Does an ant-dispersed plant, Viola reichenbachiana, suffer from reduced seed dispersal under inundation disturbances?

摘要

Many plant species use ants as seed dispersers. This dispersal mode is considered to be susceptible to disturbances, but the effect of natural, small-scale disturbances is still unknown. We investigated how small-scale disturbances due to inundation affect seed dispersal in Viola reichenbachiana, a dominant myrmecochorous herb in riparian forests. Inundation disturbances were high in depressions and low on hillocks of the forest floor. We found that V. reichenbachiana was similarly abundant at highly and less disturbed sites, contrary to other, non ant-dispersed species. We also found that the motivation of ants to disperse seeds was higher at highly disturbed sites. Nevertheless, the number of seeds dispersed was similar at highly disturbed and weakly disturbed sites and seedlings of V. reichenbachiana were equally abundant. We conclude that inundation disturbances do not interfere with mutualistic seed dispersal by ants in V. reichenbachiana, and suggest that this may possibly contribute to the persistence of V. reichenbachiana under inundation.