Slanghoek Cellar and Biodiversity

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Slanghoek Cellar and Biodiversity

Joan Isham

Joan Isham, BWI

Slanghoek cellar is only the third co-operative cellar in South Africa to become a proud member of the Biodiversity and Wine Initiative (BWI)! They have achieved this by conserving 670ha of valuable natural habitats on their members' farms, as well as by implementing the BWI's biodiversity guidelines for the management of natural areas on the farms.
Slanghoek Cellar lies in a picturesque valley, surrounded by the majestic Slanghoek Mountains, from which the cellar derives its name. This cellar is one of the 23 cellars in the Breedekloof Wine route which encompasses the Goudini, Slanghoek, Breede River and Rawsonville areas. Because, the Slanghoek valley is a prime grape producing area, and the low lying natural areas are thus already heavily transformed. The remaining natural areas (especially the seasonally damp Lowland Fynbos) are under enormous pressure to be developed. The valley has a number of regionally threatened and locally endemic plant species. In 2003, in order to avoid ad hoc decision making, the landowners of the Slanghoek area (under the co-ordination of the regional tourism and marketing organisation known as Breedekloof), in consultation with the Dept. of Agriculture, CapeNature, and a botanical specialist drew up a regional conservation plan, called the LandCare AreaWide Plan (LAWP) for the Slanghoek valley.

Wetlands
Wetlands act as giant spunges by retaining water during floods and releasing it during drier periods, thereby supplementing the water table. Consequently they play an important role to limit soil erosion and lessen the impact of floods. Wetlands assist in purifying water by acting like natural filters in that they catch pollutants, including sediment, heavy metals and disease carrying organisms. Wetlands also provide a special habitat to many plant and animal species that are dependent thereon for their entire life cycle, or part thereof (such as important pollinators), and may form a natural fire break.

Five of the six properties identified by this report as 'areas with the most critical natural habitat', belong to producers of Slanghoek.
As a proud member of the BWI, the Slanghoek cellar's management and all its producers are now committed to ongoing conservation of these very special areas. They have all signed a letter of commitment, agreeing not to develop these areas of high conservation value. The natural vegetation type of this area has been described as Breede Alluvium Fynbos This vegetation type is restricted to lowland areas in the Worcester area, primarily in the Hex river and upper Breede river valleys. Because of its suitability for agriculture, over 70% of this vegetation type has been lost, and today less than 1 % is set aside for conservation. This vegetation type is now regarded as 'endangered', which means that special care needs to be taken when planning any new developments that will impact on this vegetation type. Almost 99% of the remaining areas of Breede Alluvium Fynbos are privately owned and landowners (e.g. Slanghoek producers) are thus key roleplayers to keep this unique habitat from extinction.
Soils in the Slanghoek valley are usually acid sands derived from the nearby Table Mountain Group sandstones, and often contain a high percentage of river worn boulders (alluvial boulder terraces). Because many areas are actually parts of alluvial fans there is a substantial underground seepage, which often rises to the surface in the wet winter season, frequently in the form of braided streams. The catchment area in the Slanghoek mountains to the west is an extremely high rainfall area, receiving at least 1500mm/yr , and this accounts for the high groundwater levels in much of the valley. At least 300 different species of Fynbos plants occur in this vegetation type, about twenty species of which are restricted to this area.

Photo 1: Slanghoek mountains with Breede Alluvium Fynbos on the farm Eikeboom (Joan Isham).

Photo 2: Erica hansfordii - threatened species that occurs on one property only in the Slanghoek valley (Nick Helme).

