Giba Gorge Precinct Plan – Environmental value of the proposed area

The following account describes the environmental value of the proposed precinct area. This motivation has been divided into two parts, ‘biodiversity’ and ‘environmental goods and services’, relating both to the intrinsic and utilitarian values of the environmental assets in this area, respectively.

A.) Biodiversity

Vegetation types The proposed precinct area incorporates a significant portion of two important vegetation types that are characteristic of this general area, KwaZulu-Natal Sandstone Sourveld and Scarp Forest. An estimate of the original extent of these vegetation types in South is illustrated in Figure 1 and the descriptions of each are given below:

1. KwaZulu-Natal Sandstone Sourveld Grassland – This vegetation type is endemic (restricted to) to coastal KZN and has been classified as ‘Endangered’ by the South African National Biodiversity Institute (SANBI) 1. It has been estimated that, in , 68% of this habitat has been transformed and only 0.2% of this vegetation type’s extent is statutorily protected. The proposed precinct area incorporates a substantial portion of this habitat in the eThekwini Municipal Area (EMA) and is therefore of significant importance to the EMD.

2. Scarp Forest – These ancient forests are home to many endemic and threatened species. Only a small portion (20%) of this habitat is currently statutorily protected in South Africa with those unprotected portions under increasing threat, mostly due to over-exploitation. There are four noticeable concentrations of this habitat in the EMA: around Nanda mountain; Krantzkloof NR (the only statutorily protected scarp forest in the EMA); a small patch downstream of Nungwane Falls; and a discontinuous stretch situated in and around Giba Gorge. The latter site has been under considerable threat of late mostly due to commercial harvesting of ‘muthi’ products. Large portions of this site are incorporated in the proposed precinct area and are therefore of significant importance to the EMD.

Figure 1 . Distribution of KZN Sandstone Sourveld and Scarp Forest SANBI vegetation types in South Africa 1, showing relative location of the EMA. Note : especially in terms of KZN Sandstone Sourveld, these distributions comprise an estimate of their original modeled distribution most of which is now transformed.

Species data

The proposed precinct area forms part of a biogeographic subtraction and transition zone 2 that is characterized by a relatively high incidence of localized (endemic) and rare species. Many of these species have evolved under specific requirements (e.g. specific habitat types) that are continually being limited due to the accelerated development of incompatible land use types. As a result, many of these species have become red listed and categorized into different levels of threat dependent on the severity of their particular situation. The following is a table of red listed species, together with their general habitat requirements, that have been recorded in the proposed precinct area:

Common Name Scientific Name Habitat (in precinct area) Plants iMfingo Stangeria eriopus Forest/grassland Wild Maple Seemannnaralia Forest/cliff edge gerrardii - Helichrysum woodii Cliff edge - Senecio medley-woodii Grassland/cliff edge - Senecio ryhncholaenus Grassland/rocky outcrops Wild Begonia Begonia dregei Forest/rocky areas - Maytenus cordata Forest/streams - Crassula inandensis Forest Mountain Peach Aphloia theiformes Forest Beautiful Brachystelma Grassland/cliff edge Brachystelma pulchellum - Streptocarpus prolixus Forest/cliffs Pondo Bride’s Pavetta bowkeri Forest Bush - Aloe linearifolia Grassland/rocky outcrops Forest Crinum Crinum moorei Forest - Merwillea plumbea Grassland - Stenoglotis sp. nov. Forest/cliff edges Common Tree Cyathea dregii Grassland/riparian Fern - Brachystelma gerrardii Grassland - Plectranthus Forest/cliff edge purpuratus ssp. purpuratus - Streptocarpus Forest molweniensis ssp. molweniensis - Cynorkis compacta Cliff edge Mammals Blue Duiker Philantomba monticola Forest Large-eared Otomops martiensseni General & house roofs Free-tailed Bat Hottentot Golden Amblysomus hottentotus Forest & grassland Mole Reddish-grey Crocidura cyanea Forest & grassland Musk Shrew Greater Musk Crocidura flavescens Grassland & forest ecotone Shrew Woodland Grammomys Forest & ecotone Mouse dolichurus Single-striped Lemniscomys rosalia Forest & grassland ecotone Mouse Dark-footed Myosorex cafer Forest Forest Shrew Forest Shrew Myosorex varius Rocky grassland African Striped Poecilogale albinucha Forest & grassland Weasel Least Dwarf Suncus infinitesmus Grassland, usually termitaria Shrew Lesser Dwarf Suncus varilla Grassland, usually termitaria Shrew Anchieta’s Hypsugo anchietai Forest & savanna Pipistrelle Natal Long- Miniopterus natalensis Caves & grassland, forest fingered Bat

