Effects of Overgrazing on Peatlands
Bogs are particularly sensitive to overgrazing. In extreme situations almost all of the living vegetation is removed, and the overgrazed terrain is bare and black. Fence lines (between holdings) emphasise the huge difference in appearance between over grazed and non-overgrazed land.
Overgrazing is one aspect of the problem, there is also a dramatic change in the vegetation of the over grazed area, with the removal of Ling Heather and the invasion of Sheep’s Bent Grass (Nardus stricta). The worst affected areas are in Galway and Mayo, with isolated cases in Donegal and Kerry. Often the valley floors are worst hit.
As many of the affected bogs are in scenic areas, overgrazing has a knock on affect on tourism and associated businesses.
Restoration Measures
The Department of Agriculture and Food in association with the National Parks and Wildlife Service have undertaken surveys of the overgrazed peatlands and have designed new grazing regimes to combat the effects of prolonged grazing by large numbers of sheep in particular. Sensitive areas may need to fenced off and occasionally a proactive approach to re-introducing peat forming vegetation on bare peat areas may be necessary (please follow the link to Restoration of Industrial Cutaway Peatlands for information on the techniques involved). The major management technique is to reduce the stocking densities of sheep to a level of less than 1 sheep per hectare. This allows sheep to graze selectively. In summer more palatable grasses and sedges are grazed in preference to heather, for example. Another aspect of the recovery management is to ensure that supplementary feeding stations are moved regularly so as to lessen the impacts of prolonged trampling in one area of the peatland. A survey of the extent of the overgrazing problem is the first step before a management regime is introduced. A follow-up survey may be required 4 – 5 years after the implementation of the management regime to assess the recovery.
Text, Photographs and Images © Irish Peatland Conservation Council, Bog of Allen Nature Centre, Lullymore, Rathangan, Co. Kildare. Email: bogs@ipcc.ie; Tel: +353-45-860133.