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The Western Cape Biodiversity Spatial Plan (WCBSP) is a tool that comprises the Biodiversity Spatial Plan Map of biodiversity priority areas (this product), accompanied by contextual information and land use guidelines (the WCBSP Handbook) that make the most recent and best quality biodiversity information available for informing all aspects of sustainable development in the Western Cape; from land use and development planning, to environmental assessment and regulation, and natural resource protection and management more broadly.

The key informant in the spatial product is the Category field which speaks to broad categories defined in the Biodiversity Act and in the Guidelines regarding Bioregional Plans. These categories provide a link to the Handbook’s comprehensive set of recommendations about how to use the maps and land- and resource-use guidelines in a range planning processes. The broad categories are: Protected Areas (PAs), Marine Protected Areas (MPAs), Critical Biodiversity Areas (CBAs), Ecological Support Areas (ESAs), and Other Natural Areas (ONAs). Fields containing the definition and Desired Management Objective for each broad category are also included.

In the spatial datasets a further distinction is made between CBAs that are likely to be in a natural condition (CBA 1) and those that are potentially degraded or represent secondary vegetation (CBA 2). This distinction is based on best available land cover data, and therefore may not be an entirely accurate or current reflection of condition. Site visits are recommended to verify habitat condition. Similarly, a distinction is made between ESAs that are likely to be functional (i.e., in a natural, near-natural or moderately degraded condition; ESA 1), and Ecological Support Areas that are likely severely degraded or have no natural cover remaining and therefore require restoration where feasible (ESA 2).

Importantly, both CBAs and ESAs are further divided into sub-categories which recognise important inherent attributes of the site, allowing for greater specificity in applying land-use guidelines. The sub-categories should be used in conjunction with the WCBSP spatial plan and guidelines documents, and its proposed land use guidelines (see Chapter 4). Category 1 indicates whether the ESA sites require (where feasible) restoration from some other form of land use or land cover.

Finally, a "reasons" layer is also provided, based on planning units used in the spatial analysis. This layer provides both a summary and a detailed list of biodiversity and ecological infrastructure features found in each unit selected as CBA or ESA, and to which the unit makes a quantifiable contribution to the target.

These BSP maps should serve as the primary source of information on biodiversity and ecological infrastructure for all land- and resource-use decision-making and forward planning processes. A breakdown of use and application of Biodiversity Spatial Plan are provided in the Western Cape Biodiversity Act, No. 6 of 2021, 14 December 2021. The list is provided under chapter 5, section 37.

All data are supplied without distribution rights. You may not redistribute, copy or sell in any form (value added or not) these data to any other parties/bodies outside your organisation/department. All data sets are supplied with metadata files which, inter alias, include information on the custodian of the specific data set. Any reports and/or publications resulting from your project must acknowledge the Western Cape Nature Conservation Board (WCNCB), Scientific Services and, if different, the custodian of the data.

All data are supplied with no expressed or implied warranty as to their suitability for purpose, planimetric accuracy or completeness. The WCNCB cannot be held responsible for any errors, which may occur in provided data sets.

The Western Cape Biodiversity Spatial Plan Map was developed using a systematic biodiversity planning methodology, based on the approach outlined by Margules and Pressey (2000) and Ardron et al. (2010). The data were analysed using Marxan software (Game & Grantham 2008), which employs optimisation routines to achieve specified goals (targets) with reasonable optimality. Marxan was accessed via an open-source GIS platform, QGIS, in conjunction with the plugin (interface software) CLUZ (Smith 2016).

The production of the WCBSP Map entailed four main steps: mapping (sourcing or generating all spatial input data), setting biodiversity targets, analysing the data, and translating the results into final products for distribution.

The mapping phase started with the development of a planning unit layer which divided the entire study area (Western Cape Province) into appropriate units of analysis. GIS layers were then compiled to allow for the following to be determined for each planning unit: protection status (Protected Area layer); habitat condition (Land Cover and Ecosystem Remnant layers); contribution to biodiversity targets (see Feature layers below); and a selection ‘cost’ to influence spatial design, including efficiency and conflict avoidance (WCBSP 2017 CBA layer, Ecosystem-Based Adaptation layer, and Urban Edges). A major component of the mapping phase was the sourcing or creation of maps of biodiversity pattern features and ecological persistence features. Features included: ecosystems (terrestrial vegetation types, coastal habitats, indigenous forest types, river types, wetland types and estuaries); species (threatened plants, amphibians, fish, birds, butterflies, reptiles, odonates and mammals, as well as species for which a BMP-S exists or is in progress: Cape Mountain Zebra, Bontebok, Geometric Tortoise, Clanwilliam Sandfish, Barrydale Redfin, and African Penguin); and spatial surrogates for a variety of ecological processes, ecological infrastructure, and climate resilience attributes. Fine-scale remnants in land cover using the amended 2020 Western Cape LC was also generated.

The setting biodiversity targets phase entailed aligning provincial targets to national biodiversity thresholds for pattern and process, based on best available science, and adjusting targets where necessary to address deficits in biodiversity ‘stocks’ or features.

The analysis phase included: the creation and formatting of input files (e.g. a matrix of contributions per planning unit, summary of targets used, and targets already met by current protected areas); the calibration of Marxan parameters (Boundary Length Modifier, Feature Penalty Factor, Planning Unit Cost, Number of Runs and Iterations); running Marxan (300 000 000 iterations x 100 runs) to generate Selection Frequency Score and Best Solution results; and screening results with specific attention given to urban edges, special habitats, and corridors.

In the final phase of the spatial assessment, Marxan outputs were translated into maps of Critical Biodiversity Areas, Ecological Support Areas, and Other Natural Areas by: (1) replacing planning units with land cover-based remnant data; (2) applying a rule set to combine Marxan’s ‘high selection frequency’ (>85%) and ‘best-design’ solutions with other features that must be categorically included (e.g., all CR and EN vegetation remnants, climate adaptation corridor ecological pinch points); and (3) augmenting the resulting shapefiles with relevant attributes (subcategories and features) that link to specific land use guidelines and to explanatory reasons for selection.

SANS 1878

FGDC-STD-001-1998