Determinants of spatial variation in fire return period in a semiarid African savanna
T. G. O’Connor A B D , C. M. Mulqueeny A C and P. S. Goodman C
+ Author Affiliations
- Author Affiliations
A Centre for African Ecology, School of School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag X03, Witwatersrand, Johannesburg, ZA-2050, South Africa.
B South African Environmental Observation Network, PO Box 2600, Pretoria, ZA-0001, South Africa.
C Ezemvelo KwaZulu-Natal Wildlife, PO Box 13053, Cascades, Pietermaritzburg, ZA-3202, South Africa.
D Corresponding author. Email: timoconnor@xsinet.co.za
International Journal of Wildland Fire 20(4) 540-549 https://doi.org/10.1071/WF08142
Submitted: 8 August 2008 Accepted: 9 December 2010 Published: 20 June 2011
Abstract
Fire pattern is predicted to vary across an African savanna in accordance with spatial variation in rainfall through its effects on fuel production, vegetation type (on account of differences in fuel load and in flammability), and distribution of herbivores (because of their effects on fuel load). These predictions were examined for the 23 651-ha Mkuzi Game Reserve, KwaZulu-Natal, based on a 37-year data set. Fire return period varied from no occurrence to a fire every 1.76 years. Approximately 75% of the reserve experienced a fire approximately every 5 years, 25% every 4.1–2.2 years and less than 1% every 2 years on average. Fire return period decreased in relation to an increase in mean annual rainfall. For terrestrial vegetation types, median fire return periods decreased with increasing herbaceous biomass, from forest that did not burn to grasslands that burnt every 2.64 years. Fire was absent from some permanent wetlands but seasonal wetlands burnt every 5.29 years. Grazer biomass above 0.5 animal units ha–1 had a limiting influence on the maximum fire frequency of fire-prone vegetation types. The primary determinant of long-term spatial fire patterns is thus fuel load as determined by mean rainfall, vegetation type, and the effects of grazing herbivores.
References
Archibald S, Bond WJ, Stock WD, Fairbanks DHK (2005) Shaping the landscape: fire-grazer interactions in an African savanna. Ecological Applications 15, 96–109.| Shaping the landscape: fire-grazer interactions in an African savanna.Crossref | GoogleScholarGoogle Scholar |
Balfour DA, Howison OE (2002) Spatial and temporal variation in a mesic savanna fire regime: responses to variation in annual rainfall. African Journal of Range and Forage Science 19, 45–53.
| Spatial and temporal variation in a mesic savanna fire regime: responses to variation in annual rainfall.Crossref | GoogleScholarGoogle Scholar |
Bell RHV (1982) The effect of soil nutrient availability on community structure in African ecosystems. In ‘Ecology of tropical savannas’. (Eds BJ Huntley, BH Walker) pp. 193–216. (Springer-Verlag: Berlin)
Blackburn TM, Lawton JH, Perry JN (1992) A method of estimating the slope of upper bounds of plots of body size and abundance in natural animal assemblages. Oikos 65, 107–112.
| A method of estimating the slope of upper bounds of plots of body size and abundance in natural animal assemblages.Crossref | GoogleScholarGoogle Scholar |
Bond WJ, Archibald S (2003) Confronting complexity: fire policy choices in South African savanna parks. International Journal of Wildland Fire 12, 381–389.
| Confronting complexity: fire policy choices in South African savanna parks.Crossref | GoogleScholarGoogle Scholar |
Bond WJ, Keeley JE (2005) Fire as a global ‘herbivore’: the ecology and evolution of flammable ecosystems. Trends in Ecology & Evolution 20, 387–394.
| Fire as a global ‘herbivore’: the ecology and evolution of flammable ecosystems.Crossref | GoogleScholarGoogle Scholar | 16701401PubMed |
Bond WJ, Van Wilgen BW (1996) ‘Fire and plants.’ (Chapman and Hall: London)
Bothma J du P (Ed.) (2002) ‘Game ranch management.’ (Van Schaik Publishers: Pretoria)
Brown AA, Davis KP (1973) ‘Forest fire: control and use.’ (McGraw-Hill: New York)
Byram GM (1959) Combustion of forest fuels. In ‘Forest fire: control and use’. (Ed. KP Davis) pp. 155–182. (McGraw-Hill: New York)
Cole MM (1986) ‘The savannas: biogeography and geobotany.’ (Academic Press: London)
Dye PJ, Spear PT (1982) The effects of bush clearing and rainfall variability on grass yield and composition in south-west Zimbabwe. Zimbabwe Journal of Agricultural Research 20, 103–118..
Eastman JR (1998) ‘The IDRISI project.’ (Clark University: Worcester, MA)
Edwards D (1984) Fire regimes in the biomes of South Africa. In ‘Ecological effects of fire in South African ecosystems’. (Eds P de V Booysen, NM Tainton) pp. 19–37. (Springer-Verlag: Berlin)
Frost PGH, Robertson F (1985) The ecological effects of fire in savannas. In ‘Determinants of tropical savannas’. (Ed. BH Walker) The International Union of Biological Sciences Monograph Series, vol. 3, pp. 93–140. (IRL Press: Oxford, UK)
Fynn RWS, O’Connor TG (2000) Effect of stocking rate and rainfall on rangeland dynamics and cattle performance in a semi-arid savanna, South Africa. Journal of Applied Ecology 37, 491–507.
| Effect of stocking rate and rainfall on rangeland dynamics and cattle performance in a semi-arid savanna, South Africa.Crossref | GoogleScholarGoogle Scholar |
Gertenbach WPD (1983) Landscapes of the Kruger National Park. Koedoe 26, 9–121..
