1.0

To be used as the wetlands (including estuaries) base data layer in the Saldanha Peninsula and North-West Sandveld C.A.P.E. fine-scale biodiversity plans.

Cape Nature

Methodology for priority wetlands:

1:10 000 colour aerial photographs (obtained from DWAF and SANBI) were used as background for digitising, with SPOT5 imagery (approx. 1:55 000 scale) as support. The following existing data layers were used to assist with the location and extent of wetlands in this domain:

(i) Sensitive wetlands of the Western Cape Province: This GIS layer is available from CapeNature (Shaw and de Villiers 2001), and contains boundaries of known and sampled sensitive wetlands.

(ii) Beta Version of the South African Wetlands Map: Available on the BGIS website:

http://bgis.sanbi.org. Click the National Wetlands Inventory link on the BGIS homepage which will redirect you to the National Wetlands Inventory homepage. This GIS layer was derived as part of the National Land Cover 2000 project, using mapping and modelling techniques that enhanced wetland detection.

(iii) C.A.P.E. wetlands layer: This dataset, produced for the 2000 C.A.P.E. freshwater prioritisation project, was drawn from the layer provided by the Department of Environmental Affairs and Tourism (DEAT) for use in a directory of (major) South African Wetlands.

(iv) EIA supplementation project (DEA&DP, 2006): This project combined National LandCover Wetlands (1996, 2000), CapeNature Sensitive Wetlands, wetland point locationsfrom the National Spatial Biodiversity Assessment and Western Cape Wetland Inventory\ point data (which were buffered by 200 meters). The buffering of some of the wetlands and the lack of attribute information made it simpler to use the original datasets.

(v) Western Cape Wetlands Directory (Dallas et al., 2005): This project collated existing information on wetlands in the Western Cape into one Western Cape Wetlands Directory database. All data in the database were used to generate a point coverage. The point data corresponds to entries in database which list available information about that point.

(vi) Remote Sensing Based Botany and Groundwater Dependency Study: Northern Sandveld (GEOSS/Coastec, 2005): This project included digitising and ground-truthing of wetlands in the Northern Sandveld. These digitised wetlands were found to be accurate and could be copied across to the wetlands layer.

(vii) Olifants – Doorn Conservation Assessment of Freshwater Biodiversity in the

Olifants/Doorn Water Management Area (CSIR and DWAF, 2006): The base wetlands layer for this project were a combination of the CapeNature Sensitive Wetlands, DEAT’s perennial and non-perennial pans, South African National Wetlands Map (Beta version) and polygons created by buffering lowland rivers. All wetlands were typed according to the National Wetland Inventory Classification System, up to the structural unit level, and wetland names provided where these exist. The major impacts that could be observed off aerial photography were also recorded. A sub-sample of wetlands was ground-truthed in order to check typing, location, extent and impacts. Photographs of wetland types and wetland groups were taken, but these will be stored in an additional database.

Methodology for non-priority wetlands

The following existing data layers were combined to develop the base layer for the non-priority area:

(i) Sensitive wetlands of the Western Cape Province: This GIS layer is available from CapeNature (Shaw and de Villiers 2001), and contains boundaries of known and sampled sensitive wetlands.

(ii) Beta Version of the South African Wetlands Map: Available on the BGIS website:

http://bgis.sanbi.org . Click the National Wetlands Inventory link on the BGIS homepage which will redirect you to the National Wetlands Inventory homepage. This GIS layer was derived as part of the National Land Cover 2000 project, using mapping and modelling techniques that enhanced wetland detection.

(iii) DEAT 1:50 000 waterbodies layer: Only used the perennial and non-perennial pans from this layer. All dams were removed from the non-priority base layer by intersecting with the National dams layer (DWAF). A modeled approach was used in order to type all non-priority wetlands according to the National Wetland Inventory Classification System, up to the functional unit level. Wetlands were classified as non-isolated if they were located within 100m of a 1:50 000 river (DWAF layer), and isolated if not. Functional groups (Func_1) were modelled according to the framework below using the following data:

-soils (General Soils Pattern Map of South Africa which provides soil and terrain information at a 1:250000 scale; available from www.agis.agric.za)

-slope (US 90 m SRTM digital elevation data;

http://www.personal.psu.edu/users/j/z/jzs169/Project3.htm)

-Groundwater dependence (high and moderate areas of groundwater-surface water discharge modelled by GEOSS for the Saldanha Peninsula and North-West Sandveld

C.A.P.E. fine-scale biodiversity plans

SANS 1878

FGDC-STD-001-1998