The relationship between the spatial structure of shelter forests and the diversity of understory herbaceous plants in desert–oasis ecotones is important for maintaining biodiversity indices and protecting the oasis ecosystem. In this paper, we explore the coupling relationship between tree layer structure (competition index, angle scale, neighborhood comparison, DBH, etc.) and understory herb diversity in the transition zone of shelter forest plots near oases and near deserts; in addition, we also aim to elucidate the dominant stand structure factors affecting herb biodiversity. The results indicated the following: A total of 13 herbaceous plant species were discovered in the transitional zone, with 11 species found near the oasis area and 4 species near the desert region. The Shannon, Simpson, and Pielou indices of understory herbaceous plants were significantly higher near the oasis area compared to the desert region. The Margalef index mean was higher in the oasis area compared to the desert region. Pearson and canonical correlation analyses revealed significant associations between specific stand structure indicators and diversity in the herbaceous layer. The results of the multiple linear regression analysis revealed that the competition index had a significant impact on the Shannon, Simpson, and Pielou diversity indices of the herbaceous layer in the understory of the shelterbelt forest near the oasis, with corresponding impact coefficients of 0.911, 0.936, and 0.831, respectively. The mingling degree was found to be the primary influencing factor for the Margalef index, with an impact coefficient of 0.825. However, in the understory of the shelterbelt forest near the desert, the neighborhood comparison ratio negatively affected the Shannon and Margalef indices, with impact coefficients of −0.634 and −0.736, respectively. Additionally, tree height negatively impacted the Simpson and Pielou indices, with impact coefficients of −0.645 and −0.677, respectively. In order to enhance the diversity of understory herbaceous species in the transitional zone and preserve the ecological system of the oasis, specific modifications to the forest structure and arrangement are essential. Pruning and thinning are necessary for shelterbelt forests located near desert regions, while shelterbelt forests near oases should use a suitable mix of tree species. These measures can help preserve or enhance the diversity of understory herbaceous plants.

Land use and land cover change (LULCC), along with the conversion of natural ecosystem cover into farmland, poses significant ecological challenges for desert riparian ecosystems. The Tarim River Basin (TRB), home to the world’s largest and most densely distributed and well-preserved desert riparian ecosystem, remains exceptionally susceptible to climate change. However, our understanding of the role of climatic factors (mean annual temperature (MAT); mean temperature during the warmest month (MWMT); relative humidity in September, October, and November (RH_SON); and the annual heat–moisture index (AHM)) in driving pattern changes in these ecosystems remains limited. To address this gap, we employed a transfer matrix approach coupled with geographically weighted regression models to conduct an extensive analysis of LULCC trends and their driving factors within the TRB from 1990 to 2020. The 30-year dataset on LULCC provided invaluable insights, revealing that the proliferation of farmland and shrubberies has precipitated the decline of arbor forests and grassland expanses. Furthermore, this expansion of farmland and shrubberies has resulted in heightened ecosystem fragmentation, particularly notable between 2005 and 2010. Our assessment indicates that artificial ecosystems are gradually transitioning back into natural states, encompassing 8.24% of the total area, chiefly attributed to the expanding shrubbery regions. Additionally, in-depth scrutiny of the impacts of climatic factors on ecosystem structure unveiled that moisture exerts the most pronounced influence on ecosystem patterns, followed by air moisture content during the growing season, while temperature exerts a relatively lesser impact. Overall, this study contributes to the realization of SDG 13 (Climate Action) and SDG 15 (Life on Land) by informing conservation efforts and sustainable land management practices in dryland desert riparian ecosystems.