MAP (click on province
for worst species in each)
Invading alien plants (IAPs) are the single biggest threat to plant and animal
biodiversity. IAPs have become established in over 10 million hectares of land
in South Africa. The cost of controlling IAPs in South Africa is estimated at
R600 million a year over 20 years. If IAPs are left uncontrolled, the problem
will double within 15 years. IAPs waste 7% of our water resources; reduce our
ability to farm; intensify flooding and fires; cause erosion, destruction of
rivers, siltation of dams and estuaries, and poor water quality and can cause a
mass extinction of indigenous plants and animals.
750 tree species and 8 000 herbaceous species introduced into South Africa
1 000 introduced species are naturalised, 200 are invasive
84 species introduced from South and Central America
14 from North America
30 from Australia
29 from Europe
36 from Asia
45% of species from Australia have become important pests
WORKING FOR WATER-FUNDED RESEARCH
WfW Research Strategy [PDF
- Prinsloo, F.W.
and Scott, D.F. (1999). Streamflow responses to the clearing of alien invasive
trees from riparian zones at three sites in the Western Cape Province.
Southern African Forestry Journal 185: 1-7
- Le Maitre, D.C., Versfeld, D.B.
and Chapman, R.A. (2000). The impact of invading alien plants on surface water
resources in South Africa: A preliminary assessment, Water SA
- Larsen, E.J.,
Marais, C.M. and Görgens, AHM (2001). Water resources planning with recognition
of alien vegetation eradication. In proceedings of 10th South African National
Hydrological Symposium: 26 - 28 September, 2001. 11 pp.
- Fourie, F., Mbatha, K., and Verster,
H. (2002). The Effect of Vegetation (Prosopis spp.) on Groundwater levels in
Rugseer River, Kenhardt, South Africa, Unpublished Department of Water Affairs &
Forestry report, 8 pp.
- Brown, C. A.,
Boucher, C., Pienaar, E. and Pemberton, C. (2004). Effects of alien invasives on
the Breede River, Southern Waters, UWC & University of Stellenbosch, 69 pp.
- Everson, C.,
Moodley, M., Gush, M., Jarmain, C, Govender, M & Dye, P. (2005). Can effective
management of riparian zone vegetation significantly reduce the cost of
catchment management and enable greater productivity of land resources. WRC
Report No. K5/1284. 49 pp.
- Dye, P, and
Jarmain, C. (2004). Water use by black wattle (Acacia mearnsii):
implications for the link between removal of invading trees and catchment
streamflow response. South African Journal of Science 100:
- Marais, C and Wannenburgh,
A.M. (2008). Restoration of water resources (natural capital) through the
clearing of invasive alien plants from riparian areas in South Africa - Costs
and water benefits. South African Journal of Botany 74:
- Euston-Brown, D.
(2000). The influence of vegetation type and fire severity on catchment
stability after fire: a case study from the Cape Peninsula, South Africa. 35 pp.
- Fourie, S.,
Fabricius, C. and Shackleton, C. (2002). An ecology research strategy for
Working for Water. Rhodes University, 42 pp.
- Gibson, D. & Low,
B. (2003). National invading alien plant survey inception report. SRK
Consulting, Report No. 304201, 28 pp.
- Jayiya, T.P.,
Moses, A.G., Forsyth, G.G., and van Wilgen, B.W. (2004). The effects of invasion
by alien shrubs and trees on the fuel properties of ecosystems in the Western
Cape, South Africa, 27 pp.
- Milton, S.J. (2004).
Grasses as invasive alien plants in South Africa, South African Journal of
Science 100: 69-75.
- Samways, M.J. &
Taylor, S. (2004). Impacts of invasive alien plants on red-listed South African
dragonflies (Odonata), South African Journal of Science 100:
- Musil, C.F.,
Milton, S.J., and Davis, G.W. (2005). The threat of alien invasive grasses to
lowland Cape floral diversity: an empirical appraisal of the effectiveness of
practical control strategies. South African Journal of Science
- Mgidi, T. N., le
Maitre, D.C., Nel, J., Rouget, M., Richardson, D.M., Midgley, C., Mdzeke, N.,
van Wilgen, B.W., Schonegevel, L., Henderson, L., Neser, S., and Egoh, B.
