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Correlates of vertebrate species richness over Europe across scales

What determines patterns of species richness is a fundamental question in biogeography. A new paper led by Maud Mouchet, just published in PLoS ONE, provides new insights related to this question by assessing avian, amphibian, and mammalian richness patterns in Europe across scales using boosted regression trees. Land cover and evapotranspiration were main correlates of vertebrate species richness over Europe, correlates varied substantially among regions and across scales - with land-use/land-cover becoming more important at finer scales.


Testing the Effectiveness of Environmental Variables to Explain European Terrestrial Vertebrate Species Richness across Biogeographical Scales


Maud Mouchet | Christian Levers | Laure Zupan | Tobias Kuemmerle | Christoph Plutzar | Karlheinz Erb | Sandra Lavorel |Wilfried Thuiller | Helmut Haberl

 

We compared the effectiveness of environmental variables, and in particular of land-use indicators, to explain species richness patterns across taxonomic groups and biogeographical scales (i.e. overall pan-Europe and ecoregions within pan-Europe). Using boosted regression trees that handle non-linear relationships, we compared the relative influence (as a measure of effectiveness) of environmental variables related to climate, landscape (or habitat heterogeneity), land-use intensity or energy availability to explain European vertebrate species richness (birds, amphibians, and mammals) at the continental and ecoregion scales. We found that dominant land cover and actual evapotranspiration that relate to energy availability were the main correlates of vertebrate species richness over Europe. At the ecoregion scale, we identified four distinct groups of ecoregions where species richness was essentially associated to (i) seasonality of temperature, (ii) actual evapotranspiration and/or mean annual temperature, (iii) seasonality of precipitation, actual evapotranspiration and land cover) and (iv) and an even combination of the environmental variables. This typology of ecoregions remained valid for total vertebrate richness and the three vertebrate groups taken separately. Despite the overwhelming influence of land cover and actual evapotranspiration to explain vertebrate species richness patterns at European scale, the ranking of the main correlates of species richness varied between regions. Interestingly, landscape and land-use indicators did not stand out at the continental scale but their influence greatly increased in southern ecoregions, revealing the long-lasting human footprint on land-use–land-cover changes. Our study provides one of the first multi-scale descriptions of the variability in the ranking of correlates across several taxa.

 

Link to the manuscript: DOI: 10.1371/journal.pone.0131924

Citation: Mouchet, M. A., Levers, C., Zupan, L., Kuemmerle, T., Plutzar, C., Erb, K.-H., Lavorel, S., Thuiller, W., and Haberl, H. (2015): Testing species richness hypotheses across scales with European terrestrial vertebrates. PLoS ONE, 10, e0131924.