Ben Alder and Aonach Beag

General site character

• Inland water bodies (Standing water, Running water) (2%)
  
• Bogs, Marshes, Water fringed vegetation, Fens (20%)
  
• Heath, Scrub, Maquis and Garrigue, Phygrana (35%)
  
• Humid grassland, Mesophile grassland (7%)
  
• Alpine and sub-Alpine grassland (30%)
  
• Inland rocks, Screes, Sands, Permanent Snow and ice (6%)
  

Annex I habitats that are a primary reason for selection of this site

• 4060 Alpine and Boreal heaths

  Ben Alder and Aonach Beag represents Alpine and Boreal heaths in the central Scottish Highlands. A wide range of heaths form extensive stands, including H13 Calluna vulgaris – Cladonia arbuscula, H19 Vaccinium myrtillus – Cladonia arbuscula, H20 Vaccinium myrtillus – Racomitrium lanuginosum and H22 Vaccinium myrtillus – Rubus chamaemorus heaths. The representation of reindeer Cladonia lichens and woolly fringe-moss Racomitrium lanuginosum is intermediate, respectively, between the eastern and western Highlands. The rockier heaths provide suitable habitat for eastern outlying stations of northern Atlantic liverworts.

• 4080 Sub-Arctic Salix spp. scrub

  This site in the central Highlands is selected to represent high-altitude (950 m) Sub-Arctic Salix spp. scrub on highly calcareous schist and limestone. It has the largest known population in the UK of woolly willow Salix lanata, the rarest of the sub-Arctic willows. Downy willow S. lapponum and net-leaved willow S. reticulata are frequent, and whortle-leaved willow S. myrsinites is also represented. The willows are associated with an area of 6170 Alpine and subalpine calcareous grasslands on steep, rocky and remote ground.

• 6150 Siliceous alpine and boreal grasslands

  These ranges of hills have the largest area of ground above 1000 m in Britain outside of the Cairngorms and the extent of Siliceous alpine and boreal grassland is correspondingly high. The range of communities is representative of the higher hills of the central Highlands, with all the NVC types associated with the habitat represented. The most extensive communities are U7 Nardus stricta – Carex bigelowii grass-heath and U10 Carex bigelowii – Racomitrium lanuginosum moss-heath, the latter with an unusual occurrence of a species-rich sub-type following a band of high-altitude limestone. This site represents one of only six sites outside of the Cairngorms and Ben Nevis with extensive late-lie mossy snow-beds holding U11 Polytrichum sexangulare – Kiaeria starkei and U12 Salix herbacea – Racomitrium heterostichum snow-bed communities. Various rare plants occur in the snow-beds, including starwort mouse-ear Cerastium cerastoides and the bryophytes Dicranum glaciale, Marsupella condensata and Nardia breidleri. U8 Carex bigelowii – Polytrichum alpinum sedge-heath attains its largest extent outside of the eastern Highlands.

• 6170 Alpine and subalpine calcareous grasslands

  Ben Alder and Aonach Beag is representative of high-altitude Alpine and subalpine calcareous grasslands in the central Highlands, where the habitat is very local owing to the infrequent occurrence of calcareous rocks at high altitude. Both CG12 Festuca ovina – Alchemilla alpina – Silene acaulis dwarf-herb and CG14 Dryas octopetala – Silene acaulis ledge communities are well-represented, especially the latter. The widespread arctic-alpines purple saxifrage Saxifraga oppositifolia and yellow saxifrage S. aizoides are frequent, while rarer species that are widespread on the site include cyphel Minuartia sedoides, alpine meadow-grass Poa alpina, hair sedge Carex capillaris, black alpine-sedge C. atrata and alpine speedwell Veronica alpina. Unusually, grazing levels appear to be low enough to allow the development of mountain avens heath on slopes open to grazing animals. The low grazing levels also allow the exceptional development of moderately large populations of montane willows, including woolly willow Salix lanata, conforming to Annex I type 4080 Sub-Arctic Salix spp. scrub, for which the site is also selected. The transition between these two habitat types is unusual.

• 7240 Alpine pioneer formations of the Caricion bicoloris-atrofuscae  * Priority feature

  Ben Alder and Aonach Beag is representative of high altitude flushes in the central Highlands. Both open flushes of M11 Carex demissa – Saxifraga aizoides mire and more closed flushes of M12 Carex saxatilis mire are well-represented. The flushes are well-developed but localised and are notable for the occurrence of the rare scorched alpine-sedge Carex atrofusca, which is known to occur in only two other locations in the SAC series. Other characteristic species include three-flowered rush Juncus triglumis, Scottish asphodel Tofieldia pusilla, sheathed sedge Carex vaginata, alpine bistort Persicaria vivipara and the moss Blindia acuta. Other uncommon species include hair sedge Carex capillaris and alpine cat’s-tail Phleum alpinum.

• 8110 Siliceous scree of the montane to snow levels (Androsacetalia alpinae and Galeopsietalia ladani)

  This site is one of the best sites for siliceous scree in the central Highlands. The site has extensive base-poor schistose screes developed at moderate to high altitude. Where snow lies late there is an extensive development of U18 Cryptogramma crispa – Athyrium distentifolium snow-bed community. Within these snow-beds the endemic Newman’s lady fern Athyrium flexile occurs. The oceanic montane liverworts Scapania nimbosa, Lophozia opacifolia, Mylia taylorii and Bazzania tricrenata occur in one of their few eastern outliers in these rocky snow-beds. Siliceous scree also occurs extensively at lower levels.

• 8210 Calcareous rocky slopes with chasmophytic vegetation

  Ben Alder and Aonach Beag has an outstanding flora of rare arctic-alpine calcicoles mostly associated with a high-altitude band of limestone at 900-1000 m. The flora includes tufted saxifrage Saxifraga cespitosa, alpine saxifrage S. nivalis, hoary whitlowgrass Draba norvegica, mountain avens Dryas octopetala, black alpine-sedge Carex atrata and alpine meadow-grass Poa alpina. Various rare montane calcicolous mosses and lichens also occur on the rock faces.

Annex I habitats present as a qualifying feature, but not a primary reason for selection of this site

• 4010 Northern Atlantic wet heaths with Erica tetralix
• 4030 European dry heaths
• 6430 Hydrophilous tall herb fringe communities of plains and of the montane to alpine levels
• 7130 Blanket bogs (* if active bog)  * Priority feature
• 8220 Siliceous rocky slopes with chasmophytic vegetation

Annex II species that are a primary reason for selection of this site

• Not Applicable

Annex II species present as a qualifying feature, but not a primary reason for site selection

• Not Applicable