Biological Invasions

, Volume 3, Issue 2, pp 167–178 | Cite as

Conflicts of Interest in Environmental Management: Estimating the Costs and Benefits of a Tree Invasion

  • M.P. de Wit
  • D.J. Crookes
  • B.W. van WilgenEmail author


Some alien tree species used in commercial forestry cause major problems as invaders of natural ecosystems. One such case, the black wattle tree, was introduced into South Africa from Australia in the 19th century. It is an important commercial species, as well as an aggressive invader, giving rise to significant environmental impacts and conflicts of interest. This paper provides an analysis of costs and benefits associated with this species in South Africa at a national level. The results suggest that a ‘do nothing’ scenario (with no attempts being made to control the spread of the species beyond the limits of plantations) is not sustainable, as the benefit–cost ratio is around 0.4. The most attractive control option will be to combine physical clearing and plant-attacking biological control with the continuation of the commercial growing activities. In case this is not practically feasible the next best option is a combination of seed-attacking biological control, physical control and the development of secondary industries based on wood products from clearing programmes. There is, however, a 40% loss of benefits involved with this option when compared with the first best option. The techniques used in this study, and the findings relating to the scenarios that deliver the best returns on investment, should be of broad relevance to the problem of dealing with conflicts of interest relating to invasive alien plants that have commercial value.

Acacia mearnsii cost-benefit analysis forestry invasive alien species South Africa water resources 


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  1. Brent RJ (1997) Applied Cost-Benefit Analysis, paperback edition, reprint. Edward Elgar, Cheltenham, UKGoogle Scholar
  2. Costanza R,d'Arge R,de Groot R,Farber S,Grasso M,Hannon B,Limburg K,Naeem S,O'Neill RV,Paruelo J,Raskin RG,Sutton P andvan den Belt M (1997) The value of the world's ecosystem services and natural capital. Nature 387: 253-260CrossRefGoogle Scholar
  3. De Wit MP,Crookes DJ andGeach BGS (2000) The Costs and Benefits of BlackWattle in South Africa. CSIR Report ENV-P-C 2000-023, PretoriaGoogle Scholar
  4. Dinwiddy C andTeal F (1996) Principles of Cost-Benefit Analysis for Developing Countries. Cambridge University Press, CambridgeGoogle Scholar
  5. Dunlop R (1998) Genetic improvement of Acacias. Annual Research Report of the Institute for Commercial Forest Research, ICFR, Pietermaritzburg, pp 38-44Google Scholar
  6. Ewel JJ,O'Dowd DJ,Bergelson J,Daehler CC,D'Antonio CM,Gomez LD,Gordon DR,Hobbs RJ,Holt A,Hopper KR,Hughes CE,LaHart M,Leakey RRB,Lee WG,Loope LL,Lorence DH,Louda SM,Lugo AE,McEvoy PB,Richardson DM andVitousek PM (1999) Deliberate introductions of species: Research needs. BioScience 49: 619-630Google Scholar
  7. Hansman C (1999) A Socio-Economic Assessment of the Working for Water Projects, DRA Development Report 99/1Google Scholar
  8. Hyman EL,Stiftel B,Moreau DH andNichols RC (1988) Combining Facts and Values in Environmental Assessment. Theories and Techniques. Social Impact Assessment Series, No. 16, Westview Press, Boulder, Colorado, LondonGoogle Scholar
  9. Kaiser J (1999) Stemming the tide of invasive species. Science 285: 1836-1841Google Scholar
  10. Le Maitre DC,Van Wilgen BW,Chapman RA andMcKelly DH (1996) Invasive plants and water resources in the Western Cape Province, South Africa: modelling the consequences of a lack of management. Journal of Applied Ecology 33: 161-172Google Scholar
  11. Le Maitre DC,Van Wilgen BW,Gelderblom CM,Bailey C,Chapman RA andNel JA (2001) Invasive alien trees and water resources in South Africa: case studies of the costs and benefits of management. Forest Ecology and Management (in press)Google Scholar
  12. Richardson DM (1997) Forestry trees as invasive aliens. Conservation Biology 12: 18-26Google Scholar
  13. Scott DF andvan Wyk DB (1990) The effects of wildfire on soil wettability and hydrological behaviour of an afforested catchment. Journal of Hydrology 121: 239-256Google Scholar
  14. South African Reserve Bank (SARB) (1999) Quarterly bulletin No. 214. SARB, PretoriaGoogle Scholar
  15. Statistics South Africa (SSA) (1999) Stats in Brief 2000. SSA, PretoriaGoogle Scholar
  16. Stubbings JA (1977) ACase Against Controlling Introduced Acacias (ACACIA). South African Forestry Journal 102: 8-14Google Scholar
  17. Van der Merwe MR andScholes RJ (eds) (1999) South African greenhouse gas emissions inventory for the year 1990. CSIR Report, ENV-P-C 99049, PretoriaGoogle Scholar
  18. van Wilgen BW (1981) An analysis of fires and associated weather factors in mountain fynbos areas of the South-Western Cape. South African Forestry Journal 119: 29-34Google Scholar
  19. van Wilgen BW andRichardson DM (1985) The effects of alien shrub invasions on vegetation structure and fire behaviour in South African fynbos shrublands: a simulation study. Journal of Applied Ecology 22: 955-966Google Scholar
  20. van Wilgen BW,Le Maitre DC andCowling RM (1998) Ecosystem services, efficiency, sustainability and equity: South Africa's Working forWater programme. Trends in Ecology and Evolution 13: 378Google Scholar
  21. van Wilgen BW,van der Heyden F,Zimmermann HG,Magadlela D andWillems T (2000) Big returns from small organisms: developing a strategy for the biological control of invasive alien plants in South Africa. South African Journal of Science 96: 148-152Google Scholar
  22. Versfeld DB andVan Wilgen BW (1986) Impacts of woody aliens on ecosystem properties. In: Macdonald IAW,Kruger FJ andFerrar AA (eds) The Ecology and Control of Biological Invasions in South Africa, pp 239-246. Oxford University Press, Cape TownGoogle Scholar
  23. Versfeld DB,Le Maitre DC andChapman RA (1998) Alien Invading Plants and Water Resources in South Africa. A Preliminary Assessment. Report to the Water Research Commission. CSIR No. ENV/S-C 97154. WRC Report No. TT 99/98 September.Google Scholar
  24. Winpenny JT (1991) Values for the Environment. A Guide to Economic Appraisal. HMSO, LondonGoogle Scholar
  25. World Bank (1994) GlobalWarming. Measuring the Costs. Dissemination Notes. World Bank, Washington, DCGoogle Scholar

Copyright information

© Kluwer Academic Publishers 2001

Authors and Affiliations

  1. 1.CSIR Division of Water, Environment and Forestry TechnologyPretoriaSouth Africa

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