Loch nam Madadh

Also within

Western Isles County South Lewis, Harris and North Uist Scenic Area

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.

Geology & landscape

Geological Period: Quaternary

Landscape processes: Coastal, Fluvial, Glacial

Description

Loch nam Madadh The site comprises the southern and western parts of Loch nam Madadh, on the east coast of North Uist. The coastal geomorphology of the SSSI is both diverse and exceptional. It contains low cliffs, discontinuous shore platforms, sheltered sea-loch environments, intertidal sandflats, low rocky islands, reefs, skerries, isolated rock outcrops, rock pinnacles, intertidal rock and boulder pools. Almost all of these are related to the submergence of previously glacially scoured rock surfaces, which are presently close to sea level. It is this diversity of landforms, within a general trend of Late Quaternary submergence, that is of unique geomorphological significance. The glacial scouring has formed one of the most extensive sea loch systems in Europe, consisting of a maze of biologically important mudflats, reefs, saline lagoons and tidal rapids. The lagoons are some of the best examples of large complex brackish lochs in Britain, with the Loch Houram/Loch an Strumore system being especially important. They are characterised by a diverse range of seaweeds and other plants, including the nationally scarce foxtail stonewort Lamprothamnium papulosum, an algal plant, found within Loch an Strumore, Alioter and Oban nan Stearnan saline lagoons. Several of the lagoons have underwater beds of tasselweed and eelgrass Zostera species growing on mudflats in sheltered basins. The tidal rapids which separate Loch Houram from Loch nam Madadh have a significantly richer fauna than any other parts of the SSSI: the undersides of boulders and the fronds of seaweeds are densely colonised by species such as sea-squirts and sponges. Loch Houram’s tidal rapids are among the most species-rich examples of this habitat in the Western Isles. Areas of rocky bedrock form reefs. At Alioter, the reef is dominated by the seaweed Fucus serratus whilst steeper areas of the reefs near the outlet from Loch an Strumore are dominated by the red seaweed Furcellaria lumbricalis. Intertidal mudflats and sandflats Lagoons Reefs Shallow inlets and bays Subtidal sandbanks Otter Lutra lutra

Species mentioned