Ecological interactions in human modified landscapes : Landscape dependent remedies for the maintenance of biodiversity and ecosystem services

Sammanfattning: Modern agricultural practices have led to an intensification of the agricultural landscape which has negatively affected both biodiversity and the ecosystem services it provides. In my thesis I have used ecological theory of optimal foraging to try and explain how landscape structure, landscape composition and agricultural management can explain the loss of biodiversity and how remedies can efficiently be implemented. I present spatially explicit mechanistic models built on foraging behavior of central place foragers which details how these foragers should utilize the landscape to maximize fitness. Using these models, I present new ways of modelling habitat suitability and mechanisms for species coexistence based on scale-dependent foraging. I can show how species coexistence is dependent on how the landscape is structured in relationship to the life histories of species, giving us spatially explicit predictions of habitat use for a range of species. In order to mitigate the loss of biodiversity and ecosystem functions in the agricultural landscape, agri-environment schemes have been implemented. Using bumblebees as a model organism I present ways to predict the outcome of a specific scheme, flower strips. Studies have shown that flower strips can increase abundance of bees and aid in colony development in bumblebees, but how should they be placed and what kind of effects will they have? I show how temporal and spatial allocation of flower strips will have different predictions depending on the landscape and the behavior of the bees. Using these behavioral based modelling frameworks I have provided possibilities to make predictions on how future land-use and species composition will affect biodiversity conservation and provisioning of ecosystem services. The methods and results I present in this thesis can thusly provide us with better informed decision method tools to move us towards a more sustainable agricultural system.