Threatened Ecosystem Research
What we do
The programme aims to assess identified threats to ecosystems including the impact of land degradation and habitat fragmentation on plant diversity in vegetation types.
Currently a pilot research programme systematically targets areas of extreme degradation due to heavy grazing pressure relative to vegetation in good condition within given arid and semiarid biomes of southern Africa.
While some species may become locally extinct (extirpation) with severe degradation we recognize the converse - that some indigenous species that are uniquely associated with degradation may face extirpation in 'well-managed' vegetation. The results of this pilot study, together with a synthesis of relevant previous work, will serve to guide the refining of critical thresholds of change in biodiversity due to degradation over a wider range of vegetation types. This should assist in understanding land degradation from a biodiversity viewpoint which may not always coincide with the consequences of degradation as commonly viewed, especially in some agricultural circles.
Where we work
Our current work involves understanding degradation processes and impacts in rangeland biomes throughout South Africa.
Reason for our programme
SANBI needs to meet its obligations under its governing Act relative to understanding and reporting on the status of threatened ecosystems in South Africa. The pilot research programme was instituted following the South African National Spatial Biodiversity Assessment of 2004 which highlighted the inadequate inclusion of the impact of habitat degradation of biodiversity.
What we have achieved
The results of the pilot research programme on impacts of severe land degradation on plant diversity have been published for several rangeland biomes including:
- Rutherford, M.C., Powrie, L.W. & Husted, L.B. 2011. Plant diversity consequences of a herbivore-driven biome switch from Grassland to Nama-Karoo shrub steppe in South Africa. Journal of Vegetation Science15: 14-25. Doi: 10.1111/j.1654-109X.2011.01160.x
- Rutherford, M.C., Powrie, L.W. 2011. Can heavy grazing on communal land elevate plant species richness levels in the Grassland Biome of South Africa? Plant Ecology. 212(9):1407-1418. DOI 10.1007/s11258-011-9916-0
- Rutherford, M.C., Powrie, L.W., 2010. Severely degraded rangeland: Implications for plant diversity from a case study in Succulent Karoo, South Africa, Journal of Arid Environments 74 (2010) 692–701. Journal of Arid Environments (2009), doi:10.1016/j.jaridenv.2009.10.013
- Rutherford, M.C. & Powrie, L.W. 2009. Severely degraded dunes of the southern Kalahari: local extinction, persistence and natural re-establishment of plants. Afr. J. Ecol., 48, 930–938. African Journal of Ecology. doi: 10.1111/j.1365-2028.2009.01194.x
- Rutherford, MC, Powrie, LW and Thompson, DI. In press. Impacts of high utilisation pressure on biodiversity components in Colophospermum mopane savanna. African Journal of Range & Forage Science 2012, 29
Who we are
How to contact us
Address: Kirstenbosch Research Centre, P/Bag X7, Claremont 7735, RSA.
E-mail: Mike Rutherford
Tel: 021 799-8702