Biodiversity
A number of areas of the Levels have been designated as Sites of Special Scientific Interest. Tickenham, Nailsea and Kenn Moors SSSI is an extensive SSSI in the northern part of the Levels. Yanal Bog, a calcicolous mire near Sandford is designated for its plant communities, within which grow Black Bog-rush (Schoenus nigricans) and Blunt-flowered Rush (Juncus subnodulosus), two plant species rare in southwest England.
A number of plant species which are otherwise scarce or absent in the Bristol region are found in high concentrations on the North Somerset Levels, including Water Horsetail (Equisetum fluviatile), Rigid (Ceratophyllum demersum) and Soft (C. submersum) hornworts, Thread-leaved (Ranunculus trichophyllus), Common (R. aquatilis) and Fan-leaved (R. circinatus) water-crowfoots, Lesser Water-parsnip (Berula erecta), Tubular (Oenanthe fistulosa) and Fine-leaved (O. aquatica) water-dropworts, Tufted Forget-me-not (Myosotis laxa ssp. caespitosa), Skullcap and Fen Bedstraw. Water-violet (Hottonia palustris) is found here, mainly in the Nailsea & Tickenham areas, but also in scattered locations further south; this species is found nowhere else in the Bristol region. The introduced Water Fern Azolla filiculoides is widespread throughout.
Other plant species which are otherwise scarce or absent in the Bristol region but found in high concentrations on the North Somerset Levels are: Flowering-rush (Myles, p. 210), Lesser Water-plantain (Myles, p.210-1), Frogbit (Myles, p. 210-1), Lesser Pondweed (Myles, p.212-3), Small Pondweed (Myles, p. 212-3), Hairlike Pondweed (Myles, p213), Opposite-leaved Pondweed (Myles, p.213) and Horned Pondweed (Myles, p.213).
The introduced Canadian and Nuttall's Waterweeds are widespread throughout the levels (Myles p.211).
Read more about this topic: North Somerset Levels