1 / 23

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.

selena
Download Presentation

Kate Rowntree Catchment Research Group Department of Geography Rhodes University

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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

More Related