Assessing the degree of land degradation and rehabilitation in the Northeast Asia dryland region using net primary productivity and water use efficiency

Abstract

Changes in vegetation productivity and species composition have been used as conventional indicators of land degradation and rehabilitation assessments. The two biophysical parameters vary nonlinearly during land change process with various time lags, which provide, as a whole, a useful framework to diagnose degree of land degradation and rehabilitation. In this study, the net primary productivity (NPP) and water use efficiency (WUE), which are the proxies of vegetation productivity and eco‐physiological properties related to species composition, were combined to develop an eco‐physiological framework to assess the degree of land degradation in the Northeast‐Asia dryland regions (NADR) from 1982 to 2012. Results from long‐term trends analysis showed early, middle or late degradation stages occurred in northern grassland and central barren or sparsely vegetated regions, respectively, while the rehabilitation prevailed in eastern croplands and forest, southern, and western grassland. In contrast, short‐term trend analysis illustrated the recent rehabilitation in mid‐eastern Mongolia and Loess Plateau, which was unseen in long‐term trend analysis. The spatial patterns and temporal changes of land degradation and rehabilitation could be explained partly by either or both natural and anthropogenic factors. Long‐term drying and warming might induce land degradation in northern and central NADR, respectively, while the recovery projects and wetting conditions after 2000s promoted the land rehabilitation in Loess Plateau and mid‐eastern Mongolia. Here, our NPP–WUE framework may contribute further conceptual development and rapid assessments on land degradation and rehabilitation in wide geographic regions.

Is land degradation worsening in Northern China? Quantitative evidence and enlightenment from satellites

“…(2) Extract NPP Land degradation describes a temporary or permanent decline in land productivity (Li, Meng, et al, 2020). Vegetation productivity can act as an index reflecting land degradation or rehabilitation (Kang et al, 2020). NPP is an essential component of the terrestrial ecosystem carbon cycle, regulates ecological processes, and can directly reflect vegetation community productivity (Zhang et al, 2021).…”

Increasing precipitation during first half of growing season enhances ecosystem water use efficiency in a semiarid grassland

“…The tradeoff between plant productivity and water use can be quantified by water use efficiency (WUE), the magnitude of carbon (C) gained per unit of water consumption ( Beer et al., 2009 ; Lawson and Vialet-Chabrand, 2019 ; Bai et al., 2020 ; Dong et al., 2021 ). WUE, therefore, represents the coupling of terrestrial ecosystem C and hydrologic cycles ( Song et al., 2016 ; Kang et al., 2020 ; Zhang et al., 2020b ) and is regarded as a vital indicator for characterizing terrestrial ecosystems in response to on-going climate change ( Knauer et al., 2017 ; Li et al., 2018 ; Zheng et al., 2019 ). Higher WUE implies that plants can synthesize more C by consuming less water resources ( Tarin et al., 2020 ).…”

The Coupling Coordination between the Competitiveness Level and Land Use Efficiency of Green Food Industry in China

“…The application of ecological location theory in the 1920s further enriched the study of land use efficiency. Many scholars have conducted numerous empirical studies on land use change [18], efficiency measurement and assessment [19], and optimization modeling strategies [20]. Land use efficiency is a concept that embodies sustainable development and is driven by natural, economic, and social impacts.…”