摘要
湖滨带是湖泊生态系统的重要组成部分,对维持湖泊生态系统健康和改善水环境功能具有积极作用。由于防洪需要,我国许多湖泊在湖滨带中修建了防洪大堤,防洪大堤对湖滨带生态系统的影响还缺乏研究,识别引起大堤型湖滨带生态健康退化的驱动因子是开展湖滨带生态修复的必要前提。针对太湖湖滨带的特点,在定性筛选了太湖主体营养状态、入湖河流污染负荷通量、岸带类型、风浪强度4个主要影响因子的基础上,分别采用"多元线性逐步回归法"和"偏相关系数法"进行驱动因子识别,2种方法确定的驱动因子个数均为3个,且3者的驱动力大小排序也相同,即太湖主体营养状态>岸带类型>入湖河流污染负荷通量。3个驱动因子对太湖湖滨带生态系统健康的影响均为负效应,也即太湖主体的营养状态综合指数越高、入湖河流污染负荷通量越重、岸带状况越差,湖滨带生态系统也就越不健康。另外,从统计方法的角度解释了"风浪强度"没有入选为驱动因子的原因;澄清了现阶段环境学、生态学领域对"驱动因子"识别方法的误解及不足之处。研究结果为大堤型湖滨带的生态修复方案提供了理论支持。
Dikes have been built in the littoral zones of many lakes in China,for the purpose of flood prevention.Lake Taihu is one of these lakes and its dikes occupy as much as about 73% of the length of the total lake bank.Therefore,a case study of Lake Taihu was conducted.Being different from the natural littoral zone,the littoral zone with dikes has unique properties because dikes block the natural material flow between the surrounding land area and the lake water,consequentially,the material exchange between them was reduced to a great extent.Dike-building has brought a lot of ecological and environmental problems,such as the reduction of littoral wetland area,the decrease of aquatic animals′ habitat,the damage of vegetation cover,and even the destruction of the ecological balance in littoral zones.The deterioration of its ecological health has caused more and more concerns and as a result,many ecological restoration measures have been adopted by local governments.However,not all of them had effect because the driving forces leading to ecological health deterioration in this kind of littoral zones were still unknown. According to the characteristic of Lake Taihu,4 main factors affecting its littoral zone ecosystem health were selected including the nutrient state of major lake area,the pollutant fluxes of inflow rivers,littoral zone type and wave strength.Then,two different methods,namely,’stepwise multiple linear regression’ and ’partial correlation coefficient’,were employed to determine the driving forces from the above 4 factors.Very similar results were obtained from these two methods,i.e.,3 factors were identified as driving forces and their driving forces from stronger to weaker,listed as the following sequence,the nutrient state of major lake area 〉 littoral zone type 〉 the pollutant fluxes of inflow rivers.All the 3 driving forces have negative effects on the ecosystem health of the littoral zone of Lake Taihu.The higher nutrient state of major lake area,the heavier pollutant fluxes of inflow rivers and the worse littoral zone type,the poorer the ecosystem health of littoral zone.The reason leading to the out of ’wave strength’ as driving force was explained from the aspects of both statistical method and analysis results.Although it had significant correlation with ecosystem health of littoral zone,it showed non significant partial correlation with it when considering other 3 factors′ effects.This result is consistent with the real situations observed by other researchers.These results also suggest that human being activities played a significant driving role in ecosystem deterioration of the littoral zone with dikes,while the impact of natural force such as wave strength was quite uncertain.Therefore,it is possible to improve ecological health status of littoral zone through changing human being activities.Compared to driving force analysis in social,economic and medical fields,little study has been done on environmental and ecological sciences,so more work should be carried out.Some misunderstanding on the concept of ’driving force’ and the abuse of statistical analysis are elaborated in this paper.This study may have some inspires on the future research about ’driving force’.Additionally,the present study provides a scientific theory foundation and decision support for ecological restoration of the lake littoral zone with dikes.
出处
《生态学报》
CAS
CSCD
北大核心
2012年第12期3681-3690,共10页
Acta Ecologica Sinica
基金
国家水体污染控制与治理科技重大专项(2009ZX07101-009)
关键词
驱动因子
生态退化
生态系统健康
湖滨带
太湖
driving force
ecological deterioration
ecosystem health
littoral zone
Lake Taihu
