A study of adhesive seed dispersal of three species under natural conditions

Abstract

Seeds of three plant species, Agrimonia eupatoria L., Geum rivale L. and Triglochin palustre L., were tested for their ability to remain attached in fur of fallow deer and domestic cattle under natural conditions in the field. The plant species are relatively common in managed semi-natural pastures and all three species possess seed structures which enhance adhesive dispersal. The results indicate that seed morphology and the position of seeds on an animal's body influence the length of time that seeds are attached in fur. The relative adhesive seed dispersal ability of the plants (A. eupatoria> G. rivale> T. palustre) did not differ between the two investigated animal species. However, taking grooming behaviour into account, animal species may differ in dispersal efficiency. Seed morphological structures that increase the inherent capacity of adhesive dispersal may also be irritating to animals and initiate grooming. Potential dispersal distances were obtained for seeds on cattle, suggesting that adhesive seeds may disperse from tens of metres to a kilometre. The implications of the results of this study for plant dispersal in a fragmented landscape are discussed.