Native plants do not benefit from arriving early, but invasives pay to arrive late

Priority effects refer to the phenomenon where early-arriving species in an ecosystem influence the subsequent community structure by altering resource availability for late-arriving species. Therefore, the order and timing of native and invasive plant species arrival can have strong implications for restoring native communities resistant to invasion. However, considerable variation in priority effects limits the practical applications of this concept in ecological restoration. Through a systematic review and meta-analysis, we address the following outstanding questions in priority effects research to bridge the knowing-doing gap. (1) Who benefits the most from early arrival: native or invasive species? (2) How does extending the arrival interval (early and late) affect the performance (productivity) of native and invasive species? (3) Does planting or sowing diverse native species early protect against invasion by late-arriving invasive species? We hypothesized that (1) the benefits of early arrival are greater for invasive species than native species primarily due to their early emergence, rapid growth and spread, and resistance to biotic and abiotic stresses (H1), (2) extending the arrival interval will confer competitive benefits to native species through early and effective resource utilization (H2) and (3) early arrival of diverse native species will affect the performance of late-arriving invasive species, preventing reinvasion and secondary invasion via increased complementarity and diversity effects (H3). We reviewed 32 studies exclusively focusing on priority effects of native and invasive species and extracted biomass data, an indicator of species performance, as a primary response variable. In support to our hypothesis (H1), a meta-analysis indicated that invasive species receive benefits from arriving early; however, native species do not receive any advantage from early arrival. Delaying invasion significantly affected the performance of invasive species but not that of native species. We did not detect significant effects of extending the arrival interval by more than three weeks on the performance of native and invasive species (H2). A synthetic review of studies on priority effects revealed that diverse recipient communities strongly reduce the establishment and survival of invasive species (H3).