A Review of Bush Encroachment in Namibia: From a Problem to an Opportunity?

محورهای موضوعی : Range Management

Rosemary Shikangalah ¹ (Department of Geography, History and Environmental Studies, University of Namibia)
Benjamin Mapani ² (Department of Mining and Process Engineering, Namibia University of Science and Technology, Windhoek, Namibia)

تاریخ دریافت : 1398/10/06 تاریخ پذیرش : 1399/01/09 تاریخ انتشار : 1399/04/11

کلید واژه: problems, Bush encroachment, de-bushing benefits, value chains, Namibia,

چکیده مقاله :

Bush encroachment leads to land degradation in semiarid to arid regions. Over 45 million hectares of agricultural land in Namibia are affected. This is worrisome as nearly 70% of the Namibian population depends on agricultural activities and the beef industry is the mainstay of the farming communities. This study employed secondary data sources to provide a review of the problems and benefits of bush encroachment in Namibia. The phenomenon has led to decreased biodiversity, degradation of the functions and structures of ecological ecosystems, lowering the grasslands’ carrying capacity, displacement of wildlife, as well as impacting groundwater recharge. Encroachers include species such as Senegalia erubescens, Senegalia fleckii, Vachellia nilotica, Vachellia luederitzii, Vachellia reficiens, Colophospermum mopane, Rhigozum trichotomum, Terminalia prunioides, Terminalia sericea, Senegalia mellifera and Dichrostachys cinerea. In 2018, the beef industry made at least US$ 184 million dollars. This amount could have been more, if the carrying capacity of the grazing lands was not reduced. On the other hand, the encroachers offer extra income from de-bushed wood material, including income from charcoal industry, which currently flourishing. Namibia is presently one of the main charcoal exporters and made close to US$34 million during the year 2018, putting the country on a first 1st position in Africa and 11th position worldwide. This brings a dilemma in managing the encroachers, as to whether to eliminate them and improve the grasslands or to allow them to grow for other benefits. The study concludes that while trying to improve the ecosystems by de-bushing, managing de-bushing needs to be sustainable. There is also a need for research to largely focus on evaluating the trade-offs between the problem and opportunities.

منابع و مأخذ:

Archer, S., Boutton, T., and Hibbard, K. 2001. Trees in grasslands: Biogeochemical consequences of woody plant expansion. InE. Schulze, S. Harrison, M. Heimann, E. Holland, J. Lloyd, I. Prentice & D. Schimel. (Ed.), Global biogeochemical cycles in the climate system (pp. 47). San Diego, SD: Academic Press.

Ayelew, S., and Mulualem, G. 2018. A review on bush encroachment effect on cattle rearing in rangelands. Journal of Rangeland Science, 8(4), 403-415.

Bester, F. V. 1999. Major problem: Bush species and bush densities in Namibia. Agricola, 10:1–3.

Birch, C., Harper-Simmonds, L., Lindeque, P., and Middleton, A. 2017. Benefits of bush control in Namibia: A national economic study for Namibia and a case for the Otjozondjupa Region. Report for the Economics of Land Degradation Initiative. Retrieved from www.eld-initiave.org

Bond, W. J. 2008. What limits trees in C₄ grasslands and savannas? Annual Review of Ecology, Evolution, and Systematics, 39, 641-59.

Bond, W. J., and Midgley, G. F. 2000. A proposed CO²-controlled mechanism of woody plant invasion in grasslands and savannas. Global Change Biology, 6, 865-869.

Bond, W., Woodward, F.I., and Midgley, G.F. 2002. Does elevated CO² play a role in bush encroachment? In A.H.W, Seydach, T., Vorster, W.J., Vermeulen and I. J., van der Merwe (Eds.). Multiple use management of natural forests and woodlands: Policy refinement and scientific progress (pp. 202-208). Pretoria, South Africa: Department of Water Affairs and Forestry.

Carr, Barbour and Associates. 1996. Groundwater Resource Investigations of the Platveld Kalahari Basin Aquifer.Unpublished DWA report, Windhoek.

Charis, G., Danha, G., and Muzenda, E. 2019. Waste valorisation opportunities for bush encroacher biomass in savannah ecosystems: A comparative case analysis of Botswana and Namibia. Procedia Manufacturing, 35, 974-979.

De Klerk, J. N. 2004. Bush encroachment in Namibia. Report on Phase 1 of the Bush encroachment, monitoring and management project. Windhoek, Namibia: Ministry of Environment and Tourism.

De Wet, M. J. 2015. Harvesting Namibian encroacher bush: Compendium of harvesting technologies for encroacher bush in Namibia. Windhoek, Namibia: Support to De-Bushing Project, Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH.

Desert Research Foundation of Namibia (DRFN). 2009. Combating bush encroachment for Namibia’s development (CBEND). Windhoek, Namibia: Desert Research Foundation of Namibia.

