Abstract
Winter performance in fish is of major importance for geographical distributions, species interactions and recruitment variation. Variations in winter/ice-cover conditions have large impact on individuals and aquatic ecosystems by changing important habitat factors such as light, temperature and resource production. This project has the objective to quantify the effects of variation in winter conditions on top consumers –fish (model species Arctic char and Eurasian perch which are predicted to respond differently to climate change), and their dynamics and interactions with resources in lake ecosystems. Winter performance and dynamics are analyzed in the context of climate change and its predicted direct effects on the temporal variation in summer and winter conditions (temperature/ice cover and light conditions) and indirectly the relative availability of pelagic and benthic resources to fish in a combination of laboratory, field and whole lake system studies and modeling. We will measure foraging capacities at different temperature/light conditions (variation in winter conditions) in laboratory, estimating foraging abilities, diets and survival of differently sized individuals of top consumers in relation to season dependent resource abundances over winter in experimental ponds and natural lake systems. Long term effects of changing winter conditions and resource production on fish population dynamics is analysed using models parameterized for Arctic char and perch.
Sweden