Effects of Land Use Changes on the Plant Species Diversity in Agricultural Ecosystems

This chapter evaluates the extent to which changes in landscape feature and management affect plant species diversity. During recent decades many plant species characteristic for agricultural landscapes have suffered a severe decline. Reports on the decrease of populations and habitats include arable land, grassland and boundary structures. The results of this study show that changes in land use and redesigning the landscape led to significant increases in the number of species at the grid points in most of the ecosystem and management types. In terms of nature conservation issues this means that a lot can be done for species diversity in arable landscapes by changing to organic farming and increasing the number and size of boundary structures and set-aside fields. Only integrated farming which includes soil protection by reduced tillage as well as setting aside former grassland and abandoning maintenance of boundary structures showed no such positive effects. Although conditions for the development of plants in most of the investigated area are favorable, the lack of dispersal facilities prevents the establishment of new species from outside. Therefore, if promotion of species diversity in agricultural landscapes is intended, sophisticated strategies to intensify the interexchange of species between farms are necessary. To reduce these losses and to maintain species diversity in agricultural landscapes, several programmes such as a field margin strip programme, a programme to reduce the intensive use of grassland, and another one to support the establishment of boundary structures have been established. Experience gained up to now suggests that these programmes can be quite successful in protecting biotic resources.