Chamois in climate change
Chamois live in Switzerland today in the Jura, in some areas of the Central Plateau and especially in the Alpine region. This was not always the case: 20,000 years ago, during the last ice age, the Alps were completely covered by glaciers. At that time, chamois lived in areas with steep slopes north and south of this ice mass.
In his master's thesis at WSL, environmental scientist Flurin Leugger has now investigated how the habitat of the animals has shifted from then to now and what factors played a role in this. With the help of genetic analyses and computer simulations, he traced what has restricted the chamois' distribution routes. With this method, researchers will also be able to look into the future and predict, for example, how the animals might react to today's global warming.
A look into chamois genes
First, Leugger, together with researchers from the Universities of Grenoble Alpes and Savoie Mont Blanc (France), investigated how closely the various chamois populations in the Alpine region are genetically related to each other. For this purpose, the researchers used blood samples or fur tufts collected by various hunting administrations, nature parks and NGOs. In total, the researchers analysed the genetic information of 449 chamois from France, Austria, Italy, Slovenia, Croatia and Switzerland.
The results showed that the alpine chamois population consists of two main genetic groups. One group lives in the western Alps up to the Rhone Valley in Valais, the other east of the Rhone Valley.
From the Ice Age to the Present Day
In a second step, Leugger reconstructed the characteristics of the ideal chamois habitat from the current distribution of chamois and from climate and topography data. "Above all, the slope, the temperature and the amount of precipitation influence whether chamois feel comfortable," says Leugger. The researcher trained various machine-learning models with these characteristics. He then applied these to the climate conditions 20,000 years ago. This produced a detailed map of the possible distribution of chamois at the end of the last ice age.
In a final step, Leugger used the changing climate conditions to simulate the distribution of chamois populations during the following 20,000 years until today. The simulations showed how the chamois increasingly colonised the Alpine region as the climate warmed and the glaciers receded. The researcher varied certain parameters of the simulations, such as the average migration speed of the chamois, or he added artificial geographical obstacles. He compared the result of each simulation with the current genetic distribution of the animals. This way, Leugger understood more and more about the influences that cause chamois populations to spread.
The future of chamois
One of the findings: Chamois migrate only over short distances, mostly spending their lives in the immediate vicinity of their birthplace. In addition, there are geographical hurdles that the animals do not cross - especially large rivers and wide, flat valleys. "Chamois apparently avoid flat valley terrain where they might be exposed to their predators such as wolves and lynxes," explains Leugger. This is probably why they very rarely spread beyond these geographical borders.
These findings can now be used to study future developments. As with the climate of the ice age, Leugger's models also allow for predictions with future climate scenarios - and could thus indicate in further studies how the chamois react to increasing climate warming. "In future, we could identify particularly isolated and therefore vulnerable populations that should be hunted sparingly," says the environmental researcher. His cooperation partners are also working on refining the model to examine smaller-scale influences. This will then even make it possible to predict whether and how new constructions - roads, for example - will affect the chamois.