Silvan House 3rd Floor East COMMON 231 Road Site of Special Scientific Interest EH12 7AT SITE MANAGEMENT STATEMENT Tel. 0131 3162600 Email. @snh.gov.uk Site code: 120

Purpose This is a public statement prepared by SNH for owners and occupiers of the SSSI. It outlines the reasons it is designated as an SSSI and provides guidance on how its special natural features should be conserved or enhanced. This Statement does not affect or form part of the statutory notification and does not remove the need to apply for consent for operations requiring consent.

We welcome your views on this statement.

Description of the site Balerno Common Site of Special Scientific interest (SSSI) is located on the north side of the , 14 km south-west of Edinburgh and about 2 km south of Balerno. The site has been notified for the biological interest of its habitats – raised bog, transition open fen, bryophyte assemblage and mesotrophic loch.

Balerno Common is a composite site covering two adjacent sites, Red Moss (The Common) and Bavelaw Marsh, each with different habitats. Red Moss is an area of raised bog displaying the characteristic dome-shaped profile. The bog is relatively undisturbed and shows a hummock and hollow pattern. Heather and cotton-grass dominate the hummocks, while several species of Sphagnum moss are present in the wetter hollows.

Bavelaw Marsh is an area of open water that has, in the past, been noted for its emergent vegetation including bottle sedge, bogbean and marsh horsetail. More recently, there has been a decline in the prevalence of emergent vegetation in the open water of the marsh. To the west of the marsh, there is an area of fen with characteristic species such as marsh cinquefoil, bogbean and water horsetail.

Between Red Moss and Bavelaw Marsh is an area of birch scrub, with heather, blaeberry, Sphagnum species and occasional pools.

Raised bog, open water and fen are all rare habitats in the area. Red Moss is the largest and least disturbed area of raised bog in Edinburgh, while Bavelaw Marsh is the only area of fen of any size. In combination, these two areas form a site that is unique within Edinburgh in terms of size and diversity of both species and habitat.

1 More than 159 plants have been recorded within the SSSI, some of which are rare in the Lothian area. These include: sundew, white sedge, water sedge, divided sedge and marsh cinquefoil.

Several nationally rare bryophyte species (liverworts) occur on the mud exposed at low water levels in Bavelaw Marsh. There are also several locally rare species including caddisflies, sawflies, and other invertebrates. Some of the rarer species are included in the Edinburgh Local Biodiversity Action Plan, with action plans in place to conserve them.

The most recent site condition monitoring (SCM) assessment of the mesotrophic loch feature (Bavelaw Marsh), carried out in August 2004, found the feature to be in unfavourable condition. This was mainly due to the reduction of emergent vegetation (confined to narrow margins at the edge of the water), excessively high phosphorous levels, lack of natural hydrological regime and high sediment load.

The transition open fen feature was assessed in 2003 as being in an unfavourable condition due to a reduction of key habitat and vegetation types, a low water table (likely due to a reservoir drawdown at the time of survey), and a reduction in positive indicator plant species.

Both the bryophyte assemblage (surveyed November 2003) and the raised bog (surveyed September 2002) features were assessed as being in favourable condition.

Natural features of Condition of feature Balerno Common SSSI (and date monitored) Bryophyte assemblage Favourable, maintained (November 2003) Mesotrophic loch Unfavourable, declining (August 2004) Raised bog Favourable, maintained (September 2002) Transition open fen Unfavourable, declining (August 2003)

Red Moss raised bog Transition open fen

Past and present management Red Moss: Until the mid-18th century, the land around Balerno, including Red Moss,

2 was farmed and pastured in joint ownership by several land proprietors. In 1868, this Balerno Community was divided and enclosed but Red Moss remained as common land (Balerno Common) for the use and benefit of the 8 dominant proprietors. There have been a number of activities on the moss in the past, including sheep grazing, peat cutting, shooting, and the digging of lint holes for retting flax.

The Scottish Wildlife Trust (SWT) signed a 99 year lease with the landowners of Red Moss in March 2009 for the continued development and management of the site as an SWT Reserve. The current management deployed by SWT at Red Moss includes birch cutting on certain areas of the Moss, insertion of dams where needed, replacement of the southern half of the boardwalk, and the continued monitoring of the water level.

Bavelaw Marsh: In 1845, an Edinburgh water company purchased the land with plans to construct two reservoirs, Harlaw and Threipmuir, to act as compensatory water supplies to Edinburgh. In 1893, Threipmuir was enlarged to the present size.

The marsh was formed at the south-western end of Threipmuir Reservoir as a result of Threipmuir Dam being raised 5ft in the 1890s. The consequent flooding gave rise to a variety of wetland habitats from open water to willow carr. The current reserve boundary was established in 1989, when the site was included within Pentland Hills Regional Park (designated in 1986).

During the last 10-20 years, the emergent vegetation and bird life have diminished in the marsh. Reasons for the decline are unknown but one possible cause could be the reservoir regime creating large fluctuations in water levels in the marsh.

The City of Edinburgh Council proposed the Water of Flood Prevention Scheme in 2003 in response to severe flooding in 2000. As part of the Flood Prevention Scheme, work will be carried out at Threipmuir Reservoir. As part of this work, SNH requested that a weir be installed to separate the marsh from the reservoir. The location of this weir will be at Easter Bavelaw Causeway Bridge. At the time of writing this Site Management Statement, Bavelaw Marsh and Threipmuir Reservoir are in the process of being drawn-down in order that the weir can be installed where the Middle Loch joins Threipmuir Reservoir. The Middle Loch lies between Bavelaw Marsh and Threipmuir Reservoir and the weir will enable the water level of both Middle Loch and Bavelaw Marsh to be controlled independently from that of Threipmuir Reservoir. The intention is to achieve more stable water levels, by way of a weir, to prevent events such as reservoir drawdown’s and spring rises/floods. Initially, the trial water level will be set at -0.3m below existing top level, to allow low to moderate levels to be maintained in the marsh. The weir will provide flexibility to allow water levels to be varied, if required, allowing both higher and lower water levels to be achieved in the marsh.

It is hoped that the control of the water level in Bavelaw Marsh will lead to an improvement in the condition of the notified features of the SSSI, particularly that of the mesotrophic loch and the transition open fen.

3 Objectives for Management (and key factors influencing the condition of natural features) We wish to work with the owners and occupiers to protect the site and to maintain and, where necessary, enhance its features of special interest. SNH aims to carry out site survey, monitoring and research as appropriate to increase our knowledge and understanding of the site and its natural features. This aim has been broken down into the objectives below.

1. To maintain the biological interests for which the SSSI has been notified:

a) the raised bog and its characteristic species; b) the mesotrophic loch; c) the transition open fen; d) the bryophyte assemblage.

2. To maintain liaison with landowners and other interested parties through the Bavelaw Marsh Management Group regarding the production and implementation of Management Plans, ensuring that they meet SSSI conservation objectives.

3. To maintain liaison with landowners and other interested parties through the SWT Red Moss Management Committee regarding production and implementation of management plans, ensuring that they meet SSSI requirements.

4. To monitor the effects of water levels on the notable habitats and species of Bavelaw Marsh.

5. To maintain water at appropriate levels in Bavelaw Marsh through liaison with the City of Edinburgh Council.

6. Continue surveys and monitoring of other notable habitats and species throughout Balerno Common SSSI.

7. Encourage recreational and educational use of the site without compromising its conservation interests.

8. Investigate the possible causes of Red Moss bog drying out.

Date last reviewed: 04 March 2010

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