查看文章

Biodiversity is imperilled by the spatial homogenization of life on Earth. As new species invade ecological communities, there is urgent need to understand when native species might resist or succumb to interactions with new species. In the California Floristic Province, a global biodiversity hotspot, we show that populations of a native grass (Vulpia microstachys) have evolved to resist the competitive impacts of a dominant European invader (Bromus hordeaceus). Contrary to classic theory, which predicts that competing species co-evolve to differentiate their niches, our evidence is instead most consistent with the native species having evolved to better compete for those resources used by the invader, curtailing the invader’s spread. Evolution to resist an invader was achieved despite populations interacting within a diverse background community (22 species 0.5 m^–2 on average), refuting the oft-cited hypothesis …