Beta-diverzita ptáků napříč výškovými gradienty

Petrová, Klára

Mountains are recognized worldwide as biodiversity hotspots with a high proportion of both endemic and specialized species. This thesis describes and compares patterns of bird beta-diversity along elevational gradients in tropical and temperate mountain regions. Beta-diversity, the turnover of species composition along an environmental gradient, is a key concept in the understanding of the spatial structure of ecological communities. By linking and comparing studies from different mountain systems (e.g., the Andes, the Cameroon Highlands, the Altai Mountains, the Swiss Alps), this work attempts to document variations in beta-diversity patterns, i.e. turnover and nestedness, along elevation gradients. Results show that tropical mountains generally demonstrate high beta-diversity mainly due to high species turnover. This is associated with a gradient of environmental heterogeneity, which is also accompanied by higher specialization and limited dispersal for tropical species. In temperate regions, even if they tend to show lower beta-diversity, evident turnover is detectable, especially in ecotones such as treelines and transitions from lowland to alpine forests. Beta-diversity peaks usually occur at mid-elevation in both the tropical and temperate systems, coinciding with the areas of rapid change in...

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