Species point records from 1987 OPRU HRE Looe Estuary littoral survey

The Looe estuary is situated on the south coast of Cornwall due south of Liskeard. The banks of this small estuary have been straightened and protected by the construction of harbour walls, embankments for the railway on the east bank of the estuary, and the stabilization of the banks on bends with revetments of cobbles and boulders held in position by plastic coated wire. The western bank is more natural at the mouth with a steep bedrock shore down to about 1m ACD. The shores of the estuary are chiefly sedimentary with sand amongst small boulders and cobbles in the lower reaches, and sand banks near the junction of the two rivers. Areas where water currents are slower have muddier sediments with fringing saltmarsh appearing on the upper shores from Trenant Wood northwards. Although the fresh water inflow from the two rivers is small the estuary is also small and shallow so that at low water at spring tides the water in the channel is very brackish even at the mouth of the estuary which dries except for a residual channel. The estuary is scenically appealing and a very popular tourist destination. The present survey carried out in July 1987 aimed to collect information on the communities and habitats present in the estuary that had not previously been described. A total of four sites were visited. The abundance of species living on hard surfaces and visible on the surface of sediments were recorded in situ. Intertidal sediment fauna was collected in 0.01m2 cores and by digging, and samples were sieved over 1mm and 5mm mesh sieves. Animals were picked out of the sediments, identified and counted. Photographs were taken to illustrate habitats and communities. A series of aerial photographs was taken during a low water period of spring tides in April 1986. Within the estuary, Habitat diversity is relatively low with predominantly sedimentary lower shores bounded by walls, revetments and natural shores of rock, mixed substrates and marshes. Mid-tide regions of steep bedrock shores and walls in the south of the estuary were dominated by limpets, Patella sp and barnacles of which Chthamalus montagui was the most common species; other species were few. The lower shores were dominated by mussels, Mytilus edulis and green algae, Ulva sp and Enteromorpha sp. Here too species variety was low. Further upstream within the estuary, for example at Trenant Wood, stable hard substrate communities were dominated by fucoid algae and Enteromorpha sp with recorded macrofauna being restricted to Ligea oceanica on the upper shore and Littorina littorea and amphipoda indet. under weed and stones. Also in this area small patches of fringing saltmarsh have developed. The infauna from two different types of sediment on the lower W. Looe Estuary was characteristic of what might be expected in upper estuarine sediments. A sandy silt midshore bank was found to be dominated by Oligocheate worms, ragworms, Hediste diversicolor and amphipods, Corophium volutator. A few other species were very sparsely represented. In current-swept sand banks lugworms, Arenicola marina and the polycheate worm Pygospio elegans were the only species found in any numbers with a few individuals of a small number of other species. In the streambed, from the junction of the two rivers northwards, stable hard substrates were dominated by green algae, Ulva sp and Enteromorpha sp and Fucus ceranoides a fucoid algae indicative of low salinity conditions. The scientific and nature conservation importance of the area has been assessed using standard criteria. These have been applied to each of the habitats and communities identified which have then been provisionally graded as being of Local, Regional, National or International Importance. No species of particular scientific interest were found during this survey work. Of particular interest in this area, but not included in this survey, are the rocky shores around the mouth of the Looe Estuary and the lagoon known as the Millpond near the junction of the East and West Looe rivers.

卢伊河河口位于康沃尔郡南部海岸，位于利斯基亚德南方。该小型河口的两岸经过整治，并通过建设港口墙壁、铁路的河岸堤坝以及弯曲处的河岸加固（使用鹅卵石和巨石的护岸，并由塑料涂层钢丝固定）得到了保护。西部河岸在河口处更为自然，其底部岩石陡峭，直至约1米ACD。河口的岸线主要由沉积物构成，在下游区域有小块鹅卵石和砾石，以及靠近两条河流交汇处的沙洲。在水流较慢的区域，沉积物较为混浊，从特兰特森林向北的较高岸线上出现了边缘盐沼。尽管两条河流的淡水流入量较小，但河口本身也较小且较浅，因此在春潮的低潮期间，河道的海水变得非常咸，即使在河口处，除了残余的河道外，其余部分已经干涸。该河口风景优美，是备受游客欢迎的旅游胜地。1987年7月进行的本次调查旨在收集有关河口中尚未被描述的群落和栖息地信息。共访问了四个地点。在实地记录了生活在坚硬表面并可见于沉积物表面的物种丰富度。通过0.01平方米的岩心采集和挖掘，收集了潮间带沉积物生物，并通过1毫米和5毫米网目的筛子筛选样本。从沉积物中挑选动物，进行鉴定和计数。拍摄照片以展示栖息地和群落。在1986年4月春潮低潮期间，拍摄了一系列航空照片。在河口内，栖息地多样性相对较低，主要由墙壁、护岸和天然岩石、混合底质和沼泽的自然岸线所界定的沉积物下岸。在河口南部的陡峭岩石岸线和墙壁区域，中潮区主要受螺类、Patella sp和藤壶（其中Chthamalus montagui是最常见的物种）以及几种其他物种的支配；物种种类较少。下岸区域主要由贻贝、Mytilus edulis和绿藻、Ulva sp和Enteromorpha sp所支配。这里的物种多样性也较低。在河口上游区域，例如特兰特森林，稳定的坚硬底质群落主要由苔藓藻和Enteromorpha sp组成，记录到的宏生物限于上岸的Ligea oceanica和下岸的Littorina littorea以及石下和水草下的未定种桡足类。在此区域，也形成了小块的边缘盐沼。在卢伊河下游的两种不同类型的沉积物中，底栖动物的特征与预期在上河口沉积物中可能发现的特征相符。在中潮带的沙质淤泥岸线上，发现以寡毛虫、须腕动物、Hediste diversicolor和桡足类Corophium volutator为主，少数其他物种分布稀疏。在受水流冲刷的沙洲上，只有一些数量有限的管虫Arenicola marina和多毛类环节动物Pygospio elegans被发现，还有少量其他物种的个体。在两条河流交汇处向北的河床中，稳定的坚硬底质主要由绿藻、Ulva sp和Enteromorpha sp以及指示低盐度条件的苔藓藻Fucus ceranoides所支配。该区域的科学和自然保护重要性已根据标准准则进行评估。这些准则已应用于每个已识别的栖息地和群落，并根据地方、区域、国家或国际重要性进行了临时分级。在此次调查工作中未发现具有特殊科学兴趣的物种。该区域特别引人注目，但未包含在本调查中，包括卢伊河口周围的岩石岸线和位于东、西卢伊河交汇处的被称为Millpond的泻湖。