The colonization of dung pats and molehills in permanent pastures

摘要

The colonization of areas affected by molehills and dung pats was monitored in three adjacent pastures of different ages. Seedling establishment was infrequent, and most colonization took place by rhizomes, e.g.,Agropyron repensandPoa compressa, or by stolons, e.g.,Trifolium repens. Tillering species, e.g.,Dactylis glomerata,Holcus lanatus, andLolium perenne, were poor colonizers of disturbed areas. Invasion of gaps by a species was not proportional to its abundance in the pasture. Individual plants are eliminated at random by the disturbances. Small-scale disturbances tend to decrease community heterogeneity.Key words: disturbance, colonization, dung, molehill, pasture.