NFEPA Atlas 5.3_20111025_FINAL.indd - Biodiversity GIS - SANBI

Part 3: National mapproducts3.1 Density of Freshwater Ecosystem PriorityAreas per Water Management AreaThis part of the atlas presents six national maps that show:3.1 Density of FEPAs per Water Management Areacalculated as the percentage of the total area of thatWater Management Area that has been identified as aFEPA or associated sub-quaternary catchment3.2 Density of FEPAs per sub-Water Management Areacalculated as the percentage of the total area of thatsub-Water Management Area that has been identified as aFEPA or associated sub-quaternary catchment3.3 Free-flowing rivers of South Africa, or rivers withoutdams that flow undisturbed from their source to theconfluence with a larger river or to the sea3.4 Fish sanctuaries for threatened and near threatened fishspecies indigenous to South Africa3.5 High water yield areas, which are sub-quaternarycatchments where mean annual runoff is at least threetimes more than the average for the related primarycatchment3.6 High groundwater recharge areas, which are subquaternarycatchments where groundwater recharge is atleast three times more than the average for the relatedprimary catchmentCaroline GelderblomFreshwater biodiversity is not evenlydistributed across the country; some WaterManagement Areas have a higher densityof FEPAs than others, and thus moreresponsibility for meetingnational freshwater ecosystem goals.Figure 3.1 shows the proportion of each Water Management Area identified as a FEPA,calculated as the percentage of the total area of that Water Management Area that hasbeen identified as a FEPA or associated sub-quaternary catchment. This map shows thatsome Water Management Areas (those that are darker in colour) have more FEPAs to lookafter than others. However, lighter coloured Water Management Areas still have FEPAs toprioritise, just not as many. An important policy question is how we can support WaterManagement Areas with a high proportion of FEPAs in achieving our national freshwaterecosystem goals.The proportion of each Water Management Area made up of FEPAs varies from 10% in theBerg Water Management Area to 38% in the Thukela. This variability is a consequence ofriver and wetland ecosystem heterogeneity and fish species distribution. For example, theInkomati and Usutu to Mhlathuze Water Management Areas have high river ecosystemheterogeneity, and therefore a high proportion of FEPAs (32 and 33% respectively).The proportion of FEPAs in each Water Management Area is also influenced by rivercondition, because only rivers that are still in good condition (A or B ecological category)can be chosen as FEPAs. For example, the Crocodile (West) and Marico and Olifants WaterManagement Areas have high river ecosystem heterogeneity, but there are no longersufficient rivers in a good condition to meet biodiversity targets for river ecosystems,reducing the number of FEPAs identified. The small proportion of FEPAs identified in theseWater Management Areas are generally the only ones left in a good condition. This meansthat FEPAs in low density Water Management Areas are no less important than those in highdensity areas. In fact, in cases where low density of FEPAs results from poor condition ofrivers and wetlands, the FEPAs that have been identified are arguably more important.National map products - 34 -