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Together with the Terrestrial CBA Layer, this layer forms the basis of the NW Biodiversity Sector Plan

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A refined and updated CBA map for the planning domain was developed through integrating existing and new data. The following table lists all the input layers and where they were sourced from. The table below that highlights the important fields that resulted from this integration. The final table in this section gives us the CBA Map category. The use of CBAs here follows the definition laid out in the guideline for publishing bioregional plans (Anon, 2008):

• Critical Biodiversity Areas (CBAs) are terrestrial and aquatic areas of the landscape that need to be maintained in a natural or near-natural state in order to ensure the continued existence and functioning of species and ecosystems and the delivery of ecosystem services. In other words, if these areas are not maintained in a natural or near-natural state then biodiversity targets cannot be met. Maintaining an area in a natural state can include a variety of biodiversity compatible land uses and resource uses.

• Ecological Support Areas (ESAs) are terrestrial and aquatic areas that are not essential for meeting biodiversity representation targets (thresholds), but which nevertheless play an important role in supporting the ecological functioning of critical biodiversity areas and/or in delivering ecosystem services that support socio-economic development, such as water provision, flood mitigation or carbon sequestration. The degree or extent of restriction on land use and resource use in these areas may be lower than that recommended for CBAs. From a land use planning perspective it is useful to think of the difference between CBAs and ESAs in terms of where in the landscape the biodiversity impact of any land use activity

action is most significant:

• In CBAs where a change in land use results in a change from the desired ecological state, the impact on biodiversity as a result of this change is most significant locally at the point of impact through the direct loss of a biodiversity feature (e.g. loss of a populations or habitat).

• In ESAs, however, a change from the desired ecological state is most significant elsewhere in the landscape through the indirect loss of biodiversity due to a breakdown, interruption or loss of an ecological process pathway. For example, removing a corridor results in a population going extinct elsewhere in the landscape due to loss of connectivity, or a new plantation locally results in a reduction in stream flow at the exit to the catchment, which affects downstream biodiversity.

SANS 1878

FGDC-STD-001-1998