Exotic Plant Invasion Enhances Nitrous Oxide Emission and Methane Uptake in Forests and Grasslands: A Global Meta‐Analysis

Abstract Invasive plants can alter ecosystem primary productivity and carbon sequestration, thereby reshaping greenhouse gas (GHG) emissions. Here, we conducted a global meta‐analysis of 141 paired in situ observations to investigate how exotic plant invasion influences nitrous oxide (N 2 O) and methane (CH 4 ) emissions in forests and grasslands. By integrating a global invasion‐area data set, we further quantified invasion‐induced changes in GHG budgets from regional to global scales. Our results indicate that plant invasion significantly increased N 2 O fluxes in temperate grasslands, rising from 1.35 ± 0.77 to 4.01 ± 0.97 kg N 2 O ha −1 year −1 ( p < 0.05), whereas no significant changes were observed in forests. In contrast, CH 4 uptake rates increased significantly in tropical and subtropical forests from 2.56 ± 0.66 to 3.32 ± 0.63 kg CH 4 ha −1 year −1 following invasion ( p < 0.05), but were unchanged in tropical/subtropical grasslands and temperate forests ( p > 0.05). Globally, plant invasion resulted in a net increase in N 2 O emissions of 293.9 ± 68.2 Gg N 2 O year −1 , with temperate regions contributing 60.6% of this rise. Conversely, CH 4 uptake increased by 762.1 ± 91.2 Gg CH 4 year −1 , of which 68.0% occurred in temperate regions. Overall, plant invasion was estimated to generate a net global warming potential of 59.7 ± 21.1 Tg CO 2 eq year −1 from global forests and grasslands. Despite limited sample sizes in some biomes, these findings provide critical insights into how plant invasion alters terrestrial GHG emissions and highlight the growing risk of invasion‐driven GHG increases due to expansion of exotic plants under future climate change.