Pathogen Spillover Effects on Coexistence of Competing Host Species
Pathogen Spillover Effects on Coexistence of Competing Host Species
When does a shared pathogen help competing host species to coexist, and when does the pathogen help one host to out-compete the others? This model, based on an invasive annual grass, a native perennial grass, and the seed pathogen they share, shows that the pathogen’s effects on coexistence depend on how efficiently the plant species can infect each other. The axes represent the seed production of the two species. In the blue region the annual species persists, in the pink region the perennial species persists. Coexistence is possible in the purple region of overlap, while white space represents priority effects, in which species persistence is unpredictable.