The Guild of Myrmecochores in the Herbaceous Flora of West Virginia Forests

Abstract

Analysis of herbaceous vegetation and ant activity in random quadrats from 10 forest sites in West Virginia, USA, shows that ant—dispersed (myrmecochorous) plant species constitute about 30% of the herbaceous flora. Twenty—one such species were encountered in this study, three of which were not previously known myrmecochores: Carex jamesii, C. laxiculmis and Luzula echinata. Ant activity is a good predictor of the number of myrmecochorous species at a given site. There is also a weak correlation between ant activity and overall herbaceous species richness. A matrix of correlation coefficients and Wisconsin ordination suggest that the ant—dispersed species constitute a guild. The number of species in a guild for a given site may be limited by competition for ant diaspore vectors, and/or germination microsites. These resources are likely to be especially critical for shade—adapted forest herbs which experience nutrient stress. The ant—diaspore mutualism is viewed as a strategy to overcome nutrient scarcity, and the present study shows clearly that it is a major factor in forest herbaceous communities.