Project leader: Gilberto Pasinelli

Sponsored by: the Swiss National Science Foundation Zürcher Tierschutz Fachstelle Naturschutz des Kantons Zürich Graf Fabrice von Gundlach Stiftung Claraz Schenkung Ala Stiftung für Vogelschutz OGZ - Ornithologische Gesellschaft Zürich

Spatial dynamics and significance of small populations for (meta-)population persistence in the reed bunting Emberiza schoeniclus

Many endangered animal species throughout the world are nowadays restricted to small populations, which is generally viewed as a consequence of fragmentation of the natural landscape due to human activities. Despite the prevalence of small populations, we are largely ignorant about their significance for species persistence. Small populations have long been considered to be population 'sinks', being entirely dependent on immigration from large populations and thereby not worth to be considered in conservation plans. On the other hand, it is known that small populations may be viable, if they are spatially organized as a metapopulation. The dynamics of metapopulations consisting mainly of small populations is only poorly understood and theoretical predictions have hardly been tested with empirical data. The way that populations differing in size and/or isolation are spatially organized, is not only of theoretical interest; it is also a critical component for the management of species occurring in highly fragmented landscapes. We are examining the significance of small populations for species persistence, using a small passerine bird species, the reed bunting Emberiza schoeniclus , as a model organism.

We are addressing the significance of small populations for species persistence using 1) classical mark/recapture techniques, 2) a population genetics approach and 3) ecological modelling. The main goals of the projects are:

• to determine the spatial organisation of very small populations
• to assess the role of very small populations in a population network
• to predict the long-term viability of a reed bunting (meta-) population consisting mainly of very small subpopulations through modelling
• to measure gene flow among our study populations
• to assess the extent of genetic similarity among individuals of very small populations
• to test the hypothesis that very small populations have reduced genetic variability when compared to larger populations.

Former project co-leader: Karin Schiegg