(2005). An assessment of invasion potential of invasive alien plant species in
South Africa. CSIR Report No. ENV-S-I-2004-108, 107 pp.
Euston-Brown, D., Rathogwa, N & Richardson, D.M. (2007). Development of a
clearing protocol based on ecological criteria for mesic savannas and sweet
grassveld for the Working for Water programme. 86 pp.
- Holmes, P. (2007).
Targets for ecosystem repair in riparian ecosystems in fynbos, grassland and
savanna biomes. Cape Ecological Services, 42 pp.
- Henderson, L. (2007). Invasive,
naturalized and casual alien plants in southern Africa: a summary based on the
Southern African Plant Invaders Atlas (SAPIA). Bothalia 37,2:
N.Z., Hon, A., Israel, S., le Maitre, D., Rusinga, F., Soltau, L., Tredoux, G.,
Fey, M.V., Rozanov, A., and van der Merwe, N. (2008). Nitrate leaching from
soils cleared of alien vegetation. CSIR Natural Resources & Environment and
University of Stellenbosch. WRC Report No. K51/1696
- Marais, C.,
Turpie, J, Mullins, D., Conradie, B., Khan, A., Goldin, J., van Zyl, H.,
Grobbelaar, E., Vink, N., Ndzinge, V. (2001). A cost-benefit analysis framework
for the national Working for Water Programme. 59 pp.
- De Witt, M.P.,
Crookes, D.J. and van Wilgen, B.W. (2001). Conflicts of interest in
environmental management: estimating the costs and benefits of a tree invasion.
Biological Invasions 3: 167-178
- van Wilgen, B.
W., Richardson, D.M., le Maitre, D.C., Marais, C., and Magadlela, D. (2001). The
economic consequences of alien plant invasions: examples of impacts and
approaches to sustainable management in South Africa. Environment,
Development, and Sustainability 3 :145-168.
- van Wilgen, B.
W., de Wit, M.P., Anderson, H.J., le Maitre, D.C., Kotze, I.M., Ndala, S.,
Brown, B., and Rapholo, M.B. (2004). Costs and benefits of biological control of
invasive alien plants: case studies from South Africa. South African Journal
of Science 100: 113-122.
- Sowman, M. (2002).
January 2000 fires (on the Cape Peninsula): An assessment of perceptions.
Environmental Evaluation Unit, University of Cape Town, 30 pp.
- Du Plessis, L.L.
(2003). An assessment of selected non-water benefits of the Working for Water
Programme in the Eastern and southern Cape. MA thesis. Faculty of Arts,
University of Port Elizabeth, 156pp.
- Hosking, S.
G., and du Preez, M. (2004). A cost-benefit analysis of the Working for Water
Programme on selected sites in South Africa. Water SA
- Allsopp, M.,
and Cherry, M. (2004). An assessment of the impact on the Bee and Agricultural
industries in the Western Cape of the clearing of certain Eucalyptus species
using questionnaire survey data. Plant Protection Research Institute,
Agricultural Research Institute and AgriAfrica Consultants, 58pp.
- KPMG (2001). An investigation into the potential for the development of
secondary industries through the utilisation of biomass made available through
projects aimed at the control of invasive alien plants, KPMG, Stellenbosch
University & ENF: 106 pp.
- Breen, C., Erskine,
J., Jelinek, E., Mbowa, S., Quinn, N. and Salomon, M. (1997). Evaluation of the
Working for Water Programme for the Commission of the European Communities,
Brussels & Government of South Africa, Department of Water Affairs & Forestry.
Ingenieurbüro für Landentwicklung, Florstadt, Germany in association with
Institute of Natural Resources, University of Natal, Pietermaritzburg.
