西藏色林错-普若岗日国家公园潜在建设区夏季浮游植物群落生态特征

Ecological Characteristics of Summer Phytoplankton Community in a Potential Construction Area of Selin Co-Puruogangri Glacier National Park of Tibet

探究色-普国家公园潜在建设区浮游植物群落结构及优势种生态位特征,为该地区生物学和生态学研究以及高寒生态系统的优化管理提供科学依据。2015年和2016年8月在建设区设置22个采样点,对浮游植物群落进行调查分析,并运用生态位宽度、生态位重叠及生态响应速率等方法测定优势种的生态位量度。结果表明:调查区共鉴定出浮游植物127种,隶属于3门5纲11目18科35属,种类组成为硅藻-绿藻-蓝藻型,优势种5种,分别为嗜盐舟形藻(Navicula halophila)、丝藻属一种(Ulothrix sp.)、柔弱双菱藻具脉变种(Surirella tenera var.nervosa)、泉生菱形藻(Nitzschia fonticola)和细小桥弯藻(Cymbella pusilla);优势种生态位宽度值变化范围为[0.264,1.152],泉生菱形藻(Nitzschia fonticola)生态位宽度最大,为1.152,嗜盐舟形藻(Navicula halophila)生态位宽度最小,为0.264;浮游植物优势种生态位重叠值(O)分布范围为[0.013, 0.981],物种间对资源利用或生态适应能力的相似程度存在较大差异性,优势种生态位重叠程度不高,种间竞争弱,群落结构较为稳定;细小桥弯藻的相对资源占有量(?O)的变化幅度最大,为4.135,嗜盐舟形藻的?O变化幅度最小,为0.288,丝藻属一种发展趋势最强(R=1.283),嗜盐舟形藻的衰退趋势最强(R=-0.916)。浮游植物优势种呈发展或衰退趋势是种间竞争的必然结果。

In this study, we explored phytoplankton community structure and niche characteristics of dominant species during the summer season in a potential construction area of Selin Co-Puruogangri Glacier National Park in Tibet, China. The aim was to accumulate baseline data on phytoplankton community diversity in the park and provide scientific evidence for optimal management of alpine ecosystems. In August 2015and 2016, a phytoplankton community investigation was conducted at 22 sampling sites, representing the north, west, south and central areas of the potential construction site. Niche measurements for dominant species included niche width, niche overlap and ecological response rate. Results included:(1) A total of 127phytoplankton species were identified during the investigation, representing 35 genera, 18 families, 11 orders, 5 classes and 3 phyla, with absolute dominance by bacillariophyta(83.46%), chlorophyta(9.45%) and cyanophyta(7.09%). Phytoplankton community composition was typed as bacillariophyta-chlorophyta-cyanophyta, and the dominant species were Navicula halophila, Ulothrix sp., Surirella tenera var. Nervosa,Nitzschia fonticola and cymbella pusilla;(2) The niche width range of dominant species was 0.264-1.152,with the largest niche width held by Nitzschia fonticola(1.152), and the smallest by Navicula halophila(0.264);(3) The range of niche overlap values(O) of dominant phytoplankton species was 0.013-0.981.There were large differences in resource utilization and ecological adaptability among species. The niche overlap degree among dominant species was low, indicating that interspecific competition was weak, and the community structure was relatively stable;(4) The development and decline of phytoplankton dominant species was the inevitable result of competition among different phytoplankton species. Changes in the range of relative resource occupation(?O) of p. minutiae was largest(4.135) and smallest for Navicula halophila(0.288). The strongest positive trend was for Ulothrix sp.(R=1.283), and the strongest negative trend was for N. halophila(R=-0.916).