Geographical boundary line of the Yellow River's 'Ji Zi Bend' and its main ecological issues

Due to different positions, goals, and research contents, there was no consistent geographical boundary line on Yellow River's 'Ji Zi Bend'. On the basis of geographical location and key ecological position within the national strategic layout, we defined Yellow River's 'Ji Zi Bend' as the geographical boundary lines of "Ji-shaped" area, which started from Lanzhou City on the west till Sanmenxia City on the east, and from Baotou City on the north till the southern fringe of Sanmenxia City, forming a distribution area of the upper and middle reaches of Yellow River. The area covers 24 cities in six provinces, including Gansu Province, Ningxia Hui Autonomous Region, Inner Mongolia Autonomous Region, Shanxi Province, Shaanxi Province, and Henan Province. It includes desertified regions in northwestern area, and soil and water loss regions in southeastern area, as well as wetland and alluvial plain alongside both sides of Yellow River, with an area of about 6.04×10⁵ km² and a population of 6.01×10⁷ persons. The main ecological issues in this region are as below: scarcity and uneven distribution of water resources together with frequent occurrence of extreme climatic events; unequilibrium and poor regulation of water and sand together with serous soil and water loss; great desertification intensification and conflict between land utilization efficiency and ecological security; the conflict between energy resource exploitation and fragile ecological protection; land degradation and environmental pollution. The reasons for these aforementioned issues include: poor natural resources, and susceptible ecological conditions; history brand of desertification and soil and water loss in recent hundred years; the coupling drivers of climate change and human perturbation; the imbalance between increasing intensity of resource exploitation and utilization and regional development. More attention needs to be paid, including: enhancing management and configuration of water resources and the ability of prevention and reduction of natural disasters, being active response to climate changes; suitable measures to local real conditions and categorical policy for the improvement of ecosystem quality and the restoration and conservation of fragile ecosystems; policy coordination and management synergy, and the enhancement of holistic approach and integrating restoration. In the future, we should focus on ecological protection, concentrate on green development of energy resources, promote technological innovation in biodiversity conservation, strengthen the deep integration of biodiversity with ecological industries and green development, cultivate new quality productivity, and help win the battle against the ecological protection "bend" of the Yellow River.