Background: Desert steppe, as an ecotone between desert and grassland, has few species and is sensitive to climate change. Climate change alters species diversity and the stability of functional groups, which may positively or negatively affect community stability. However, the response of plant community stability in the desert steppe to experimental warming and increasing precipitation remains largely unexplored.Methods: In a factorial experiment of warming and increasing precipitation for five to seven years (ambient precipitation (P0), ambient precipitation increased by 25% and 50% (P1 and P2), ambient temperature (W0), ambient temperature increased by 2°C and 4°C (W1 and W2)), we estimated the importance value (IV) of four functional groups (perennial grasses, semi-shrubs, perennial forbs and annual herbs), species diversity and community stability.Results: Compared to W0P0, the IV of perennial grasses was reduced by 37.66% in W2P2, whereas the IV of perennial forbs increased by 48.96%. Although increasing precipitation and experimental warming significantly altered species composition, the effect on species diversity was insignificant (P > 0.05). In addition, increasing precipitation and experimental warming had a significant negative impact on community stability. The stability of perennial grasses significantly explained community stability.Conclusion: Our results suggest that the small number of species in desert steppe limits the contribution of species diversity to regulating community stability. By contrast, maintaining high stability of perennial grasses can improve community stability in the desert steppe.

With rapid urbanization in China, the dramatic land-use changes are one of the most prominent features that have substantially affected the land ecosystems, thus seriously threatening sustainable development. However, current studies have focused more on evaluating the economic efficiency of land-use, while the loss and degradation of ecosystem services are barely considered. To address these issues, this study first proposed a land use-based input–output index system, incorporating the impact on ecosystem services value (ESV), and then by taking 30 provinces in China as a case study. We further employed the super-efficiency slacks-based model (Super-SBM) and the Stochastic Impacts by Regression on Population, Affluence and Technology (STIRPAT) model to explore the spatial–temporal changes and driving factors of the evaluated land-use eco-efficiency. We found that the evaluated ESV was 28.09 trillion yuan (at the price of 2000) in 2015, and that the total ESV experienced an inverted U-shaped trend during 2000–2015.The average land-use eco-efficiency exhibited a downward trend from 0.87 in 2000 to 0.68 in 2015 with distinct regional differences by taking into account the ESV. Our results revealed that northeastern region had the highest efficiency, followed by the eastern, western, and central region of China. Finally, we identified a U-shaped relationship between the eco-efficiency and land urbanization, and found that technological innovation made great contributions to the improvement of the eco-efficiency. These findings highlight the importance of the ESV in the evaluation of land-use eco-efficiency. Future land development and management should pay additional attention to the land ecosystems, especially the continuous supply of human well-being related ecosystem services.

Plant photosynthesis has a non-negligible influence on forage quality and ecosystem carbon sequestration. However, the influence of long-term warming, increasing precipitation, and their interactions on the photosynthesis of dominant species in desert steppe remains unclear, and the main factors regulating plant photosynthesis in desert steppes have remained unrevealed. Therefore, we measured the photosynthetic parameters and specific leaf area of the dominant species and calculated the water and nitrogen content of leaves and soil in a desert steppe after long-term warming and increasing precipitation (air temperature, W0, air temperature increases of 2 °C and 4 °C, W1 and W2; natural precipitation, P0, natural precipitation increases of 25% and 50%, P1 and P2). Results showed that warming and increasing precipitation significantly enhanced photosynthesis in C₃ and C₄ species (p < 0.05). Compared to W0P0, the net photosynthetic rate of C₃ and C₄ species in W2P2 increased by 159.46% and 178.88%, respectively. Redundancy analysis showed that soil water content significantly explained the photosynthesis of C₃ and C₄ plants (the degree of explanation was 48% and 67.7%), followed by soil-available nitrogen content (the degree of explanation was 19.6% and 5.3%). Therefore, our study found that climate change enhanced photosynthesis in C₃ and C₄ plants, and soil water content plays a critical role in regulating photosynthesis in desert steppes.

The impacts of large herbivores on plant communities differ depending on the plants and the herbivores. Few studies have explored how herbivores influence root biomass. Root growth of vegetation was studied in the field with four treatments: sheep grazing alone (SG), cattle grazing alone (CG), mixed grazing with cattle and sheep (MG) and no grazing (CK). Live and total root biomasses were measured using the root ingrowth core and the drilling core, respectively. After 2 years of grazing, total root biomass showed a decreasing trend while live root biomass increased with time during the growing seasons. Belowground net primary production (BNPP) among the treatments varied from 166 ± 32 to 501 ± 88 g m ⁻² and root turnover rates (RTR) varied from 0.25 ± 0.05 to 0.70 ± 0.11 year ⁻¹ . SG had the greatest BNPP and RTR, while the CG had the smallest BNPP and RTR. BNPP and RTR of the MG treatment were between those of the CG and SG treatments. BNPP and RTR of the CK were similar to MG treatment. Compared with other treatments, CG had a greater impact on dominant tall grasses species in communities. SG could decrease community diversity. MG eliminated the disadvantages of single-species grazing and was beneficial to community diversity and stability.