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SUMMARY
As part of the European Commission (EC) funded Wet Woods
LIFE Project, on behalf of the Caledonian Partnership, a hydrological
survey was commissioned by Scottish Natural Heritage (SNH)
to assess the condition of the bog woodland habitat of Inshriach.
The site includes part of the Cairngorms candidate Special
Area of Conservation (cSAC), Site of Special Scientific Interest
(SSSI) and Special Protection Area (SPA). A range of management
options were identified to preserve or improve site condition.
An initial survey was completed using both desk and field
exercises. Desk work covered relevant literature on hydrological
studies, interpretation of aerial photographs and examination
of photomontages, previous NVC surveys, historical maps and
estate records, current site management reports and forest
design plans, analysis of maps looking at current land use,
geomorphology, topography, soils, geology and water catchment
analysis, limited meteorological data and current drainage
management plans.
Field exercises consisted of gathering data on the physical
attributes of each site, such as peat depths, watercourses,
location and condition of drains, vegetation, forest physiognomy
and condition, management operations, topography, mire status
and surface water movement. Verification of the information
found from the desk studies was ascertained, and any new data
added.
Principal findings for Inshriach are that commercial forestry
and associated drainage operations on site have contributed
to the degradation and erosion of the bog woodland habitat
in varying degrees. Remnants of bog woodland are displayed
in a unique range of habitats from inactive, degraded peatland,
planted nutrient poor waterlogged soils, and active bog woodland.
Several distinct hydrological units have been identified
on the Inshriach site - one Topo-hydrological Unit (THU),
and six Bio-hydrological Units (BHUs) - Mires 1-5 and Lochan
Gorm.
(These units are illustrated in the map appendices, p.35,
in map 7 'Proposed Management Boundaries' and map 8 'Summary
of Hydrological Management Features'.)
An area of bog woodland between mires 5 and 6 was shown to
have existed previously, from earlier surveys. Afforestation
has caused the decline of this wet wood.
Recommended essential management to restore and enhance the
bog woodland habitat consists of a comprehensive clearfelling
of all non-native plantations growing on former bog woodland
sites; an appropriate thinning of existing Scots pine and
the blocking of all active forestry drains.
Further management objectives would be the blocking of all
drains that are influencing the hydrology of the site, and
all non-native trees felled in peatland areas.
Ideal scenarios are the restoration of mire 2 (which was
previously linked to mire 3); the felling of trees between
mires 5 and 6 to benefit the hydrological strength of the
site; and consideration of re-creating the original path of
the canalised Allt a’Mharcaidh Burn.
Long-term management would include establishment of hydrological
sampling procedures and monitoring programmes to gauge the
ongoing effects of any restoration work.
Due to the rarity of the Inshriach Caledonian Forest habitat
and bog woodland system in Scotland, the protection of this
mire is of prime conservation interest. The hydrological units
as defined within this report can be used to give a flexible
approach to the hydrological management of the site, and contribute
towards maintaining the natural regeneration of the wooded
bog community.
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