Grasslands are highly diverse ecosystems providing important ecosystem services, but they currently face a variety of anthropogenic stressors simultaneously. Quantifying grassland responses to global change factors (GCFs) is crucial for developing effective strategies to mitigate the negative impacts of global change on grassland communities and to promote their resilience in the face of future environmental challenges. We conducted a field experiment in the Songnen grassland, northeastern China, to test the combined effects of 0, 1, 2, 4, 6, and 8 GCFs, including fungicide, herbicide, insecticide, antibiotic stress, heavy metal pollution, light pollution, microplastic pollution, nitrogen deposition, tillage disturbance, and increased precipitation. We found that within one year, the increasing number of GCFs negatively impacts both the productivity and diversity of grassland communities. In comparison to exposure to a single GCF, exposure to 8 GCFs led to a reduction in productivity and species richness by 42.8% and 42.9%, respectively. Furthermore, these negative effects seem to be linked to the reduction of dominant species and the concurrent increase in neonative species (i.e., species that have expanded their geographic range into a new area without direct human assistance, but as an indirect consequence of human-induced environmental changes). The results of hierarchical diversity-interaction modeling suggested that the adverse impacts of an increasing number of GCFs on community productivity and diversity are attributable to both the specific identities of GCFs involved and their unique pairwise interactions. The results suggest that grasslands may quickly lose stability and degrade more rapidly in response to multiple co-occurring GCFs. Greater efforts should be made to conserve the functions and services of grassland ecosystems by reducing the impacts of human activities.

Plant and soil microbial communities jointly sustain ecosystem multifunctionality (EMF) in temperate grasslands, yet their relative contributions to EMF under grazing management remain poorly understood. We simultaneously investigated three temperate grasslands to assess the effects of grazing management, climate, edaphic properties, and plant and microbial communities (diversity and community composition) on EMF (quantified by potential soil nitrogen (N) mineralization, arbuscular mycorrhizal fungal infection rate, phospholipid fatty acid, soil total carbon (C) and N, inorganic N, and plant biomass). Using random forest modeling, we identified important predictors, followed by structural equation modeling (SEM) to disentangle their relative roles. The results showed consistent declines in plant diversity and EMF with increasing grazing intensity, while soil bacterial and fungal diversity exhibited minimal responses. Heavy grazing management significantly reduced the abundance of perennial forbs and rhizome grasses, but increased that of annuals and legumes. Concurrently, we observed a significant decrease in copiotrophic Proteobacteria abundance accompanied by an increase in oligotrophic Gemmatimonadetes abundance. Random forest modeling identified grazing intensity, climate, soil properties, plant diversity and community composition, and bacterial community composition as important predictors of EMF. SEM revealed that plant diversity was the dominant biotic predictor of EMF, exceeding the influence of microbial communities across all grasslands. Notably, aridity indirectly influenced EMF through plant diversity rather than direct regulation. These findings demonstrate that plant diversity primarily maintains EMF under grazing pressure, highlighting the importance of biodiversity-focused management strategies in temperate grassland conservation.

In grassland ecosystem management, mowing influences the tolerance mechanism of plants by modifying their growth and reproductive traits; however, the specific processes involved remain unclear. This study focused on the Elymus species (Elymus nutans ‘Aba’, Elymus sibiricus ‘Qingmu No.1’, Elymus submuticus ‘Tongde’, Elymus breviaristatus ‘Tongde’ and E. sibiricus ‘Tongde’) and systematically evaluated the effects of different mowing intensities (no mowing, light, moderate and heavy mowing) at three growth stages (jointing, booting and flowering) on plant tolerance and the role of growth and reproductive traits in this mechanism. The results revealed that mowing generally reduced plant height and the reproductive branch quantity, while significantly increasing the tiller number, seedling number and relative growth rate. However, the responses of rhizome length and vegetative branch height varied across the growth stages. Mowing during the jointing stage had the most significant effect on morphological traits, with vegetative reproduction contributing the most to tolerance and increasing with mowing intensity. Overall, the plant response to mowing timing was more pronounced than its response to changes in individual traits. Moderate mowing at the jointing stage significantly increased growth rate, tiller number and seedling number, thereby enhancing mowing tolerance. In contrast, heavy mowing at the booting and flowering stages markedly reduced reproductive branch quantity and rhizome length, resulting in diminished mowing tolerance. The study indicated that differences in the mowing stage and forage species regulated adaptive changes in growth and reproductive traits, thereby influencing tolerance mechanisms. Grassland management should fully consider the effects of mowing at different growth stages to optimize the utilization and management of the Elymus grasslands.

Shrubland functions as an important carbon sink. However, uncertainties have still persisted regarding shrubland C storage and its underlying drivers. In this study, we conducted a field survey encompassing 45 sites to investigate all sectors of C stocks in shrublands distributed in northern China, in order to accurately estimate the regional C storage and to explore the potential drivers. Our results showed that the total C density of shrubland was 78.78 Mg C ha^–1, with soil C density, vegetation C density and litter C density contributing 75.16, 2.99 and 0.64 Mg C ha^–1, respectively. Distinct C density sectors were driven by different factors: vegetation C density was primarily driven by plant community richness, litter C density by shrub diversity and soil C density by total annual sunshine and soil total phosphorus in our study. Climate factors, plant community traits and soil properties independently explained 5.15%, 6.79% and 23.73% variation of the shrubland ecosystem C density, respectively. Furthermore, the interactions between community structural traits and climate factors, as well as between community structural traits and soil properties, can explain 10.44% and 18.50% of the variation, respectively. Our findings, based on direct field measurements, refined estimates of C storage in shrubland ecosystems in northern China, and these findings provided crucial data for the validation and parameterization of C models both within China and globally.

Alien plants exhibit varied performance and distribution patterns across latitudinal gradients depending on species invasiveness and target community invasibility. Although numerous researches have studied the latitudinal patterns of plant invasiveness, few have focused on community-level invasibility. We hypothesize that community invasibility increases with latitude due to a reduction in native species richness (diversity-resistance hypothesis) and stronger environmental filtering (pre-adaptation hypothesis) at higher latitude. We conducted a field survey at 18 sites across 6 latitudes in southeast China to explore how the community invasibility changes with latitude and identify the key drivers underlying these patterns. We found that the community invasibility positively correlated with latitude, primarily due to a decrease of native species diversity at higher latitude. Climate factors exerted indirect effects on community invasibility by shaping native species diversity. The mean pairwise phylogenetic distance between species did not change with latitude indicating minor effects of pre-adaptation. Our study emphasizes the importance of native species diversity in shaping latitudinal patterns of community invasibility. These findings highlight biodiversity conservation as an effective strategy to mitigate biological invasions, particularly in regions vulnerable to climate change.