Spatio‐Temporal Dynamics of Aboveground Biomass in China's Oasis Grasslands Between 1989 and 2021

Abstract

Grassland provides multiple ecosystem services and plays a key role in preventing desert encroachment and maintaining oasis stability. In China, the area of cropland in oases has expanded significantly in recent decades, which results in a rapid increase in agricultural water demand and encroachment on grassland subsistence space. However, our knowledge about how the expansion of cropland affects oasis grasslands remains limited. We used machine learning, temporal segmentation of spectral trajectories, and maximum covariance analysis to generate an annual oasis grassland aboveground biomass (AGB) data set at 30‐m resolution from 1989 to 2021 based on multiple remotely sensed and ground observation data sets, and investigated the dynamics of grassland AGB under cropland expansion in oases. We found that overall oasis grassland AGB increased significantly (0.3 gm−2 yr−1, P < 0.01) during 1989–2021, but trends in AGB were not consistent across basins. In the Yellow River, Turpan Hami, Qaidam, and southern Altai Mountains River Basins, AGB was dominated by a significant increase. Conversely, in all basins in southern Xinjiang, AGB showed a decreasing trend due to the rapid cropland expansion. Spatially, cropland expansion and AGB dynamics were strongly coupled. In regions characterized by agricultural concentration, grassland AGB benefitted from resource spillover via edge effects. However, in downstream areas or those with a low proportion of cropland, where most grasslands are distributed, the relationship between the two shifted to a trade‐off. Our study provides a scientific basis for identifying priority areas for ecological restoration and for science‐based planning of the scale of cropland in oases.

Study on the Expansion Potential of Artificial Oases in Xinjiang by Coupling Geomorphic Features and Hierarchical Clustering

“…On the one hand, fallowing has turned some cultivated artificial oases into unused land or natural oases. On the other hand, after treatment, the area of soil erosion in Xinjiang in 2019 was about 839,800 km 2 , which was 45,600 km 2 less than that in 2012 [31], and desertification control has changed some land from desert to natural oases [63,64], which, in turn, have the possibility of being developed into artificial oases. Additionally, priority development areas with favorable policies and the significant deployment of policy needs will lead to urban and population relocation, resulting in a significant increase in the area of artificial oases represented by built-up land.…”

Assessment of Grassland Biomass Prediction Using AquaCrop Model: Integrating Sentinel-2 Data and Ground Measurements in Wielkopolska and Podlasie Regions, Poland

“…Grasslands, as dynamic biological systems, are crucial for providing essential ecosystem services like climate regulation and carbon sequestration [1], contributing significantly to global food security and having substantial ecological and economic impacts [2]. They offer a diverse array of benefits to humans, including biodiversity preservation, habitat creation, and the protection of water supplies [3]. In Poland, expansive grasslands are regarded as a significant natural resource of ecological and agricultural importance.…”