Claerwen National Nature Reserve is an expanse of mountain upland lying halfway between Rhayader in Powys and Pontrhydfendigaid in Ceredigion. The mainly peaty and acidic soil provides an environment home for many species of plants and animals which thrive in these conditions. These biomes include several highly oligotrophic lakes and ponds, raised mires and large areas that have seen little or any man-made changes. These include the nationally scarce water plantain (Luronium natans) as well as carnivorous plants such as Drosera rotundifolia, and butterworts. It is a known breeding site for red kite and merlin .
