A space occupancy model for the vegetation succession that occurs on set-aside

Recent changes in the set-aside scheme in the UK have allowed limited winte r grazing of former arable land. The results from field plots show that ver y different plant communities develop under different cutting and grazing m anagement regimes. A computer model is presented which defines individual p lants as three-dimensional entities. The behaviour of these individuals is limited by rules based upon known life-history attributes of the species. H owever, they have no information about the competitive ability of other spe cies they may encounter. Once defined, the interactions of five different l ife histories were simulated in three-dimensional arenas in which the envir onmental parameters could be altered to mimic the experimental treatments a pplied in the field. This modelling approach was fairly successful in descr ibing five vegetation successions observed in the field. Although many ecol ogical systems undoubtedly operate simultaneously, it is suggested that the descriptive abilities of the modelling approach used may relate to the pre dominance of a very few systems during the early stages of succession on ex -arable land. (C) 1999 Elsevier Science B.V. All rights reserved.