The Alpine Marmot Project

Welcome to the Alpine Marmot Project

Climate change

Currently, climate change manifests as an increase in average temperatures and increased climactic disasters (extreme events such as storms, floods, etc.). These changes are already affecting the functioning of many ecosystems, which results in changes in distribution, number, and performance of many plant and animal populations. Understanding climate change is essential in predicting what challenges animal populations will face. Some phenotypic changes have already been observed in many plant and animal species, as well as changes in phenology (the temporal sequence of events in the life cycle). For example, in response to an early spring, the average date of egg laying of the Great Tit (Parus major) is 14 days earlier than it was 47 years ago. In 2007, the first eggs of the Rosalia longicorn (Rosalinia alpina L.) hatched in late May, a month earlier than in previous years. Where before, the first beetles hatched in May and June, they now appear in April. Research highlighting the impact of climate change on mammals is rare (16.4% of climate change research is on mammals compared to 41.7% on birds), and almost nonexistent in the alpine environment.

An initial study conducted on the yellow-bellied marmot (Marmota flaviventris), a species of marmot living in North America, has shown that in response to environmental changes, these marmots have adjusted their hibernation and reproduction. These changes in phenology led to a longer season of activity, and thus they were able to store more fat before the winter. This extension in the period of activity promotes both the survival and reproduction of the marmots, resulting in an increase in the population. In contrast, with the Alpine marmot we have shown that the average thickness of the snow insulating the burrows has gradually declined since the 90s. Winters are therefore especially harsh on the Alpine marmots, especially females, since the temperature inside the burrow is lower. It is likely that they spend more energy to maintain their body temperature high enough to survive the winter. Because of these climate changes, the females emerge from hibernation with a lower weight and give birth to smaller and smaller litters. This phenomenon could greatly reduce the size of our population of Alpine marmots. It is clear from these two marmot case studies that establishing strong predictions about the consequences of climate change on biodiversity requires detailed knowledge of the effects of climate on the biology and demographics of each species. For example, these two species of marmots evolve in different environments; the American marmot is benefited by snowfall that is on average four times higher than found in our study site. In addition, these two species differ notably in metabolism during hibernation, so the balance of snowfall and metabolism is much better in the American marmot.

Diminution of Alpine marmot litter size with decreasing snow depth in the population f of La Grande Sassière Nature Reserve since 1990

Understanding the responses of organisms to environmental disturbances, in order to implement management policies and plans of action, is a major challenge in ecology, responding to a pressing societal need. Currently, the impact of climate change is mainly studied using correlative approaches between biology and climate over time, determining how phenotypic traits (such as reproduction/survival) are changing in response to changes in the environment. However, if we want to predict the response of populations to climate change in the future, we need to know not only how phenotypic traits and fitness of individuals are changing, but also why. In other words, it is now important to identify the underlying mechanisms which explain the relationship between environmental stress and the biological changes observed.

In this context, we seek to understand firstly, how climate change will affect the dynamics of populations, and whether the observed changes are due to changes in the structures of populations and families (e.g. number of individuals, sex, age, number of auxiliary individuals helping to raise the young). Secondly, we seek to explore the physiological and behavioral mechanisms at the individual level which explain the observed changes in the population levels. Lastly, we want to discover what evolutionary processes are involved in the responses of species to climate change. The time frame with which data for the Alpine Marmot Project were collected in addition to the extent and accuracy of the data collected, give us a great opportunity to answer these questions.

We use the data collected, as well as possible scenarios of climate change, to explore the likely impact of future climate change on this population of Alpine marmots and to predict the future of all populations of marmots in the Alps. Thus, we can respond formally to the issues of climate change impact on the future of the Alpine marmot and we can define plans for appropriate management and conservation for maintaining alpine biodiversity. The fundamental knowledge gained from this project will also be used to effectively protect other marmot species in critical danger of extinction such as Marmota vancouverensis.