Effects of natural forest and tree plantations on leaf‐litter frog assemblages in Southern Brazil

Abstract

Anuran amphibians are extremely sensitive to changes in the environment and are severely threatened with extinction by human activities. The conversion of natural habitats to tree plantations is expanding in southern Brazil, emphasising the need for both scientists and society to understand the potential effects of this practice on animal communities. Here, we evaluated whether the richness, composition and abundance of leaflitter frogs change among natural forests, plantations of the native Araucaria angustifolia and plantations of an introduced pine Pinus spp. We obtained data on the composition of the leaf-litter frog assemblages by sampling natural forest and tree plantations in the Passo Fundo National Forest, southern Brazil. We sampled leaf-litter frogs using pitfall trap arrays from March 2017 to February 2018. We used generalised linear mixed models to estimate the effect of habitat type on leaf-litter frogs while considering variation induced by season effect and spatial autocorrelation. We recorded 311 individual leaf-litter frogs belonging to nine species and five families. We did not find differences in species richness and composition, total abundance and abundance of the most frequent species Physalaemus cuvieri, P. carrizorum and Rhinella icterica among Pinus plantations, Araucaria angustifolia plantations and natural forests. These results indicate that tree plantations and natural forests can be equally suitable to leaf-litter frogs. Such suitability is promoted by the light levels of management exerted on these plantations, the old age of the plantations and the heterogeneous mosaic of habitat types maintained within this National Forest. Our study shows that some management decisions can preserve habitat quality to wildlife in modified landscapes.

Leaf-Litter Anurans in An Agricultural Landscape in the araucaria Forest: A Case Study for Southern Brazil

“…Indeed, this result reinforces the conclusion that it is important to consider not only the taxonomic component but also the biological characteristics (traits) when verifying the type of environment in which a species is found. Also, when evaluating the effect of monocultures of tree plantations in assemblages of leaf-litter amphibians in the same region (northern Rio Grande do Sul), Cicheleiro et al (2021) found no differences among the species richness and taxonomic composition of species between these different plantations and the natural forests.…”

“…These landscape conversion processes led to the Araucaria Forest becoming a tremendously degraded environment, with most forest fragments being smaller than 80 ha (Ribeiro et al, 2009). Although these forests have been highly impacted, their leaf-litter layer provides moisture and a wide diversity of microhabitats, allowing the coexistence of a large number of individuals and species, as is the case of leaf-litter anurans (Fauth et al, 1989; Cicheleiro et al, 2021). Leaf-litter frogs are terrestrial anurans living in the layer of plant remains formed by fallen leaves, branches, and trunks deposited on the soil of the forests, participating in the food webs in this environment (Pontes and Rocha, 2011) and benefiting from the accumulation of this material.…”