Dull adnabod

Dynodydd

NRW_DS24715

Teitl Amgen

• Phase 1 Habitat Survey of Wales 1979-1997
• Phase 1 Survey- Upland Vegetation Survey
• Habitats of Wales Phase 1 Data, 1979-1997 Lowlands and Uplands
• Cynefinoedd Cymru: Gorchudd cynefin Cyfnod i digidol

Laith Metadata

English

Datganiad

Uplands are classified as open upland landscapes coming down as far as the upper limit of enclosure; lowlands and uplands are mutually exclusive. The fieldwork was conducted in two main stages. Most upland areas were surveyed during the first stage (the Upland Vegetation Survey) between 1979 and1989, and areas were assigned to habitat types using the Ratcliffe and Birks classification. The survey methods employed during the initial upland phase are given in more detail in a Wales Field Unit report (Day, A. 1989. Upland vegetation survey 1979–1989. Background, methodology and summary of data collected. NCC report no. W91/2, Nature Conservancy Council, Bangor). Some upland regions were surveyed between 1991 and 1999 using the National Vegetation Classification, and small patches were covered between 1982-1992 using the NCC scheme for SSSI recording or the NCC/RSNC classification (NCC/RSNC Habitat Classification and Description, 1984). Mapping was carried out on foot, using mostly 1:10,000 scale aerial photographs for locating habitat polygons (rarely 1:25,000 during the upland stage). The rest of Wales including all the lowlands and some previously unsurveyed upland areas was covered during the second stage (the lowland phase) between 1987-1997 and habitats assigned to the Phase I classification (Handbook for Phase I habitat survey- a technique for environmental audit, NCC, 1990), with some minor modifications adopted for use in Wales (Supplementary Notes for Phase 1 survey in Wales, Howe E.A. and Blackstock T.H., 1991, CCW, Bangor). Habitats were recorded field-by-field by using public rights of way and obtaining access permission to look more closely at some fields. Habitats were mapped onto 1:10,000 scale 5 x 5 km master-maps. The minimum size of habitat patch recorded lies predominantly within the range 0.1 – 0.25 ha, although smaller areas were mapped in the in lowlands.

Gwybodaeth ychwanegol

With such a vast dataset (approximately 481,000 polygons and 434,000 points), it is inevitable that some transcription errors remain. Users detecting significant differences between the digital data and the habitat maps from which they were derived are encouraged to report these to Jonathan Rothwell (from NRW) quoting polygon Unique_ID. About 30% of the upland polygons are mixed habitat and therefore should not be used to calculate habitat area. A voronoi version of the vegetation layer has been crested to help address this. The 1 km square dataset is the definitive source of habitat area statistics. Phase 2 Lowland Grassland Survey of Wales (Tir Stent site number SH71/2)

Dyddiad cyfeirnod y set ddata (Cyhoeddiad)

2023-08-16

Rhychwant

Rhychwant

Hyd

Wales (WLS)

N

W

E

S

 

Dosbarthiad

Ansawdd

Allweddeiriau

System Cyfeirio Gofodol

Cynnwys

Cyfyngiadau