Loch Siadar

Also within

Western Isles County

Condition (NatureScot)

Climate exposure

This is about exposure to a nationwide pressure this habitat type carries — not a verdict on this site's own management.

Habitats

Saline lagoon

Geology & landscape

Geological Feature: Gorge / Ravine

Landscape processes: Coastal, Fluvial, Volcanic / Igneous

Description

Loch Siadar Loch Siadar is a small enclosed inlet draining into East Loch Roag. It consists of two pools separated from each other by a culverted dam. There is a narrow gorge-like channel with a sill at high water level connecting Loch Siadar to Loch Roag. The loch is bounded by crofts at the eastern end and elsewhere by rocky shores below rough grazing. This loch is an excellent example of a rock-silled saline lagoon; a habitat which is very rare in Europe outside the Western Isles and Shetland. Loch Siadar displays several of the special features which distinguish saline lagoons from other marine habitats. At the entrance to the loch is a fine example of the species rich tidal rapids communities which are characteristic of rock-silled saline lagoons. This community is notable because of its high diversity of filter-feeding invertebrates; the undersides of boulders and the seaweed fronds are densely colonised by filter-feeding animals such as sea squirts, bryozoans, sponges and bivalves associated with fast water flow. Despite its small size, Loch Siadar has a good range of the rocky substrate biotopes found in rock-silled saline lagoons. These include assemblages dominated by, in turn, the sheltered water form of kelp, bladder wrack, spiral wrack and channel wrack. In comparison to the shores of the open coast, the intertidal zonation is of particular interest because it is compressed into a narrow band due to the reduction of the tidal range within the loch. The entrance to Loch Siadar is more exposed to wave action than most other saline inlets in the Western Isles.

Plant communities