|IPA Factsheet - Roslin Glen|
Site Description The IPA could be regarded as an urban fringe site, lying near to Edinburgh, and within its commuter-belt. It encompasses a range of habitat types, of which the greater component is deciduous broadleaved woodland. The steep-sided gorge supports a natural flora, while the more open and level areas support mature estate woodland with exotic tree species. Dutch Elm Disease in the 1980s resulted in the death of most of the elms Ulmus sp. in the site, with Beech Fagus sylvatica and Sycamore Acer pseudoplatanus now gaining a strong hold. The woodland has a good age structure and has a species-rich understorey characteristic of ancient woodland. A diverse topography gives rise to a variety of physical conditions, resulting in a large range of higher plants (more than 200 species recorded) and also a rich lichen flora. Bryophytes do not receive any mention in the SSSI citation or management statement despite the existence of humid conditions within the sandstone gorge.
Botanical Significance A diverse vascular flora indicative of ancient woodland, with a rich lichen flora. The presence of the critically endangered Slender Thread-moss Orthodontium gracile receives no mention in the SSSI citation or management statement, but there is a Species Action Plan for it in the UK Biodiversity Action Plan, and also in the Midlothian Biodiversity Action Plan. The location of this bryophyte lies outwith the SWT Wildlife Reserve part of the IPA.
General Habitat Description
Conservation Issues Non-native invasive plant species, Japanese Knotweed Fallopia japonica and Few-flowered Leek Allium paradoxum are vigorous colonisers and pose a recurring problem to the natural ground flora. A large percentage of the woodland is under management by the Scottish Wildlife Trust, with 5-year Management Plans to guide activities. East Lothian Ranger Service manage the Country Park, of which part lies in the IPA. Other areas within the IPA are in private ownership with no overall nature conservation objectives. Regarding Slender Thread-moss O.gracile, the issues identified within the Species Action Plan include: competition from the more vigorous Cape Thread-moss O. lineare, which looks very similar to O. gracile; the possibility of fire on an urban fringe site poses potential problems; removal of the tree canopy through woodland management would change the humidity of the habitat, with implications for the survival of an isolated population of O. gracile.