What is ‘special’ about Tyddyn y Waen SSSI?

Tyddyn y Waen has one special feature:

There are both acidic and alkaline areas in the fen meadow; in the former, plants such as purple moor-grass and bog asphodel occur, while in the latter, black bog-rush is often seen and the vegetation includes a number of unusual plants, including broad-leaved cotton-grass and the liverwort Leiocolea bantriensis. There are also large stands of great horsetail and tall clumps of greater tussock-sedge.

As well as the features listed above, Tyddyn y Waen has other habitats that contribute to the special interest. These include willow scrub and an area of swamp consisting largely of lesser pond sedge. This mixture of habitats is important for much of the wildlife including many birds, insects and other invertebrates. 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 Tyddyn y Waen to look like?

Fen meadow should be abundant on site with occasional clumps of willow or gorse scrub, covering no more than 10% of the site. Lesser pond-sedge and great horsetail should form stands. The sward should be fairly open in most parts of the site with very little leaf litter. Black bog-rush and blunt-flowered rush will be abundant in many parts of the site where the necessary supply of calcium-rich water occurs. Plants typical both of acid conditions; such as cross-leaved heath and bog asphodel and alkaline conditions; such as tawny sedge and flea sedge, should continue to grow here.

What management is needed on Tyddyn y Waen SSSI and why?

Although Tyddyn y Waen is an excellent place for wildlife it will only remain so if the necessary management continues. 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 Tyddyn y Waen if they are not properly managed. These are the ones we regard as most important.

Scrub encroachment: Willow is a valuable wildlife habitat, particularly for invertebrates and birds, but has spread at the expense of the important fen meadow Some control may be necessary, followed by an appropriate grazing regime using horses or cattle. Small clumps of scrub should be left birds and other wildlife.

Water supply and drainage: A secure water supply and high soil moisture are essential for the important wetland communities. Any changes to the site’s drainage including management of existing ditches, could adversely affect the fen meadow and other wetland communities, which rely on a high water table. No new drainage of any kind should be installed. Cleaning of existing shallow drains should be limited to the removal of accumulated vegetation.

Water quality: The area is supplied with moisture, nutrients and minerals by seepage from higher ground. Differences in the acid/alkaline balance, and in the supplied nutrients and minerals (along with the history of grazing) have resulted in a range of plant communities within this small site. Any increase in the nutrient levels (such as nitrates and phosphates from artificial fertilisers, manure, silage and other waste (abattoir waste products etc.) or from septic tank outflows) will damage the wetland by allowing competitive plants, such as bulrush, to outgrow the less vigorous species of greater conservation interest. . There should be no use of fertilisers or similar material on the site. Applications of fertilisers etc. on land within the catchment should be made with care to avoid contamination of water supply to the site. Herbicides (e.g. Asulam) and pesticides of any type will also directly damage plants and animals of interest: they should not be used within the SSSI without CCW consent and great care should be taken if using them in surrounding fields to avoid spray drift.

Grazing: Grazing is an important management tool to control the balance of scrub and meadow and light grazing, probably with ponies or cattle, should occur throughout the site. Grazing removes coarse, rank vegetation and prevents the build up of leaf litter allowing less competitive species of plants to flourish and encourages a wider range of invertebrates. Grazing levels should be determined by the natural carrying capacity of the land such that supplementary feeding is not required.


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