The five farmers who have made great efforts to conserve areas of this highly threatened veld type are as follows:
On the farm Witelsrivier, belonging to Mr. C.C. Le Roux, a beautiful erica called Erica hansfordii can still be found, which is completely endemic to this single property (i.e. found no where else on the planet!) is classified in the Red Data Book (RDB) list of plants as Endangered. This conservation area has been identified by botanist, Nick Helme as the site with the highest conservation value in the valley. The seasonally wet areas are especially important habitat to conserve (see more on the management of these areas further down). Additional species on this property include Drosera regia (giant sundew; RDB - Rare; found only here and in Bainskloof), Diastella parilis (Slanghoek silkypuff; RDB - Critically Endangered), Protea scorzonerifolia (RDB - Vulnerable), Spatalla propinqua (RDB - Endangered; only known lowland population), and Lachnaea capitata (RDB - Vulnerable),
On the farm Rustfontein, belonging to Mr. P.P. Du Toit, some Breede Alluvium Fynbos areas aswell as Mountain Fynbos, is conserved. The key elements here are large populations of Diastella parilis and Leucadendron chameleae (RDB - Critically Endangered).
On the farm Luiperdsfontein of Mr. Du Toit Stofberg, another area of Breede Alluvium Fynbos is conserved. This area includes a seasonal wetland on acid sands, with well drained manganese gravels nearby. The key species in the wetlands is the tiny cryptic fern called Isoetes stellenbosiensis, along with Lachnaea capitata (RDB - Vulnerable). Restio stereocaulis is quite common in the wetland and is the first lowland record of this species.
On Philip Du Toit's section of Witelsrivier, some 130ha is conserved. The biodiversity features on this farm comprises two areas - a seasonally wet area below the road to Witelsrivier, and a well drained area with manganese rich soils just west of the Slanghoek river. The Critically Endangered Geissorhiza geminata (river iris) was recorded in a small stream in this area. Other key elements are Diastella parilis and Leucadendron chamelaea. The well drained area supports large populations of the vygie Ruschia diversifolia (RDB - Vulnerable), and Protea scorzonerifolia (RDB - Vulnerable).

Photo 3: Diastella parilis (Slanghoek Silkypuff) - a critically endangered species that occurs only in this type of vegetation (Nick Helme).

Photo 4: Breede Alluvium Fynbos in the Slanghoek valley (Nick Helme).

Photo 5: Seasonal 'wetlands' areas on the farm Witelsrivier (Joan Isham).

On Eikeboom, belonging to Mr. I.F. van der Merwe Du Toit, as in the rest of the valley, the seasonal, braided streams are of high conservation value. This area supports the critically endangered bulb Geissorhiza geminate.This species is now known only from two streams in this valley, and one in the Koue Bokkeveld. This area is a good example of the original alluvial terrace habitat that has been largely destroyed in the valley.
Altogether these 5 producers conserve an area of 670 ha. The driving forces behind Slanghoek's conservation efforts is cellar manager and winemaker Pieter Carstens and his assistant Nico Grundling . They are committed to an ongoing conservation project for the cellar and one of their objectives is to involve all the other producers, who still have natural areas on their farms.
The ultimate dream is also to secure all these conservation areas under the CapeNature Stewardship Programme. Garth Mortimer, the newly appointed extension officer for this area has already started negotiations with the various landowners about entering into stewardship contracts with CapeNature. For more information on the Stewardship Programme and the advantages for landowners, when signing such an agreement with CapeNature , you can contact Garth at 089 490 8889.
For more information on the Biodiversity and Wine Initiative, you can contact either Joan Isham or Sue Winter or at Tell: 021 886 8428, e-mail: bwi.joan@sawb.co.za or bwi@sawb.co.za.
Also check our website for more information: www.bwi.co.za.
Management guidelines for wetlands

