镇江通江城市河道浮游植物优势种群生态位分析

基于2011年对镇江市典型通江城市河道--古运河4个季节浮游植物组成与分布的现场调查与分析，采用改进的Levins公式和Petrailis指数分析了河道内浮游植物优势种群生态位宽度值和生态位重叠程度变化。结果表明：不同季节各优势种的生态位有较大差异，各物种对环境因子的适应能力存在较大差别。河道内春、秋季分别以十字藻、微囊藻生态位最宽，河道内以蓝、绿藻为主要发展型优势种；夏、冬季均以小环藻生态位最宽，硅藻门优势地位明显。不同时期河道内生境条件变化影响了藻类种群结构变化与优势种生态位的差异

NICHE ANALYSIS OF PHYTOPLANKTON IN AN URBAN RIVER #br# CONNECTED WITH THE YANGTZE RIVER|ZHENJIANG|CHINA

As a key indication of aquatic ecosystems，phytoplankton is essential for the management of rivers health，and laws of the distribution of phytoplankton have attracted extensive attention Under the condition of urbanization，algae population characteristics and formation of laws in rivers were very complicated In recent years，niche research played an important role in exploring the biological community structure characteristics，population evolution and biodiversity In this study，niche was applied to study phytoplankton distributions in the ancient canal，an urban river connected with the Yangtze River in Zhenjiang In the spring （April 23），summer （August 20），autumn （October 10） and winter （December JP3]17） of 2011，the composition and quantity of phytoplankton were investigated in 8 field sampling sites，and the modified JP2]Levins and the Petrailis formulae were used to measure niche breadths and overlaps of the phytoplanktons JP]dominant species The results showed that there were 11 dominant species of phytoplankton belonging to 4 phyla，including Dactylococcopsis， Microcystis，Aphanizomenon，Cyclotella，Melosira，Navicula，Chroomonas， Euglena，Crucigenia，Chlorella，and Scenedesmus，and dominant species were diverse in 4 seasons in this river Furthermore，niche breadths and overlaps of dominant species JP2]differed in different periods Different dominant species had different adaptive capacity to the environmental JP]factors In spring and autumn，Crucigenia and Microcystis had broadest niche respectively，and Chlorphyta，Cyanophyta were the main developing dominant species In summer and winter，Cyclotella had the broadest niche，and diatom was obviously dominant Being connected with the Yangtze River，habitat conditions in this river are affected by the operating of floodgate Some factors including the water temperature，the nutrient level and the suspended sediments in water are also under the effects Accordingly，phytoplanktons niche features were also affected Therefore，in this river，changes of the structure of phytoplankton community，and differences of niche among dominant species，both closely related to changes of river habitat conditions in different periods This study revealed the functional status and ecological adaptability relationship of dominant species of phytoplankton in this river Relevant results are expected to provide some references for obtaining phytoplankton distribution characteristics in similar rivers