Marmots successfully reintroduced into the Pyrenees

13/07/2016

Researchers Mariona Ferrandiz-Rovira, Bernat Claramunt (CREAF and UAB) and Irene Figueroa (CREAF) have studied the genetic variability and origin of the three Alpine marmot colonies (Marmota marmota) located in three areas of the Pyrenees mountains (Andorra, Cerdanya and Ripollès). The research has allowed scientists to discover that the marmots reintroduced into the Pyrenees differ only slightly when it comes to genetics, originate from only two different Alpine locations and, moreover, there have been no genetic exchanges among the groups.

Genetic diversity in populations is important in general, but it is even more so when the populations are small, as happens when a species is reintroduced. The reason is that "when there is little genetic diversity, the probability of extinction rises and the capacity to adapt to new surroundings diminishes, and this implies inevitable change", Ferrandiz-Rovira states. For these reasons, researchers soon plan to study how climate change affects these populations.

The low number of founding individuals - some 400 reintroduced during 40 years - together with the geographic and genetic isolation "has caused a reduction in the genetic diversity of the three colonies. The colony in the Ripollès region is genetically very different from the other two", Mariona Ferrandiz-Rovira explains.

The founders come from two different geographic areas
"Since they have not mixed, each of the Pyrenees' colonies still maintains similarities with the original colony in the Alps, and that is why we were able to identify where they came from with such precision", the researcher says. At first, researchers suspected that all marmots reintroduced came from the same Alpine region, but later discovered they came from two different places: those reintroduced into Andorra and Cerdanya originate from Mercantour, in the southern Alps; while those in the Ripollès region come from the northern Alpine region of Vanoise.

The reintroduction nevertheless has been a success
The reintroduction of alpine marmots into the Pyrenees during a large part of the 20th century was often a poorly coordinated and badly documented process, without any clear registry of the origins of the individuals reintroduced. Marmots in the Pyrenees became extinct some 15,000 years ago, and were reintroduced into different parts of the French Pyrenees between the years 1948 and 1988, where they soon made it their home and colonised almost all of the southern slope. At first, almost 400 founding marmots were released and soon they grew to become 1,000. Therefore, despite the lack of monitoring and low genetic diversity in the populations studied, the reintroduction has been a success and marmots once again roam the Pyrenees.

This study aims both to become a base of knowledge and a guide for other reintroductions, of these and other species. It especially aims to help - after many failed attempts - in the final reintroduction of this species into the eastern Alps, and in the reintroduction of the Vancouver Island marmot (Marmota vancouverensis), on the brink of extinction.

Original article: Bichet, C., Ferrandiz-Rovira, M., Claramunt, B., Figueroa, I. et al. "Multiple geographic origins and high genetic differentiation of the Alpine marmots reintroduced in the Pyrenees." (2016) Conservation Genetics. DOI: 10.1007/s10592-016-0851-4