P1-12: Scale and context mediated conservation management in fragmented landscapes and populations

PhD student: Urs Kormann
Thesis Committee: Prof. Teja Tscharntke, Dr. Christoph Scherber, Prof. Thomas Kneib
Graduation Date: 1/2014

The conservation of biodiversity in human dominated landscapes is a major challenge of todays society: The human population has roughly doubled during the last 40 years and the global agricultural production has increased by 40% between 1990 and 2006. Up to now, most studies aimed to answer questions such as how a limited input (money dedicated to conservation) should be distributed among relevant variables ( i.e. management of reserves, maintaining/increasing population connectivity and so on) in order to maximize the longterm persistence of biodiversity.

Most of these studies were based on the underlying, often implicit assumption that the world consists of habitat, intervening non habitat (matrix) and in good cases in something such as corridors. Such an understanding of the environment is likely based on island-mainland and metapopulation frameworks, and might hold partly true for habitat specialists. However, it is now recognized that many species perceive landscapes in a more complex way and use ressources from different covers types. Hence, it has recently been suggested that, to understand the effects of landscape structure on biodiversity, the habitat-matrix view should be replaced with a heterogeneous landscape view. This might be epecially relevant for agricultural landscapes that show a high spatial and temporal fluctuations in ressource availabilty (i.e. nectar of massflowering crops such as oil seed rape) through crop harvest and annual crop rotation.

Previous studies suggested the existence of so called spill-over effects, i.e. the enrichement of biodiversity in habitat A through immigration (spillover) from an adjacent habitat B. Such a spillover effect has been shown from natural to agricultural areas, but evidence of the reciprocal process (i.e. immigration from farmland to neighbouring natural area) is rare. Beside the scientific relevance, such a process would have strong implications not only for future conservation planning. In the first year of my project, i will investigate spillover effects from agricultural areas to natural areas. For this, i will select calcareous grasslands, an endangered but species rich natural habitat, having adjacent fields of oil seed rape and/or wheat. By means of directed traps and capture-recapture experiments, i will infer movements of ground dwelling beetles and pollinators before and after crop harvest. Explicitely, exclusion experiments in combination with predation and pollination experiments will hopefully lead to meaningful results.


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