西部地区生态状况变化及生态系统服务权衡与协同

Ecological changes and the tradeoff and synergy of ecosystem services in western China

西部大开发战略实施20年以来,一系列重大生态建设工程使得西部地区的生态状况和生态服务发生了重要变化,本文分析西部地区生态状况变化及其生态服务时空变化特征,并运用相关分析法研究其服务功能权衡协同关系。研究发现西部地区2000—2019年间:①聚落和湿地生态系统面积显著增加,草地有逐年下降趋势。②植被覆盖度呈波动上升趋势,存在年际差异且空间差异较大。③水源涵养服务有轻微下降趋势,下降区域主要分布在藏东南地区、三江源西部地区、喀斯特石漠化地区等;土壤保持服务波动中呈上升趋势,上升区域主要黄土高原地区、川滇西部地区、藏西北地区、藏东南地区等;防风固沙服务呈下降趋势,大幅下降区域主要位于内蒙古中西部地区、西藏和北疆部分地区。④生态系统供给与水源涵养、土壤保持主要为协同关系,与防风固沙主要为权衡关系且分布在农牧交错带地区。⑤生态工程区内生态系统服务协同程度大于非工程区。定量评估生态系统服务变化及其权衡协同关系有助于进行科学化生态管理,最大化生态效益。

Since the implementation of the government initiative-the Development of Western Regions for 2000-2019, a series of major ecological construction projects have been launched,leading to great changes in the ecological conditions and ecological services of western China.This study calculated the amount of total ecosystem services in the western region from 2000 to2019, and analyzed ecological changes and the characteristics of spatio-temporal variations in ecological services. And a relevant analysis method was applied to explore the trade-offs and synergy of service. It was found that the area of settlements and wetland ecosystems in the study area increased significantly from 2000 to 2015, whereas grassland showed a downward trend year by year. The vegetation fraction showed a decreasing zonal distribution from south to north. A fluctuating increase was observed during 2000-2019, with inter-annual and large spatial differences. The water conservation service had a slight downward trend from 2000 to2019, and the main decreasing areas were distributed in southeastern Tibet, the western part of the Three Rivers Source Region, and the karst rocky desertification area. The soil conservation service showed an increasing but fluctuating trend, with the greatest increases observed in the Loess Plateau, western Sichuan and Yunnan provinces, northwest Tibet, and southeast Tibet.The windbreak and sand fixation showed a downward trend, and the sharp decline was mainly found in the central and western parts of Inner Mongolia, Tibet and parts of northern Xinjiang.Ecosystem supply, water conservation, and soil conservation were synergistically connected,they were observed north of the Huaihe River-Qinling Mountains, especially in Ningxia and Inner Mongolia. Ecosystem supply was mainly trade-offs with windbreak and sand fixation,and it was observed in the farming-pastoral transitional zone. The synergistic degree of ecosystem services in areas subjected to ecological engineering policy was greater than that in non-engineering areas. Quantitative assessment of ecosystem service changes and their tradeoffs is helpful for scientific ecological management and maximizing ecological benefits.