富营养湖泊中轮虫群落结构季节变化的环境驱动力研究(英)

通过对桥墩湖一周年的逐月采样，比较了影响轮虫群落结构季节变化的3种环境驱动力的相对重要性。桥墩湖是一个富营养湖泊，具有较高的营养盐和Chl a含量以及低的透明度。研究发现：水温和营养水平是影响轮虫数量和群落结构季节变化最重要的理化因子。由于大型枝角类数量的稀少，其对轮虫数量并没有显著的负面影响。短尾秀体溞是影响轮虫群落结构季节变化的最重要的枝角类；然而大多数优势轮虫与短尾秀体溞密度峰值的共同出现可能反映了它们对高营养水平和高水温的共同喜好。在浮游植物中，绿藻是决定轮虫密度的最重要的浮游植物门类；而其中的隐藻则是影响轮虫群落结构变化的最重要属。3组环境因子(理化因子、浮游植物、浮游甲壳动物)对轮虫群落结构的季节变化具有相似的解释大小。这些结果表明：在该富营养湖泊中，轮虫群落结构的季节变化可能主要受理化因子和食物资源的影响；浮游甲壳动物对轮虫群落结构的塑造作用有限

FORCES DRIVING THE SEASONAL CHANGES OF A ROTIFER COMMUNITY IN A EUTROPHIC CHINESE LAKE

The relative importance of forces driving the seasonal changes of a rotifer community in Lake Qiaodun, located in China, was assessed through monthly sampling. The lake was eutrophic, characterized by high concentrations of nutrients and Chl a, as well as, low transparency. The water temperature and the trophic status of the lake were the most important physicochemical factors influencing rotifer abundance and community dynamics. Due to the rarity of large sized cladocerans in abundance, cladocerans showed no negative impacts on rotifer abundance. Diaphanosoma brachyurum was the most important cladoceran in impacting rotifer community dynamics. However, the positive association of most dominant rotifers with D. brachyurum might be a reflection of their common favorites for high trophic level and high water temperature. Among the phytoplankton, Chlorophyta was the most important phylum in determining total rotifer density, and Cryptomonas the most important genus in shaping the rotifer community. The three explanatory data sets showed a similar contribution on seasonal rotifer community dynamics. These results suggest that in this eutrophic lake, the seasonal changes of a rotifer community are likely controlled by physicochemical factors and food resources. Crustacean zooplankton might play only a minor role in shaping the rotifer community