Spotted Ground Zoothera guttata Forest Thrush African Crowned Stephanoaetus coronatus Forest Eagle Lanner Falcon Falco biarmicus Cliffs above forest Bush Blackcap Lioptilus nigricapillus Forest African Broadbill capensis Forest & ecotone Amphibians Kloof Frog Natalobatrachus Forest streams bonebergi Spotted Shovel- Hemisus guttatus Grassland nosed Frog Striped Caco Cacosternum striatum Grassland Natal Leaf-folding Afrixalus spinifrons Grassy wetlands Frog Invertebrates Yellowish Durbania amakosa Rocky grassland Amakosa flavida Rocksitter Pink-footed Giant Doratogonus rubipodus Forest & ecotone Black

It is important to note that of the ‘Key’ red listed species (refers to species of higher priority as listed in 3) that have been recorded in the EMA, three of the 14 mammal species (21%), four of the five amphibian species (80%), and 2 of the 8 invertebrate species (25%) have been recorded in the proposed precinct area, an area that occupies only 0.4% of the EMA.

B.) Environmental goods and services

The Umbilo and Umhlatuzana catchments comprise two of only four catchments that have their entire catchment areas within the EMA boundary; the other two are the oHlange in the north and the Ngane in the south. The eThekwini Municipality plays a significant role in regulating the various land uses in these areas and therefore has a direct bearing on the future of these catchments. The Umbilo and Umhlatuzana catchments have the highest proportion of hard surfaces of all the catchments in the EMA 3, these typically concentrated in their lower reaches (Figure 2). As one moves up the catchments there is more open space relative to built up areas, especially in the vicinity of the proposed precinct area (Figure 2). This situation will not last long into the future unless measures are established to regulate land uses in this area.

There are a large number of people residing in the vicinity and ‘downstream’ from the precinct area that derive a range of environmental goods and services from these catchments. Of these environmental goods and services those that are directly associated with maintaining the natural state of the upper catchments include:

• Disturbance regulation – in this instance this specifically refers to the amelioration of the effects of flooding through the maintenance of ‘soft’ surfaces. • Water regulation –natural surfaces (as opposed to hardened surfaces) act as regulators of water flow to users downstream. • Soil erosion prevention – through the maintenance of natural surfaces. • Waste treatment and water purification – purification of pollutants (including toxins) through natural filtration processes. Note : there are a large number of poor residents who utilize water directly from the Umhlatuzana River just downstream from the precinct area.

Figure 2. Position of the proposed precinct area (red polygon) relative to the Umbilo and Umhlatuzana catchments. The land use coverage assessment (2003) has been simplified to show only built-up and open areas. Note : the proportion of built-up areas to open areas has changed (potentially considerably) since this assessment.

There are other environmental goods and services, apart from those directly associated with the two catchments, in the precinct area. These include, but are not limited to:

• Climate regulation – the prevention of high temperatures associated with urban heat islands. • Gas regulation – regulation of the chemical composition of the atmosphere. • Soil formation processes. • Nutrient cycling – e.g. nitrogen cycling through food chains. • Pollination – facilitation of plant reproduction (for e.g. agriculture). • Biological control – regulation of and plant pests • Food production – e.g. farming on fertile floodplains that derive their fertility from processes upstream. • Natural products – e.g. production of grasses for thatching. • Genetic resources – genes for medicines, ornamental plant species etc. • Recreational – there are currently a number of recreational activities in the precinct area that are directly associated with the aesthetically pleasing nature of the surrounds, e.g. hiking, watching, mountain biking, horse riding etc. • Cultural – the landscape character of the precinct area provides a unique sense of place to both the residents and visitors to the area. The precinct also provides opportunities for environmental education activities which were a prominent activity in the past and which still have the potential to continue. • Research – the unique locality of this area in terms of its biodiversity value (discussed above) provides good opportunities for biological research into various aspects. The EMA has a number of tertiary education institutions with biology-related faculties that could utilize this area for research projects.

Summary The area in question is rated as one of the highest priority environmental sites in the eThekwini Municipal Area; there are few areas of this nature left in the EMA. The rate of transformation of the relevant habitats during the past 50 years, and in particular during the last ten years is of noticeable concern (see accompanying comparative maps of similar habitat transformation around Krantskloof Nature Reserve, Maps 1 & 2). It is this alarming rate of change that has necessitated zoning amendments to safeguard this important asset for future generations.

Map 1. Aerial view over Krantzkloof Nature Reserve and surround, 1954.

Map 2. Aerial (bird’s eye) view over Krantzkloof Nature Reserve and surrounds, 2007.

References 1.Mucina, L. & Rutherford, M.C. (eds.) 2006. The vegetation of South Africa, and Swaziland. SANBI, Pretoria.

2. Poynton, J.C. 1961. Biogeography of south-east Africa. Nature 189: 801-803.

3. EThekwini Municipality Environmental Management Department. 2007. EThekwini Municipality Biodiversity Report 2007. Local Action for Biodiversity.

4. EThekwini Municipality Environmental Management Department. 2001. EThekwini Municipality

Environmental Services Management Plan.

Acknowledgements

David Styles – botanist Peter Taylor – mammologist David Allan – ornithologist Johan Marais - herpetologist