The drought-induced succession decreased ecosystem multifunctionality of alpine swamp meadow

Rapid climate change and intensified anthropogenic disturbances have dropped groundwater level and altered hydrology conditions, provoked the drought-induced succession in alpine swamp meadows. However, we currently lack general cognition on how the drought-induced succession influence the ecosystem structure and functions in alpine swamp meadows. Here, we examined the changes of the main above- and below-ground ecological functions following the drought-induced succession, including swamp meadow to alpine meadow, shrub meadow, and steppe meadow. We found that both above- and below-ground ecosystem multifunctionality (EMF) indexes of the swamp meadows both decreased with the drought-induced succession. Specifically, ecosystem functions of alpine swamp meadow such as plant productivity, soil water content, soil fertility, and carbon and nitrogen all declined consistently following the drought-induced succession. Further, our analysis showed that the dynamics of the above- and below-ground EMF were positively related to plant productivity, soil hydrological properties, and nutrient availability. The decreases in soil water and nutrient contents by the drought-induced succession were the major factors that resulted in the decreased EMF. Taken together, our results demonstrated that the drought-induced succession decreased EMF of alpine swamp meadow, and our finding revealed that soil water and nutrient contents changes were critical indicators of the EMF change during the drought-induced succession. Thus, soil hydrology and nutrient functions conservation are key to maintaining the EMF of alpine swamp meadows under ongoing climate changes.