The role of phytophysiognomies and seasonality on the structure of ground-dwelling anuran (Amphibia) in the Pampa biome, southern Brazil

Abstract

Considering that habitat use by amphibians is related both with climate and environmental features, we tested the hypothesis that anuran assemblages found in different phytophysiognomies and in different seasons vary in structure. Additionally, we searched for species which can be indicators of habitat and seasons. The study was conducted in the Pampa biome, southern Brazil. Sampling was done through pitfall traps placed in three phytophysiognomies: grassland, ecotone grassland/forest; and forest. The seasonality factor was created by grouping months in warn and cold seasons. Sixteen species were found and the assemblages were influenced both by phytophysiognomies and climatic seasonality. In a paired comparison, the three phytophysiognomies differed in structure of assemblage from each other. Physalaemus henselii, P. riograndensis, Pseudopaludicola falcipes and Pseudis minuta were indicators of ecotone. Leptodactylus gracilis and Physalaemus biligonigerus were indicators of grassland. None species was indicator of forest. Most of the species were indicators of warm season: Elachistocleis bicolor, Leptodactylus fuscus, L. gracilis, L. latinasus, L. latrans, L. mystacinus, Physalaemus biligonigerus, P. cuvieri and Pseudis minuta. None species was indicator of cold season. We found that even for species of open areas, as Pampa, heterogeneous phytophysiognomies are important for maintaining abundance and constancy of populations of anuran.

Seasonal variation in the composition of ground-dwelling anuran (Amphibia) assemblages in southern Brazil

“…Here, we further support previous findings (Inger and Colwell, 1977;Maragno et al, 2013) that assemblages from structurally less stable habitats suffer high variation in composition across seasons. Seasonality in temperature, rainfall and photoperiod influence the phenology and productivity of plant communities (Soares et al, 2005;Overbeck et al, 2006;Liebsch and Mikich 2009;Longhi et al, 2011), causing changes to habitat heterogeneity and resource availability, which consequently influence the peaks of anuran species reproduction and their patterns of habitat use (Inger and Colwell, 1977;Both et al, 2008;Canavero et al, 2008;Santos et al, 2008;Maragno et al, 2013). As forest habitats are seasonally more stable than grassland habitats in regard to habitat structure, we initially suspected that anuran taxonomic, functional and phylogenetic composition would be more stable throughout the changing seasons in the forest habitat.…”

“…Many studies show evidence for within-habitat variation in anuran assemblage composition across seasons due to the varying environment (e.g., Both et al, 2008;Canavero et al, 2008;Santos et al, 2008;Santos-Pereira et al, 2011;Rievers et al, 2014). However, a few studies attempt to understand whether assemblages from different habitats show distinct degrees of variation in composition across seasons (e.g., Inger and Colwell, 1977;Maragno et al, 2013).…”

“…It has been suggested that seasonality in temperature, photoperiod and rainfall might control the peaks of anuran reproduction and richness in subtropical and temperate regions, whereas abundant rainfall might sustain continuous anuran reproduction in tropical regions Both et al, 2008;Canavero et al, 2008). Further, climate seasonality can differentially influence the vegetation heterogeneity and resource quality of an area, as the effects of climate seasonality depend on the habitat type (Maragno et al, 2013;Gonçalves et al, 2015). Here, we evaluated the seasonal variations in the composition of anuran assemblages from forest and grassland habitats, which are two habitats differently influenced by climate seasonality.…”

“…Structural particularities of habitats, as well as their intrinsic dynamics, should strongly influence not only species but also the functional and phylogenetic composition of anuran assemblages (Inger and Colwell, 1977;Urbina-Cardona et al, 2006;Maragno et al, 2013). Differences in richness have been observed when comparing anuran assemblages in stable and heterogeneous habitats to assemblages in unstable and homogeneous habitats (Inger and Colwell, 1977;Xavier and Napoli, 2011;Oliveira et al, 2013;Jimenez-Robles et al, 2017).…”

Anurans of a remnant forest in Urussanga, Santa Catarina, southern of Brazil

“…Temporary habitats (including the MOA site) tend to have less pressure from predators than permanent environments (Heyer et al 1975), thereby allowing diversity and species richness (Skelly 1997). In contrast with permanent environments tend to be colonized by species with long reproductive periods, such as Dendropsophus minutus and Hypsiboas faber and species of the family Leptodactylidae (Maragno et al 2013;Wells 1977). The abundance of rare species observed in this study may be due to occasional records while anurans were moving to breeding sites or to shelter areas, which were not the sampling sites themselves (e.g., Phyllomedusa distincta, Scinax granulatus, and Scinax perereca).…”