摘要
随着人类活动的增强与全球气候变暖的持续,近年来云南湖泊的生态系统功能持续退化,而目前对云南湖泊生态系统的研究还主要集中于单一环境压力的生态效应。以星云湖为研究对象,通过沉积物记录与现代监测资料,识别在湖泊富营养化、气候变化以及人类强烈干扰下硅藻群落结构响应的过程,并甄别驱动群落变化的主要环境压力及其强度。结果显示随着湖泊生产力水平(如沉积物叶绿素a浓度)的增加,硅藻物种组成发生了明显的变化,主成分分析表明了水体富营养化是驱动群落变化的主要环境因子(r=-0.63,P<0.001)。简约模型与方差分解的结果表明近200年来(钻孔长度38cm),湖泊营养水平和水动力是驱动星云湖硅藻群落变化的主要环境因子,分别解释了群落变化的18.8%和2.9%;而1951年以后,湖泊营养水平和温度分别解释了硅藻群落结构变化的31.4%和26.8%。研究结果表明了硅藻群落长期变化的主控因子是湖泊营养水平,而人类活动及气候变化等可以通过改变湖泊水动力及湖水温度来驱动硅藻群落的演替,同时抚仙湖-星云湖的连通性也对硅藻群落的演替产生了一定影响。
Intensified human activities and global climate change have led to the deterioration of the environment,degradation of ecosystem functioning,and loss of biodiversity in lakes in many parts of China over the past few decades. To date,lakes in Yunnan have been adversely affected by the synergic effects of multiple environmental stressors,such as eutrophication,climate change, and hydrological regulation. However, previous studies have mainly focused on the ecological impacts of a single environmental stressor. In this study,paleolimnological methods in combination with long-term monitoring data were used to understand the patterns of diatom community responses to eutrophication,climate change,and hydrological regulation in Xingyun Lake. First,the history of diatom community shift and limnological changes were reconstructed for the past two centuries. In addition,key environmental stressors and their strengths in driving diatom communities were identified by selecting minimum adequate models and using variance partitioning. Our sediment pigmentresults showed a clear trajectory of lake eutrophication during the last century,particularly since the 1980 s. The diatom community changed significantly with an increase in lake productivity（ i. e.,sediment Chl-a concentrations）. Principal component analysis and correlation analysis showed that lake eutrophication was the major driver that affected diatom community change（ r =- 0. 63,P〈0. 001）. In addition,the minimum adequate models showed that lake production（ 18.8%） and hydrodynamics（ 2.9%） were the major drivers of diatom community changes over the last 200 years（ i.e.,core length of 38 cm）. Since 1951,the major drivers were lake production（ 31.4%） and temperature（ 26.8%）,and both factors showed a strong interaction while driving the community shift（ 16.2%）,suggesting that increasing temperatures also contributed significantly to the increase in lake production during the past few decades. Our results suggested that nutrient enrichment was the most significant factor in driving the shift in the diatom community in Xingyun Lake during the last two centuries. Global warming and anthropogenic activities, which included hydrological fluctuation and the connectivity between Xingyun Lake and the neighboring Fuxian Lake,also played important roles,but to a lesser degree than lake eutrophication. Overall,the sediment-based patterns of lake ecological changes can help us identify multiple environmental stressors and quantify their ecological impacts. These can be further used to facilitate the ecological restoration of polluted lakes and conservation of lake ecosystems in Yunnan.
出处
《生态学报》
CAS
CSCD
北大核心
2016年第10期3063-3073,共11页
Acta Ecologica Sinica
基金
国家自然科学基金项目(U1133601
41171048)
教育部科学技术研究项目(213034A)
云南省中青年学术技术带头人培养计划(2012HB012)
关键词
星云湖
湖泊沉积物
硅藻群落
富营养化
气候变化
水动力
Xingyun Lake
lake sediment
diatom community
eutrophication
climate changes
hydrodynamics
作者简介
通讯作者Corresponding author．E—mail：guangjiechen@gmail．com
