Year: 2015
Type: dissertation
Abstract: The global climate change is predicted to cause notable alterations in winter conditions in northern areas. This raises many questions about its possible consequences on northern species and ecosystems. In many areas the time period with an intact snow cover is about to get shorter or even vanish altogether. As the overwintering success of many small mammals is strongly dependent on the protection provided by the snow cover against severe weather conditions and predation, it is obvious that these kinds of environmental alterations should affect the overwintering physiology and behavior, as well as the initiation of breeding after winter. In this thesis I have studied the winter ecology of a small boreal rodent species, the bank vole (Myodes glareolus), and the possible consequences of climate change on the physiology, behavior and onset of reproduction in this species. I conducted four experiments under laboratory (II-IV) and semi-natural conditions (I, III). One of my experiments was purely methodological (IV), providing me with validated and accurate endocrinological study methods, and thereby enabling my other experiments. I found that the sex-ratio of the overwintering population affects the physiology and behavior of bank voles and thus, leads to divergent overwintering strategies (1). I was also able to show that the changing winter conditions related to climate change alter the circadian activity pattern and possibly even the anti-predator behavior of this species (Il). Further, my studies showed contrasting sex differences in the response to environmental cues regulating the onset of reproduction after winter (III). In case of rapid environmental changes, this could lead to a reproductive mismatch between the sexes and thus, strongly affect fitness. The results of my thesis provide new information about the overwintering mechanisms of a winter-active small boreal rodent, and may help us to predict some of the possible consequences of climate change on northern boreal ecosystems.
Author: Saana Sipari
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
SDG: Life on land
Open Access status: green
OpenAlex ID: W2337273572