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Prof Mary Scholes

PROF Mary Scholes


PhD - Botany (Plant Physiology) University of the Witwatersrand

011 717 1000
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Co-operative Research Projects

Joint research projects with the following organizations:

Nutrient cycling and sustainability of plantations. Research work is ongoing with Sappi, Global Forest Products and the Institute for Commercial Forestry Research. This work forms part of a bilateral agreement with Sweden and funding is sourced from Sida and the NRF. Prof Sune Linder is my Swedish colleague.

I have been actively involved with the Tropical Soil Biology and Fertility Programme, an Institute of the International Centre for Tropical Agricultural Research for the last 10 years. This programme aims at improving the sustainability of agriculture in tropical regions through an understanding of soil biological properties.

I am actively involved in nutrient cycling research in the Kruger National Park together with a number of national and international colleagues.

The Southern African Fire Atmosphere Research Initiative (SAFARI) in 1992 and 2000 was the start of collaboration with NASA, EPA (USA) and the Max Planck Institute (Mainz-Germany). These projects are all associated with improving the understanding of biogenic trace gas emissions and the modelling of these emissions on a regional scale.

Biogeochemistry of Savanna Ecosystems, Soil Biological Processes

This is an endowed position in the School, sponsored by Sappi. I currently chair the Management Committee for the WITS Institute for the Study of the Environment and I co-ordinate the cross-faculty interdisciplinary MSc in Environmental Science.

Undergraduate courses in "Soils: an introduction? and "Functional Ecology in a Changing Environment?. Postgraduate courses in "Global change and its impacts on Southern African ecosystems" and "Biogeochemistry in semi-arid savanna systems.


I believe that I have developed skills, which allow me to make significant contributions to these research activities. My strengths lie in good teaching, implementing ideas, collecting the necessary data and making sure that the product is delivered. I have also developed skills in decision-making, critical appraisal and synthesizing information. These skills have been recognised nationally and internationally by the following:

  • In 2004, I was elected as a fellow of the Royal Society of South Africa.
  • In 2002, I was elected as a foreign member of the Royal Swedish Academy of Agriculture and Forestry.
  • In 1994 and 1995, I was awarded the Science Faculty Distinguished lecturer?s medal and the Vice-Chancellors Distinguished Teaching award respectively;
  • In 2000, I was awarded the Vice-Chancellors Distinguished Research award;
  • I am the first incumbent of an endowed position at the University supported by Sappi (a forestry company);
  • I co-chaired the Science Steering Committee of the International Global Atmospheric Chemistry Programme (IGAC) for 2001 and 2002. I am a Board member and chairman of the audit and financial committee for the International Centre for Tropical Agricultural Research. I serve as the vice-chairperson on the Science Advisory Council for the Tropical Soil Biology and Fertility Institute. I serve on the Science Advisory Council for the National Botanical Institute of South Africa. I serve on the scientific steering committee for the International Geosphere Biosphere Programme (IGBP). I also serve on the science steering committee the Science Advisory committee for the Nitrogen Initiative (a joint SCOPE/IGBP programme). I was elected as a member of the Commission on Atmospheric Chemistry and Global Pollution in 2002;
  • I was the associate editor of the Journal of Geophysical Research and serve on the editorial boards for Applied Soil Ecology, Ecosystems and Biogeochemistry;
  • I serve on the executive of the University Research Committee and am a member of the University Senate and Council.
  • I have given 11 invited lectures in the last year at various international and national conferences and symposia.
  • Thirty-two graduate students, under my supervision, have been awarded their degrees since 1995 and I am currently supervising 16 graduate students.
  • Significant funding (approx R700, 000) is raised per year for research from a variety of donors.

Research Interests

Over the last five years I have focussed my research in three main areas. These activities include:

  1. Improving the productivity and sustainability of South African plantation forests and natural savanna ecosystems by applying ecosystem based scientific approaches,
  2. Improving the understanding, at the process level, of the factors controlling trace gas emissions from soils and vegetation and the extrapolation of these data to the Southern African region and globally,
  3. The development of a strong, cohesive postgraduate school and research network of national and international scientists in which I act as both a supervisor and advisor.

Specific topics: Biogeochemistry of savanna and plantation ecosystems. Controls on nitrogen, carbon and phosphorus cycling in savannas. Soil-root interactions, biological nitrogen fixation and mycorrhizae, nutrient acquisition and the rhizosphere. Sustainability of plantations in South Africa. Biogenic trace gas emissions, focusing on biosphere-atmosphere interactions. Tropical soil fertility, soil biological processes and sustainable agriculture. I usually have a postgraduate school of about 10-12 students, doing MSc and PhD degrees under my supervision. Projects for students are offered in the areas listed below.


