The threat posed by poisonous weeds to grassland ecosystems may be exacerbated by climate change mainly driven by carbon dioxide (CO2) emissions. Achnatherum inebrians is a common and poisonous grassland weed that is seriously endangering the sustainable development of prairie animal husbandry in Western China. Understanding the influence of future climate change under different CO2 emission scenarios on the potential distributions of A. inebrians is critical for planning agricultural strategies to manage the continued invasion. An ecological niche model (ENM) was developed using Maxent to predict the potential distribution of A. inebrians under three different CO2 emission scenarios. Occurrence records of A. inebrians were selected utilizing the nearest neighbor method. Six environmental variables, which were identified through principal component analysis, correlation analysis and their contribution rates, were used to perform the ENM. At the same time, considering the uncertainties of predicting future climates, four global circulation models were used for the Maxent projections with average results calculated. Our results demonstrate differential influences of various CO2 emission scenarios on the potential distributions of A. inebrians. Before 2050, high CO2 emission scenarios resulted in a wider potential distribution of A. inebrians, when compared to low CO2 emission scenarios. However, after 2050, the low CO2 emission scenarios were more conducive to an expanded potential distribution. In addition, after 2050, high CO2 emission scenarios maintain the geographical distribution centroids of A. inebrians in lower latitudes, while low CO2 emission scenarios result in distribution centroids rising to higher latitudes. Further, low CO2 emission scenarios resulted in the average potential distribution elevation dropping lower than in high CO2 emission scenarios.
HIGHLIGHTS. The revegetation of Caragana korshinskii had a positive effect on the local habitat restoration.In the younger revegetated site, C. korshinskii exhi
Soil profile CO2 transport and production are vital in the carbon stock in desert artificial vegetation ecosystem. In this study, the soil profile CO2 concentration, soil water content and temperature at depths of 0–40 cm were measured at four revegetated sites (1956, 1964, 1981 and 1987), located in the southeastern edge of Tengger desert, China. The gradient method was applied to simulated soil gas diffusion coefficient and soil profile CO2 efflux. We found that the soil profile CO2 concentration increased with depths, while the soil CO2 diffusion coefficient, soil CO2 efflux and production in upper layers were significantly higher than those in bottom layers. The CO2 diffusion coefficient decreased at first and then increased with revegetation age. The soil profile CO2 concentration, CO2 efflux and production increased with revegetation age. The simulated soil surface CO2 efflux were 0.54 µmol·m− 2·s− 1, 0.49 µmol·m− 2·s− 1, 0.44 µmol·m− 2·s− 1 and 0.25 µmol·m− 2·s− 1 at 1956, 1964, 1981 and 1987 revegetated sites, respectively. The soil surface CO2 efflux mainly came from the layers of 0–10 cm, which contributed to 76.4% − 94.9% of the total. The structural equation modeling (SEM) explained 97.0% of the variations in soil surface CO2 efflux (F0). The effects of soil CO2 concentration, temperature and water content in the layers of 10 cm, and plant properties on soil surface CO2 efflux were 0.977, 0.516, -0.358 and − 0.156, respectively, and the interaction between soil temperature and water content was 0.439, which meant that the soil temperature and water content significantly influenced soil CO2 efflux.