Gertenbach WPD, Potgieter ALF (1979) Veldbrandnavorsing in die struikmopanieveld van die Krugerwildtuin. Koedoe 22, 1–28..
Gill AM, Ryan PG, Moore PHR, Gibson M (2000) Fire regimes of World Heritage Kakadu National Park, Australia. Austral Ecology 25, 616–625..
Goodman PS (1990) Soil, vegetation and large herbivore relations in Mkuzi Game Reserve, Natal. PhD thesis, University of the Witwatersrand, Johannesburg.
Grau HR (2001) Regional-scale spatial patterns of fire in relation to rainfall gradients in sub-tropical mountains, NW Argentina. Global Ecology and Biogeography 10, 133–146.
| Regional-scale spatial patterns of fire in relation to rainfall gradients in sub-tropical mountains, NW Argentina.Crossref | GoogleScholarGoogle Scholar |
Heady HF, Child RD (1994) ‘Rangeland ecology and management.’ (Westview Press: Boulder, CO)
Heyerdahl EK, Brubaker LB, Agee JK (2001) Spatial controls of historical fire regimes: a multiscale example from the interior west, USA. Ecology 82, 660–678.
| Spatial controls of historical fire regimes: a multiscale example from the interior west, USA.Crossref | GoogleScholarGoogle Scholar |
Higgins SI, Bond WJ, Trollope WSW (2000) Fire, resprouting, and variability: a recipe for tree-grass co-existence in savanna. Journal of Ecology 88, 213–229.
| Fire, resprouting, and variability: a recipe for tree-grass co-existence in savanna.Crossref | GoogleScholarGoogle Scholar |
Huffman TN (2007) ‘Handbook to the Iron Age.’ (University of KwaZulu-Natal Press: Pietermaritzburg)
Luke RH, McArthur AG (1978) ‘Bushfires in Australia.’ (Australian Government Publishing Service: Canberra)
Milchunas DG, Lauenroth WK (1993) Quantitative effects of grazing on vegetation and soils over a global range of environments. Ecological Monographs 63, 327–366.
| Quantitative effects of grazing on vegetation and soils over a global range of environments.Crossref | GoogleScholarGoogle Scholar |
Moll EJ (1968) Some notes on the vegetation of Mkuzi Game Reserve, Natal. The Lammergeyer 8, 25–30..
Moll EJ (1980) Terrestrial plant ecology. In ‘Studies on the Ecology of Maputaland’. (Eds MN Bruton, KH Cooper) pp. 52–68. (Rhodes University and The Wildlife Society of Southern Africa: Grahamstown)
Mucina L, Rutherford MC (2006) The vegetation of South Africa, Lesotho and Swaziland. In ‘Strelitzia, vol. 19’. (South African National Biodiversity Institute: Pretoria)
Mulqueeny CM, Goodman PS, O’Connor TG (2010) Landscape-level differences in fire regime between block and patch-mosaic burning strategies in Mkuzi Game Reserve, South Africa. African Journal of Range and Forage Science 27, 143–150.
| Landscape-level differences in fire regime between block and patch-mosaic burning strategies in Mkuzi Game Reserve, South Africa.Crossref | GoogleScholarGoogle Scholar |
Mulqueeny CM, Goodman PS, O’Connor TG (2011) Determinants of inter-annual variation in the area burnt in a semiarid African savanna. International Journal of Wildland Fire 20, 532–539.
| Determinants of inter-annual variation in the area burnt in a semiarid African savanna.Crossref | GoogleScholarGoogle Scholar |
Norton-Griffiths M (1979) The influence of grazing, browsing, and fire on the vegetation dynamics of the Serengeti. In ‘Serengeti: dynamics of an ecosystem’. (Eds ARE Sinclair, M Norton-Griffiths) pp. 310–352. (University of Chicago Press: Chicago)
O’Connor TG, Haines LM, Snyman HA (2001) Influence of precipitation and species composition on phytomass of a semi-arid African grassland. Journal of Ecology 89, 850–860.
| Influence of precipitation and species composition on phytomass of a semi-arid African grassland.Crossref | GoogleScholarGoogle Scholar |
Pammenter NW, Berjak M, MacDonald IAW (1985) Regeneration of a Natal coastal dune forest after fire. South African Journal of Botany 51, 453–459..
