On the relevance of nonequilibrium concepts to arid and semiarid grazing systems

Ecological Applications

Volumn 9, Issue 3, 1999, Pages 798-813

  Illius, A W ^a   O'Connor, T G ^b  

^a UNIVERSITY OF EDINBURGH   (United Kingdom)

^b UNIVERSITY OF KWAZULU NATAL   (South Africa)

Author keywords

Climatic variability; Consumer resource dynamics; Degradation; Grazing; Livestock; Nonequilibrium systems; Pastoralism; Plant herbivore relations; Rangeland

Indexed keywords

ECOLOGY; HERBIVORY; PLANT ANIMAL INTERACTION; POPULATION DENSITY;

ECOSYSTEM FUNCTION; EQUILIBRIUM; GRAZING; RANGELAND; SEMIARID REGION;

AFRICA;

ANIMALIA;

EID: 0033178314     PISSN: 10510761     EISSN: None     Source Type: Journal    
DOI: 10.1890/1051-0761(1999)009[0798:OTRONC]2.0.CO;2     Document Type: Article

References (96)

1. Abel, N. O. J. 1993a. What's in a number? The carrying capacity controversy of the communal rangelands of southern Africa. Monograph Number 14, School of Development Studies, University of East Anglia, Norwich, UK.
2. -. 1993b. Reducing cattle numbers on Southern African communal range: is it worth it? Pages 173-195 in R. H. Behnke, I. Scoones, and C. Kerven, editors. Range ecology at disequilibrium. Overseas Development Institute. London, UK.
3. Abel, N. O. J., and P. M. Blaikie. 1989. Land degradation, stocking rates and conservation policies in the communal rangelands of Botswana and Zimbabwe. Land Degradation and Rehabilitation 1:102-123.
4. Ash, A. J., J. G. McIvor, J. P. Corfield, and W. H. Winter. 1995. How land condition alters plant-animal relationships in Australia's tropical rangelands. Agriculture. Ecosystems and Environment 56:77-92.
5. Behnke, R. H., and C. Kerven. 1994. Redesigning for risk: tracking and buffering environmental variability in Africa's rangelands. Natural Resource Perspectives. Number 1. Overseas Development Institute, London, UK.
6. Behnke, R. H., and I. Scoones. 1993. Rethinking range ecology: implications for rangeland management in Africa. Pages 1-30 in R. H. Behnke, I. Scoones, and C. Kerven, editors. Range ecology at disequilibrium. Overseas Development Institute, London. UK.
7. Behnke, R. H., I. Scoones, and C. Kerven. 1993. Range ecology at disequilibrium. Overseas Development Institute, London, UK.
8. Biot, Y. 1991. How long can livestock production be sustained in the hardveld of Botswana? Pedologie 41:133-47.
9. -. 1993. How long can high stocking densities be sustained? Pages 153-172 in R. H. Behnke, I. Scoones, and C. Kerven, editors. Range ecology at disequilibrium. Overseas Development Institute, London, UK.
10. Breman, H., and C. T. de Wit. 1983. Rangeland productivity and exploitation in the Sahel. Science 221:1341-1347.
11. Caughley, G. 1987. Ecological relationships. Pages 159-186 in G. Caughley, N. Shepherd, and J. Short, editors. Kangaroos: their ecology and management in the sheep rangelands of Australia. Cambridge University Press. Cambridge, UK.
12. Caughley, G., N. Shepherd, and J. Short. 1987. Kangaroos: their ecology and management in the sheep rangelands of Australia. Cambridge University Press, Cambridge, UK.
13. Charley, J. L., and S. W. Cowling. 1968. Changes in soil nutrient status resulting from overgrazing and their consequences in plant communities of semi-arid areas. Proceedings of the Ecological Society of Australia 3:28-38.
14. Chesson, P. L., and T. J Case. 1986. Nonequilibrium community theories: variability, history, and coexistence. Pages 229-239 in J. Diamond and T. J. Case, editors. Community ecology. Harper and Row, New York, New York, USA.
