基于参照系的中国陆地生态系统质量变化研究

Quality changes of China′s terrestrial ecosystem based on reference system

提升生态系统质量(ESQ)是国家生态文明建设的重大需求和生态治理工程的最终目标。目前有关生态系统功能、健康和质量的评估以受气候主导的现实值为主,不同地区之间评价结果的可比性较低,难以满足国家生态系统管理的需求。采用基于参照系的生态系统质量评估框架,按照由中国生态地理分区和植被类型划分出的168个评估单元,以国家自然保护区核心区、中国生态系统研究网络(CERN)永久观测样地以及生产力主要受气候影响的区域等较少受人类活动干扰且生态系统结构和功能优良的生态系统作为参照系,评估了1990—2015年基于参照系的中国陆地生态系统质量(ESQ′)及其变化情况。结果表明:与参照生态系统相比,中国陆地生态系统质量指数平均值总体偏低28%。1990—2000年和2000—2015年ESQ′全国平均值分别下降1.2%和上升3.69%。ESQ′转变比较明显的区域集中分布在“陕-甘-宁”的黄土高原丘陵沟壑水土保持生态功能区、长白山地区和西南石漠化治理工程县域。在这些区域实施的退耕还林还草、防护林和石漠化治理工程等措施对提升生态系统结构、功能和稳定性发挥了重要作用,从而促使生态系统质量的改善。基于参照系的生态系统质量评估方法可以在一定程度上消除不同区域气候波动差异对质量评估的影响,为量化人类活动对生态系统的影响提供了一种可行的新途径,可为我国的生态系统和土地利用管理提供参考。建议未来加强全国不同区域、不同类型的参照生态系统联网观测,并重点关注未来气候变化及生态系统功能权衡关系对生态系统质量的影响。

Improving the ecosystem quality(ESQ)is a major requirement for national ecological civilization construction and the ultimate goal of the ecological restoration project.However,the assessment of ecosystem function,health and quality was based on actual values of the ecological indicators dominated by climate in previous studies,and the comparability of evaluation results between different regions was too low to meet the needs of national ecosystem management.In this paper,based on a reference system-based ecosystem quality assessment framework and 168 assessment units divided by China′s eco-geographical zones and vegetation types,we used ecosystems that were less disturbed by human activities and had excellent ecosystem structure and functions,such as the core area of the National Nature Reserve,the permanent observation plots of the Chinese Ecosystem Research Network(CERN),and areas where productivity was mainly affected by climate as reference benchmarks,and estimated China′s terrestrial ecosystem quality based on reference system(ESQ′)and its changes during 1990-2015.The results show that the average value of China′s terrestrial ecosystem quality index was 28%lower than that of the reference ecosystem.China′s ESQ′decreased by 1.2%during 1990-2000 and increased by 3.69%during 2000-2015,respectively.The regions with obvious transformations were mainly distributed in the Shaan-Gan-Ning loess plateau hilly and gully water and soil conservation ecological function zone,Changbai Mountain and counties in the southwest of the rocky desertification control project.Ecological restoration projects such as the Grain for Green Project,shelter forests and comprehensive control of rocky desertification in these regions have played an important role in improving the structure,function and stability of the ecosystem,thereby promoting the improvement of ecosystem quality.The method of ecosystem quality assessment based on reference system can eliminate the impact of differences in climate conditions on the quality assessment between different regions to a certain extent,provide a feasible new way to quantify the impact of human activities on the ecosystem,and provide references for China′s ecosystem management and land use management.We suggest that the government should strengthen the networked observations of reference ecosystems in different ecological geographic regions and different vegetation types of China in the future,and focus on the impact of future climate change and the trade-off relationship between ecosystem functions on ecosystem quality.