Wetlands should firstly be identified and delineated, so that they may be conserved. Winter is the best time to identify wetlands, seeing that it is not easy to notice some seasonal wetlands in the dry summer months.
Retain undeveloped buffer zones, free of aliens, around the wetlands. The width of the buffer zone depends on the size of the wetlands, as well as the impact of the adjacent land usage, but widths of 25 - 75 m are recommended.
The source and downstream areas of the wetlands should not be separated.
All activities in the catchment area have an effect on wetlands (e.g. hardening of the catchment area such as roads and paved areas, which will result in more run-off and possible eroding of wetlands).
Ensure that over-extraction of surface or soil water running into wetlands does not occur, as this may cause the wetlands to dry out. No strong boreholes should be sunk near natural wetlands.
By damming up wetlands, seasonal wetlands will change into permanent bodies of water, and the special habitat formed by the wetlands will be lost. Damming up requires consent from the Department of Waterworks and Forestry.
Be aware of any source of pollution, such as seepage from manure and compost heaps, domestic garbage dumps or areas where grape skins are stored, which may impact on the quality of the water.
Alien plants use large quantities of water from wetlands and must be removed at all costs. Note: Always use "manual instruments" such as machetes or chain saws (i.e. no machinery) to remove aliens from wetlands, because wetlands are very sensitive to disturbance of the soil.
It is illegal to interfere with the flow pattern of water by channelling a wetlands through the natural course of the water, or by digging drainage trenches or filling by dumping either soil or garbage. Functioning of wetlands may sometimes be re-established successfully if the flow pattern is restored to its original state by making trenches and canals.
Wetlands may be used for grazing on condition that pressure from grazing is not too heavy, that it occurs in the appropriate season (usually summer), and that livestock are kept well away from the deeper, wetter areas with their unstable soil. It is important to monitor wetlands for signs of degradation and erosion as a result of overgrazing.

For more information about wetlands management and rehabilitation, visit: www.wetland.org.za-pracmanage.htm.
For wetlands delineation: Use 'A practical field procedure for identification and delineation of wetlands and riparian areas' (Department of Waterworks and Forestry, 2003) - see www.dwaf.gov.za.
Correction
In the September issue of WineLand Tony Hansen was incorrectly quoted as saying that producers may now become BWI members even if they do not have any natural areas on the farm.
This is not the case, however. Although we regularly receive enquiries about this, we have decided on the following, after discussions with our current members:
Another category will not be created, but the current main criteria stating that a producer should have a minimum of 2 ha of natural habitat, will in future read: "A minimum of 2 ha of natural habitat or rehabilitated area".
This will therefore enable producers who spend money and time to rehabilitate areas on their farms (i.e. plant indigenous plants to create new natural areas) to become BWI members in future.
Summary
Slanghoek Cellar is only the third co-operative cellar to become a proud member of the Biodiversity and Wine Initiative (BWI). They have achieved this by conserving 670 ha of valuable natural habitats on their members' farms, as well as by implementing the BWI's biodiversity guidelines for the management of natural areas on the farms.
Slanghoek Cellar lies in a picturesque valley, surrounded by the majestic Slanghoek Mountains. The Slanghoek valley is a prime grape producing area, and the low lying natural areas are thus already heavily transformed. The remaining natural areas (especially the seasonally damp Lowland Fynbos) are under enormous pressure to be developed. In 2003, in order to avoid ad hoc decision making, the landowners of the Slanghoek area (under the co-ordination of the regional tourism and marketing organisation known as Breedekloof), in consultation with the Department of Agriculture, CapeNature, and a botanical specialist drew up a regional conservation plan, LandCare AreaWide Plan (LAWP) for the Slanghoek valley.
As a proud member of the BWI the Slanghoek Cellar's management and all its producers are now committed to ongoing conservation of these very special areas. They have all signed a letter of commitment, agreeing not to develop new vineyards on these areas of high conservation value. Most of the 670 ha they conserve consists of Breede Alluvium Fynbos (an endangered veld type). At least 300 different species of fynbos plants occur in this vegetation type, of which twenty (8%) are restricted to this specific area.
The five landowners who have made great efforts to conserve areas of this highly threatened veld type are as follows: Mr C C le Roux (Witelsrivier), Mr P P du Toit (Rustfontein), Mr Du Toit Stofberg (Luiperdshof), Philip du Toit's (section of Witelsrivier) and Mr I F van der Merwe Du Toit (Eikeboom).

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