Llyn Goddionduon

Site of Special Scientific Interest · 53.1100, -3.8640

Description

Description A natural, shallow, acid lake with a fairly low nutrient status and a very low level of productivity. It has some well developed areas of emergent and floating-leaved vegetation, dominated by such plants as water horsetail Equisetum fluviatile, common spike-rush Eleocharis palustris, common reed Phragmites australis, floating pondweed Potamogeton natans, bogbean Menyanthes trifoliata and white water lily Nymphaea alba. There is a good population of water lobelia Lobelia dortmanna and excellent swards of benthic species such as shore-weed Littorella uniflora. The lake is reasonably rich in phytoplankton and in aquatic invertebrate animals. Remarks: Within the Snowdonia National Park.

Species mentioned

English name
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Latin name
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IUCN / Red List Type Family
common reed Phragmites australis LC grass poaceae
water horsetail Equisetum fluviatile LC herb equisetaceae
shoreweed Littorella uniflora LC herb plantaginaceae
water lobelia Lobelia dortmanna LC herb campanulaceae
bogbean Menyanthes trifoliata LC herb manyanthaceae
white water-lily Nymphaea alba LC herb nymphaeaceae
broadleaved pondweed Potamogeton natans LC herb potamogetonaceae
common spike rush Eleocharis palustris LC rush juncaceae

Insects to look out for

These moths, butterflies and beetles are known to feed on plants recorded at this site, and carry a notable UK conservation status — but a host-plant being present doesn't mean the insect has actually been recorded here. Treat this as "worth watching for," not a confirmed sighting.

SpeciesStatusVia host-plant
White-mantled wainscot
Archanara neurica
Near Threatened Phragmites australis
Garden tiger
Arctia caja
Near Threatened Equisetum fluviatile
Reed leopard
Phragmataecia castaneae
Near Threatened Phragmites australis
Fenn's wainscot
Protarchanara brevilinea
Near Threatened Phragmites australis

Host-plant data: Cook et al. (2025), Traits data for the butterflies and macro-moths of Great Britain and Ireland, 2024, UK Centre for Ecology & Hydrology / Butterfly Conservation; and Padovani et al. (2020), Database of Insects and their Food Plants (DBIF), UK Centre for Ecology & Hydrology (both Open Government Licence). Contains data supplied by UK Centre for Ecology & Hydrology.