Area: 104.2 hectares.
Other Information: Within the Bodmin Moor Area of Outstanding Natural Beauty.
Description and Reasons for Notification:
Dozmary Pool is an ancient natural moorland lake unique on Bodmin Moor in having sown very little natural succession to bog and marsh. It is the largest natural freshwater lake in Cornwall and is at an altitude which makes it without parallel in the south-west. The underlying granite yields a nutrient-poor soil which supports a mosaic of acid grassland and heathland in the surrounding areas.
Dozmary Pool provides an important palynological record of Flandrian vegetation history and environmental change in south-west England. It is a reference locality not only for Bodmin Moor but also as part of a network of key sites for reconstructing wider regional patterns of vegetation history. The pollen record from Dozmary Pool allows important comparisons, and demonstrates strong similarities with other areas on the Atlantic fringe of urope.
The Pool itself is oligotrophic and hence supports a limited but very interesting flora. The fine granitic gravel bottom supports the nationally rare spring quillwort Isoetes echinospora for which this is the only Cornish site. Six-stamened waterwort Elatine hexandra, another rare plant, occurs in quantity in the pool margins.
To the north is Dozmary Downs, an extensive area of wet and dry acid grassland and heathland. It consists of a mosaic, dominated equally by purple moor-grass Molinia caerulea and heather Calluna vulgaris, with cross-leaved heath Erica tetralix in in wetter parts. Other species occurring frequently include lousewort Pedicularissylvatica, western gorse Ulex gallii, heath rush Juncus squarrosus, carnation sedge Carex panicea, green-ribbed sedge C. binervis, sheep’s fescue Festuca ovina and bilberry V accinium myrtillus.
To the south of Dozmary Pool on steeper drier slopes, the vegetation is somewhat different, being dominated equally by bristle bent Agrostis curtisii, purple moor-grass, heather and tormentil Potentilla erecta with frequent common bent Agrostis capillaris, brown bent A. vinealis, bell heather Erica cinerea and heath milkwort Polygala serpyllifolia.
In addition, there is to the south-west of the Pool an area of species-rich mire consisting largely of deer grass Trichophorum cespitosum, heather, purple moor- grass and cross-leaved heath but with an unusually large flush containing abundant bog asphodel Narthecium ossifragum, carnation sedge, and the bog mosses Sphagnum fallax, S. palustre and S. rubellum. Associated species include marsh violet Viola palustris, common cottongrass Eriophorum angustifolium, hare’s-tail cottongrass E. vaginatum, and the insectivorous round-leaved sundew Drosera rotundifolia. Of particular interest is the occurrence of small-fruited yellow-sedge Carex serotina and bottle sedge C. rostrata both of which species are uncommon in Cornwall.
In a county with few inland pools, Dozmary has considerable value for wildfowl on passage, and as winter visitors. It attracts considerable numbers of coot Fulica atra, wigeon Anas penelope, and teal A. crecca, and dunlin Calidris alpina have nested there. The surrounding moorland provides habitat for breeding stonechat Saxicola torquata, curlew Numenius arquata, snipe Gallinago gallinago and lapwing Vanellus vanellus. Two rare invertebrates have strong populations in the pool, a copepod Diaptomus vierzejskii and a cladoceran Drepanothrix dentata.