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A Transformation Layer of the Garden Route (GR) was prepared as part of the Overberg Fine Scale Biodiversity (FSB) Project, which will be used for Systematic Conservation Planning in the area. Land cover is one of the most important information layers used in a conservation assessment. As transformed areas are generally considered to have very little biodiversity value, a land cover map tells us how much biodiversity is left and where this is located.

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A Transformation/Landcover map for the Garden Route, covering the area south of the R62, from the western boundary of the George Municipality to the Seekoeirivier. The map is a key input layer into the conservation planning process for the Garden Route Initiative.

A detailed new landcover layer was developed for the project. This was based on heads up digitisation and interpretation of detailed aerial photograph interpretation undertaken at approximately 1:5000 scale of colour aerial photographs, obtained from DWAF (captured in 2001), and updated with SPOT5 satellite imagery (2005); and finally by transformation data captured during aerial surveys. A transformation dataset covering the eastern portion of the George municipality assembled by Nick Cole and Johan Baard was incorporated and modified. This data was supplemented by a detailed alien vegetation mapping exercise which was undertaken for the whole planning domain. The data went through an intensive verification exercise, which included cross referencing against known Indigenous forest areas from DWAF and a comparison of natural areas from the National Land Cover Theme (NLC, 2006). Randomised checking against other imagery (SPOT5 and Google Earth) was undertaken to detect any classification or editing errors.

Details of the Transformation/Land Type Categories Classified

Due to the difficulty in accurately classifying land types remotely, it is expected that there will be errors.

Natural

The Natural Category included essentially pristine natural areas, and areas in which the majority of natural functions and processes were perceived to still be operating. The natural category includes areas with scattered alien vegetation, but not in densities that were estimated to prevent natural ecosystem functioning. Natural Water bodies, for example, rivers, and lakes such as the Rondevlei-Groenvlei system, were classified as natural.

Degraded

The Degraded Category included the broadest range of land types in the transformation dataset. Land types that were included in this category included areas where alien vegetation had become quite dense, such as along river courses. The density and type of the alien trees was an important consideration in the demarcation of this category. From the IAP Mapping exercise, areas with a habitat cost of >=0.3 or alien densities of >=0.25 from the alien mapping exercise were reclassified as degraded, due to the negative effects of alien vegetation. However, individual trees, or even sparse clumps and farm woodlots were not highlighted, due to practical and logistical reasons. Substantial windbreaks on farms also fell into this category, though were these windbreaks were small, they were classified as part of the farm matrix. Due to the difficulty of identifying tree species from aerial photographs, especially were certain taxa may appear similar, it is anticipated that there will be some error in this category. Error prone areas include river courses, gorges, and areas of irregular terrain. Finally, natural vegetation, if sufficiently fragmented and isolated, to the extent that natural ecosystem functioning was perceived to be impaired, was also classified under degraded.

Heavy Alien Degradation

Areas exhibiting dense alien infestation, with a habitat cost >=0.6 and under 0.75 were included within this category. The cost depended on a combination of the alien species type and density.

Alien Transformed.

Areas where very heavy alien infestation have completely transformed and nearly completely replaced natural vegetation, with a habitat cost of >= 0.75.

Dams

The Dam Category in this classification system consisted of artificial water bodies, of fairly large size, though no formal measurements or calculations of size were conducted. Smaller dams occurring on farmland were not highlighted, and formed part of the farm complex.

Farm

The entire farming unit formed part of the Farm Category, including the actual land under agriculture, associated farm buildings whether residential or agricultural, and farm dams. Smaller windbreaks and hedges were also classified as farm, rather than degraded.

Plantation

Areas in which active forestry was being undertaken were classified here, including nonresidential forestry buildings, when there was no ambiguity with farm structures. Boundaries were set at the furthest extent of forestry activity, for example, on the outside of firebreaks.

Urban

The predominant landcover classified here included urban residential property. Also included were light industry, heavy industry (including mining), small holdings, golf courses, and isolated rural dwellings, if they had no discernable association to forestry, farming activities, or residential forestry villages.

Available documentation:

Holness, S. D., Bradshaw, P. L., & Brown, A. E. (2010). Critical Biodiversity Areas of the Garden Route: Conservation Planning Technical Report, Garden Route Initiative. SANParks, Port Elizabeth.

Vromans, D.C., Maree, K.S., Holness, S.D., Job, N. and Brown, A.E. (2010). The Garden Route Biodiversity Sector Plan for the George, Knysna and Bitou Municipalities. Supporting land-use planning and decision-making in Critical Biodiversity Areas and Ecological Support Areas for sustainable development. Garden Route Initiative. South African National Parks. Knysna.

Vromans, D.C., Maree, K.S., Holness, S. D., Job, N. and Brown, A.E. (2010). The Garden Route Biodiversity Sector Plan for the southern regions of the Kouga and Koukamma Municipalities. Supporting land-use planning and decision-making in Critical Biodiversity Areas and Ecological Support Areas for sustainable development. Garden Route Initiative. South African National Parks. Knysna.

Project Name:

Garden Route Initiative Fine-Scale Biodiversity Planning project, as part of Component 5.1 of Cape Action Plan for People and the Environment (C.A.P.E.).

Creator Organisation:

SANParks

SANS 1878

FGDC-STD-001-1998