Dramatic Declines of Montane Frogs in a Central African Biodiversity Hotspot

PLoS One. 2016 May 5;11(5):e0155129. doi: 10.1371/journal.pone.0155129. eCollection 2016.

Abstract

Amphibian populations are vanishing worldwide. Declines and extinctions of many populations have been attributed to chytridiomycosis, a disease induced by the pathogenic fungus Batrachochytrium dendrobatidis (Bd). In Africa, however, changes in amphibian assemblages were typically attributed to habitat change. We conducted a retrospective study utilizing field surveys from 2004-2012 of the anuran faunas on two mountains in western Cameroon, a hotspot of African amphibian diversity. The number of species detected was negatively influenced by year, habitat degradation, and elevation, and we detected a decline of certain species. Because another study in this region revealed an emergence of Bd in 2008, we screened additional recent field-collected samples and also pre-decline preserved museum specimens for the presence of Bd supporting emergence before 2008. When comparing the years before and after Bd detection, we found significantly diminished frog species richness and abundance on both mountains after Bd emergence. Our analyses suggest that this may be the first disease-driven community-level decline in anuran biodiversity in Central Africa. The disappearance of several species known to tolerate habitat degradation, and a trend of stronger declines at higher elevations, are consistent with Bd-induced declines in other regions. Not all species decreased; populations of some species remained constant, and others increased after the emergence of Bd. This variation might be explained by species-specific differences in infection probability. Increased habitat protection and Bd-mitigation strategies are needed for sustaining diverse amphibian communities such as those on Mt. Manengouba, which contains nearly half of Cameroon's frog diversity.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Africa
  • Animals
  • Anura / growth & development*
  • Anura / microbiology*
  • Biodiversity
  • Cameroon
  • Chytridiomycota
  • Ecosystem
  • Museums
  • Mycoses / microbiology
  • Retrospective Studies
  • Species Specificity
  • Specimen Handling

Grants and funding

This work was supported by Elsa Neumann Stipend (scholarship from the federal state of Berlin), MH; German Academic Exchange Service, https://www.daad.de/en/, MH; German Herpetological Society (DGHT Leipzig), http://www.terraristik-leipzig.de/index.htm, MH; Museum of Comparative Zoology (Harvard University), http://www.mcz.harvard.edu/, DCB; Project Exploration, http://www.projectexploration.org/, DCB; California Academy of Science, http://www.calacademy.org/, DCB; US National Science Foundation (DEB 1202609), http://www.nsf.gov/, DCB; Royal Zoological Society of Scotland, http://www.rzss.org.uk/, DCB; Zoological Society of London, http://www.zsl.org/, TMD-B; University of Aberdeen, http://www.abdn.ac.uk/, TMD-B; Mohammed bin Zayed Conservation Fund, http://www.speciesconservation.org/, TMD-B; European Association of Zoos & Aquaria, http://www.eaza.net/, TMD-B. The publication of this article was funded by the Open Access fund of the Leibniz Association. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.