Development Consultants for Southern Africa (DECOSA). 2016. Concept for sustainable labour-based de-bushing in Namibia. Retrieved from https://www.l2b.co.za/Tender/Concept-for-Sustainable-Labour-Based-De-Bushing-in/545809

Donaldson, C. H. 1969. Bush encroachment and methods of control with special reference to the Blackthorn (Acacia mellifera) problem of the Molopo area. Armoedsvlakte research station, Vryburg.

DWA & GSN. 2001. Groundwater in Namibia: An Explanation to the hydrogeological pap. Prepared by Christelis, G. and Struckmeier, W. Editors for the Division Geohydrology, Directorate of Water Affairs. Retrieved from https://www.bgr.bund.de/EN/Themen/Wasser/ Projekte/abgeschlossen/TZ/Namibia/groundwater_namibia.pdf?_blob=publicationFile&v=3

Eldridge, D. J., Bowker, M. A., Maestre, F. T., Roger, E., Reynolds, J. F., and Whitford, W. G. 2011. Impacts of shrub encroachment on ecosystem structure and functioning: towards a global synthesis. Ecology Letters, 14(7), 709-722.

Factsheet. 2018. Namibian wood charcoal. https://www.dasnamibia.org/download/brochures/Charcoal-Factsheet-July-2018.pdf

Haines-Young‚ R., and Potschin, M. 2013. Common International Classification of Ecosystems Services (CICES, version 4, August-December 2012). Report to European Environmental Agency. Retrieved from https://unstats.un.org/unsd/envaccounting/seearev/GCComments/CICES_Report.pdf

Harper-Simmonds, L., Mendelsohn, J., Roux, J., Pallet, J., Brown, C., Middleton, A., and Kruse, J. 2015. Development of an Inventory of Ecosystem Services in Namibia (draft). Windhoek, Namibia: Namibia Nature Foundation.

Hauwanga, W. N., McBenedict, B., and Strohbach, B. J. 2018. Trends of phanerophyte encroacher species along an aridity gradient on Kalahari sands, central Namibia. European Journal of Ecology, 4(2), 41-48.

Honsbein, D., Peacocke, C., and Joubert, D. 2009. Incentive scheme for invader bush management – A cost benefit analysis. Windhoek, Namibia: Namibian Agronomic Board. Windhoek.

Huang, C. Y., Archer, S. R., McClaran, M. P., and Marsh, S. E. 2018. Shrub encroachment into grasslands: End of an era? Peer-reviewed journal, 6, e5474.

IPCC. 2001. Climate change 2001: The scientific basis: Contribution of Working Group 1 to the Third Assessment Report of the intergovernmental panel on climate change. Cambridge, UK: Cambridge University Press.

IPCC. 2007. Climate change 2007:Impacts, adaptation and vulnerability: Summary for policymakers. Working Group II Contribution to the Intergovernmental Panel on Climate Change. Fourth Assessment Report. Retrieved from https://www.ipcc.ch/site/assets/uploads/2018/03/ar4 _wg2_full_report.pdf

Larcher, W. 1983. Physiological plant ecology. In V. Springer, B. Mendelsohn J, A. Jarvis, C. Roberts and T. Robertson 2002. Atlas of Namibia: A portrait of the land and its people. New Africa Books (Pty) Ltd. Cape Town.

Liu, F., Archer, S. R., Gelwick, F., Bai, E., Boutton, T. W., and Wu, X. B. 2013. Woody plant encroachment into grasslands: Spatial patterns of functional group distribution and community development. PLoS ONE, 8(12), e84364.

Lukomska, N., Quaas, M., and Baumgärtner, S. 2010. Bush encroachment control and risk management in semi-arid rangelands, Working Paper Series in Economics, No. 191. Lüneburg, Leuphana Universität Lüneburg: Institut für Volkswirtschaftslehre.

Meat Board of Namibia, 2017. https://www.nammic.com.na/index.php/library/send/51-other/88-previous-monthly

Mendelsohn J, A. Jarvis, C. Roberts and T. Robertson 2002. Atlas of Namibia: A portrait of the land and its people. New Africa Books (Pty) Ltd. Cape Town.

Mendelsohn, J., and El Obeid, S. 2005. Forests and woodlands of Namibia. Windhoek, Namibia: Ministry of Agriculture, Water and Forestry.

Midgley, G., Hughes, G., Thuiller, W., Drew, G. and Foden, W. 2005. Assessment of potential climate change impacts on Namibia’s floristic diversity, ecosystem structure and function. For the Namibian National Biodiversity Programme, Directorate of Environmental Affairs, Ministry of Environment and Tourism. Cape Town, South Africa: South African National Biodiversity Institute.

