Coll and Tiree IPA
Location: Off the west coast of Scotland, in the Inner Hebrides, north west of Mull.
Grid Reference: NM 116 514
Coll & Tiree IPA has been recognised as one of 165 Important Plant Areas in the UK.
The key features of this IPA are:
Machairs (coastal dune pasture in Scotland);
Nutrient rich lakes with abundant vegetation;
Shifting dunes along the shoreline;
Nutrient poor lakes with sparse vegetation;
Among the most isolated of the Inner Hebrides, Coll and Tiree are low-lying and treeless with white sandy beaches. Although they are exceptionally windy they have the highest sunshine records in Scotland.
The two islands contain a range of habitats, Coll being naturally wild and rugged with many small freshwater lochs and streams and Tiree having much flat, fertile, sandy soil and coastal machairs, home to an array of wild flowers.
Coll’s strongly oceanic climate combined with diverse soils supports a rich assemblage of plants. Cool summers result in the presence of a number of arctic alpine species like bearberry and hoary whitlow grass. The nationally-scarce and threatened bog orchid may be found with the bog-moss in bog pool communities, the nationally-scarce and threatened bog hair-grass is found in peaty margins of pools and the nationally-rare Irish lady’s tresses is found in wet heath and rush pasture.
On higher ground and rock outcrops are colonies of juniper. Areas of thinner peat on uneven higher ground are dominated by ling and bell heather with crowberry and bearberry. In the coastal areas between Eileraig and Sorisdale is a species-rich plant community of ling and spring squill with creeping willow, crowberry, common dog violet, thyme, common birds-foot-trefoil, heath spotted-orchid and northern marsh-orchid.
Ten of the small lochs support one of the largest British populations of the nationally-rare water pipewort, and one loch supports a population of the nationally-rare slender naiad and Potamogeton coloratus. Spring quillwort and awlwort may also be found in a number of lochs.
On the south west coast of the Isle of Tiree is the only example in south west Scotland of a machair site with an unimpeded habitat sequence from sea cliff to mobile and stable sand dunes, dry and wet machair, and eutrophic loch to the inland heathlands. Loch a’ Phuill is a large freshwater loch which has a very rich assemblage of aquatic plants including ten species of pondweed, among them the nationally-rare Swedish pondweed, and two nationally-scarce pondweeds, the slender-leaved pondweed and fen pondweed.
Wet meadows along the loch margins are home to abundant marsh cinquefoil and parsley water-dropwort. Also here are species more typical of salt-marshes such as the sea arrowgrass and mud rush, indicating the influence of salt-spray.
A large area of machair lies in the lee of the Ceann a’ Mhara headland, on either side of which are sandy beaches. The foreshore supports a vigorous population of sea holly. Within the extensive calcareous dune grassland the drier dune slopes support the red fescue and lady’s bedstraw fixed dune community, generally herb-rich with typical plant species such as lesser meadow-rue, wild thyme, wild carrot and kidney vetch.
Uncommon plants found here include rue-leaved saxifrage, common cornsalad, purple milk-vetch, frog orchid and the nationally-scarce hoary whitlowgrass. Damper areas occur in some depressions between the dunes and the machair. They are colonized with swamps of sedge, marsh cinquefoil and common spike-rush. Creeping willow grows here with early marsh orchid and adder’s-tongue fern.
The nationally-scarce Baltic rush is found in dune slacks close to Loch a’ Phuill. Other features of interest include the cliff ledges of Ceann a’ Mhara that support roseroot and thrift communities.