珠江口大型底栖动物数量与生物多样性的分布特征

为了更好地了解河口生物多样性的演变规律及退化机制,根据2015年1—12月珠江口大型底栖动物调查资料对珠江口大型底栖动物现存量和生物多样性的分布特征进行了研究。结果表明,11次采样(受台风影响7月珠江口未采集到大型底栖动物)共获取大型底栖动物67种,其中环节动物多毛纲27种,节肢动物24种,软体动物12种,其它类群4种,主要是底栖鱼类、刺胞动物和纽形动物。2015年珠江口各站位大型底栖动物丰度的变化范围在8~1192个·m^-2之间,珠江口大型底栖动物丰度的高值出现在6月和9月的崖门(分别为1192个·m^-2和1048个·m^-2)以及9月的虎跳门(1048个·m^-2),日本大螯蜚(Grandidierella japonica)、中华拟亮钩虾(Paraphotis sinensis)、凸壳肌蛤(Musculus senhousei)和彩虹明樱蛤(Moerella iribescens)丰度较高。大型底栖动物生物量变化范围在0.02~42.50g·m^-2之间,生物量的高值出现在9月的崖门、5月的鸡啼门、2—3月的磨刀门及4月的蕉门,上述站位的生物量均大于30.00g·m^-2,缢蛏(Sinonovacula constricta)、光滑河篮蛤(Potamocorbula laevis)、黑龙江河篮蛤(P.amurensis)、凸壳肌蛤和日本大螯蜚生物量较高。珠江口大型底栖动物香浓威纳指数高值出现在3月鸡啼门,为2.46;低值出现在10月磨刀门,为0.21。香浓威纳指数均值在1.11~1.81之间。鸡啼门和虎跳门大型底栖动物香浓威纳指数值月际变化较稳定。运用ABC曲线对珠江口大型底栖动物扰动状况进行评价,结果表明,1月珠江口大型底栖动物受到中等程度扰动,2—4月大型底栖动物群落有受到中等程度干扰的趋势。

Distribution of quantity and diversity of macrobenthos in the Pearl River Estuary

The increasing impact of human activities, global warming, rising sea levels and alien species invasion are major drivers of ecological changes in the benthic ecosystems of the Pearl River Estuary.Despite of the large number of estuary investigation projects carried out in the Pearl River Estuary, evidence for long-term dynamic diversity of macrobenthos is scarce. To improve the understanding of the evolution and degradation mechanism of diversity, 11 standardized field studies were carried out in the Pearl River Estuary in 2015. Based on macrobenthos data collected in 2015 in the Pearl River Estuary, biological parameters such as diversity, richness, biomass and abundance were calculated.A total of 67 macrobenthic species were collected from six cruises. The main taxonomic groups identified were polychaeta (27 taxa), crustacea (24 taxa), mollusca (12) and other groups (4).The values of abundance and biomass varied from 8 to 1 192 ind·m^-2 and from 0.02 to 42.50 g·m -2 , respectively. The highest abundance values were recorded in Yamen in June(1 192 ind·m^-2 ) and September(1 048 ind·m^-2 ), and Hutaomen in September(1 048 ind·m^-2 ). The highest biomass values were recorded in Yamen in September, Jitimen in May, and Modaomen in February-March, Jiaomen in April, with values all over 30.00 g·m^-2 . Grandidierella japonica , Paraphotis sinensis , Musculus senhousei and Moerella iribescens dominated the macrobenthic abundance. These species represented 70% of total macrofauna abundance in Yamen. Overall, these sites (Yamen, Jitimen and Modaomen) were represented by Sinonovacula constricta , Potamocorbula laevis and G. japonica for 70% of the total biomass.Dominant macrobenthos species revealed that the macrobenthos community structure of the Pearl River Estuary showed simple and individual miniaturization.The mean values of two indices ranged from 1.11 to 1.81 and from 0.22 to 2.02 for Shannon-Wiener index ( H ′) and richness index ( D ) respectively. The ranges of H ′ diversity index values in eight sites indicated poor and deteriorative ecological status.The highest values of H ′(2.46) was recorded in Jitimen in March 2015.Abundance-biomass comparison (ABC) was applied to assess the estimated ecological quality in different months in the Pearl River Estuary.The study is to assess the environmental changes in different months by ABC curve and Shannon-Wiener ( H ′) index in the studied areas. The ABC plots showed that the Pearl River Estuary could be classified as moderately disturbed and polluted in January.In frequent disturbance area, ABC must thus be used with singleness and combined with other indicators or indices, for an accurate and connected characterization.