Spatiotemporal Dynamics of Vegetation Index in an Oasis-Desert Transition Zone and Relationship with Environmental Factors

Abstract

The oasis-desert transition zone (TZ) is an ecological buffer zone between a mobile desert and an oasis, which are important in reducing the forward mobility of sand dunes and wind and sand hazards in an oasis. In this study, the Dunhuang Oasis and its TZ in the Hexi Corridor (China) were examined. Based on the annual normalized vegetation index (NDVI) at each buffer distance of the TZ from 1987 to 2015, combing the watershed hydrology, oasis crop cultivation structure and industrial economic status, partial least squares regression models and a correlation analysis were used to examine the spatial and temporal changes in the vegetation gradient of the oasis TZ and the factors influencing those changes. (1) Spatially, the NDVI values in the TZ generally decreased gradually before stabilizing with a buffer distance (average decrease of 0.01–0.03 per 300 m). (2) Temporally, the mean values of the NDVI in the TZ show an overall wavelike variation across years. The annual average maximum NDVI value was 0.11 in 1987, whereas the annual average minimum value was 0.07 in 2014. (3) During the 1987–2015, runoff, tourist populations and water consumption for orchards were significantly and positively correlated with the NDVI; the year-end arable land area and the total industrial output value were significantly and negatively correlated with the NDVI; the rural per capita net income and water consumption for grain planting were not significantly and positively correlated with the NDVI; water consumption for the sum of vegetable and melon planting, water consumption for cotton planting, urbanization and rural populations were not significantly and negatively correlated with the NDVI. (4) The farm TZ NDVI is more strongly influenced by human activities than the undisturbed natural TZ.

Vegetation–Lake–Sand Landscape of Northeast China Sandy Land between 1980 and 2022: Pattern, Evolution, and Driving Forces

“…The awareness of the general public regarding environmental protection should be strengthened, and new environmental policies should be formulated and implemented. It should be pointed out that to restore environmental functions and promote the development of an ecological economy in Northeast China, ecological restoration measures should be adjusted according to the local conditions and ecological principles, combined with the characteristics and mechanisms of different landscape changes, to achieve the coordinated development of the environment and society [81].…”

Stem sap flow of Haloxylon ammodendron at different ages and its response to physical factors in the Minqin oasis-desert transition zone, China

“…The oasis-desert transition zone is the most intensive and prominent area of oasis and desert inter-conversion activities (Pan, 2000;Cao et al, 2021). This type of area is therefore extremely fragile and sensitive, being vulnerable to human activities and quite difficult to restore once degraded or destroyed (Ding, 2018;Lu et al, 2023). Moreover, this zone was also the interface area with the most frequent material cycle, energy flow, and information exchange between oasis and desert ecosystems (Thomas et al, 2006;Chang et al, 2007).…”