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...