Plant strategies and agricultural landscapes : survival in spatially and temporally fragmented habitat

In agricultural landscapes many plant species are limited to the network of landscape elements that are not used for agricultural production. This habitat is fragmented in space and time due to anthropogenic, biotic and abiotic factors. Therefore, plant populations are spatially sub-divided and their persistence might be dependent on the spatial dynamics in the network of local populations. Dispersal characteristics and seed bank persistence are main determinants of colonization ability which in turn is a key determinant of metapopulation viability. We propose a conceptual model that relates plant population dynamics to habitat quality, configuration and dynamics. In this model, the habitat is arranged as a network of suitable and unsuitable patches, and the distribution of the patches is assumed to be dynamic in time. Based on dispersal and seed bank characteristics four plant strategies are distinguished: species having either long (> 100 m) or short (< 100 m) distance dispersal and either a long (> 5 yr) or short (< 5 yr) term persistent seed bank. We expect that species with contrasting strategies have different survival probabilities in landscapes with contrasting habitat arrangement in space and time. We found few empirical studies for testing the hypotheses based on the model. Therefore the relation between landscapes and plant survival needs to be further explored, especially the quantitative aspects. We propose an iterative process of empirical and modelling research to determine this relation and to define management options for multifunctional farms in which biodiversity is one of the land use aims