Llyn Glasfryn

Also within

Gwynedd County

Geology & landscape

Geological Period: Ordovician

Landscape processes: Glacial

Birds & fish recorded

Birds

Fish

Description

Description This site is selected for its biological importance, both as an example of open water habitat and for its botanical interest. Situated on a gently undulating landscape of glacial drift deposits over Ordovician sedimentary rocks. Llyn Glasfryn is a shallow lowland lake of oligotrophic/mesotrophic (low to medium) nutrient status. Surrounded by an area of freely draining acid brown earths (Arfon soil series) the surface catchment of the lake is very small, supporting woodland and pasture. It is thought that the lake may be augmented by underground springs and drains to the south via an artifical sluice. The site supports a varied aquatic flora, including alternate water-milfoil Myriophyllum alterniflorum, blunt leaved pondweed Potamogeton obtusifolius, small pondweed Potamogeton berchtoldii and perfoliate pondweed Potamogeton perfoliatus. Large beds of stonewort Nitella flexilis, a large branching alga are particularly abundant. A number of rare vascular plants occur including six-stamened and eight-stamened waterworts Elatine hexandra and Elatine hydropiper and needle spike-rush Eleocharis acicularis. Floating water-plantain Luronium natans has also been recorded here in recent years. The lake is stocked with brown trout, mallard are reared and the site is shot over for wildfowl. Open water is a scarce feature in the Lleyn Peninsula and Llyn Glasfryn supports locally significant wintering numbers of Pochard, Teal, Tufted Duck, Goldeneye and coot.

Species mentioned