15. Chesson, P. L., and N. Huntley. 1989. Short-term instabilities and long-term community dynamics. Trends in Evolution and Ecology 4:293-298.
16. Chesson, P. L., and R. R Warner. 1981. Environmental variability promotes coexistence in lottery competitive systems. American Naturalist 117:923-943.
17. Connell, J. H., and W. P. Sousa. 1983. On the evidence needed to judge ecological stability or persistence. American Naturalist 121:789-824.
18. Coppock, D. L. 1993. Vegetation and pastoral dynamics in the southern Ethiopian rangelands: implications for theory and management. Pages 42-61 in R. H. Behnke, I. Scoones, and C. Kerven, editors. Range ecology at disequilibrium. Overseas Development Institute, London, UK.
19. Crawley, M. J. 1983. Herbivory. Blackwell, Oxford, UK.
20. Dean, W. R. J., and I. A. W. Macdonald. 1994. Historical changes in stocking rates of domestic livestock as a measure of semi-arid and arid rangeland degradation in the Cape Province, South Africa. Journal of Arid Environments 26:281-298.
21. DeAngelis, D. L. 1995. Equilibrium and non-equilibrium concepts in ecological models. Encyclopedia of Environmental Biology 1:687-695.
22. DeAngelis, D. L., and J. C. Waterhouse. 1987. Equilibrium and non-equilibrium concepts in ecological models. Ecological Monographs 57:1-21.
23. De Jager, P. 1988. Environmental degradation in communal land. M.Sc. thesis, University of Zimbabawe, Harare, Zimbabwe.
24. Dunne, T. 1979. Sediment yield and land use in tropical catchments. Journal of Hydrology 42:281-300.
25. Du Preez, C. C., and H. A. Snyman. 1993. Organic matter content of a soil in a semi-arid climate with three longstanding veld conditions. African Journal of Range and Forage Science 10:108-110.
26. Edroma, E. L. 1985. Effects of clipping on Themeda triandra Forsk and Brachiaria platynota (K Schum.) Robyns in Queen Elizabeth National Park, Uganda. African Journal of Ecology 23:45-51.
27. Ellis, J. E. 1994. Climate variability and complex ecosystem dynamics: implications for pastoral development. Pages 37-46 in I. Scoones, editor. Living with uncertainty. Intermediate Technology Publications, London, UK.
28. Ellis, J. E., and D. M. Swift. 1988. Stability of African pastoral ecosystems: Alternate paradigms and implications for development. Journal of Range Management 41:450-459.
29. Friedel, M. H. 1991. Range condition assessment and the concept of thresholds: a viewpoint. Journal of Range Management 44:422-426.
30. Fryxell, J. M. 1987. Food limitation and demography of a migratory antelope, the white-eared kob. Oecologia 72:83-91.
31. Fryxell, J. M. and A. R. E. Sinclair. 1988. Seasonal migration by white-eared kob in relation to resources. African Journal of Ecology 26:17-31.
32. Galvin, K., and J. Ellis. 1996. Climate patterns and human socio-ecological strategies in the rangelands of sub-Saharan Africa. Pages 57-62 in E. Odada, O. Totolo, M. Stafford Smith, and J. Ingram, editors. Global change and subsistence rangelands in Southern Africa. GTCE Working Document Number 20. Core Project Office, Global Change and Terrestrial Ecosystems, Canberra, Australia.
33. George, M. R., J. R. Brown, and W. J. Clawson. 1992. Application of nonequilibrium ecology to management of Mediterranean grasslands. Journal of Range Management 45:436-440.
34. Gifford, G. F., and R. H. Hawkins. 1978. Hydrologic impact of grazing on infiltration: a critical review. Water Resources Research 14:305-313.
35. Griffin, G. F., and M. H. Friedel. 1985. Discontinuous change in central Australia: some implications of major ecological events for land management. Journal of Arid Environments 9:63-80.
