Priority effects: natives, but not exotics, pay to arrive late

摘要

Assembly history can determine ecosystem structure and function by influencing the relative abundances of species. Priority effects (impacts associated with early arrival) likely promote the success of exotic invaders, which often arrive at larger propagule sizes and germinate earlier than native species and tend to grow more quickly. However, the potential for exotic species to tolerate late arrival is unknown. Using a suite of native and exotic old-field plant species, we established a mesocosm experiment varying the order of species arrival to address the following question: Does plant origin influence a species' response to priority effects? We found that, while all plant groups benefited from arriving early to a similar extent, arriving late came at a lower cost for exotic species.Synthesis. We suggest that, when exploring assembly mechanisms in community ecology, the costs associated with late arrival may be as important as the benefits of arriving early. These priority effects may ultimately play a role in promoting the local success and overall distribution of exotic invaders.