广东鉴江水系底栖硅藻多样性与时空分布特征

为了解广东省鉴江水系底栖硅藻多样性和时空分布特征,对全流域进行了底栖硅藻采样调查。结果表明,从19个采样点4次采样中共检出底栖硅藻10科52属242种,其中舟形藻属(Navicula)、菱形藻属(Nitzschia)和异极藻属(Gomphonema)是优势类群,出现频次和相对丰度较高。硅藻多样性指数(丰富度、真香农多样性指数和真辛普森多样性指数)随河流等级呈现一定的空间分布特征,但它们季节变化不明显。底栖硅藻群落相异性在上游和下游河段较高,从一级到三级河流递减,四级河流又增加。底栖硅藻群落结构空间变化明显,季节变化显著。群落丰富度的稀疏曲线表明,热带河流底栖硅藻群落以400个体计数,不能完整反映底栖硅藻多样性。这些为鉴江水系河流健康监测和水生态保护奠定了基础。

Species Diversity and Temporal-spatial Distribution of Benthic Diatoms in Jianjiang River, Guangdong Province

To understand species diversity and distribution of benthic diatoms in typical tropical rivers, the benthic diatoms were investigated seasonally in Jianjiang River, Guangdong Province. The results showed that there were 242 benthic diatoms, belonging to 52 genera and 10 families were detected from 19 sites and 4 times sampling. Navicula, Nitzschia and Gomphonema were the main dominant genera with high frequency and relative abundance. Three diatom diversity indexes of benthic diatom, such as richness, true Shannon-Wiener diversity index, and true Simpson diversity index, showed certain spatial distribution with increasing of river class, but there was no significance in season. Community dissimilarity of benthic diatoms decreased from class 1 to class 3 but increased in class 4. Structure of benthic diatoms showed clear temporal and spatial patterns by Two-Way PERMANOVA analysis. Rarefaction curve indicated that counting with 400 individuals for each sample would underestimate richness and diversity of benthic diatoms in the tropical river. These would establish the foundation for river health monitoring and water ecological conservation of Jianjiang River system.