Report Cover Vol I - Clare County Library

The County Clare Wetlands Survey Patrick Crushell & Peter Foss 2008
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Links with Annex I: As for upland blanket bog - PB2 above.
PB4 Cutover bog
This category should be used in situations where part of the original mass of peat has been removed
through turf cutting or other forms of peat extraction. Areas of high bog that have been exploited using
Difco cutters, or 'sausage' machines, are included only if the surface vegetation has been removed.
Cutover can be associated with all peat-forming systems, including fens and some areas of wet heath -
HH3. Turf cutting activity is characterised by vertical face banks or rectangular peat ramparts where the
cutover section is at a distinctly lower level than the uncut high bog. These banks vary in height,
depending in part on the depth of peat, and remain in evidence for a long time after turf cutting ceases.
Old turf banks may be overgrown with vegetation. Cutover bog occurs on a much larger scale in the case
of industrial or commercial peatlands where peat is harvested mechanically (sod, milled or moss peat
production). Areas of bog that are actively being worked are included in this category, as are areas of
abandoned or exhausted cutover.
Cutover bog is a variable habitat, or complex of habitats, that can include mosaics of bare peat and
revegetated areas with woodland, scrub, heath, fen and flush or grassland communities. The nature of
the recolonising vegetation depends on numerous factors including the frequency and extent of
disturbance, hydrology, the depth of peat remaining, and the nature of the peat and the underlying
substratum. Standing water is usually present in drains, pools or excavated hollows. Some large areas of
cutover bog have been reclaimed as farmland or planted with trees, particularly conifers. If the
regenerating habitats of cutover bog cover a sizeable area and can easily be fitted elsewhere in the
classification, this should be done. The full extent of the cutover may be difficult to establish as it
frequently grades into other marginal habitats or farmland.
Links with Annex I: The annexed habitat, 'depressions on peat substrates of the Rhynchosporion (7150)'
can occur in pockets on cutover bog, mostly in association with areas of cutover raised bog.
PB5 Eroding blanket bog
This category should be used in situations where part of the original peat mass has been lost through
erosion, as opposed to extraction (See cutover bog - PB4), and where sizeable areas of bare peat are
exposed. Eroding blanket bog is most commonly associated with upland areas, and mountain peaks and
ridges in particular. Causes are numerous; some erosion may have occurred as a natural process but,
over the last two decades, overgrazing by livestock (particularly sheep) has been a major contributory
factor. Eroding blanket bog is often characterised by networks of channels and gullies that have cut down
through the protective layer of vegetation to expose the underlying peat. As erosion continues, these
channels widen, deepen and coalesce until eventually the rocky substratum is reached. Some small
blocks of the original bog, known as peat haggs, may remain.
To be categorised as eroding blanket bog, a substantial proportion of the original bog surface should be
missing and peat should have eroded below the rooting zone of the surface vegetation. In such
situations, the process is likely to be irreversible, or recovery very slow, even if damaging activities
cease. If erosion has occurred to such an extent that large areas of the rocky substratum are exposed,
the habitat should be considered elsewhere in the classification. This also applies to formerly eroded
areas where most of the peat has been removed but where the underlying mineral or peaty substratum
has been extensively recolonised by vegetation. Peatlands damaged by bog bursts can be included here if
sizeable areas of bare peat are exposed.
PF Fens and Flushes
Fens are peat-forming systems that differ from bogs in that they are fed by groundwater or moving
surface waters. They occur in river valleys, poorly-drained basins or hollows, and beside open stretches
of water (lake margins or river floodplains). Fens may also be associated with the fringes or other parts
of acid bogs where there is enrichment of the water supply. Any areas of fen that have been modified by
turf cutting should be considered under cutover bog - PB4. Flushes are usually smaller features that are
maintained by the movement or seepage of water. They occur on slopes and may or may not be peatforming.
Some flushes feed into fens while others may be associated with a range of different habitat
types including bogs, woodlands and grasslands. Flushes in bogs are usually characterised by changes in
the vegetation that are brought about by an enhanced supply of nutrients. Note that springs are
considered in the freshwater section (FP1-2).
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