IUCN Management Category IV (Managed Nature Reserve)

Biogeographical Province 3.11.06 (Cape Sclerophyll)

Geographical Location 60km from Bredasdorp in Cape Province. 34°21'-31'S, 20°19'-38'E.

Date and History of Establishment 1956

Area 17,846ha

Land Tenure Government. Administered by the Department of Nature and Environmental Conservation, Cape Provincial Administration.

Altitude Minimum 611m

Physical Features The reserve is characterised by a varied geology and physiography and includes the highest part (611m) of the low, isolated Potberg mountain range which consists of siliceous quartzites of Palaeozoic age (Ordovician - Silurian); a range of low calcareous sandstone (cf limestone) hills up to 200m high of Mio-Pliocene age and marine/aeolian origin and a coastal plain of low, undulating limestone pavements and ridges interpersed with sandy flats. A broad zone of low vegetated dunes is present along the coast, but a 1,000ha area consists of shifting dunes. Notable features are a 12km long coastline with a zone of shifting sand dunes and low limestone cliffs. Along the coast area, there are a number of deep caves in the limestone, one of which seasonally contains a breeding colony of more than 100,000 bats. All streams are temporary and flow only after heavy rains. Drainage over much of the plain and limestone hills is subterranean and numerous depressions with internal drainage are present. A large shallow lake, De Hoopvlei of 1,000ha when full, lies partly within the reserve and is fed by a river which originates outside the reserve as well as springs along the edge of the lake. Soils are predominately sandy and of aeolian origin (sand dunes along the coast) or derived from in situ weathering of sandstones and quartzites and sandy limestones. They are generally nutrient-poor and acid over sandstones and quartzites and base-rich (calcareous) over limestones. Annual average temperature range: minimum 13°C, maximum 19°C., annual rainfall: 400mm, falling mainly in winter (March to August).

Climate No information

Vegetation Vegetation types consist of Coastal Rhenosterbosveld (Veld Type 46), Coastal Macchia (Veld Type 47), and Macchia (Veld Type 69). Economically important species: thatching reed (Thamnochortus spp.) and numerous species of flowering plants especially Proteaceae which are utilised commercially on surrounding farmland as cut flowers, but no harvesting of flora is allowed in the reserve. Endemic species: a number of plant species are endemic or near-endemic, for example Brachysiphon mundii, Erica uysii, Aspalathus potbergensis, Protea aurea ssp. Potbergensis, Osteospermum elsieae, and some as yet undescribed species. Numerous other species are regarded as threatened.

Fauna There is a good variety of large mammals including the eland Tragelaphus oryx (60), springbok Antidorcas marsupialis (125), grey rhebok Pelea capreolus, Cape grysbok Raphicerus melanotis, steenbok Raphicerus campestris, common duiker Sylvicapra grimmia, klipspringer Oreotragus oreotragus, and 39 smaller mammal species. There are also 210 bird, 20 reptile, two fish, and six amphibian species. De Hoopvlei supports a varied avifauna with particularly large populations of ducks, geese, coot (the latter number tens of thousands at times), flamingos (both lesser and greater), and piscivorous bird species, which includes three breeding pairs of the fish eagle Haliaeetus vocifer. Endangered species: Cape mountain zebra Equus zebra zebra (T) and bontebok Damaliscus dorcas dorcas (O), Cape vulture Gyps coprotheres (V) (50). The southernmost breeding-colony of the Cape vulture Gyps coprotheres (V), is situated in the Potberg mountain range. Caves in the limestone hills support five bat species; Rhinolophus clivosus, R. capensis, Myotis tricolor, Miniopterus schreibersi, and Mycteris thebaica.

Cultural Heritage No information

Local Human Population No information

Visitors and Visitor Facilities The reserve is at present open to the public for one day a week only, but an education centre is under construction. A hiking trail has been developed. Numbers: 10,000 per annum (mainly day visitors). Potential: maximum almost reached.

Scientific Research and Facilities Departmental surveys and monitoring programmes are undertaken as well as ecological research by universities. A complete fauna list (vertebrates) is available, a floristic list is being compiled, and studies and classification of the vegetation have been completed or are in progress. Detailed studies of the biology of the bontebok Damaliscus dorcas dorcas, Cape zebra Equus zebra zebra, Cape vulture Gyps coprotheres and cave-dwelling bats have been undertaken. Detailed ecological studies of the fynbos ecosystems and De Hoopvlei are envisaged.

No special research facilities are available, although there is accommodation for visiting scientists.

Conservation Value No information

Conservation Management Total

A zoning scheme is being devised as part of the management plan revision.

The management plan is being updated following a recent (1980) major extention of the reserve.

Management Constraints Exotic woody plant invaders especially Acacia spp. from Australia present a major problem and threat to the reserve's ecosystems. Veld fires, which originate on adjacent farmland, are a further problem which is compounded by unsatisfactory boundary alignments. A small area of formerly ploughed fields is included in the reserve. The use of parts of the reserve for a missile testing range had been the subject of a Commission of Enquiry and will be subject to rigorous controls.

Staff One senior reserve manager, three reserve managers and 30 labourers

Budget R150,000 per annum (including salaries)

Local Addresses

The Officer-in-Charge, De Hoop Nature Reserve, Private Bag X16, Bredasdorp 7280.

References

Various unpublished internal reports

Date May 1982