Habitat Loss Reduces the Diversity of Frog Reproductive Modes in an Atlantic Forest Fragmented Landscape

Abstract

Several amphibian species have ecological traits that can make them vulnerable to landscape changes, such as habitat preference and reproductive strategies. We evaluated how anuran species and their respective reproductive modes were distributed in an Atlantic Forest fragmented landscape, Southeastern Brazil. We sampled through visual encounter surveys three continuous forest sites, 12 forest fragments and five pasture areas (matrix) between July 2007 and March 2010. We recorded 50 anuran species with 15 reproductive modes, a third of them (33.3%) recorded only in continuous forest sites (modes 3, 8, 19, 25 and 36). These reproductive modes found only in continuous forest sites are typically forest-associated, and seem to be more vulnerable to habitat loss. Additionally, we found a trend for larger fragments to harbor both higher number of types of reproductive sites and diversity of frog reproductive modes. Our findings suggests that fragment sizes can better predict the number of frog reproductive modes than the species richness in Atlantic Forest fragmented landscapes, and highlights the need to consider frog reproductive traits in future studies.Abstract in Portuguese is available in the online version of this article.

Habitat amount drives the functional diversity and nestedness of anuran communities in an Atlantic Forest fragmented landscape

“…Species closely associated with rivers and streams inside the forest seem to be the most affected by habitat loss because most are recorded only inside continuous forest areas and large forest fragments (Almeida‐Gomes & Rocha, ). In previous studies in the same area, the diversity of frog reproductive modes was much lower in forest fragments compared to continuous forest sites, and there was a trend for larger fragments to harbor both the higher number of types of reproductive sites and diversity of frog reproductive modes (Almeida‐Gomes & Rocha, ; Almeida‐Gomes, Vieira et al., ). Indeed, in fragmented rainforests of Madagascar, the presence of streams was the factor that most contributed to functional richness of frogs in all land‐use categories (Riemann, Ndriantsoa, Rödel & Glos, ).…”

“…To test these hypotheses, we used a dataset obtained during the largest empirical study (in terms of number of fragments and range of fragment sizes) ever conducted in tropical forests with amphibians (Almeida‐Gomes, Vieira et al., ). Amphibians are considered key indicators of landscape changes (Cushman, ; Schneider‐Maunoury et al., ), and there is evidence that some species and some ecological traits (especially reproductive modes) are more prone to disappear in the environments outside large remnants in fragmented forest landscapes (Almeida‐Gomes & Rocha, ; Almeida‐Gomes, Vieira et al., ; Fonseca et al., ).…”

“…Third, we determined whether the communities we studied were functionally nested by the amount of forest habitat. Based on previous evidence of trait-mediated loss due to habitat loss (Almeida-Gomes & Rocha, 2015;Bregman, Sekercioglu & Tobias, 2014;Newbold et al, 2013), our hypothesis was that some ecological traits are present only in local landscapes with high amount of habitat, and that progressive habitat loss causes non-random loss of ecological functions.…”

Amphibian sensitivity to habitat modification is associated with population trends and species traits

“…Several recent field studies, however, have reported decreases in functional diversity with decreasing habitat area as well as traits correlated with the dependence of species on forest habitat (Almeida‐Gomes & Rocha, ; Trimble & van Aarde, ). For example, diversity of reproductive modes decreased in forest fragments and pastures compared with intact forest in Brazil (Almeida‐Gomes & Rocha, ), and functional groups of amphibians characterized by ground‐dwelling microhabitat use and terrestrial egg‐laying were most sensitive to land use in South Africa (Trimble & van Aarde, ). A meta‐analysis also reported that sensitivity of wetland vertebrates [including amphibians] to habitat loss was associated with low reproductive rates (Quesnelle, Lindsay, & Fahrig, ).…”

State of the World's Amphibians

“…For example, a study found that larger fragments of a tropical forest contained a greater diversity of reproductive modes than smaller fragments, and that one-third of all reproductive modes were restricted to forest habitats (64). The loss of functional diversity will alter ecosystem dynamics and provision of ecosystem services.…”