- Common Ground
(2003). External evaluation of the Working for Water programme. Synthesis
Report, Common Ground Consulting, 95 pp.
- Levendal, M.R.,
le Maitre, D.C., van Wilgen, B.W. and Ntshotso, P. (2008). The development of
protocols for the monitoring and evaluation of benefits arising from the Working
for Water Programme. CSIR Natural Resources and the Environment, Report No.
CSIR/NRE/ECO/ER/2008/0066/C, 103 pp.
- van Wilgen, B.W., Forsyth,
G.G., and le Maitre, D.C. (2008). The prioritisation of species and primary
catchments for the purposes of guiding invasive alien plant control operations
in the terrestrial biomes of South Africa. CSIR Natural Resources and the
Environment Report No. CSIR/NRE/ECO/ER/2008/0070/C, 51 pp.
- Forsyth, G.G., le Maitre, D.C., and van Wilgen, B.W. (2009). Prioritising quaternary catchments for invasive alien plant control within the Fynbos and Karoo biomes of the Western Cape province, CSIR Natural Resources and the Environment Report No. CSIR/NRE/ECO/ER/2009/0094/B
INVASIVE ALIEN PLANT DISSERTATIONS:
- Fatoki, O. B. (2007). Monitoring the re-growth rate of alien vegetation after
fire on Agulhas Plain, South Africa. Department of Geography, University of
Stellenbosch. MSc thesis: 68 pp.
- Jasson, R. (2005). Management of Acacia species seed banks in the Table Mountain
National Park, Cape Peninsula, South Africa. Department of Conservation Ecology,
University of Stellenbosch. MSc thesis: 72 pp.
- Vosse, S. (2007). The restoration potential of fynbos riparian seed banks after
alien clearing. Department of Conservation Ecology & Entomology, University of
Stellenbosch. MSc thesis: 201 pp.
- Law, M. C. (2007). Willingness to pay for the control of water hyacinth in an
urban environment of South Africa. Faculty of Commerce. Grahamstown, Rhodes
University. MComm thesis: 135 pp.
- Marais, C. (1998). An economic evaluation of invasive alien plant control
programmes in the mountain catchment areas of the Western Cape province, South
Africa. Faculty of Forestry, University of Stellenbosch. PhD thesis: 189 pp.
- Te Roller, K.S. (2004). Evaluating success of an integrated control programme of
Hakea sericea Shrader (Proteaceae) in the Western and Eastern Cape
Provinces, South Africa through cartographic analysis. MSc thesis. University of
Stellenbosch. 64 pp.
- Ralston, S. (2004). The role of legislation in the management of invasive alien
plants: human dimensions affecting the implementation of legal instruments on
the Cape Peninsula, South Africa. MSc thesis. Percy Fitzpatrick Institute,
University of Cape Town, 50pp.
- Magoba, R.N.N. (2005). Effect of invasion and clearing of alien riparian
vegetation on benthic macroinvertebrate and adult Odonata assemblages in
Soutpansberg rivers. MSc thesis, University of Stellenbosch, 127 pp.
- Cochran, A.N. (2005). Colour infra-red imagery as a medium for mapping alien
vegetation. MSc thesis, Department of Geography & Environmental Management,
University of Johannesburg. 52 pp.
- Cobbing, B. L. (2006). The use of Landsat ETM imagery as a suitable data capture
source for alien Acacia species for the Working for Water programme. MSc thesis,
Department of Geography, Rhodes University, 146 p.
- Wannenburgh, A.M. (2006). a systematic spatial prioritization for invasive alien
plant control in South Africa. MSc thesis. Department of Environmental &
Geographical Science, University of Cape Town, 107pp.
- Guthrie, G. (2007). Impacts of the invasive reed Arundo donax on
biodiversity at the community-ecosystem level. MSc thesis. Biodiversity &
Conservation Biology Department, University of the Western Cape, 156pp.
- Krug, R. M. (2008). Modelling Seed Dispersal in Restoration and Invasions. Ph.D.
thesis, Stellenbosch University.