Paruelo JM, Lauenroth WK, Burke IC, Sala OE (1999) Grassland precipitation-use efficiency varies across a resource gradient. Ecosystems 2, 64–68.
| Grassland precipitation-use efficiency varies across a resource gradient.Crossref | GoogleScholarGoogle Scholar |
Pickup G (1994) Modelling patterns of defoliation by grazing animals in rangelands. Journal of Applied Ecology 31, 231–246.
| Modelling patterns of defoliation by grazing animals in rangelands.Crossref | GoogleScholarGoogle Scholar |
Polakow DA, Dunne TT (1999) Modelling fire-return interval T: stochasticity and censoring in the two-parameter Weibull model. Ecological Modelling 121, 79–102.
| Modelling fire-return interval T: stochasticity and censoring in the two-parameter Weibull model.Crossref | GoogleScholarGoogle Scholar |
Roques KG, O’Connor TG, Watkinson AR (2001) Dynamics of shrub encroachment in an African savanna: relative influences of fire, herbivory, rainfall and density dependence. Journal of Applied Ecology 38, 268–280.
| Dynamics of shrub encroachment in an African savanna: relative influences of fire, herbivory, rainfall and density dependence.Crossref | GoogleScholarGoogle Scholar |
Sala OE, Parton WJ, Joyce LA, Lauenroth WK (1988) Primary production of the central grassland region of the United States. Ecology 69, 40–45.
| Primary production of the central grassland region of the United States.Crossref | GoogleScholarGoogle Scholar |
Scholes RJ, Archer SR (1997) Tree-grass interactions in savannas. Annual Review of Ecology and Systematics 28, 517–544.
| Tree-grass interactions in savannas.Crossref | GoogleScholarGoogle Scholar |
Sinclair ARE (1979) The eruptions of the ruminants. In ‘Serengeti: dynamics of an ecosystem’. (Eds ARE Sinclair, M Norton-Griffiths) pp. 82–103. (University of Chicago Press: Chicago)
Skinner JD, Smithers RHN (1990) ‘The mammals of the southern African subregion.’ (University of Pretoria: Pretoria)
Smit GN, Richter GGF, Aucamp AJ (1999) Bush encroachment: an approach to understanding and managing the problem. In ‘Veld management in South Africa’. (Ed. NM Tainton) pp. 246–260. (University of Natal Press: Pietermaritzburg)
Thomson JD, Weiblen G, Thomson BA, Alfaro S, Legendre P (1996) Untangling multiple factors in spatial distributions: lilies, gophers and rocks. Ecology 77, 1698–1715.
| Untangling multiple factors in spatial distributions: lilies, gophers and rocks.Crossref | GoogleScholarGoogle Scholar |
Thornthwaite CW (1948) An approach towards a rational classification of climate. Geographical Review 38, 55–94.
| An approach towards a rational classification of climate.Crossref | GoogleScholarGoogle Scholar |
Trollope WSW (1984a) Fire in savanna. In ‘Ecological effects of fire in South African ecosystems’. (Eds P de V Booysen, NM Tainton) pp. 149–175. (Springer-Verlag: Berlin)
Trollope WSW (1984b) Fire behaviour. In ‘Ecological effects of fire in South African ecosystems’. (Eds P de V Booysen, NM Tainton) pp. 199–217. (Springer-Verlag: Berlin)
Trollope WSW, Potgieter ALF (1986) Estimating grass fuel loads with a disc pasture meter in the Kruger National Park. Journal of the Grassland Society of Southern Africa 3–4, 148–152.
Van Wilgen BW, Everson CS, Trollope WSW (1990) Fire management in Southern Africa: some examples of current objectives, practices, and problems. In ‘Fire and tropical biota’. (Ed. JG Goldammer) pp. 179–215. (Springer-Verlag: Berlin)
Van Wilgen BW, Govender N, Biggs HC, Ntsala D, Funda XN (2004) Response of savanna fire regimes to changing fire-management policies in a large African National Park. Conservation Biology 18, 1533–1540.
| Response of savanna fire regimes to changing fire-management policies in a large African National Park.Crossref | GoogleScholarGoogle Scholar |
Walker BH, Langridge JL (1997) Predicting savanna vegetation structure on the basis of plant available moisture (PAM) and plant available nutrients (PAN): a case study from Australia. Journal of Biogeography 24, 813–825.
| Predicting savanna vegetation structure on the basis of plant available moisture (PAM) and plant available nutrients (PAN): a case study from Australia.Crossref | GoogleScholarGoogle Scholar |
Walker BH, Noy-Meir I (1982) Aspects of the stability and resilience of savanna ecosystem. In ‘Ecology of tropical savannas’. (Eds BJ Huntley, BH Walker) pp. 556–590. (Springer-Verlag: New York)
Williams RJ, Gill AM, Moore PHR (1998) Seasonal changes in fire behaviour in a tropical savanna in northern Australia. International Journal of Wildland Fire 8, 227–239.
| Seasonal changes in fire behaviour in a tropical savanna in northern Australia.Crossref | GoogleScholarGoogle Scholar |
Witkowski ETF, O’Connor TG (1996) Topo-edaphic, floristic and physiognomic gradients of woody plants in a semi-arid African savanna woodland. Vegetatio 124, 9–23.
| Topo-edaphic, floristic and physiognomic gradients of woody plants in a semi-arid African savanna woodland.Crossref | GoogleScholarGoogle Scholar |
