Plant translocations in Europe and the Mediterranean: Geographical and climatic directions and distances from source to host sites

Abstract

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.

Exploring the potential for plant translocations to adapt to a warming world

“…While the translocations presented by Diallo et al. (2021) were not initiated to investigate plant response to climate change, the large number of locations across a range of climatic conditions form a dataset that could contribute to plant response monitoring in the future. Diallo et al.…”

“…Diallo et al. (2021) work provides an important dataset upon which to base such an initiative but information about historical ranges and conditions, as well as the effects of climate on recruitment, growth, vulnerability to disease or herbivory, and other factors affecting population demography will be important to add to the existing data. The study by Pedlar et al (2021) uses provenance trials to understand plant growth response (measured as tree height) to climate variability.…”

“…The analyses of Pedlar et al (2021) and Diallo et al. (2021) represent important steps forward in the use of plant translocation data and highlight the need for improved monitoring of translocations so that valuable insights can be made regarding plant response to climate change. There are also many additional translocations detailed in the databases of Plant Translocation Network members (e.g.…”

“…Developing a global monitoring array from existing plant translocations can constitute a significant contribution to tracking and understanding plant responses to climate change but existing translocation databases (Colas & Sarrazin, 2017; Dalrymple et al., 2011; Godefroid et al., 2011; Winder, 2017), and indeed, the papers by Pedlar et al (2021) and Diallo et al. (2021) featured in this Special Focus are static snapshots in time. ‘Living’ platforms that continuously collate and accumulate data could facilitate the identification of critical response thresholds and better guide the timing and extent of potential adaptation activities.…”

“…However, recognising that existing field trials can have utility beyond their original purpose is not without precedence(Sykes & Silvertown, 2020), and there is an opportunity to learn more. Assembling data on plant translocations can start now and we can draw up new baselines that chart plant response to recent climate change and monitor the future response as warming accelerates.In this Special Focus, we present a series of papers that draw together data on many species to demonstrate how the use of translocation studies/experiments to monitor climate change is feasible Diallo et al (2021). collated data from the source and recipient sites of 638 translocations in Europe and the Mediterranean representing 280 taxa.…”