County Wildife Site Criteria for Cornwall Appendices

INTERTIDAL MUDFLATS PHTGeneral DescriptionThese mudflats are sedimentary intertidal habitats created by deposition in low energy coastalenvironments, particularly estuaries and other sheltered areas. Their sediment consists mostly of siltsand clays with a high organic content. Towards the mouths of estuaries where salinity and waveenergy are higher the proportion of sand increasesMudflats are highly productive areas which, together with other intertidal habitats, support largenumbers of predatory birds and fish. They provide feeding and resting areas for internationallyimportant populations of migrant and wintering waterfowl, and are also important nursery areas forflatfish.National ContextThe total British estuarine resource has been estimated at over 500 000 ha of which 55% is intertidalarea, mostly mud and sandflats with a lesser amount of saltmarsh. Intertidal flats cover about 250 000ha.They are widespread in the UK with significant examples in the Wash, the Solway Firth, MerseyEstuary, Bridgwater Bay and Strangford Lough.Area of PHT in Cornwall (ha): 25941.0% National TotalNumber of polygons: 593The habitat is: UncommonDistribution by Administrative DistrictDistrict P K CK R CN NC ΣNumber 31 108 155 42 212 45 593Area (ha) 135 160 608 167 980 544 2594Distribution by Natural AreaDistrict Pe Lz CKG BM Cu ΣNumber 0 36 557 0 0 593Area (ha) 0 37 2557 0 0 2594*Strictly speaking, these may not lie within the respective boundary, but lie adjacent to them.For this habitat the threshold is 2.0 haAppendix 4 - Information Relating to Priority Habitat TypesCounty Wildlife Sites Criteria