摘要
近几十年来，气候变化与人类活动显著影响了长江中下游浅水湖泊生态系统状态，导致服务功能急剧退化。对湖泊生态系统状态转变过程的深入理解是进行科学管理的重要依据。文章以大型浅水湖泊——巢湖为例，利用硅藻作为系统状态的替代指标，并结合多指标记录探讨了过去150年来巢湖生态系统转变过程。研究表明，湖泊水动力、营养和温度分别在不同时间尺度上驱动了巢湖生态系统状态变化，使其抵抗力下降；营养是触发1970s末期巢湖从清水态突变至浊水态的主要因素，而增温使这一转变进一步恶化。对比巢湖和太白湖的研究发现，大型和小型湖泊稳态转换的触发因素和维持机制有明显区别，建议根据不同湖泊生态系统状态长期变化过程和驱动因素施行针对性的管理措施。
In recent decades, shallow lakes in the middle and lower reaches of Yangtze River Basin（MLYB） are significantly influenced by climate change and human activities, probably rendering ecological regime shifts with degraded lake ecosystem services. Improved understanding of regime shifts and their transforming processes in shallow lakes is important for proper lake management. In this study, we focus on a typical big shallow lake in the MLYB——Chaohu Lake（31°25＇28″～31°43＇28″N, 117°16＇54″～117°51＇46″E）, and take use of diatom as the proxies to show the ecological regime shifts in lakes. Two sediment cores, C1（31°35＇47″N, 117°23＇58″E） and C20（31°32＇08″N, 117°37＇12″E） were taken with a piston corer in the deepest part of Chaohu Lake in 2007 and 2009, respectively. C1 core is the main core, conducting multi-proxies analysis（including chronology, TOC, particle sizes, elements and diatom）; while C20 core is the supplementary one, conducting only diatom identification to compare with the results in C1 core. Besides, historical documents including climate change（annual temperature and precipitation）, hydrologic data（dam construction and annual average water level）, water resources（vegetation coverage, TP, TN and fish production）, and social-economic data（GDP, cropland, population and consumption of fertilizer） in Chaohu Lake and its catchment were also collected. By combining historical documents and palaeolimnological records, the specific ecological regime shifts and its transforming processes were analyzed in Chaohu Lake since 1850. Results of diatom assemblages using STARS methods based on PCA scores of diatom in both C1 and C20 cores reveals that, at least a regimes shift took place in late 1970s in Chaohu Lake, showing high regime shift index at that time. Redundancy analysis（RDA） reveals that weakened hydrodynamics, increased nutrients and climate warming posed effects on Chaohu＇s ecological states in different time periods, rendering the loss of its resilience. However, increased inputs of nutrients were the main driving forces of the ecological regime shift, which made Chaohu Lake change into current turbid water state from clear water state. And not only that, climate warming further aggravated this change afterwards. By comparing the results of ecological regime shifts in Chaohu and Taibai Lake, which are typical big and small lakes in MLYB respectively, it shows that the driving forces of ecological state change and regime shift processes are different in above two lakes. That means targeted management measures are necessary to lakes with different size and characteristics on temporal perspective.
作者
徐敏
王荣
羊向东
陈旭
赵雁捷
杨浩
Xu Min;Wang Rong;Yang Xiangdong;Chen Xu;Zhao Yanjie;Yang Hao(School of Geography Science, Nanjing Normal University, Nanjing 210046, Jiangsu;State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, Jiangsu;School of Earth Science, China University of Geosciences（Wuhan）, Wuhan 430074, Hubei;University of Southampton, Southampton SO17 1BJ, UK)
出处
《第四纪研究》
CAS
CSCD
北大核心
2018年第4期953-962,共10页
Quaternary Sciences
基金
国家自然科学基金重点项目（批准号：41530753）、国家自然科学基金面上项目（批准号：41472314）和中国科学院青年创新促进会专项项目（批准号：2017364）共同资助
关键词
稳态转换
巢湖
长江中下游
古湖沼
湖泊管理
regime shift
Chaohu Lake
the middle and lower reaches of Yangtze River Basin（MLYB）
palaeolimnology
lake management
