Some consequences of diffuse competition in a desert ant community

Exploitative and interference competition are investigated in detail in a community of six coexisting species of granivorous desert ants . A linear model that includes both direct and indirect competitive interactions is used to predict positive or negative correlations in the abundances of competitors. Data on the abundances of the six ant species on 23 1/4-ha plots provide empirical support for the four predictions so generated. "Apparent facilitation." in the for of positive interspecific spatial associations of colonies, is detected between two competitors and interpreted as arising from indirect pathways of interspecific interaction. The results illustrate how indirect interactions among species at a single trophic level may play a significant role in organizing natural communities.