This volume is the result of a Symposium, held in October, 1985, to celebrate the Silver Jubilee of the De- partment of Plant Ecology of the University of Groningen. The Department of Plant Ecology was founded by Professor Dingeman Bakker and has, since its incep- tion, been involved with studies of grasslands, and especially with the effects of human interference on grassland communities. It has been especially involved in an almost unique enterprise to convert areas of grassland from intensive agricultural production to nature reserves. With over-production of most food commodities in the EEC, and increasing interest in various types of 'set aside' schemes, this initiative now seems to be remarkably prescient. The Netherlands have a long history of human manipulation of the environment. Indeed, the Dutch en- vironment is probably more man-made than that of any other country. In view of this, and the Laborato- ry's interest in managed grasslands, it is not surprising that 'Disturbance in Grasslands' was selected as the topic for the Laboratory's Jubilee Symposium.
Although both the Symposium and the resulting vo- lume, have a strong Dutch component, the organisers invited a number of contributors from Europe and elsewhere to provide key chapters. The result is a volume which covers many aspects of disturbance in a variety of grasslands. Disturbance is considered at both the community and the population level, and the principles and processes underlying those responses are explored.
One: Disturbance in Perspective.- 1. Disturbance of grasslands - Outline of the theme.- 2. Population responses to environmental disturbance.- Two: Vegetation Response to Changing Soil Conditions.- 3. Soil variation caused by plants: a mechanism of floristic change in grassland?.- 4. Soil fertility and the composition of semi-natural grassland.- 5. Hybridization of the habitat in disturbed hay meadows.- 6. Disturbances in transplanted grasslands and wetlands.- 7. Vegetation responses to changes in tidal inundation of salt marshes.- 8. Vegetation development from denuded ground to grassland.- Three: Vegetation Response to Defoliation and Pathogens.- 9. The herbivore as prisoner of its food supply.- 10. Ecological modeling of short-term plant community dynamics under grazing with and without disturbance.- 11. Modelling the structural changes in vegetation under different grazing regimes.- 12. Restoration of species-rich grassland after a period of fertilizer application.- 13. The function of plant pathogenic fungi in natural communities.- Four: Population and Species Responses.- 14. Population differentiation in grassland vegetation.- 15. Population responses in Agrostis stolonifera to selective forces in inland and coastal habitats.- 16. A physiological analysis of genotypic variation in relative growth rate: Can growth rate confer ecological advantage?.- 17. Ecological significance of size variation within populations.- 18. Population responses of Rhinanthus angustifolius to disturbance of grassland communities.- 19. Pollination and pollen flow disturbed by honeybees in bumblebee-pollinated Rhinanthus populations?.- 20. Disturbance, hybridization and hybrid speciation.- Epilogue.- Species index.- Communities index.