Strauß, L., Lima, R.F., Riesbeck, F. & Rödel, M.O. (2018) São Tomé Island endemic treefrogs (Hyperolius spp.) and land-Use intensification: a tale of hope and caution.Tropical Conservation Science, 11, 1-14. DOI:10.1177/1940082918776434 (IF2018 1,327; Q3 Biodiversity Conservation)
Forest degradation is a major driver of the global biodiversity declines. However, responses to forest degradation vary greatly between taxa and are predominantly understudied. This study investigates the effects of land-use change on the endemic amphibian fauna of São Tomé Island (Central Africa), where a fast-growing human population increases pressure on forest resources. We sampled acoustic data on reed frog (Hyperoliusspp.) abundance at eight transects in each of four land-use categories, representing different levels of forest degradation: old-growth forest, secondary forest, agroforest, and horticulture. While Hyperolius molleri was most abundant in secondary forest and horticulture, Hyperolius thomensis was almost exclusively found in agroforest. We interpret these differences based on reproductive traits, since both species deposit terrestrial eggs and have aquatic larvae, but reproduce in different microhabitats. H. molleri utilizes open water bodies bordered by vegetation for calling and oviposition, which human disturbance has made available in secondary forest and horticulture. In contrast, H. thomensis breeds in water-filled tree holes (phytotelmata), which predominantly occurred in agroforest, often within coral trees (Erythrina spp.). This first study on Santomean amphibian abundances revealed that H. molleri and H. thomensis males exhibit distinct nonlinear responses to forest degradation and may reap some benefit from human habitat alteration. However, despite their apparent tolerance to some anthropogenic disturbance, further land-use intensification may reduce overall habitat suitability for these and other endemic species.