What is ‘special’ about Cors Bodwrog SSSI?

Cors Bodwrog has one special feature:

As well as the features listed above, Cors Bodwrog has other habitats that contribute to the special interest. These include areas of acid grassland, open water (Llyn Hendref) and alder and willow scrub. This mixture of habitats is important for wildlife including mammals such as water voles and otters, insects such as dragonflies and damselflies, barn owls and other breeding birds including teal, reed warbler, grasshopper warbler and curlew. Unless specified below, management of this site should aim to look after these habitats and species as well as the listed features of interest.

What do we want Cors Bodwrog to look like?

There should be large areas of acid mire on deep peat in the northern half of the site with plants such as cross-leaved heath, bog asphodel, tormentil, purple moor grass and bog myrtle underlain by bog mosses (Sphagnum). Along the site margins this habitat should merge into wet meadow with grasses such as Yorkshire fog and creeping bent and common rushes including soft rush. Patches of black bog rush should occur in with blunt-flowered rush and great fen-sedge where more lime-rich water irrigates the land. Bottle sedge, slender sedge, common cotton-grass, marsh cinquefoil, bogbean, greater tussock-sedge and lesser tussock-sedge should be present in old peat cuttings, ditch-lines and wet hollows.

Uncommon plants such as greater spearwort and lesser bulrush should be present. In the southern half of the site common reed and reed canary-grass should form extensive stands around the lake, providing habitat for bittern. Small areas of willow scrub and alder can be tolerated but should not be allowed to encroach on wetland areas. The lake should cover extensive areas of the southern part of the site, supporting indigenous water plants birds and wildfowl. A rich variety of invertebrates including many species of dragonflies and damselflies should continue to occupy the site.

What management is needed on Cors Bodwrog SSSI and why?

Although Cors Bodwrog is an excellent place for wildlife it has been damaged by past events and will only remain of wildlife value if the necessary maintenance or restoration management occurs. CCW’s aim is to work with you to ensure that this management is carried out.

What does this mean in practice?

There are many factors that could damage the special features at Cors Bodwrog if they are not properly managed. These are the ones we regard as most important:

Grazing: Light grazing removes excess plant material, prevents buildup of leaf litter and prevents succession to scrub and woodland, mimicking a natural grazing regime. The most appropriate modern grazers here are small cattle or ponies as they can maintain open areas in wetland by browsing , grazing and by minor poaching of the ground. Cattle, sheep or ponies (in appropriate numbers) should graze areas of grassland. Animal dung also provides an important food resource for some invertebrates. There should be no supplementary feeding with silage, as this increases soil nutrient levels. Hay may be fed in severe weather and mineral licks used to enable the animals to digest coarse material.

Water levels: Maintaining a high water table level is essential for the survival of wetland plants and animals. The water level in this site was lowered in 1970s, which has had adverse effects on the extent and quality of wetland plant communities. It is therefore important that no work is carried out which would further lower water levels on the site – for example by widening or deepening the ditches, especially the main ditch/drain.. Although raising water levels should not be undertaken without careful assessment and agreement of all stakeholders it would be desirable to reinstate Llyn Hendref and restore water levels to the mire. However, some wetland plants and animals require only very shallow surface water or moving groundwater, so deep or prolonged flooding can destroy these. Equally important is the need to maintain the current water supply to the site through springs, groundwater seepage, ditches and surface run off. Any actions that would reduce the amount of water entering Cors Bodwrog would be damaging to the site.

Water quality: Good water quality is essential for maintaining the characteristic assemblage of wetland plants and animals at Cors Bodwrog. Nutrients such as nitrogen and phosphorus, often derived from agricultural fertilizers or from sewage effluent or other wastes encourage the spread of strongly growing plants such as floating sweet-grass and common reed, which can out-compete the less common (and more desirable) species of Cors Bodwrog. This in turn would impact upon the animals that depend on these plants. Such nutrients in the lake stimulate growth of algae, causing the loss of species that need clear and clean water, including fish. Any measures to enhance soil fertility within the catchment of the site are therefore likely to harm the special interest features of Cors Bodwrog. Any sewage treatment facilities within the catchment must be well maintained in order to function efficiently and consideration given to tertiary treatment of the effluent. Toxins such as sheep dip could also damage the site’s wildlife, particularly in the aquatic environment.

Scrub. Encroachment: Scrub (including willow) provides nesting places for birds and shelter for other animals. However too much scrub can alter the special qualities of the wetland site. Existing scrub round the lake could be controlled by cutting willow and raising water levels to cover the stumps. In other areas an appropriate grazing regime will help to control scrub, but may require additional manual control by cutting or stem injection.


Our knowledge and understanding of wildlife is continually improving. It is possible that new issues may arise in the future, whilst other issues may disappear. This statement is written with the best information we have now, but may have to change in the future as our understanding improves, in particular, of the possible/probable impact of climate change. Any information you can provide on the wildlife of your site, its management and its conservation would be much appreciated.

If you would like to discuss any aspect of your SSSI, or have any concerns about your SSSI, please contact your local CCW office.

Your local office is:

Countryside Council for Wales

North Wales Region

Llys y Bont

Ffordd y Parc

Parc Menai



LL57 4BN

Telephone: 01248 672500

Fax: 01248 679259