Compensation and colonization offset the impacts of biodiversity loss over time in grasslands

Understanding the long-term impacts of biodiversity loss on ecosystem functioning is a major challenge in ecology. While studies suggest that biodiversity loss exerts increasingly negative impacts over time, it is unclear whether this pattern, observed in artificial assemblages, applies to natural ecosystems. Here, we report findings from a 16-year plant functional group (PFG) removal experiment in the Inner Mongolia grassland, where four levels of PFG richness were established through targeted removals from 2006 to 2009, followed by natural recolonization from 2010 onward. We found that the initially positive biodiversity-productivity relationship (BPR) gradually flattened over time, indicating that the negative impacts of diversity loss diminished. This temporal shift of BPRs was co-regulated by abundance, compensation, and colonization effects, with their relative contributions varying over time. Notably, when the compensatory growth of remaining species and colonization of new species offset productivity decline caused by species removal, the adverse impacts of diversity loss were mitigated. These findings underscore the need to incorporate compensation and colonization dynamics when predicting the long-term ecosystem consequences of biodiversity loss.