LLYN LLYWENAN SITE OF SPECIAL SCIENTIFIC INTEREST
SITE MANAGEMENT STATEMENT
What is ‘special’ about Llyn Llywenan SSSI?
Llyn Llywenan has 2 special features.
A shallow lowland lake with moderate nutrient levels and a rich assemblage of aquatic plants and animals, including extensive reedswamp.
Uncommon aquatic plants such as eight-stamened water-wort, spring quillwort and needle spike rush.
As well as the features listed above, Llyn Llywenan has other species and habitats that are key components of the special interest. These include an assemblage of wintering birds, a black-headed gull colony, breeding wildfowl including gadwall, and willow scrub. Unless specified below, management of this site should aim to look after these habitats and species as well as the listed features of interest.
The lake should continue to support eight-stamened water-wort, spring quillwort and needle spike-rush as indicators of moderately nutrient rich waters. There should be extensive areas of marginal swamp characterised by common reed, reed canary grass and common club-rush.
The site should support a good assemblage of wintering wildfowl such as teal, wigeon, shoveler, tufted duck and pochard and an assemblage of breeding birds including gadwall and black headed gull. The habitat should be suitable for breeding bittern.
In the long-term the lake may shrink as natural processes result in siltation, the expansion of swamp and development of wet woodland and other habitats. When this happens some aquatic species may be lost but new habitats will be provided for other species.
What management is needed on Llyn Llywenan SSSI and why?
Although Llyn Llywenan is an excellent place for wildlife/geology 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 Llyn Llywenan if they are not properly managed. These are the ones we regard as most important:
Use of fishing boats is unlikely to have adverse effects providing that care is taken to avoid accidental pollution from engines. Engines should be well maintained to minimise risk of oil/fuel leaks caused by mechanical failure and to limit noise levels as far as possible. Speed should be limited to prevent damage to lake shore and vegetation by “wash”.
Care should be taken to limit silt inputs to the lake; ploughing within the catchment should leave a buffer zone on the margins of any tributary or along the lake shore to prevent soil being washed into the lake. Stock should be allowed only limited access to the lake where essential for drinking water, since they can exacerbate siltation and nutrient enrichment. The remainder of the lake shore should be stockproofed.
Invasive non-native species: Plants such as water fern Azolla filiculoides, swamp stonecrop Crassula helmsii or Japanese knotweed Fallopia japonica can spread extremely rapidly and out-compete native species. These species are present on Anglesey and could be introduced by root fragment, fronds or other plant material. Any equipment, including machinery, fishing tackle and even boots and waders, brought on site should be thoroughly cleaned beforehand, regardless of whether they have been in contact with any invasive species. Measures should be taken to eradicate any accidental introductions as soon as possible.
Our knowledge of wildlife is far from complete. It is possible that new features of value may appear and new management 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. 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;
Cyngor Cefn Gwlad Cymru/Countryside Council for Wales
Llys y Bont,
Ffordd y Parc,
Gwynedd, LL57 4BN,
Fax: 01248 679259