Plant Translocations In Europe And The Mediterranean: Geographical And Climatic Directions And Distances From Source To Host Sites

Although the number of plant translocations has been rapidly increasing for two decades, no study is available to date that examines the directions and distances of plant displacements, which is essential (though not sufficient) information for considering translocations as a management tool to enable species to cope with the consequences of climate change.In this paper, we study the geographical and climatic directions and distances from source to host sites in 638 source-and-host site pairs of plant translocations that aimed to achieve viable populations in the last decades in the Western Palearctic (Europe and the Mediterranean). Translocation distances ranged from 0 to 661 km, but were generally short, most (82%) being <25 km, due to both ecological considerations and legal and administrative constraints. The host sites were not preferentially located in any geographical direction or in any altitude relative to the source sites. In contrast, on a climate compass constructed from a principal component analysis of seven bioclimatic variables, the host sites were slightly, but significantly, under colder climatic conditions than the source sites.This observation appears more to be the consequence of an effort to counteract already felt effects of climate change than to anticipate future changes. The climatic distance between source sites and actual host sites was generally smaller than between source sites and randomly selected host sites at a given distance or within a given geographical area, which may be the result of a desire to minimise climatic differences or differences in other ecological factors correlated with climatic differences.Synthesis. This study is the first to compare, geographically and climatically, the source sites of biological material and the host sites in translocations of wild plant species to obtain viable populations. Past translocations in the Western Palearctic are in line with mitigating the consequences of global warming on plant species because the host sites were in slightly cooler conditions than the source sites. Despite this, climate considerations seem to have little been taken into account in plant translocation projects and will certainly have to be much more so in a future with rapid anthropogenic climate change.