36. Hary, I., H.-J. Schwartz, V. H. C. Pielert, and C. Mosler. 1996. Land degradation in African pastoral systems and the destocking controversy. Ecological Modelling 86:227-233.
37. Hodgkinson, K. 1995. A model for perennial grass mortality under grazing. Pages 240-241 in N. E. West, editor. Proceedings of the Fifth International Rangeland Congress. Society for Range Management, Denver, Colorado, USA.
38. Hoffman, M. T., W. J. Bond, and W. D. Stock. 1995. Desertification of the eastern karoo, South Africa: conflicting paleoecological, historical and soil isotopic evidence. Environmental Monitoring and Assessment 37:159-177.
39. Homewood, K. 1994. Pastoralists, environment and development in East African rangeland. Pages 311-323 in B. Zaba and J. Clarke, editors. Environment and population change. Derouaux, Liege, Belgium.
40. Homewood, K., and J. Lewis. 1987. Impact of drought on pastoral livestock in Baringo, Kenya 1983-85. Journal of Applied Ecology 24:615-631.
41. Illius, A. W., J. F. Derry, and I. J. Gordon. 1998. Evaluation of strategies for tracking climatic variation in semi-arid grazing systems. Agricultural Systems 57:381-398.
42. Ingram, J. 1991. Soil and water processes. Pages 1-69 in I. Scoones, editor. Wetlands in drylands: the agroecology of savanna systems in Africa. Part II. Drylands Programme, International Institute for Environment and Development. London, UK.
43. Kelly, R. D., and B. H. Walker. 1976. The effects of different forms of land use on the ecology of a semi-arid region in southeastern Rhodesia. Journal of Ecology 64:553-576.
44. Laflen, J. M., L. J. Lane, and G. R. Foster. 1991. WEPP - a new generation of erosion prediction technology. Journal of Soil and Water Conservation 46:35-38.
45. Lavorel, S., and P. L. Chesson. 1995. How species with different regeneration niches coexist in patchy habitats with local disturbances. Oikos 74:103-114.
46. Le Houérou, H. N. 1984. Rain use efficiency: a unifying concept in arid-land ecology. Journal of Arid Environments 7:213-247.
47. -. 1989. The grazing land ecosystems of the African Sahel. Ecological Studies 75, Springer-Verlag, Berlin, Germany.
48. Le Houérou, H. N., R. L. Bingham, and W. Skerbek. 1988. Relationship between the variability of primary production and the variability of annual precipitation in world arid lands. Journal of Arid Environments 15:1-18.
49. Livingstone, I. 1991. Livestock management and "overgrazing" among pastoralists. Ambio 20:80-85.
50. McFarlane, M. J., and R. Whitlow. 1990. Key factors affecting the initiation and progress of gulleying in dambos in parts of Zimbabwe and Malawi. Land Degradation and Rehabilitation 2:215-235.
51. Milchunas, D. G., and W. K. Lauenroth. 1993. Quantitative effects of grazing on vegetation and soils over a global range of environments. Ecological Monographs 63:327-366.
52. Milner, C., and D. Gwynne. 1974. The Soay sheep and their food supply. Pages 160-194 in P. A. Jewell, C. Milner, and J. Morton Boyd, editors. Island survivors. Athlone, London, UK.
53. Mufandaedza, J. T. 1976. Effects of frequency and height of cutting on some tropical grasses and legumes, Hyparrhenia filipendula and Heteropogon contortus. Rhodesian Journal of Agricultural Research 14:21-38.
54. Murray-Rust, D. H. 1972. Soil erosion and reservoir sedimentation in a grazing area west of Arusha, Northern Tanzania. Geografiska Annaler 54A:325-343.
55. Mwendera, E. J., and M. A. M. Saleem. 1997. Infiltration rates, surface runoff, and soil loss as influenced by grazing pressure in the Ethiopian highlands. Soil Use and Management 13:29-35.
