Local population differentiation in Bromus tectorum L. in relation to habitat-specific selection regimes

Abstract

A central question of invasion biology is how an exotic species invades new habitats following its initial establishment. Three hypotheses to explain this expansion are: (1) the existence of 'general purpose' genotypes, (2) the in situ evolution of novel genotypes, and (3) the dispersal of existing specialized genotypes into habitats for which they are pre-adapted. Bromus tectorum is a selfing exotic winter annual grass that has achieved widespread dominance in semiarid western North America and that is actively invading salt desert habitats. We examined mechanisms driving this invasion in three complementary studies. In reciprocal seeding experiments with ten populations from saline playa, salt desert shrubland, and upland sagebrush communities along a salinity gradient in western Utah, we found that seeds from the playa population were able to establish better than those of most other populations across all habitats, including two highly saline sites.

Citation

Scott, Jason W.; Meyer, Susan E.; Merrill, Keith R.; Anderson, Val J. 2010. Local population differentiation in Bromus tectorum L. in relation to habitat-specific selection regimes. Evolutionary Ecology. 24: 1061-1080.