Do biological traits drive geographic patterns in European amphibians?

Journal article

Aims: The contemporary biogeography of European amphibians has been hypothesized to have arisen from range expansion and recolonization of the northern part of the continent from southern late Pleistocene refugia, such that northern species generally possess large ranges, while southerly species are mostly small-ranged. Here, we test the hypothesis that these patterns are likely to be underpinned by biological traits associated with dispersal ability, by means of analyses of data for anurans and urodeles, the two main groups of European amphibians.
Location: Europe.
Methods: We built a database of biological traits (body size, fecundity, life span, habitat specialization) of European amphibians, excluding island endemics. We mapped basic macroecological patterns of range size and position, and analysed the causal pathways for range size using structural equation models (SEM).
Results: Amphibian species of small-range size are largely restricted to areas in Southern Europe associated with putative Pleistocene refugia. Those present in Northern Europe are exclusively large-ranged species whose distributions extend all the way from Southern Europe. SEMs explained 54% of range size variation for anurans, with long life span and high fecundity being influential explanatory variables, and explained 61% of range size variation within urodeles, with measures of species fecundity influential.
Main conclusions: Species that have successfully recolonized the north following deglaciation have the largest ranges, for both groups of amphibians. These large-ranged species generally possess traits that indicate rapid range expansion potential, with differences apparent in the balance of traits between anurans and urodeles. The traits linked to northern distributions (and large range size) appear to be a mix of r and K traits, indicating that intermediate life history strategies have proved to be optimal for range expansion into northern regions. These results integrate species biology with geographical history in explaining contemporary patterns of species distribution, range size and diversity.

Authors: Whittaker, R; Trakimas, G; Borregaard, M

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Wiley
• Journal: Global Ecology and Biogeography
• Volume: 25
• Issue: 10
• Pages: 1228–1238
• Publication date: 2016-06-06
• Acceptance date: 2016-05-12
• DOI: 10.1111/geb.12479
• EISSN: 1466-8238
• ISSN: 1466-822X
• Keywords: amphibian biogeography; developmental biology; structural equation models; macroecology; trait biogeography; habitat specialization; geographic range size; body size; Europe; clutch size