56. Ndawula-Senyimba, M. S. 1972. Some aspects of the ecology of Themeda triandra. East African Agriculture and Forestry Journal 38:83-93.
57. Noy-Meir, I. 1975. Stability of grazing systems: An application of predator-prey graphs. Journal of Ecology 63:459-481.
58. O'Connor, T. G. 1985. A synthesis of field experiments concerning the grass layer in the savanna regions of Southern Africa. South African National Scientific Programmes Report 114 CSIR, Pretoria, South Africa.
59. -. 1995. Transformation of a savanna grassland by drought and grazing. African Journal of Range and Forage Science 12:53-60.
60. O'Connor, T. G., and G. A. Pickett. 1992. The influence of grazing on seed production and seed banks of some African savanna grasslands. Journal of Applied Ecology 29:247-260.
61. O'Connor, T. G., and P. W. Roux. 1995. Vegetation changes (1947-71) in a semi-arid, grassy dwarf shrubland in the Karoo, South Africa: influence of rainfall variability and grazing by sheep. Journal of Applied Ecology 32:612-626.
62. Owen-Smith, N. 1990. Demography of a large herbivore, the greater kudu, Tragelaphus strepsiceros, in relation to rainfall. Journal of Animal Ecology 59:893-913.
63. Owen-Smith, N., and S. M. Cooper. 1989. Nutritional ecology of a browsing ruminant, the kudu, (Tragelaphus strepsiceros) through the nutritional cycle. Journal of Zoology 219:29-43.
64. Pickup, G. 1985. The erosion cell - a geomorphic approach to landscape classification in range assessment. Australian Rangeland Journal 7:114-121.
65. -. 1995. A simple model for predicting herbage production from rainfall in rangelands and its calibration useing remotely-sensed data. Journal of Arid Environments 30:227-245.
66. Pickup, G., G. N. Bastin, and V. H. Chewings. 1994. Remolesensing-based condition assessment for nonequilibrium rangelands under large-scale commercial grazing. Ecological Applications 43:497-517.
67. Pickup, G., and V. H. Chewings. 1986. Random field modelling of spatial variations in erosion and deposition in flat alluvial landscapes in arid central Australia. Ecological Modelling 33:269-296.
68. Pickup, G., and D. M. Stafford Smith. 1987. Integrating models of soil dynamics, animal behaviour and vegetation response for the management of arid lands. Australian Geographer 18:19-23.
69. Prins, H. H. T., and I. Douglas-Hamilton. 1990. Stability in a multi-species assemblage of large herbivores in East Africa. Oecologia 83:392-400.
70. Quirk, M. F., A. J. Ash, and G. McKillop. 1996. A case study of Dalrymple Shire, North-East Queensland. Pages 71-83 in N. Abel and S. Ryan, editors. Sustainable habitation in the rangelands. CSIRO, Canberra, Australia.
71. Reid, R. S., and J. E. Ellis. 1995. Impacts of pastoralists on woodlands in south Turkana, Kenya: livestock-mediated tree recruitment. Ecological Applications 5:978-992.
72. Rietkerk, M., and J. van de Koppel 1997. Alternate stable states and threshold effects in semi-arid grazing systems. Oikos 79:69-76.
73. Rosenzweig, M. L., and R. H. McArthur. 1963. Graphical representation and stability condition of predator-prey interactions. American Naturalist 97:209-223.
74. Sæther, B.-E. 1997. Environmental stochasticity and population dynamics of large herbivores: a search for mechanisms. Trends in Evolution and Ecology 12:143-149.
75. Scoones, I. 1990. Livestock populations and the household economy. A case study from Southern Zimbabwe. Ph.D. thesis. University of London, London, UK.
76. -. 1992. Land degradation and communal livestock production in Zimbabwe's communal areas. Land Degradation and Rehabilitation 3:99-113.
