What is ‘special’ about Y Werthyr SSSI?

Y Werthyr has one special feature.

As well as the features listed above, Y Werthyr has other habitats that contribute to the special interest. These include marshy grassland and scrub. This mixture of habitats is important for much of the wildlife including many invertebrates and birds. 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 Y Werthyr to look like?

Fen vegetation should dominate the site with small patches of water and very little accumulation of leaf-litter. Large stands of rushes, particularly blunt flowered rush, should be present along with various sedges such as bottle sedge and slender sedge and wetland herbs including marsh cinquefoil and bogbean. A well-developed layer of mosses and liverworts should be present and include Calliergon (formerly Acrocladium) spp. Among the less common species present, greater spearwort should be widely distributed within the site. Small patches of willow scrub should be available to provide cover for other wildlife.

What management is needed on Y Werthyr SSSI and why?

Although Y Werthyr 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 Y Werthyr if they are not properly managed. These are the ones we regard as most important:

Grazing: Light grazing removes excess plant material, prevents the smothering of delicate species by leaf litter and limits scrub encroachment. This allows less competitive species of plants to flourish and encourage a wider range of insects and other invertebrates. Light trampling by livestock creates opportunities for plants to seed into bare ground and maintains shallow depressions in the mud and peat for invertebrates. Grazing levels should be determined by the natural carrying capacity of the land so that supplementary feeding is not required.

Scrub encroachment: Willow scrub may expand and encroach over much of the site if suitable grazing does not take place. It may be necessary to control the scrub by cutting and stump treatment. Some scrub should be left to provide cover for other wildlife but should not exceed 10%% of the site.

Water levels and changes in drainage operations: Wetland wildlife needs water! Any changes to the site’s drainage which causes lowering of the water level, including cleaning or excavation of existing ditches, could damage the marshy grassland and wetland communities, which rely on a high water table. . No new drainage of any kind should be installed.

Water quality: The site is supplied with water, nutrients and minerals by seepage from higher ground. Increased nutrients will damage the wetland habitats by allowing more vigorous plants to outgrow the less competitive plants of greater conservation interest. Nutrients such as nitrates and phosphates can come from artificial fertilisers, manure, silage and other waste (abattoir waste products etc.) applied to, or stored on, neighbouring farmland, or from septic tank drainage.

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 and great care should be taken if using them in surrounding fields.

Invasive non-native plants: plants such as water fern (Azolla filiculoides), Japanese knotweed and Himalayan balsam are not known to occur at present, but could damage the special interest if they were introduced in future. Fly tipping in the lay-by to south of the site is a potential route for the introduction of Japanese knotweed. Care should be taken not to introduce these species deliberately or accidentally. Should they be discovered on site action may be required to control them.

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