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To derive significant clusters of wetlands embedded in a relatively natural landscape matrix through which dispersal between wetlands can occur (e.g. frogs and invertebrates). This allows for important ecological processes such as migration of frogs and insects between wetlands. In many areas of the country, wetland clusters no longer exist because the surrounding land has become too fragmented by human impacts. A goal of NFEPA is to ensure that at least 20% of the wetland cluster area identified for each wetland vegetation group is managed in a way that supports dispersal between wetlands within the cluster, ideally a natural or near-natural condition.

Biodiversity targets for representing wetland clusters were set in addition to those for representing wetland ecosystem types. Because the biodiversity planning software (MARXAN) strives for meeting as many biodiversity targets in the same area, the clusters selected as FEPAs often contained wetland FEPAs selected for achieving wetland ecosystem type targets.

Wetland clusters focus on maintaining lateral connections in the landscape matrix. As such, only nonriverine wetlands were used to identify wetland clusters (channelled valley-bottom wetlands, floodplain wetlands and valleyhead seeps were excluded in the cluster identification process). Unchannelled valleybottom wetlands were treated as non-riverine wetlands.

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All non-riverine wetlands were buffered by 500 m in GIS to collapse wetlands within 1 km of each other to form initial clusters. These initial clusters were also assigned a wetland vegetation group that occupied the majority of their area. Initial clusters only qualified as final NFEPA wetland clusters if they satisfied all of the following criteria:

• Comprised of three or more wetlands;

• Area of natural wetlands, compared to that of artificial wetlands, is 50% or more; and

• The majority of the wetland cluster area (i.e. = 50%) is under natural land cover, as determined using the same land cover as that used for modelling condition of tributaries. Three wetland vegetation groups that could not achieve wetland cluster targets in clusters where the area of natural land cover was = 50% (Mesic Highveld Grassland Group 7; Southern Shale Band Vegetation and Eastern Fynbos-Renosterveld Shale Renosterveld). For wetland clusters in these wetland vegetation groups, the natural land cover threshold of 50% was lowered to a threshold of 25%.

In many areas of the country (notably Gauteng and Western Cape provinces), wetland clusters no longer exist because the surrounding land has become too fragmented by human impacts. The potential for identifying smaller wetland clusters at a finer scale of planning should be investigated in these areas, similar to the work that has been done for the City of Cape Town Municipality wetlands.

Available documentation:

Nel, J.L., Murray, K.M., Maherry, A.M., Petersen, C.P., Roux, D.J., Driver, A., Hill, L., Van Deventer, H., Funke, N., Swartz, E.R., Smith-Adao, L.B., Mbona, N., Downsborough, L. and Nienaber, S. (2011). Technical Report for the National Freshwater Ecosystem Priority Areas project. WRC Report No. K5/1801.

SANS 1878

FGDC-STD-001-1998