Aim: The persistence and stability of habitats through time are considered predictors of high levels of biodiversity in some environments. Long-term habitat persistence and stability may explain the species-rich, endemic forest fauna and flora of the Eastern Afromontane Biodiversity Region (EABR). Using comple- mentary phylogenetic and biogeographical approaches, we examine evolution- ary patterns in EAR brevicipitid frogs. Using these data, we test whether brevicipitid history reflects patterns of long-term forest persistence and/or sta bility across the EABR.
Location: East Africa.
Methods: A dated phylogeny for brevicipitids was constructed using two nuclear and three mitochondrial markers. Alternative diversification modes were used to determine signal for constant or varying net diversification rates. Using our dated tree, we identified areas of high phylogenetic diversity (PD), and inferred ancestral areas using likelihood and Bayesian approaches.
Results: Brevicipitids have a long history, with generic diversification among extant lineages pre-dating the Oligocene (> 33 Ma). Ancestral-area reconstruc- tions indicate the presence of brevicipitids in the EAR since the Oligocene, and support a scenario of palacoendemics surviving in EABR refugia. Ancestral-area reconstructions indicate that the central Eastern Arc Mountains (FAM) formed the initial centre of diversification of forest brevicipitids. Measures of PD show that diversity varies across the EABR but is highest in the AM. Constant net diversification rate in brevicipitids is a significantly better fit than alternative, rate-variable models.
Main conclusions: The degree of persistence of forest habitats appears to be a contributing factor to the varying levels of diversity across the EAR in brevicipitids (and other organisms). In contrast to the Southern Highlands and Ethio pian Bale Mountains, the EAM stands out as an area that enabled the constant accumulation of brevicipitid species over a long period of time.
Copyright © 2014, Wiley.
Loader, P. S., Ceccarelli, F. S., Menegon, M., Howell, K.M., Kassahun, R., Mengistu, A. A., Saber, S. A, Gebresenbet, F., de Sá R. O., Davenport, T.B.D., Larson, J., Müller, H., Wilkinson, M., and Gower, D.J. 2014. Persistence and stability of Eastern Afromontane forests: evidence from brevicipitid frogs. Journal of Biogeography 41(9)1781-1792.