Long-term phosphorus addition alters plant community composition but not ecosystem stability of a nitrogen-enriched desert steppe

Rodent disturbance reduces ecosystem stability through regulating plant and soil functions in Hulun Buir steppe

Brandt's vole (Lasiopodomys brandtii), a typical rodent in the eastern Eurasian Steppe, has unclear impacts on ecosystem stability. In our field study in the Hulun Buir steppe, a multifunctional grazing ecosystem in this region, we used burrow entrance area and burrow density as alternative disturbance indices to derive a Disturbance Index (DI) for quantifying disturbance levels from rodents, and employed generalized linear mixed-effects model and the N-dimensional hypervolume framework to assess the influence of Brandt's vole disturbance on plant and soil functions, and then on the ecosystem functional stability. Our findings unequivocally illustrate that various plant functions including vegetation cover (Cover), aboveground biomass (ABG) and shoot carbon (ShootC) significantly declined with increasing disturbance, while shoot nitrogen (ShootN) and root nitrogen (RootN) show significantly positive responses. Soil functions such as soil nitrogen (SoilN), soil phosphorus (SoilP) and soil organic carbon (SoilC) showed significantly negative responses. Notably, the burrow entrance area exerts a more pronounced impact on both plant and soil functions in comparison to burrow density. Additionally, both disturbance indicators have a more significant influence on plant functions than on soil functions. Overall, the ecosystem functional stability progressively decreases with intensified disturbance, with varying response patterns for plant and soil functions, the former exhibited heightened stability as disturbance intensified, while the latter proved more stable at moderate disturbance levels. Our findings suggest that plant functions were more susceptible to disturbance by Brandt's vole compared to soils. Additionally, an ecosystem destabilization was synchronized with increasing Brandt's vole disturbance, although alterations in the functional stability of plants and soil show a different pattern.

Differential responses of ecosystem stability to climatic and anthropogenic factors in connected and isolated lake basins on the Yangtze River

Maintaining optimal ecological security in the Yangtze River-connected and isolated lake basins is of great significance to national projects involving Yangtze River protection. Ecosystem stability and associated factors are important components of ecological security in these basins. However, few studies have focused on ecosystem stability and its driving factors over long periods in the Yangtze River Basin. In this study, a remote sensing index was used to analyze the spatiotemporal variation in the ecosystem stability of the Dongting Lake Basin (DTL), Poyang Lake Basin (PYL), and the isolated Chaohu Lake Basin (CHL) and Taihu Lake Basin (THL) in the Yangtze River over the period 2000-2022 to determine the potential affecting factors. The results showed fluctuations in the ecosystem stability of the DTL and PYL, while a V-shape was observed for the CHL and THL during the same period; the closer to the lake, the weaker the stability of the ecosystem, especially in the DTL and PYL. Moreover, the ecosystem stability was greater in the DTL and PYL than in the CHL and THL. The spillover effect of anthropogenic activities on the ecosystem stability of the four basins and the direct effect of temperature have the greatest effect on the ecosystem stability. Specifically, the ecosystem stability index for the area around the DTL and PYL decreased with increasing human interference, whereas the opposite was observed in the CHL and THL. The effect of temperature was negative for the ecosystem stability of DTL and PYL and significantly positive for CHL and THL, at a level of 0.01 %. The findings of this study provide significant information for targeted ecological restoration of the Yangtze River Basin.