Fen Management Handbook - Scottish Natural Heritage

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Case Study 6.1
Fen Vegetation Management
– Whitlaw Mosses National Nature Reserve
The Whitlaw Mosses National Nature Reserve (NNR) (Whitlaw Mosses) forms the
core of an important series of around 200 basin mires in the central part of the
Scottish Borders. The four component mosses occupy small shallow elongated
basins in a corrugated landscape which formed from locally calcareous and tightly
folded Silurian shales, from which base-rich groundwater arises in the form of
springs and up-wellings. Each of the mosses on the composite site demonstrates
at least one stage of hydroseral succession from open water/poor fen to willow carr.
The mosses support a wide range of northern rarities such as holy grass, coralroot
orchid and narrow small reed. In addition, the fens are home to rare mosses
and several Red Data Book fly and water beetle species. Management of these
small sites (2ha to 10 ha), therefore takes account of a wide range of specialised
species. The overall aims of the NNR are to support those rare and specialised
species by maintaining suitable conditions across the mosaic of habitats.
Overview of Murder Moss
part of the Whitlaw Mosses
NNR (A.McBride).
Historical Management
As a result of legal disputes, records of the historical management and use of the
mosses are well detailed from the 1770s onwards. Uses and management at that
time included all year grazing by sheep and lambs, cutting of bog hay and reeds,
wood and brush cutting, and paring and burning of adjacent rough pasture to grow
five successive arable crops before reseeding.
The two further historical operations which have created the mosses we see today
are peat cutting and digging of marl, a substance found under the peat formed
from the tiny shells of molluscs. Marl was used as a liming agent to improve acid
land around the mosses before ground limestone was made widely available
once the railways arrived. As traditional in other parts of Scotland, the turfs were
replaced after peat cutting, which on Whitlaw Mosses rejuvenated the hydrosere
whilst retaining some of the original surface vegetation. The digging of the marl
had lowered the fen surface and also increased the pH of the water. In time, the
drainage channels that allowed the removal of peat and marl fell into disrepair
allowing water levels to rise.