摘要
探究湖泊生态系统稳态转换机制对科学管理湖泊环境具有重大的意义.本文通过西氿沉积岩芯XJ2018中的生物指标(摇蚊亚化石)及地球化学指标(总氮和总磷),探讨了其环境演变历程以及生态系统的稳态转换.摇蚊亚化石群落变化和系统突变指数(RSI)结果均表明,西氿生态系统在近40年内经历了明显的稳态转换.1990s前,湖泊营养状态较低,水生植被覆盖度较高,摇蚊群落以附植型摇蚊(Cricotopus trifasciatus、Dicrotendipes spp.)为主,广食性的长足类摇蚊丰度最低,此时西氿为草型-清水态湖泊;以1990年为节点一直到2000年前后,由于宜兴市围网养鱼以及农业发展迅速,湖泊营养状态在较短的时间内,发生了一次显著的转变,附植型类群逐步减少,广食型类群(Tanypus chinensis、Microchironomus tabarui)暴发且逐步占据统治地位,湖泊营养化程度逐渐加剧,由草型逐步向藻型过渡;20002010年,湖泊生态系统进一步恶化,附植型类群几乎消失,广食型长足亚科(Tanypus chinensis、Procladius choreus)占绝对优势,2010年以后,附植型摇蚊类群的恢复和广食型摇蚊数量的下降,表明随着生态保护的重视和生态治理的实施,西氿环境略有改善,但藻型富营养湖泊的状态仍未改变.
Tracking regime shifts and procession of transforming ecosystem is an essential and efficient approach for lake management.In this study,a sediment core labeled XJ2018(31°23′48.8″N,119°43′33.8″E)was extracted and analyzed for reconstructing the past transitional processes of Lake Xijiu based on the biological(chironomid subfossils)and geological parameters(total nitrogen and total phosphorus).The changes of chironomid subfossil assemblage structure and the results of STARS based on PCA scores of chironomid assemblages both indicated Lake Xijiu had undergone a distinct stable-state transition in the past 40 years.The RSI index combined F-test revealed that an ecological shift took place in 1990s.Before 1990,there are high aquatic vegetable coverage and the chironomid was characterized by the macrophyte-related taxa(Cricotopus trifasciatus and Dicrotendipes spp.),thus the ecosystem in this stage can be regarded as plants dominated clear state.In 1990-2000,a remarkable ecology shift was detected due to the enclosed fish-farming and rapid agriculture developments,the macrophyte-related taxa have been gradually reduced while the euryphagic taxa(Tanypus chinensis and Microchironomus tabarui)has increased and gradually occupied a dominant position.The water status had been changed into the phytoplankton dominated turbid-water.During 2000-2010,the lake ecosystem deteriorated further and the macrophyte-related taxa were almost disappeared.After 2010,The reappearance of some macrophyte-related taxa and the decline of the euryphagic taxa indicate that with the implementation of the ecological restorations and managements,the environment of Lake Xijiu has improved slightly,but the phytoplankton dominated turbid-water was still sustained.
作者
张楚明
倪振宇
唐红渠
ZHANG Chuming;NI Zhenyu;TANG Hongqu(Institute of Groundwater and Earth Sciences,Jinan University,Guangzhou 510632,P.R.China;Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008,P.R.China)
出处
《湖泊科学》
EI
CAS
CSCD
北大核心
2020年第2期587-595,共9页
Journal of Lake Sciences
基金
国家自然科学基金项目(41672346,41572337)资助
关键词
摇蚊亚化石
西氿
富营养化
稳态转换
Chironomid subfossil
Lake Xijiu
eutrophication
regime shift
