Conserving intraspecific diversification in a warmer world – a case study on endemic high-mountain plants of the Pyrenees

Southern European mountain ranges harbor a remarkable plant biodiversity. The Pyrenees, the principal mountain range of southwestern Europe, are home to more than 4300 plant species of which c. 300 are endemic. Upslope migration of alpine plants caused by temperature increase conferred by climate change has the most dramatic consequences for relatively low ranges such as the Pyrenees. It is therefore of urgent importance to set conservation strategies.

For a long time conservation efforts have targeted ecosystems or species, but in recent years a new focus has been put on cryptic intraspecific diversity on the genetic level. The idea of phylogenetic endemism combines phylogenetic and distribution data to identify unique intraspecific lineages, which are distributed in a limited area. Conserving the intraspecific diversity of species increases their chance of adaptation through maintenance of their genetic resources. Apart from that, it is important to focus conservation strategies on areas, which do not only possess high levels of inter- and intraspecific diversity and endemism, but also enable long-term survival of species by offering the possibility of niche tracking via upslope migration. To this end, we will integrate molecular data obtained from the next generation sequencing based technique “restriction site associated DNA sequencing”, species richness data and retrospective as well as prospective distribution modelling of species and intraspecific lineages.

The aims of the project are to 1) identify glacial refugia for alpine plants endemic to the Pyrenees, 2) identify areas of high phylogenetic endemism for alpine plants endemic to the Pyrenees and compare them with the geographic distribution of alpine species’ richness, and 3) model the future distribution of alpine habitats and identify areas with high stability of climatic suitability under different climate change scenarios. Finally, priority areas for conservation of alpine plants will be defined where diversity and endemism indicators as well as future stability of climatic suitability are maximized.

We will test the following hypotheses: (1) Glacial refugia for endemic alpine plants in the Pyrenees are found along their eastern and western margins, the southern Pre-Pyrenees and formerly unglaciated areas along the main chain. (2) Pyrenean endemics show a geographically structured distribution of intraspecific lineages, with areas of high phylogenetic endemism overlapping with glacial refugia. (3) Areas of future stability of climatic suitability are found in the central Pyrenees, where mountains reach the highest altitude, thus allowing for future niche tracking. The present project is the first comparative intraspecific phylogeographic study of alpine plants of the Pyrenees, with the added value of a direct application of the results towards prioritizing areas for conservation.