Three Decades of Oasis Transition and Its Driving Factors in Turpan–Hami Basin in Xinjiang, China: A Complex Network Approach

Abstract

As a predominant ecosystem-providing area and distinctive landscape in arid regions, an oasis plays an important role in maintaining land stability, human production, and daily activities. Studying the dynamics of oasis and its driving factors is vital to supporting arid regions’ sustainable development. As a typical mountain–desert–oasis landscape, the Turpan–Hami (Tuha) Basin, located in Xinjiang, China, includes complex interactions among different land types. For this study, we revealed the spatio-temporal patterns and transition processes of the oasis using a complex network method between 1990 and 2020 in the Tuha Basin. In the oasis transition network, the degree value, betweenness centrality, and average path length were calculated to express the transition relationship, key oasis type, and oasis structural stability, respectively. Six factors related to climate change and human actives were selected to investigate the driving forces behind oasis transitions, including the average temperature and precipitation in the growing season, the total power of agricultural machinery (TAMP), the production of raw coal (PRC), the total output value of the plantation industry (TPI), and the population (Pop). Our results show that the oasis area of the Tuha Basin, including the natural oasis and artificial oasis, all grew from 1990 to 2020, with the natural oasis expanding more than the artificial oasis. The transitions between oasis types became more frequent as the area of oasis land types increased throughout the study period. Grassland acted as the most important oasis type in the network, with the highest betweenness centrality, but its importance declined due to the increasing complexity of the oasis transition network from 1990 to 2020. The transitions between oasis types became simpler, and the oasis structural stability decreased. Through driving force analysis, the oasis changes showed a positive correlation with the temperature (p-value < 0.05, r = 0.88), and urbanization and industrialization factors prompted transitions to built-up areas and cropland from grassland and shrubland. In summary, our results suggest that to create a harmonious symbiotic relationship between the natural environment in dryland and human activities, preventing grassland degradation and excessive reclamation of land cover is an available way. Meanwhile, the protection of shrubland and water resources is also important. This study provided reference and theory support for promoting the sustainable development of oases.

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

“…Since the 1990s, land use in Xinjiang has changed considerably, and scholars have examined change statistics from the perspectives of oases [45,46], arable land [13,27,29], and construction land [12,47] across the whole territory. Existing studies have found that the total area of artificial oases has substantially increased due to the development of agricultural technology before and after 2010, and the trend of southward movement is obvious in general [14,27]. However, most of the analyses on oasis changes in previous work only examined the time trend of oasis changes and the changes in the transfer matrix of land-use types, and there is a lack of separate analyses on the relationship between changes in artificial oases and geomorphological types.…”

“…Unlike plains where a flat river can expand uniformly in all directions, some of the artificial oases in Xinjiang will stop or slow down their expansion when they are blocked by mountains such as the Tianshan Mountains, Altay Mountains, and Kunlun Mountains, and the mountainous terrain also prevents the merging of these artificial oases on both sides, which reflects the influence of morphological landform types on the development of oases. In addition, water resources are one of the most important factors limiting the development of oases [14,51]. As the lifeline of irrigated agriculture, water determines the distribution of farmland [52], and without the support of water resources, arable land will be abandoned and degraded.…”

“…Undeniably, policy factors have an important impact on the development of artificial oases. From 2006 to 2020, various ecological protection measures such as returning farmlands to forests and desertification control were implemented in Xinjiang [14,31,62], which have greatly influenced the distribution pattern of artificial oases in the territory. On the one hand, fallowing has turned some cultivated artificial oases into unused land or natural oases.…”

“…At present, studies on oasis Remote Sens. 2024, 16, 1701 2 of 20 changes in arid zones have mainly focused on oasis vegetation [5][6][7], the dynamic monitoring of land-use changes [8][9][10], the driving factors of oasis land-cover changes [8,[11][12][13][14], oasis desert mapping and evaluation [15,16], oasis carrying capacity, the development suitability scale [17][18][19][20], and oasis landscape pattern changes and ecological impacts [21], among other topics. In existing studies on artificial oases, Xinjiang, as a typical arid region in western China, has an important position in the study of Chinese oases.…”

“…Song et al used the Automata-Markov model to simulate the future development of a typical artificial oasis and its landscape ecological pattern under different scenarios in the Northwest Alar Reclamation Area, and put forward recommendations for the development of the oasis under different scenarios [25]. Zhang et al used a constructed oasis transition network to study the oasis transition processes and structural stability at the Tuha Basin between 1990 and 2020 [14].…”