Increasing water availability and facilitation weaken biodiversity-biomass relationships in shrublands.

摘要: Positive biodiversity-ecosystem-functioning (BEF) relationships are commonly found in experimental and observational studies, but how they vary different environmental contexts under the influence of coexisting life forms is still controversial. Investigating these variations important for making predictions regarding dynamics plant communities carbon pools global change. We conducted this study across 433 shrubland sites northern China. fitted structural equation models (SEMs) to analyze variation species-richness-biomass shrubs herbs along a wetness gradient general liner (GLMs) shrub or herb biomass affected relationship other form. that positive both became weaker even negative with higher water availability, likely indicating stronger interspecific competition within more benign conditions. After accounting using residual regression, we effect greater facilitation by larger reduced herbs, causing them become nonsignificant. Different levels biomass, however, did not change shrubs, possibly because alter stress level shrubs. conclude biodiversity studied particularly production arid conditions it might be possible use as nurse plants facilitate understory establishment ecological restoration.