Patterns of invasion within a grassland community

摘要: Summary 1 Relatively few studies have looked for patterns of invasion by non-native species within communities. We tested the hypotheses that: (i) some types microhabitats a community are more invasible than others; (ii) microhabitat that differ in also resource availability; and (iii) invasibility is mediated effects these resources on competition between native species. 2 To test first two hypotheses, we measured plant cover soils coastal grassland northern California. Consistent with plants was consistently high where nitrogen-fixing shrubs had recently grown, bottoms sides gullies deep soils, tended to relatively nitrogen or water availability. 3 Cover number be lower higher, indicating as group negatively affected species. However, total non-natives higher. This suggests excluded natives other alike. 4 To third hypothesis, grew common non-native, annual grass Lolium multiflorum, native, perennial Hordeum brachyantherum, at different levels nitrogen. The relative competitive ability higher availability but not availability. When 10-week-old were grown seedlings low, out-competed non-native. all when both seedlings. Competition grasses this system may thus help prevent irreversible.