Plant invasions alter soil biota and microbial activities: A global meta-analysis

Plant invasion is a major component of global environmental change that
can significantly alter soil biota, which are essential for organic matter
decomposition and nutrient cycling in terrestrial ecosystems. However, the
particular linkage between invasive plants, soil biotas, and enzymatic
activities remains unclear. Here, we conducted a comprehensive
meta-analysis using 688 paired observations from 107 studies to evaluate
to the impact of plant invasion on soil biota, enzymatic activities and
nutrient cycling. Our results showed that plant invasion significantly
reduced herbivores (45%), detritivores (27%) and omnivores (45%)
abundance, while allelopathy, woody invaders and forest ecosystems
significantly reduced predator abundance by 47, 46, and 32%, respectively.
Invasive plants also slightly reduced bacterial and fungal biomass, but
significantly increased arbuscular mycorrhizal fungal (AMF) biomass, MBC
and MBN by 29, 19 and 32%, respectively. Moreover, invasive plants had
inconsistent impact on the activities of C-decomposing enzymes, but
invertase, phenol oxidase and β-glucosidase were found significantly
higher in invaded than uninvaded sites.  Invaded sites had
significantly higher activities of N- and P-releasing soil enzymes ranged
from 18 to 27% than uninvaded sites. Soil microbial biomass,
N-mineralization, soil respiration, available (N, P) nutrients, NH4+-N and
nutrient stocks were all higher in invasive than native plants rhizosphere
soils. Our findings suggest that invasive plants had negative impact on
soil functional groups, however, they enhanced soil nutrient-releasing
enzymes and soil available nutrients. This in turn accelerates nutrient
cycling and promote the persistence and success of invasive plants.