Abundance and survival rates of three leaf-litter frog species in fragments and continuous forest of the Mata Atlântica, Brazil

Abstract

Habitat destruction and fragmentation alter the quality of habitats and put populations under the risk of extinction. Changes in population parameters can provide early warning signs of negative impacts. In tropical forests, where habitat loss and fragmentation are vast, such indicators are of high relevance for directing conservation efforts before effects are irreversible. Most of our knowledge from tropical ecosystems originates from community level surveys, whereas our understanding of the influence of habitat conversion on vital rates of species is limited. This study focused on the influence of anthropogenic habitat fragmentation on the survival probability and abundance of three leaf-litter frog species (Rhinella ornata, Ischnocnema guentheri and I. parva) in forest patches of the Atlantic rainforest of South-east Brazil compared to a continuous forest. The species differ in their matrix tolerance: high for R. ornata and low for I. guentheri and I. parva and, thus, we examined whether their survival and abundance correspond to this classification. Ischnocnema guentheri showed highest abundances in all study sites and low mortality in the forest patches compared to the continuous forest; I. parva was encountered only in isolated fragments, with very low mortality in one isolated fragment; and the matrix tolerant species had generally low abundance and showed no clear pattern in terms of mortality in the different sites. Our counter-intuitive results show that even matrix sensitive amphibian species may show high abundance and low mortality in RESEARCH ARTICLE Launched to accelerate biodiversity conservation A peer-reviewed open-access journalHenning Steinicke et al. / Nature Conservation 26: 77-96 (2018) 78 small forest patches. Therefore, these patches can be of high value for amphibian conservation regardless of their degree of matrix aversion. Landscape level conservation planning should not abandon small habitat patches, especially in highly fragmented tropical environments.

Reproductive Cycle, Size and Age at Sexual Maturity, and Sexual Dimorphism in the Stream-Breeding Frog Crossodactylus schmidti (Hylodidae)

“…Estimaciones de las tasas supervivencia para anfibios neotropicales solo están disponibles para unas pocas especies y se han centrado principalmente en la respuesta a la fragmentación (Steinicke, et al, 2018), variación temporal y entre clases de edad (Molina-Zuluaga et al, 2014;Loaiza -Piedrahita et al, 2016;Bardier, et al, 2019) o sobre en el efecto de quitridio (Ryan et al, 2008, McCaffery et al, 2013, manejo y conservación .…”

A meta‐analysis of the effects of fragmentation on the megadiverse herpetofauna of Brazil

“…For example, some generalist species inhabiting grasslands and open areas respond positively to habitat degradation associated with the introduction of alien plant species in the Pantanal (Moreira et al, 2016). Likewise, smaller fragments in the Atlantic Forest may provide higher availability of leaf‐litter invertebrates for amphibian species less sensitive to fragmentation (Steinicke et al, 2018). The reduction in the number and diversity of predators following fragmentation can similarly increase the abundance and survival probability of Neotropical anuran species (Poulin et al, 2001).…”