太湖湖滨生态修复区大型底栖动物群落结构及梯度分布

Community structure and gradient distribution of macrobenthos in a riparian ecological restoration pilot area of Taihu Lake

2010—2011年对太湖贡湖湾湖滨带生态修复区滨岸挺水植物带(Ⅰ)、湾相沉水植物带(Ⅱ)和堰外开敞水体(Ⅲ)3个滨岸生境梯度带的水质状况和底栖动物群落特征进行了研究。结果表明:调查共发现底栖动物13科18种,其中仅出现于1个生境梯度带的物种7个;在其余的11个物种中,有5个种群的密度在生境梯度带间存在显著差异;比较发现,按底栖动物摄食功能类群的相对比例,刮食者相对丰度在带Ⅰ最高,收集者在带Ⅱ最高,滤食者在带Ⅲ最高,不同生境梯度带间底栖动物的摄食功能类群构成存在显著差异。对底栖动物相对丰度和水环境参数的冗余分析显示,环节动物和昆虫与DO、NO3--N和PO43--P浓度正相关,软体动物则与NO3--N和PO43--P负相关,一些腹足类对低DO耐受能力较强,与NH4+-N和COD正相关。修复区3个梯度带水动力条件、水质状况和底质类型的差异性对底栖动物的分布有重要影响,形成了生活习性、摄食特征等显著不同的3个底栖动物群落。

In order to understand the relationships between habitat gradient and macrobenthos composition, a field investigation was conducted on the macrobenthos community in three different habitats, i.e., riparian zone with emerged vegetation （zone Ⅰ）, lake-bay zone with submerged vegetation （zone Ⅱ）, and open water zone outside the weir （zone Ⅲ）, in a riparian ecological restoration pilot area of Gonghu Bay, Taihu Lake in 2010-2011. A total of 18 macrobenthos species were identified, of which, 7 species only existed in one habitat type, and 5 of the other 11 species had significant difference in abundance across the habitat gradient. As for the distribution of the functional feeding groups of macrobenthos, significant differences were observed among the habitat types. Scrapers had the highest relative abundance in zone Ⅰ, while gather-collectors and filter-collectors had the highest relative abundance in zone Ⅱ and zone Ⅲ, respectively. The redundancy analysis on the effects of water quality on the macrobenthos composition showed that annelids and aquatic insects were positively correlated with water DO, NO3--N, and PO43--P, while mollusks were negatively correlated with water NO3--N and PO43--P. Some mollusks were able to endure the stress from low DO, and correlated positively with water NH4＋-N and COD. Overall, the differences in the hydraulic conditions, water quality, and substrates among the three habitat types had great effects on the distribution of macrobenthos, leading to the formation of three macrobenthos communities with significant differences in life form and feeding attributes.