The fact that competition, predation and symbiosis with other species influence a species’ distribution was recognized long before the experiments of Davis et al . (1998a, 1998b ). For example, Connell (1961 ) studied the factors that limit the range of a species of barnacle ( Chthamalus stellatus ) in the intertidal zone and showed that the lower edge of the range was set by interactions with other intertidal species, notably competition with another barnacle ( Balanus balanoides ) and predation by a snail ( Thais lapillus ). Similarly, Silander & Antonovics (1982 ) found complex responses when experimentally removing one species at a time from a salt-marsh community and observing the reactions of the others. Results showed that removal of one grass species ( Muhlenbergia capillaris ) led to equal range expansions by five other plants, whereas removing a sedge ( Fimbristylis spadicea ) resulted in the expansion of only one other plant (the grass Spartina patens ).