Order and timing of species arrival can strongly affect community assembly. Early-arriving species can reduce available resources or change the niche types for late-arriving species, affecting local abundances and species identities in the community. A similar rationale can be used to state that the order and timing of species removal should be also important (i.e. inverse priority effect). Manipulation of priority effects is gaining recent attention to manage invasive species. Yet, evidence of inverse priority effects focus only on trophic interactions. Removal of invasive plant species is a common restoration practice but secondary invaders frequently hinder native recovery. Interactions among invasive plants have been pointed as key mechanisms underlying secondary invasions. Removing an invasive strong competitor can release co-occurring invasives from competition while removing a benefactor invader might hinder co-occurring nonnative beneficiaries. Little is known yet about the effects of removing target invaders within the same trophic level and how the order and timing of removal can affect their interactions. To evaluate the state of knowledge on the importance of the order and timing of invasive species removal on post-removal community structure, we conducted a literature search focused on invasive species removal and interactions among nonnative species.
Results/Conclusions
We found 1535 articles from which we selected 65 relevant articles after abstract screening. We found that late-removing invasive species might produce temporal changes on other species that affect post-removal community structure. Based on our results we propose three scenarios regarding the type of nonnative interaction: (1) invader early removal might release secondary invaders from competition whereas its late removal might favor native recovery. (2) Early removal of a direct invasive benefactor might favor native recovery whereas its late removal favors secondary invaders. And (3) early removal of an invasive that facilitates other nonnative through negative effect on natives might produce strong positive effects on natives whereas its late removal might favor secondary invasions. The outcome, however, might substantially change if the facilitation force persists after removal (e.g. legacy effects). We also found that timing of removal per se can influence post-removal assemblages. Phenology of target and non-target species can modulate their ability to resprout or colonize at a specific time. Moreover, environmental conditions at the timing of removal can shape the strength of biotic interactions. Accounting for the order and timing of removal can help improve our understanding of historical contingencies in community disassembly and invasive species management.