Amphibian diversity on the roof of Africa: unveiling the effects of habitat degradation, altitude and biogeography

作者：Zancolli Giulia^*; Steffan Dewenter Ingolf; Roedel Mark Oliver

来源：Diversity and Distributions, 2014, 20(3): 297-308.

DOI：10.1111/ddi.12161

<jats:title>Abstract</jats:title><jats:sec><jats:title>Aim</jats:title><jats:p>Elevational gradients and land use changes can act together as drivers of species richness and composition. Responses to these drivers can be multidirectional, and resulting patterns of diversity might be unexpected or difficult to interpret. Present ecological relationships often reflect a legacy resulting from the influence of past geological, climatic and environmental changes on species dispersal, extinction and speciation. Here, we investigate amphibian diversity along altitudinal and disturbance gradients and evaluate how historical events may underlie contemporary distributional patterns.</jats:p></jats:sec><jats:sec><jats:title>Location</jats:title><jats:p>Mount Kilimanjaro, Tanzania.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>During two rainy seasons in 2011, we recorded anurans at 36 sites from the foothills to 3500 m altitude. A combination of multiple regression, ordination technique and cluster analysis were used to determine the effects of altitudinal changes and habitat modification on species richness and composition. Furthermore, we compared the anuran fauna of Mt. Kilimanjaro with other East African mountains by means of cluster analysis and analysed patterns of distributions with a special focus on montane forest species.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Species richness declined with elevation and species assemblages were distinctly separated between lowland and highland altitudes. Presence of water bodies locally increased species richness, but we did not find significant correlations of species richness with other environmental variables. Mountains clustered into two major groups which reflected latitudinal position and differences in species distributions.</jats:p></jats:sec><jats:sec><jats:title>Main conclusions</jats:title><jats:p>This study highlights the importance of considering the geological history of a place especially when assessing the effects of anthropogenic disturbance. The young age of the volcano and the complex biogeographical processes which occurred in East Africa during the last 20 million years prevented most montane forest frogs from colonizing Mt. Kilimanjaro. Increasing aridification and land use changes may cause contraction of breeding sites with consequent local extinctions in the near future.</jats:p></jats:sec>

• 出版日期2014-3