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Kate Rowntree Catchment Research Group Department of Geography Rhodes University

Rangelands in the New Millenium: geographical reflections on the VIIth International Rangeland Conference, Durban, 26 July – 1 August 2003. Kate Rowntree Catchment Research Group Department of Geography Rhodes University.

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Kate Rowntree Catchment Research Group Department of Geography Rhodes University

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  1. Rangelands in the New Millenium: geographical reflections on the VIIth International Rangeland Conference,Durban, 26 July – 1 August 2003. Kate Rowntree Catchment Research Group Department of Geography Rhodes University

  2. Rangelands are those natural and semi-natural ecosystems in which husbandry of large herbivores is the principle economic activity

  3. Geographic importance of rangelands in Africa • 70 % of the land area is occupied by rangelands • Importance of livestock to livelihoods • Includes conservation areas • Concerns for land degradation

  4. Rangelands in Africa Fire and grasslands Cattle densities

  5. Key characteristics • Located in drier parts of the continent • Productivity closely linked to spatial and temporal variability of moisture availability • Unpredictable systems • Drinking water as a limiting factor – significance of watering points

  6. Models of rangeland managementSue Vetter & others • Equilibrium model • Non-equilibrium model

  7. EQUILIBRIUM CARRYING CAPACITY MODEL Long term rainfall Climax vegetation Livestock numbers at carrying capacity Sub-climax vegetation Livestock numbers above carrying capacity Degradation

  8. Equilibrium model:conventional paradigm • Based on a fixed carrying capacity • Rotational grazing • Supplementary feeding during droughts • Purchase of cattle to make good stock losses during a drought

  9. EQUILIBRIUM CARRYING CAPACITY MODEL Communal rangeland Long term rainfall Sub-climax vegetation Livestock numbers above carrying capacity Degradation

  10. NON-EQUILIBRIUM MODEL (Ellis and Swift 1988; Behkne & Scoones 1993) Variability in time and space Variable rainfall wet spells Variable vegetationbiomass Stock numbers increase Mortality reduces numbers drought Fluctuatinglivestock numbers

  11. Non-equilibrium model • Vegetation condition related to rainfall rather than grazing pressure • Stocking rates variable: coupled to vegetation & therefore to rainfall • High mortality during droughts • Importance of recovery period after drought • Mobility exploits local spatial variability in rainfall

  12. Response to drought • Equilibrium model: • supplementary feed and restocking • no lag in recovery of stock numbers after drought • Non-equilibrium model • high stock mortality • recovery of stock numbers tracks recovery of vegetation

  13. Key Resources Andrew Illius & Tim O’Connor • Those resources that support livestock during the dry season • Livestock numbers coupled to key resources • Wet season grazing pressure dependent on dry season key resources • Supplementary feed increases pressures on non-key resources

  14. 3 2 1 Rainfall tracking Pattern & scale in landscape heterogeneity Dry-season grazing e.g upland zone; flood plain Seasonal movements

  15. Mobility and drought • Seasonal drought: Movement between landscape units to utilise key resources • Local drought: spatial variability of rainfall, movement within available territory, stock numbers maintained. • Regional drought: too widespread to be mitigated by movement, mortality of stock. • Ability to cope with drought depends on available territory.

  16. Causes: fences Changes to ownership Land use change (to cultivation) FragmentationTom Hobbs Dry-season grazing 3 e.g upland zone; flood plain Seasonal movements 2 1 Rainfall tracking

  17. Complexity in rangeland ecosystems • Cascade effects in the landscape (Tim Hoffman) • Removal of woody skeletons • Loss of protection for seedlings • Loss of insect nesting sights • Loss of pollinators • Importance of life cycles (Peter Carrick) • Browsing flowers reduces regenerative capacity • Unpalatable species may have palatable flowers • Livestock can spread seeds • Ability of a plant community to regenerate is a key consideration

  18. Who are the grazers?Mark Dangerfield • termite biomass - 70-110 kh/ha • ungulate biomass 10-80 kg/ha • turnover by termites120 kg/ha • nests become foci of nutrients. In Okavango can eventually form islands due to vegetation growth on nutrient rich soils. • importance of concentrating resources in small areas - landscape heterogeneity.

  19. Range management in dynamic systems • Many development strategies have been based on the equilibrium model • The non-equilibrium model may be a better basis for rangeland management in drier areas • Key components of a N-E development strategy: • Mobility (reduce fragmentation) • Slow recovery of stock numbers after drought • Strategy to maintain livelihoods following stock mortality • How do you maintain a stable livelihood in a dynamic system?

  20. Who uses rangelands and for what? • Ranchers, conservation areas, water catchments • What is the contribution of rangelands to livelihoods? • What are the impact of global changes on rangelands? • Lack of understanding of the temporal-spatial variability in these complex, dynamic systems. • Lack of concensus as to best way to manage these systems.

  21. Rangeland management – emerging themes Topographic gradients Economics & livelihoods Landscape ecology Human adaptation Global warming livestock Culture Globalisation Governance Rainfall variability

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