Natural history of Castle Bottom National Nature Reserve
The site supports a wide range of habitat and community types. These are dominated by the two valley mire complexes which run through the reserve, each with a small acidic stream running through the centre. The mires are mainly fed by water seeping out of the gravel beds at seepage steps. The two mires differ in community terms, the eastern being more open and dominated by Bog Myrtle Myrica gale and Purple Moor Grass Molinia caerulea.
There are also small pools of open water, some natural and some man-made. The western bog is grown over in many places with mature birch. There are also open areas with carpets of Bog Moss Sphagnum spp.
Above the mires on the drier slopes and on the plateaux gravels is Ling Calluna vulgaris dominated heathland, with scattered birch and pine scrub with some standards. This becomes Cross-Leaved Heath Erica tetralix dominated heathland on the lower slopes below the seepage steps and this grades down into the mire communities.
There are also several different woodland community types on the site. At the western end of the site on the drier ground is Silver Birch Betula pendula dominated woodland, with scattered Oak Quercus robur and Scots Pine Pinus sylvestris. This has a poor understorey, with scattered Bracken Pteridium aquifolium and along the northern boundary a strip of Bluebells Hyacinthoides non-scripta. Around the northern edge of the site is tall pole Birch (both Silver and Downy Betula pubecens) on wet ground, fringing and partly covering the western mire, with carpets of Sphagnum underneath. On the high plateaux to the western end of the site is also an area of suckered Aspen Populus tremula, which is of high ecological importance and is associated with nationally scarce invertebrates. Finally there are a few stands of tall birch with underlying grassland communities.
The composition of these communities has been mapped using the Global Positioning System of satellite mapping.
The habitats and communities within the reserve support a diverse range of wildlife, including many species which are of local, national or international importance.
The links left provide details of some of the important species.