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Background and Aims: Global changes (precipitation changes and nutrient deposition) profoundly impact structure and function of steppe ecosystem. However, it is unclear the mechanism by which multiple limiting resources affect plant aboveground net primary productivity (ANPP) in desert steppe. Methods: We conducted a field experiment manipulating both precipitation (3 levels: ambient and ± 50% precipitation) and nutrients addition (3 levels: ambient; nitrogen (N) addition; N/phosphorus (P)/potassium (K) addition) in a factorial design. We focused on the effects of these treatments on species diversity (species richness, Shannon index, abundance), ANPP, plant functional traits, and soil properties. We used structural equation model (SEM) to evaluate the direct and indirect effects of precipitation amount and nutrient addition on ANPP through affecting species diversity and functional traits. Results: Increasing precipitation increased species diversity and ANPP. NPK addition and increased 50% precipitation significantly increased ANPP over all other treatment combinations. Drought (-50%) reduced plant height and leaf dry matter content (LDMC), but increased leaf nitrogen content (LNC). Species richness, abundance, height and LDMC were positively correlated with ANPP, while specific leaf area (SLA) and LNC were negatively correlated with ANPP. SEM suggested that precipitation amount indirectly affected ANPP through its effect on abundance and SLA, while nutrient addition indirectly affected ANPP only through its effect on abundance. Conclusion: In desert steppe, the interaction of precipitation and nutrient addition had a significant positive effect on ANPP, which was mainly mediated by species diversity and functional traits. Our results highlight the importance of species diversity and functional traits in driving short-term responses of ANPP to environmental factors in desert steppe ecosystems. [ABSTRACT FROM AUTHOR]

Aims: Drought significantly impacts ecosystem structure and function, especially the transformation rates of soil carbon and nitrogen. This study explores how drought affects ecosystem respiration (Re), methane (CH4) uptake and nitrous oxide (N2O) emissions in temperate desert steppes and the underlying mechanisms. Methods: An in-situ experiment was conducted in the Inner Mongolia desert steppe in northern China to study the effect of drought on Re, CH4 and N2O fluxes. Structural equation modeling (SEM) was used to establish the relationship between Re, CH4 uptake and N2O emissions and plant functional traits and environmental factors. Results: Ecosystem respiration and CH4 uptake were both significantly reduced by chronic drought (66 % precipitation reduction from 1 May to 31 August) but not by pulse drought (100 % precipitation reduction in June and July). In contrast, no significant impact on N2O emissions was observed under chronic or pulse drought. There were no significant direct effects of soil moisture on Re, CH4 uptake or N2O emissions. However, soil moisture had an important indirect effect on Re, CH4 uptake and N2O emissions, mainly through its influence on plant functional traits, plant above-ground biomass and soil nutrients. Plant biomass and soil temperature were the key indicators of Re, and plant leaf nitrogen content was the key plant trait associated with N2O emissions. In contrast, plant specific leaf area and biomass were the key traits associated with CH4 uptake. Conclusions: Overall, Re and CH4 uptake were reduced by chronic drought in this desert steppe, but there was no significant effect on N2O emissions. Ecosystem respiration, CH4 uptake and N2O emissions were associated with plant functional traits. This provides new insight for the understanding of soil carbon and nitrogen dynamics in desert steppe systems under drought conditions and an important theoretical basis for the revision of model parameters. [ABSTRACT FROM AUTHOR]

The frequency and amount of precipitation exert profound impacts on plants and the soil subsystem in dryland ecosystems. To quantitatively assess the effect of precipitation on ecosystem carbon fluxes during the growing season, a field experiment was carried out in a native desert‐grassland ecosystem in Inner Mongolia to determine the dynamics of ecosystem carbon fluxes along a precipitation gradient (−60%, −40%, −20%, CK, +20%, +40%, and +60%; CK is natural precipitation). The net ecosystem productivity (NEP) and gross ecosystem productivity (GEP) exhibited a single peak, whereas ecosystem respiration (Reco) exhibited a bimodal peak across all precipitation treatments. Reco reached its highest value at the beginning of August, whereas NEP and GEP reached their highest values at the end of August. Mean values of carbon fluxes increased with an increase in precipitation (from NEP: 0.06 μmol · m−2 · s−1, Reco: 0.37 μmol · m−2 · s−1, GEP: 0.42 μmol · m−2 · s−1 at −60% to NEP: 1.25 μmol · m−2 · s−1, Reco: 0.93 μmol · m−2 · s−1, and GEP: 2.18 μmol · m−2 · s−1 at +60%). Increased precipitation stimulated GEP more so than Reco during the growing season, resulting in an enhanced NEP, and decreased precipitation reduced GEP more so than Reco, leading to a reduced NEP. We concluded that the carbon sequestration capacity was enhanced by increased precipitation in the desert‐grassland ecosystem. Key Points: Ecosystem carbon flux increased with precipitation increaseCarbon sequestration capacity was enhanced by increased precipitation in the desert‐grassland ecosystem [ABSTRACT FROM AUTHOR]

Abstract: As a renewable energy source, wind turbine generators are considered to be important generation alternatives in electric power systems because of their non-exhaustible nature. As wind power penetration increases, power forecasting is crucially important for integrating wind power in a conventional power grid. A short-term wind farm power output prediction model is presented using fuzzy modeling derived from raw data of wind farm. Using wind data from a wind farm in Inner Mongolia of China, an interpretable model which reveal a useful qualitative description of the prediction system is developed, and a power forecasting map is illustrated. The comparative study of model prediction with different periods is conducted. [Copyright &y& Elsevier]

[Display omitted] • Shrub encroachment simplifies herbaceous community compositions in desert steppe. • Shrub encroachment can amplify spatial heterogeneity of herbaceous vegetation. • Spatial scale changes strongly affect spatial heterogeneity of shrub and herbaceous vegetation. • Shrub and herbaceous vegetation have different spatial heterogeneity with increased scale. Spatial heterogeneity plays a crucial role in affecting the ecologial processes in natural ecosystems, yet how spatial heterogeneity of herbaceous vegetation in desert-grassland transitional zone varies with increased spatial scale are still poorly known. We measured plant height, density, species richness and aboveground plant biomass (AGB) at the small (0.25 × 0.5 km), medium (0.5 × 0.5 km) and large (0.5 × 1 km) spatial scales in two adjacent plant communities (shrub- and grass-dominated) in desert steppe, Inner Mongolia. We used the geostatistical methods to examine the magnitude and degree of spatial heterogeneity of herbaceous vegetation characteristics with the increasing scale in both two plant communities. We found that compared to grass-dominated community, shrub-dominated community had the lower plant height and density at the large scale, the higher AGB at the small or medium scale, and the lower species richness at all three scales. Plant height, density and AGB in grass-dominated community were higher at the large scale than at the small scale, but they did not differ across three scales in shrub-dominated community. Species richness in both two communities were higher at the small scale than at the medium or large scale. All vegetation characteristics at three scales had the higher spatial heterogeneity in shrub- than in grass-dominated community. Spatial heterogeneity of all vegetation characteristics in shrub-dominated community decreased from the small to the large scale, while their spatial heterogeneity of plant height, density and species richness in grass-dominated community increased with the increasing scale. Our study highlights that shrub encroachment can simplify community composition and amplify spatial heterogeneity of herbaceous vegetation at multiple scales. Scale effects on spatial heterogeneity of herbaceous vegetation in desert steppe are dependent on plant community dominated by shrub or grass. [ABSTRACT FROM AUTHOR]