Spatiotemporal dynamic evolution and driving factors of desertification in the Mu Us Sandy Land in 30 years

Abstract

The Mu Us Sandy Land is located in the middle of the farming pastoral ecotone of northern China. The direction of the development of desertification has a direct impact on the economy and development of the northern region. Six remote sensing images acquired during 1990–2017 served as data sources. Using an ENVI 5.3 and ArcGIS 10.3 platform an analysis was conducted of the dynamic changes nearly 30 years in desertified land using a center of gravity moving model, annual change rate, a transfer matrix, and an aeolian desertification index; the factors driving desertification were discussed. The research shows that the time period can be divided into three stages of desertification: development (1990–2000), rapid reversal (2000–2010), and stable reversal (2010–2017). A total of 1680 km2 of desertification were managed over the three stages. Spatially, the distribution of the center of desertification from west to east includes mild, moderate, severe, and extreme desertification, which is consistent with the spatial distribution trends of desertified land in the Mu Us Sandy Land. By the end of 2017, the degree of desertification of the Mu Us Sandy Land was in the central area > northwest > southwest > east > south. Nearly 30 years, the wind speed has decreased year by year at the rate of 0.1 m s−1, which directly reduce the ability to winds to transport soil in the Mu Us Sandy Land and promoted the reversal of desertification. From 1990 to 2010, the climate tended to become warmer and drier. Environmental protection policies along with human intervention and control of desertification have played important roles in reversing desertification. From 2010 to 2020, under the general background of a warm-wet climatic tendency, rational use of sand resources and strengthening scientific control of desertification inducing factors are the keys to reversing desertification.

Spatial and temporal dynamics of desertification and its driving mechanism in Hexi region

“…There are few and generally short rivers in Hexi region, mainly inland rivers such as Shule River, Heihe River and Shiyang River, and the relative shortage of water resources is the limiting factor for the ecological environment in the region. In recent years, with the vigorous economic development in the region, unreasonable agricultural and pastoral practices, mining, etc., have continued to intensify land desertification, and the conflict between human and nature has been highlighted (D'Odorico et al, 2013;Kefi et al, 2007;Li et al, 2015), which has brought about frequent dust storms, reduced species diversity, loss of soil nutrients, water scarcity, and other hazards (Cheng et al, 2018;Liu, Wang, et al, 2020;Prince & Podwojewski, 2020;Reynolds, Smith, et al, 2007). Although the current policy of returning farmland to forest and grass has slowed down desertification to a certain extent, the poor natural environmental conditions and the low economic status of the population make the ecology of the region still fragile, and there is still a trend of overall reversal but partial deterioration manifest as desertification (Feng et al, 2019;Li et al, 2013;Ma & Fan, 2006).…”

“…This indicates that the desertification of land in the study area gradually tends to be good, but at the same time, the ratio of non-desertified to lightly desertified land is still low, indicating that the serious desertification situation in the study area is still severe under the ecological fragility. The fragile ecology has also led to a highly sensitive vegetation recovery process in the study area (Bakr et al, 2012), which is susceptible to disturbance by external conditions, with land degradation during 2010-2015 mainly attributed to the warm and dry climate and frequent dust storms in the Alxa region (Guo et al, 2021;Liu, Wang, et al, 2020). Desertification control in China has gone through three important development stages from the 1950s to the present (You et al, 2021) Source Control Project, which includes sustainable grazing and cultivation practices, planting of windbreaks, and water use quotas (Zhang & Huisingh, 2018).…”

“…Understanding the causes of desertification is essential for desertification control and related policy development (Han et al, 2020; Wang, 2014). Desertification is often caused by multiple factors, with climatic variations and anthropic events being the main drivers (Reynolds, Maestre, et al, 2007; UNEP, 1991; Zika & Erb, 2009), both of which act in combination on fragile ecosystems, resulting in vegetation destruction and the onset and development of desertification (Ma et al, 2021; Schlesinger et al, 1990; Wang et al, 2015; Zhang & Huisingh, 2018).…”

Bidirectional coupling between land‐use change and desertification in arid areas: A study contrasting intracoupling and telecoupling

“…By regression analysis of the normalized albedo and NDVI data, the k value was found to be À0.1461 (R 2 = 0.7009), and the DDI expression is thus: (DDI > 2.41). On this basis, referring to previous studies (Han et al, 2020;Zhang et al, 2021), we introduced the desertification index (DI) to monitor the evolution of desertification in the Tarim River from 2001 to 2019, which can be calculated as:…”

Monitoring and assessment of desertification using remote sensing

“…La evaluación del impacto de la degradación del suelo en la vegetación se puede observar a través de imagen a partir de diferentes tipos de indicadores (Han et al 2020;Hein et al 2011). Dentro de indicadores de CF, encontramos variables que afectan principalmente al estado de la vegetación, tales como el contenido en pigmentos y el contenido de agua de las cubiertas vegetales; y distintas variables relacionadas con el estado fisiológico de las plantas, como pueden ser la fotosíntesis, el potencial hídrico o la conductancia estomática.…”