Plymouth Marine Laboratory, Prospect Place, West Hoe, Plymouth PL1 3DH, UK.
Mar Pollut Bull. 2010;61(1-3):92-9. doi: 10.1016/j.marpolbul.2009.12.016. Epub 2010 Jan 20.
The severity of the physical regime in the hypertidal Severn Estuary and Bristol Channel decreases in intensity in the seaward direction. As a result, the diversity of benthic macrofaunal species is very low in the Estuary and Inner Channel, but is still relatively low in the Outer Channel compared with more benign conditions elsewhere in the UK. Nevertheless, the taxonomic spread of species (taxonomic distinctness) throughout the area is no lower than expected. Barrage construction would result in an increase in the area of soft sediment relative to hard bottom benthic assemblages and the disappearance of reduced communities seaward of the barrage, although the time-scale of such a change is not known. Above the barrage the overall species richness, density and biomass of the benthos are likely to increase, factors that will ameliorate the loss of inter-tidal area.
在强潮河口的塞文河口和布里斯托尔海峡，物理条件的严重程度从近岸向海方向逐渐减弱。因此，河口和内航道的底栖大型动物物种多样性非常低，但与英国其他地方更为温和的条件相比，外航道的多样性仍然相对较低。然而，整个区域的物种分类分布（分类独特性）并不低于预期。水坝的建设将导致相对于硬底底栖生物群增加软沉积物的面积，并导致水坝外的贫化群落消失，尽管这种变化的时间尺度尚不清楚。在水坝上方，底栖生物的总体物种丰富度、密度和生物量可能会增加，这些因素将减轻潮间带区域的损失。