77. -. 1993. Why are there so many animals? Cattle population dynamics in the communal areas of Zimbabwe. Pages 62-76 in R. H. Behnke, I. Scoones, and C. Kerven, editors. Range ecology at disequilibrium. Overseas Development Institute, London, UK.
78. -. 1994. New directions in pastoral development in Africa. Pages 1-36 in I. Scoones, editor. Living with uncertainty. Intermediate Technology Publications, London. UK.
79. -. 1995. Exploiting heterogeneity: habitat use by cattle in dryland Zimbabwe. Journal of Arid Environments 29: 221-237.
80. Sinclair, A. R. E. 1975. The resource limitation of trophic levels in tropical grassland ecosystems. Journal of Animal Ecology 44:497-520.
81. Sinclair, A. R. E., and R. P. Pech. 1996. Density dependence, stochasticity, compensation and predator regulation. Oikos 75:164-173.
82. Slack, D. C., and C. L. Larson. 1981. Modelling infiltration, the key process in water management, runoff and erosion. Pages 433-450 in R. Lal and E. W. Russell, editors. Tropical agricultural hydrology. John Wiley, Chichester, UK.
83. Snyman, H. A., and H. J. Fouché. 1991. Production and water-use efficiency of semi-arid grasslands of South Africa as affected by veld condition and rainfall. Water SA 17: 263-267.
84. Snyman, H. A., W. L. J. Van Rensberg, and D. P. J. Opperman. 1986. Toepassing van 'n gronderosievergelyking op natuurlike veld van die sentrale Oranje-Vrystaat. Journal of the Grassland Society of Southern Africa 3:4-9.
85. Stafford Smith, M., and G. Pickup. 1993. Out of Africa, looking in: Understanding vegetation change. Pages 196-226 in R. H. Behnke. I. Scoones, and C. Kerven, editors. Range ecology at disequilibrium. Overseas Development Institute, London, UK.
86. Stroosnijder, L. 1996. Modelling the effect of grazing on infiltration, runoff and primary production in the Sahel. Ecological Modelling 92:79-88.
87. Tacheba, G., and W. N. Mphinyane. 1993. Dry matter yield of herbaceous rangeland plants and livemass gain of Tswana steers in eastern Botswana in response to stocking rate and phosphorus supplementation. African Journal of Range and Forage Science 10:103-107.
88. Taylor, A. D. 1990. Metapopulations, dispersal, and predator-prey dynamics: an overview. Ecology 71:429-436.
89. Terborgh, J., R. B. Foster, and P. V. Nuñez. 1996. Tropical tree communities: a test of the nonequilibrium hypothesis. Ecology 77:561-567.
90. van de Koppel, J., M. Rietkerk, and F. J. Weissing. 1997. Catastrophic vegetation shifts and soil degradation in terrestrial grazing systems. Trends in Evolution and Ecology 12:352-355.
91. Veenendaal, E. M. 1991. Adaptive strategies of grasses in a semi-arid savanna in Botswana. Ph.D. thesis. Free University of Amsterdam, Amsterdam, The Netherlands.
92. Walker, B. H. 1993. Rangeland ecology: understanding and managing change. Ambio 22:80-87.
93. Walker, B. H., R. H. Emslie, R. N. Owen-Smith, and R. J. Scholes. 1987. To cull or not to cull: lessons from a southern African drought. Journal of Applied Ecology 24:381-401.
94. Westoby, M., B. H. Walker, and I. Noy-Meir. 1989. Opportunistic management for rangelands not at equilibrium. Journal of Range Management 42:266-274.
95. Wiens, J. A. 1984. On understanding a non-equilibrium world: myth and reality in community patterns and processes. Pages 439-457 in D. R. Strong, D. Simberloff, L. G. Abele, and A. B. Thistle, editors. Ecological communities: Conceptual issues and the evidence. Princeton University Press, Princeton, New Jersey, USA.
96. Wilson, A. D., and N. D. MacLeod. 1991. Overgrazing: Present or absent? Journal of Range Management 44:475-482.