Invasion impacts in terrestrial ecosystems: Global patterns and predictors.

Biological invasions can alter ecosystems, yet their impacts vary across ecological contexts. Using a global meta-analysis of 775 studies (2223 effect sizes) in terrestrial systems, we show that the most consistent negative impacts are reductions in native plant diversity caused by invasive plants and increases in greenhouse gas emissions driven by both invasive plants and animals. However, evidence of publication bias suggests the latter should be interpreted with caution. Invader residence time emerged as a key predictor: Longer residence times intensified the negative effects of invasive plants on native diversity, whereas impacts on soil abiotic properties tended to weaken over time. Our synthesis reveals that some properties, such as native plant diversity, remain persistently sensitive to invasion, whereas others are more variable as invasions persist. Editor's summary: Humans have introduced myriad species to non-native ecosystems, but the effects of these species vary widely and can be difficult to predict. Thakur et al. analyzed invasive species' effects on terrestrial systems from 775 studies and investigated whether they relate to attributes of the invasive species or the ecosystems that they colonize. More than 75% of studies focused on invasive plants, highlighting a need for research on other invasive taxa. Invasive plants generally had negative effects on native plant diversity and greenhouse gas emissions. Unlike in previous studies, native plant diversity was not a strong predictor of invasive plants' effects. However, invasive species' residence time modified their impacts, with native plant diversity decreasing more the longer the invasive species was present. —Bianca Lopez [ABSTRACT FROM AUTHOR]