structured processes, was more related to broad spatial processes than other components. However, selected fine-scale spatial predictors denoted negative autocorrelation, which may be revealing the existence of differences in unmeasured habitat variables among samples. Although overall important, local environmental-based processes explained better functional and taxonomic beta diversity, as these diversity components carry an important ecological value. We highlight the importance of assessing different components of diversity patterns at different scales by spatially explicit models in order to improve our understanding of community structure and help to unravel the complex nature of biodiversity.

Beta diversity patterns are the outcome of multiple processes operating at different scales. Amphibian assemblages seem to be affected by contemporary climate and dispersal-based processes. However, historical processes involved in present patterns of beta diversity remain poorly understood. We assess and disentangle geomorphological, climatic and spatial drivers of amphibian beta diversity in coastal lowlands of the Atlantic Forest, southeastern Brazil. We tested the hypothesis that geomorphological factors are more important in structuring anuran beta diversity than climatic and spatial factors. We obtained species composition via field survey (N = 766 individuals), museum specimens (N = 9,730) and literature records (N = 4,763). Sampling area was divided in four spatially explicit geomorphological units, representing historical predictors. Climatic descriptors were represented by the first two axis of a Principal Component Analysis. Spatial predictors in different spatial scales were described by Moran Eigenvector Maps. Redundancy Analysis was implemented to partition the explained variation of species composition by geomorphological, climatic and spatial predictors. Moreover, spatial autocorrelation analyses were used to test neutral theory predictions. Beta diversity was spatially structured in broader scales. Shared fraction between climatic and geomorphological variables was an important predictor of species composition (13%), as well as broad scale spatial predictors (13%). However, geomorphological variables alone were the most important predictor of beta diversity (42%). Historical factors related to geomorphology must have played a crucial role in structuring amphibian beta diversity. The complex relationships between geomorphological history and climatic gradients generated by the Serra do Mar Precambrian basements were also important. We highlight the importance of combining spatially explicit historical and contemporary predictors for understanding and disentangling major drivers of beta diversity patterns.

We investigated schooling behavior of Phasm ahyla cochranae including its periodicity based on periodic regression models. The school structure and differences between day and night were discussed. We found that tadpoles formed aggregative schools, which were significantly more frequent during the day than at night. During the day, from 06:30 to 18:00 h, tadpoles formed one or two polarized schools at the water surface. Based on these results and on observations of specific behaviors, we suggest that daylight may be a significant environmental factor related to schooling behavior in P. cochranae, although this hypothesis needs to be further investigated.

Investigate how ecological and/or evolutionary factors could affect the structure of ecological communities is a central demand in ecology. In order to better understand that we assessed phylogenetic and functional structure of 33 tadpole communities in the Atlantic Forest coastal plains of Southeastern Brazil. We tested the assumption that phylogenetic conservatism drive tadpole traits. We identified 32 communities with positive values of phylogenetic structure, with 18 of those being significantly clustered. Twelve of 33 communities showed aggregated functional structure. Trait diversity was skewed towards the root, indicating phylogenetic trait conservatism and evolutionary factors as important drivers of tadpoles community structure. Six out of 11 environmental variables were selected in the best explanatory model of phylogenetic structure. Water conductivity, external and internal diversity of vegetation structure, canopy cover, and dissolved oxygen were negatively related with phylogenetic clustering, whereas presence of potential fish predators was positively related. Four of those environmental variables and area were also included in the best explanatory model of functional structure. All variables represent factors related to performance, survivorship, and distribution of anuran communities. From the 12 functionally structured communities, 10 were also phylogenetically structured. Thus, environmental factors may be acting as filters, interacting with phylogenetically conserved species traits, and driving linage occurrence in tadpole communities. Our study provides evidence that phylogenetic and functional structure in vertebrates are a result of interacting ecological and evolutionary agents, resulting in structured anuran assemblages.