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首页> 外文期刊>Estuarine Coastal and Shelf Science >The benthic macrofauna of the St. Lucia Estuary during the 2005 drought year
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The benthic macrofauna of the St. Lucia Estuary during the 2005 drought year

机译：2005干旱年圣卢西亚河口底栖大型动物

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The St. Lucia Estuary is the largest estuarine system in Africa. The estuary is part of the Greater St. Lucia Wetland Park, which has been declared a World Heritage Site. This ecosystem has been subjected to severe drought conditions over the last four to five years, resulting in its mouth being closed off from the ocean in June 2002 for a period of over four years. The main aim of this study was to document the effects of the prevailing drought on the macrofauna of the system, since the last work on this benthic component had been undertaken over a decade ago, during a normal-to-wet phase. Macrofauna samples together with physico-chemical data were collected at representative sites in the Narrows, and the South and North lakes in February, April, August and October 2005. The drought exerted a strong influence on the system, leading to hypersaline conditions developing in its northern regions (maximum of 126 at Hell's Gate), and to the loss of aquatic habitat. Ordinations and clustering indicated that the macrofauna of the system could generally be separated into three clusters viz. (1) the Narrows and the southern portion of South Lake, (2) the northern half of South Lake, and (3) the North Lake—False Bay complex. Multivariate correlations indicated weak relationships between macrofaunal community structure and physico-chemical parameters. The distinction in macrofaunal assemblages between these clusters was probably caused by these habitats being physically separated at the peak of the drought, with no water flow between them, thereby preventing exchange of planktonic larvae and retarding colonisation of habitats. There was a northward decline in taxonomic richness and diversity of macrofauna in the system, which correlated positively with water depth and negatively with the biomass of microphy-tobenthos. It is evident that the drought structured macrofauna communities primarily through its effects on water depth and habitat fragmentation. The results of this investigation provide valuable information regarding the effects of droughts on estuarine—lake systems and the possible mechanisms by which they occur.
机译：圣卢西亚河口是非洲最大的河口系统。该河口是大圣露西亚湿地公园的一部分，该公园已被宣布为世界遗产。在过去的四到五年中，该生态系统遭受了严重的干旱条件，导致其嘴在2002年6月从海洋中关闭了四年。这项研究的主要目的是记录当前干旱对系统大型动物的影响，因为对底栖动物的最后一次工作是在十年前的正湿阶段进行的。 2005年2月，4月，8月和10月，在狭窄的地区以及南湖和北湖的代表性地点收集了大型动物样本以及理化数据。干旱对该系统产生了强烈的影响，导致该地区出现了高盐条件。北部地区（地狱之门最多126个），以及水生生物的丧失。排序和聚类表明，系统的大型动物一般可以分为三个聚类。 （1）南湖的狭窄和南部部分，（2）南湖的北半部分，和（3）北湖-假湾综合体。多元相关性表明大型动物群落结构与理化参数之间的关系较弱。这些集群之间大型动物群落的区别可能是由于这些生境在干旱高峰时被物理隔离了，它们之间没有水流，从而阻止了浮游幼虫的交换并阻碍了生境的定居。该系统中大型动物的分类学丰富度和多样性向北下降，这与水深呈正相关，与微生底栖动物的生物量呈负相关。显然，干旱主要是通过对水深和栖息地破碎的影响来构造大型动物群落。这项调查的结果提供了有关干旱对河口-湖泊系统的影响及其发生的可能机制的有价值的信息。

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