Cultivated oasis evolution in the Heihe River Basin over the past 2,000 years

Abstract

Cultivated oases play an important role in supporting human civilization in arid regions. Few quantitative analyses have been conducted on the influence of natural disturbances and human interventions on this fragile system over a long timescale. This paper presents an empirical study to investigate the quantitative relationship between cultivated oasis evolution and a set of natural and human factors in Heihe River Basin (HRB) over a timeframe of approximately 2,000 years (206 BC–1949 AD). Multiple data sources, including documentary records, historical atlas reconstruction data, and published papers, were used. Stepwise multiple linear regression analysis was adopted to quantify any significant contributions of the selected variables. The results showed that cultivated oasis in the HRB had experienced substantial fluctuations. Population size, agricultural policies, military clashes, and grain yield per unit area were 4 major human related factors determining historical cultivated oasis development, while flood was the only significant natural factor. In combination of similar studies in recent decades, this study shows that the dynamics of oasis development and its transition is important for determination of the sustainable size of a cultivated oasis in the HRB.

Quantifying the effects of human activities and climate variability on vegetation cover change in a hyper‐arid endorheic basin

“…The NDVI increased over the last 16 years from 2000 to 2015 with the population growth and agricultural expansion in the HRB. The reason for this increase must be because people always expand the scale of agriculture on borders of oases (i.e., reclaiming abandoned cropland, grassland and desert) (Al‐Faraj & Tigkas, ; Tang et al, ). A similar result was found in the Tarim River Basin (Kong et al, ).…”

“…The main natural vegetation types are temperate dwarf shrubs and subshrub desert vegetation, including Populus Gansuensis , Populus bolleana , Calligonum mongolicum , Hedysarum scoparium , Tamarix chinensis , Nitraria sphaerocarpa , Reaumuria soongorica , Bassia dasyphylla , Halogeton arachnoideus , Suaeda glauca , Agriophyllum squarrosum , and Eragrostis pilosa (Lu, Li, & Cheng, ). The area is a typical irrigated agricultural economic zone, and the most rapid development of agriculture and economy occurred from 1980 to 2010 (Tang et al, ). The irrigation districts in the middle reach occupy 98% of the agricultural lands in the basin, and irrigation amount accounts for more than 80% of the total water usage.…”

“…However, human activity played a pivotal role in vegetation cover change that was irrespective of precipitation, especially in the areas with high-intensity human activities (Brinkmann et al, 2011). Dawelbait and Morari (2012) found that changes in land use and mismanagement of natural resources were the main driving factors affect- The reason for this increase must be because people always expand the scale of agriculture on borders of oases (i.e., reclaiming abandoned cropland, grassland and desert) (Al-Faraj & Tigkas, 2016;Tang et al, 2018). A similar result was found in the Tarim River Basin (Kong et al, 2010).…”

“…The objectives of this study were to (1) detect the spatial and (Lu, Li, & Cheng, 2003). The area is a typical irrigated agricultural economic zone, and the most rapid development of agriculture and economy occurred from 1980 to 2010 (Tang et al, 2018). The irrigation districts in the middle reach occupy 98% of the agricultural lands in the basin, and irrigation amount accounts for more than 80% of the total water usage.…”

“…The Heihe River originates from the Qilian Mountains, flows through the middle oasis area and then enters the lower Gobi Desert (Cheng et al, 2014). The middle reach of the HRB is a flat oasis area that has been densely populated since ancient times and has a history of agricultural development that began before 140 BC (Tang, Zhao, Zhang, Feng, & Wei, 2018). Due to arid climate, rapid agricultural and socio-economic development, especially the ecological water diversion project (EWDP) started in 2000, the vegetation cover in the middle of the HRB has undergone extensive change (Cheng et al, 2014).…”