My main research interest concerns the impact of habitat fragmentation on plant community assembly and the fitness of plant populations. The nowadays human induced level of landscape fragmentation has far going consequences for both the assembly of plant communities and the fitness of individual plant populations. Habitat patches have become smaller and more isolated from each other, which is associated with a decreased habitat quality and hampered plant dispersal between the patches.

I studied the effects of habitat isolation on plant community assembly and pollination limitation in dune slacks. Dune slacks are calcareous-rich and nutrient-poor habitat conditions and harbour specific calciphilous pioneer plant communities. When the dune slack is formed by blowing out the sand until the groundwater level, a primary succession process starts and the slack becomes gradually colonized. Dune slacks can be considered from a landscape ecological viewpoint as habitat islands into a matrix of hostile habitat. Species accumulation on habitat islands during primary succession is the result of the colonization of new species by seed dispersal from other slacks. As a consequence, species richness in the slack will be related to the distance to source areas and the availability of dispersal vectors. The results indicate that important changes occur in community characteristics in a chronosequence of dune slacks, covering a succession period of 50 years. However, differences in community composition with increasing age were smaller when the slack is more isolated or smaller, suggesting a slower succession rate and biomass accumulation. Together with a lower contribution of slow dispersing species in more isolated slacks, this indicates that species accumulation in the isolated dune slacks is dispersal limited and thus influenced by regional factors. The stochastic variation resulting from this dispersal limited species accumulation causes a divergent successional pathway.