  • Louw, JH and Scholes, MC. 2003 Foliar nutrient levels as indicators of site quality for Pinus patula in the Mpumalanga Escarpment Area. Southern African Forestry Journal 197: 21-30.
  • Dames, JF, Scholes, MC and Straker, CJ 2002 Nitrogen and phosphorus budgets for a Pinus patula plantation of the Mpumalanga province, South Africa. Applied Soil Ecology 595:1-16.
  • Louw, JH and Scholes MC 2002 The influence of site factors on nitrogen mineralization in forest soils of the Mpumalanga escarpment area: South Africa. Southern African Forestry Journal, 193: 47-63.
  • Zeidler, J., Hanrahan, S and Scholes, MC 2002 Termite species richness, composition and diversity at five farms in Southern Kunene Region, Namibia. African Zoology, 37(1): 7-11.
  • Zeidler, J., Hanrahan, S and Scholes, MC 2002 Landuse intensity affects range condition in arid to semi-arid Namibia. Journal of Arid Environments. 52: 389-403.
  • Scholes, MC 2002 Biological processes as indicators of sustainable plantation forestry. Southern African Forestry Journal. 195: 57- 62.
  • Du Toit, B and Scholes, MC 2002 Nutritional sustainability of forest plantations: A case study at Karkloof, South Africa. Southern African Forestry Journal, 195: 63-72.
  • Bird, T.L. and Scholes, MC 2002 The impact of the addition of Eucalyptus grandis wood chips on nitrogen availability in plantation soils. Southern African Forestry Journal, 196: 9-14.
  • Louw, JH and Scholes, MC 2002 Forest site classification and evaluation: A South African Perspective. Forest Ecology and Management, 171: 153-168.
  • Scholes, MC 2002 Games worth playing: effective science teaching through active learning. South African Journal of Science, 98(9/10): 497-499.
  • Scholes, MC and Andreae, MO 2004 Wildland fire emissions from Africa and their impact on the Global Atmosphere. Annex II Wildland Fire Management Handbook for Sub-Sahara Africa. Edited by Johann G Goldammer & Cornelis de Ronde. Compress, pp403-415.
  • Scholes, MC, Matrai PA, Andreae, MO, Smith, KA and Manning, M 2003. Biosphere-Atmosphere Interactions. In: Atmospheric Chemistry in a changing world. Brasseur, G, Prinn, R and Pzenny, A (Eds), 19-71, Springer-Verlag, Heidelberg.
  • Tyson, P., Odada, E., Schulze, R., Vogel, C., Arntzen, J., Chanda, R., Gatebe, C., Hoffman, T., Lutjeharms, J., Marufu, L., Midgley, G., Monteiro, P., Obura, D., Otter, L., Partridge, T., Perks, L., Ringrose, S., Scholes, MC., Scholes, RJ. 2002. Regional-Global Change Linkages: Southern Africa. In Global-Regional Linkages in the Earth System (eds) Tyson, P., Fuchs, R., Fu, C., Lebel, L., Mitra, A.P., Odada, E., Perry, J., Steffen, W.,Virji, H. IGBP Series, Springer, Berlin. pp 3-73.
  • Scholes, MC, Scholes, RJ, Otter, LB and Woghiren, A. 2003. Biogeochemistry: the cycling of nutrients in the Kruger National Park. In: The Kruger Experience: Ecology and Management of Savanna Heterogeneity. du Toit, J, Biggs, H and Rogers, KH.(eds), pp 130-148. Island Press, Washington.
  • Scholes, MC and Woghiren, A. 2003. Elemental interactions and constraints on root symbiont functioning. In: Interactions of the Major Biogeochemical Cycles: Global Change and Human Impacts, Melillo JM, Field CB & Moldan B (eds), pp 211-226. Island Press, Washington DC.
  • Ollinger, S., Sala, O., Agren, G., Berg, B., Davidson, E., Field, C., Lerdau, M., Neff, J., Scholes, MC and Sterner, R. 2003. New frontiers in the study of element interactions. In: Interactions of the Major Biogeochemical Cycles: Global Change and Human Impacts, Melillo JM, Field CB & Moldan B (eds), pp 63-91. Island Press, Washington.
  • van Teinhoven AM and Scholes, MC 2003 The potential for gaseous air pollutant impacts on vegetation in South Africa. In: Air Pollution Reviews: Vol 4 Air pollution impacts on crops and forests: a global assessment. Ashmore, M, Emberson, L and Murray, F. (Eds) Stockholm Environmental Institute, pp 237-263. Imperial College Press.

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