Species point records from 1987 OPRU HRE Dart Estuary survey

The Dart Estuary is situated on the south coast of Devon and opens into Start Bay. The estuary itself runs through a steep sided channel from Totnes, some 18 km to the north, to Dartmouth and Kingswear at the mouth. It then opens out, through a vry narrow entrance, and with a bend in the channel, into a bay called the Range. The freshwater flow to the estuary is comparitively greater than most other inlets on the south Devon coast and the water is therefore considerably less than fully marine until it reaches the Range. The shores and subtidal in the upper and middle estuary are predominently of mud with occasional bedrock outcrops on the shore. The lower estuary also has muddy shores and subtidally but usually incorporating shingle and with more frequent bedrock and other hard substrata. The shores adjacent to Dartmouth and Kingswear are man-made walls, but in the entrance to the estuary and in the Range they are of predominently steep Dartmouth slate bedrock. The subtidal in the Range is mostly of muddy sand with outcrops of bedrock in places. The area is very popular for sailing and around Dartmouth there are many hundreds of boats in marinas and on moorings. These have had an inevitable effect on the concentrations in the water of the antifouling paint TBT. The concentrations of this pollutant are very high in the Dart. Due to the height and steepness of the coast the area has been poorly developed for industry, but this also creates disadvantages for the marine environment - in particular the poor disposal methods of sewage and refuse. Fishing activity is small and mostly confined to salmon netting and periwinkle collecting. Access is differcult to most shores or diving sites without a boat, and minimal use is made of the marine habitats for education or research. There have been very few previous marine biological studies, although in recent years there have been two baseline environmental impact studies in the lower estuary. Seventeen intertidal and fifteen subtidal habitats and associated communities have been described from this survey. Descriptions are given of these and lists of species found are tabulated. The habitats and communities in the Range are of open coast type but are not very diverse. The communities on the bedrock outcrops were quite rich and interesting. The narrow entrance and bending channel creates a very rapid transition from exposed marine conditions to sheltered estuarine conditions. The subtidal communities in the entrance are unusual. Within the estuary there is a gradual salinity gradient and communities are generally typical of estuaries elsewhere. The communities on the Anchor Stone are quite rich and make a very interesting dive site. Bedrock on the shore in the upper estuary was colonised by communities rarely recorded from elsewhere. The scientific interest and conservation importance of the area has been assessed using standard criteria and the conservation importance of habitats and communities in the area have been provisionally graded as of Local, Regional or National importance. Species of particular scientific interest have been tabulated and their conservation importance provisionally graded as of Regional or National importance. Records currently considered sensitive have been removed from this dataset.

达特河口位于德文郡南部海岸，向斯塔特湾敞开。该河口自托尼斯向北延伸约18公里，贯穿陡峭的航道，直至河口处的达特茅斯和金斯韦尔。随后，通过一个极为狭窄的入口，河道转弯进入被称为兰奇的海湾。与南德文海岸其他入海口相比，达特河口的新鲜水流较为丰富，因此直至兰奇处，水质仍明显低于完全的海洋水质。上游和中游河口的岸线和潮间带主要以淤泥为主，偶尔在岸边可见基岩露头。下游河口同样以淤泥为主，但通常混有砾石，且基岩和其他硬质底质出现的频率更高。达特茅斯和金斯韦尔附近的岸线为人工构筑的墙体，而在河口入口和兰奇处，主要为陡峭的达特茅斯板岩基岩。兰奇的潮间带主要由淤泥沙组成，并在某些地方可见基岩露头。该区域因其优美的航海条件而备受青睐，达特茅斯周围有数百艘船只停泊在船坞和系泊处，这不可避免地对水中防污漆TBT的浓度产生了影响。在达特河口，这种污染物的浓度非常高。由于海岸线的高峻，该区域工业发展相对滞后，但也为海洋环境带来了不利因素——尤其是污水处理和废物处理方法的落后。渔业活动规模较小，主要限于鲑鱼网捕和鲍鱼采集。除非有船只，否则大多数岸线或潜水地点难以进入，海洋栖息地用于教育或研究的使用也极为有限。尽管以往对海洋生物的研究寥寥无几，但近年来在下游河口进行了两次基准环境影响研究。此次调查描述了十七个潮间带和十五个潮下带栖息地及其相关群落。对这些栖息地和群落的描述已给出，并附有物种列表。兰奇的栖息地和群落属于开阔海岸类型，但种类多样性不高。基岩露头上的群落丰富而有趣。狭窄的入口和弯曲的河道形成了从暴露的海洋条件到隐蔽的河口条件之间的快速转变。入口处的潮下带群落较为罕见。在河口内部，存在逐渐的盐度梯度，群落总体上与其他地区的河口相似。锚石上的群落相当丰富，成为了一个极具吸引力的潜水地点。上游河口岸线的基岩被其他地方罕见记录的群落所占据。该区域的科学价值和保护重要性已根据标准准则进行评估，该区域栖息地和群落的保护重要性已初步分级为地方、区域或国家重要性。具有特定科学兴趣的物种已列表，其保护重要性也初步分级为区域或国家重要性。目前被认为敏感的记录已从本数据集中移除。