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Holkham National Nature Reserve is England's largest national nature reserve (NNR). It is on the Norfolk coast between Burnham Overy Staithe and Blakeney, and is managed by Natural England with the cooperation of the Holkham Estate. Its comprise a wide range of habitats, including grazing marsh, woodland, salt marsh, sand dunes and foreshore. The reserve is part of the North Norfolk Coast Site of Special Scientific Interest, and the larger area is additionally protected through Natura 2000, Special Protection Area (SPA) and Ramsar listings, and is part of both an Area of Outstanding Natural Beauty (AONB) and a World Biosphere Reserve. Holkham NNR is important for its wintering wildfowl, especially pink-footed geese, Eurasian wigeon and brant geese, but it also has breeding waders, and attracts many migrating birds in autumn. A number of scarce invertebrates and plants can be found in the dunes, and the reserve is one of the only two sites in the UK to have an antlion colony. This stretch of coast originally consisted of salt marshes protected from the sea by ridges of shingle and sand, and Holkham's Iron Age fort stood at the end of a sandy spit surrounded by the tidal wetland. The Vikings navigated the creeks to establish Holkham village, but access to the former harbour was stopped by drainage and reclamation of the marshes between the coast and the shingle ridge which started in the 17th century, and was completed in 1859. The Holkham estate has been owned by the Coke family, later Earls of Leicester since 1609, and their seat at Holkham Hall is opposite the reserve's Lady Anne's Drive entrance. The 3rd Earl planted pines on the dunes to protect the pastures reclaimed by his predecessors from wind-blown sand. The national nature reserve was created in 1967 from of the Holkham Estate and of foreshore belonging to the Crown. The reserve has over 100,000 visitors a year, including birdwatchers and horse riders, and is therefore significant for the local economy. The NNR has taken steps to control entry to the fragile dunes and other areas important for their animals or plants because of the damage to sensitive habitats that could be caused by unrestricted access. The dunes are an essential natural defence against the projected rises in sea level along this vulnerable coast. == Description == The reserve lies to the north of A149 coast road, starting just west of Burnham Overy Staithe and extending west past Holkham to Beach Road, Wells-next-the-Sea. It also includes the tidal salt marshes continuing further east to Blakeney.〔Natural England (2009) pp. 17–19.〕 Its total area of about makes it the largest NNR in England.〔 The reserve can be accessed by footpaths from Wells and the local villages〔 Retrieved 3 September 2012.〕 including the Peddars Way/Norfolk Coast long-distance trail that traverses the main part of the reserve, and National Cycle Route 1 loops through the core of the NNR between Holkham and Wells.〔 Retrieved 3 September 2012.〕 There is a car park near Holkham village at the north end of Lady Anne's Drive that gives access to two bird hides, and another parking area at the end of Beach Road in Wells. To the east of the Wells channel, the reserve is mainly salt marshes and mud flats, and is difficult and potentially dangerous to access, although a public footpath runs along the southern edge of these tidal areas.〔〔 Retrieved 3 September 2012.〕 The salt marshes on this coast are stated in the Site of Special Scientific Interest (SSSI) notification document to be "among the best in Europe ... the flora is exceptionally diverse". Holkham also has good examples of sand dunes, and the pines planted on the dunes have provided shelter for other trees and shrubs to become established, making this the only substantial area of woodland in the North Norfolk Coast SSSI.〔 The dunes are created and altered by the elements, and the sand islands in Holkham Bay have formed only within the last 60 years.〔 The flat ground inland from the dunes is reclaimed salt marsh that was used as pasture until the 1940s, but converted to arable land during World War II. The value of the fields to wildlife was reduced by the resulting lower water table, but Natural England's management measures have raised the water levels, attracting breeding and wintering birds.〔 Water management can also be used to ensure a high water table in summer, benefiting breeding waders, and drier conditions in winter, preferred by the geese. The management of water levels and grassland increased the numbers of breeding wetland birds from 120 pairs of ten species in 1986 to 795 pairs of 26 species in 1994, and the number of wintering birds of four key wildfowl species rose from 1,215 to 17,305 in the decade from 1983/84. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Holkham National Nature Reserve」の詳細全文を読む スポンサード リンク
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