Annual rainfall variation and dispersal limitation combine to alter invaded plant community diversity, dominance hierarchies and seeding phenology

Natural ecosystems are threatened by climate change, fragmentation, and non-native species. Dispersal-limitation potentially compounds impacts of these factors on plant diversity, especially in isolated vegetation patches. Changes can impact the phenology native species distinct ways from non-natives, resulting cascading communities. Few empirical studies have examined combined effects change dispersal limitation community diversity or phenology. Using a five-year dispersal-restriction experiment an invaded semi-arid annual system Western Australia, we investigated interactive inter-annual rainfall variation composition, dominance seed production timing. We found to be principal driver dynamics. Drought years had long-term, stable with evidence shifts toward dominance. Surprisingly, composition remained largely unchanged under restriction. A subtle ‘dispersal rescue’ effect was evident for dominant forb grass but only average years. The timing primarily driven grasses having opposite responses. There no that seeding affected over time. Our study demonstrates is not major factor driving this invaded, system. Results do suggest, however, increases drought frequency likely benefit natives long term.