Ministry of Agriculture, Water and Forestry (MAWF). 2012. The National rangeland management policy part 1. Windhoek, Namibia: Republic of Namibia

Ministry of Agriculture, Water and Forestry (MAWF). 2014. Baseline assessment for the de-bushing programme in Namibia. Windhoek, Namibia: Republic of Namibia.

Ministry of Agriculture, Water and Forestry (MAWF). 2017a. Animal feed from Namibian encroacher bush. Windhoek, Namibia: Republic of Namibia.

Ministry of Agriculture, Water and Forestry (MAWF). 2017b. Bush control manual. Windhoek, Namibia: Republic of Namibia.

Ministry of Industrialisation, Trade and SME Development (MITSMED). 2016. Growth strategy for the Namibian wood charcoal industry and associated value chains. Windhoek, Namibia: Republic of Namibia.

Moore. A. 1989. Die ekologie en ekofisiologie van Rhigozum trichotomum. Unpublished PhD Thesis, University of Port Elizabeth, Port Elizabeth.

Namibia Agricultural Union (NAU). 2010. The effect of bush encroachment on groundwater resources in Namibia: A desk top study.Windhoek, Namibia: Namibia Agricultural Union. Retrieved from http://www.agrinamibia.com.na/wp-content/uploads/2018/02/

Namibia Nature Foundation (NNF). 2016. An assessment of the economics of land degradation related to bush encroachment in Namibia. Retrieved from http://www.the-eis.com/data/literature/An%20assessment%20of%20the%20economics%20of%20land%20degradation%20related%20to%20bush%20encroachment%20in%20Namibia.pdf

National Drought Task Force. 1997. Towards a drought policy for Namibia. A discussion document prepared by the National Drought Task Force for a workshop at Neudamm Agricultural College 11-13 March 1997. Windhoek, Namibia: National Drought Task Force.

Nesongano, W. 2018. The effects of climate change, land-use and elevated carbon dioxide on tree-grass interactions in Southern African savannas. Universät Tübingen, Germany. Retrieved from https://publikationen.uni-tuebingen.de/xmlui/handle/10900/83341

Poage III, G. W., Scott, C. B., Bisson, M. G., and Hartmann, F. S. 2000. Activated charcoal attenuates bitterweed toxicosis in sheep. Journal of Range Management, 53 (1), 73-78.

Schroter, M., Jakoby, O., Olbrich, R., Eichhorn, M. and Baurngartner, S. 2009. Remote Sensing of bush encroachment on commercial cattle farms in semi-arid rangelands in Namibia. Working Paper Series in economics (pp 327-343). IGI global. University of Lüneberg. Retrieved from https://www.econstor.eu/bitstream/10419/30216/1/608019437.pdf

Sweet, J. and Burke, A. 2000. Country pasture/forage resource profiles: Food and agriculture organisation of the United Nations. Retrieved from http://www.fao.org/ag/agp/agpc/doc/counprof/Namibia/namibia.htm

Sweet, J. and Burke, A. 2006. Country pasture/forage resource profiles. Retrieved from http://www.fao.org/ag/agp/agpc/doc/counprof/namibia.htm#1.

Temmerman, M. 2016. Toward a cleaner charcoal production process. Small. 2 (3-1).

The Namibia Water Corporation Ltd (NamWater). 2018. Hydrological Services. https://www.namwater.com.na/index.php/services

Uchezuba, D. I., Mbai, S., Zimmermann, I., and Bruwer, J. 2019. Investigating wood pellet torrefaction investment and its economic feasibility in the Krumhuk, Khomas region of Namibia. SN Applied Sciences, 1(5), 402.

United Nations Development Program (UNDP). 2019. Report on sustainable management of Namibia’s forested lands (NAFOLA). UNDP-GEF project, 2014 – 2019. Retrieved from https://info.undp.org/docs/pdc/Documents/NAM/Consolidaed%20Report%20NAFOLA.PDF

United Nations Framework Convention on Climate Change (UNFCCC). 2010. Namibia second national communication to the United Nations framework convention on climate change. Windhoek, Namibia: Republic of Namibia.

Van Auken, O. W. 2009. Causes and consequences of woody plant encroachment into western North American grasslands. Journal of Environmental Management, 90(10), 2931-2942.

Vegter, J. R. 1993. Effect of clearing arid sweet bushveld vegetation on groundwater, Northwestern and Northern Transvaal. Unpublished Constancy Report, No GH 3811, to Directorate of Geohydrology, Department of Water Affairs and Forestry, Pretoria. Retrieved from https://www.bgs.ac.uk/sadc/fulldetails.cfm?id=ZA1314

Workman, D. 2019. World's Top Exports. Retrieved from http://www.worldstopexports.com/top-charcoal-exporters-by-country/