Recent studies have shown distinct soil microbial assembly patterns across taxonomic types, habitat types and regions, but little is known about which factors play a dominant role in soil microbial communities. To bridge this gap, we compared the differences in microbial diversity and community composition across two taxonomic types (prokaryotes and fungi), two habitat types (Artemisia and Poaceae) and three geographic regions in the arid ecosystem of northwest China. To determine the main driving factors shaping the prokaryotic and fungal community assembly, we carried out diverse analyses including null model, partial mantel test and variance partitioning analysis etc. The findings suggested that the processes of community assembly were more diverse among taxonomic categories in comparison to habitats or geographical regions. The predominant driving factor of soil microbial community assembly in arid ecosystem was biotic interactions between microorganisms, followed by environmental filtering and dispersal limitation. Network vertex, positive cohesion and negative cohesion showed the most significant correlations with prokaryotic and fungal diversity and community dissimilarity. Salinity was the major environmental variable structuring the prokaryotic community. Although prokaryotic and fungal communities were jointly regulated by the three factors, the effects of biotic interactions and environmental variables (both are deterministic processes) on the community structure of prokaryotes were stronger than that of fungi. The null model revealed that prokaryotic community assembly was more deterministic, whereas fungal community assembly was structured by stochastic processes. Taken together, these findings unravel the predominant drivers governing microbial community assembly across taxonomic types, habitat types and geographic regions and highlight the impacts of biotic interactions on disentangling soil microbial assembly mechanisms.

The scarcity of water resources is becoming a global focus, and water conservation has become one of the most crucial service functions in the water security and sustainable development of ecosystems. Hulunbuir forest–steppe ecotone, as an important water conservation area in the northeastern provinces of China, plays an irreplaceable role in Northeastern China. However, the water yield and water conservation are rarely understood in the ecotone. In this study, the InVEST model was employed to analyze the spatiotemporal dynamics of water yield and water conservation from 2000 to 2020. Meanwhile, we explored the response of water conservation to climatic factors and human disturbance. The results demonstrated that water yield and water conservation presented a decreasing trend in the first decade and then increased. The land use transfer obvious from 2000 to 2010, and most vegetation types were converted into unused land. This transition intensified reduction of water conservation. The main factor affecting the water conservation was climate Precipitation had the greatest impact on water conservation. The findings of this study have great and important implications for regional sustainable water resource management and ecological protection policies and provide a convenient method for evaluating water conservation in other areas that are lacking climate, hydrology, and geological data.

Rising temperature causes a process of phosphorus release, which can be characterized well using phosphorus release rates (V_P). The objective of the present study was to investigate the major factors affecting sediment phosphorus release rates through a wetland habitat simulation experiment. The results showed that the V_P of different wetland sediments were different and changed with the order of W–R (river wetland) > W–L (lake wetland) > W–M (grassy marsh wetland) > W–A (reservoir wetland). The main driving factors which influenced sediment phosphorus flux velocity in the sediment–water interface were sediment B-SO₄²⁻, B-MBN and A-MBP content. Path analysis and determination coefficient analysis indicated the standard multiple regression equation for sediment phosphorus release rates in the sediment–water interface, and each main factor was Y = −0.105 + 0.096X₁ + 0.275X₂ − 0.010X₃ (r = 0.416, p < 0.01, n = 144), where Y is sediment phosphorus release rates; X₁ is sediment B-SO₄²⁻ content; X₂ is sediment B-MBN; and X₃ is sediment A-MBP content. Sediment B-SO₄²⁻, B-MBN and A-MBP content and the interaction between them were the main factors affecting sediment phosphorus release rates in the sediment–water interface. Therefore, these results suggest that soil chemical properties and microbial activities likely play an important role in phosphorus release rates in the sediment–water interface. We hope to provide effective scientific management and control methods for relevant environmental protection departments.