Raised Peatbogs

Hinweis der Redaktion

1. Bogs are a distinctive and important part of our landscape. They form an important part of our post-glacial inheritance. After the ice retreated, peat bogs formed over large stretches of lowland and upland Scotland.
2. In a waterlogged soil, the pore spaces are filled with stagnant water which becomes de-oxygenised. Where free oxygen is not present in a soil, the rate of decomposition of organic matter will be slowed down, leading to the formation of peat. This could occur on flat uplands with impermeable sub-soil or on valleyfloors which have a high water table.Extensive areas of peat blanket the oceanic upland regions of northwest Europe.
3. Sphagnum is like a sponge. It is able to absorb water and hold it in the plant cells, and thus maintain its own water supply. As a result the peat bog is always saturated with water.
4. Only acid tolerant plants such as ling heather (Callunavulgaris) and cotton grass (Eriophorum) can survive in this environment, but the dominant component is usually different species of bog moss (Sphagnum).
5. In the Forth Valley large parts of the Carse of Stirling became covered with peat as the ice margins retreated into the Highlands. Initially the sea level fell sufficiently for the Buried Beach to become forested with trees such as alder and birch. (The middle part of the lowest layer of peat in the Carse of Stirling contains numerous branches, trunks and pollen of these trees.) This forest was drowned by a rise in sea level about 8,500 years ago. The peat layer was then covered almost everywhere by a thick deposit of carse clay.
6. As the sea continued to rise and the estuary grow wider the beach sand and its covering of peat were in turn interred by the muddy carse. Under East and West Flanders Moss however the carse clay is totally absent and a thick layer of peat occurs instead. The peat, in at least these two areas, continued to grow , managing to (just) keep the raised bog above the rising sea level. Isostatic recovery in the western part of the basin may have played a part in maintaining the bogs as islands.
7. In 1973, in a bid to stop this degradation, the Scottish Wildlife Trust bought a small part of Flanders Moss as a nature Reserve. Seven years later, SNH were able to declare 210 hectares (520 acres) of the Moss as a National Nature Reserve (NNR). Since then SNH has entered into agreements with landowners and purchased other areas to extend the Reserve size. Today SNH looks after 821 hectares (2,030 acres) as an NNR. The aim is to restore the active living peatland, and to provide a home for all the peatland plants and animals. Trees have a valuable role on the Reserve, but we need to keep these in their place.