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Chapter 13 - How Large Herbivores Transform Savanna Ecosystems

from Part III - The Big Mammal Menagerie: Herbivores, Carnivores and Their Ecosystem Impacts

Published online by Cambridge University Press:  09 September 2021

Norman Owen-Smith
Affiliation:
University of the Witwatersrand, Johannesburg
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Summary

This chapter looks more broadly at interactions. Total herbivore biomass and consequent consumption of vegetation depends on the basic soil fertility. Mean levels underestimate local offtake, particularly in drought years. Heavy grazing suppresses the spread of fires so that more vegetation gets digested than incinerated. Browsing on tree seedlings can counteract woody plant expansion following heavy grazing. Elephants cause large tree mortality by toppling and debarking and can transform savanna woodlands into open grasslands or shrub coppice, especially on fertile soils. Termites promote the decomposition of vegetation not consumed by herbivores or incinerated by fires and contribute to nutrient cycling. Sodium is available through different routes. Large herbivores amplify the spatial heterogeneity inherent in savannas in various ways.

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Only in Africa
The Ecology of Human Evolution
, pp. 199 - 219
Publisher: Cambridge University Press
Print publication year: 2021

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References

Suggested Further Reading

Owen-Smith, N. (1988) Megaherbivores. The Influence of Very Large Body Size on Ecology. Cambridge University Press, Cambridge.Google Scholar

References

Briske, DD, et al. (2020) Strategies for global rangeland stewardship: assessment through the lens of the equilibrium–non‐equilibrium debate. Journal of Applied Ecology 57:10561067.Google Scholar
Bell, RHV. (1982) The effect of soil nutrient availability on community structure in African ecosystems. In Huntley, BJ; Walker, BH (eds) Ecology of Tropical Savannas. Springer, Berlin, pp. 193216.CrossRefGoogle Scholar
Fritz, H; Duncan, P. (1994) On the carrying capacity for large ungulates of African savanna ecosystems. Proceedings of the Royal Society of London Series B: Biological Sciences 256:7782.Google ScholarPubMed
Rutherford, MC. (1980) Annual plant production–precipitation relations in arid and semi-arid regions. South African Journal of Science 76:5357.Google Scholar
Deshmukh, IK. (1984) A common relationship between precipitation and grassland peak biomass for east and southern Africa. African Journal of Ecology 22:181186.Google Scholar
Deshmukh, I. (1986) Primary production of a grassland in Nairobi National Park, Kenya. Journal of Applied Ecology 23:115123.CrossRefGoogle Scholar
Cox, GW; Waithaka, JM. (1989) Estimating aboveground net production and grazing harvest by wildlife on tropical grassland range. Oikos 54:6066.Google Scholar
Strugnell, RG; Pigott, CD. (1978) Biomass, shoot-production and grazing of two grasslands in the Rwenzori National Park, Uganda. The Journal of Ecology 66:7396.Google Scholar
Anderson, TM, et al. (2007) Rainfall and soils modify plant community response to grazing in Serengeti National Park. Ecology 88:11911201.Google Scholar
Waldram, MS, et al. (2008) Ecological engineering by a mega-grazer: white rhino impacts on a South African savanna. Ecosystems 11:101112.CrossRefGoogle Scholar
Arsenault, R; Owen-Smith, N. (2011) Competition and coexistence among short-grass grazers in the Hluhluwe-iMfolozi Park, South Africa. Canadian Journal of Zoology 89:900907.CrossRefGoogle Scholar
Cromsigt, JPGM; te Beest, M. (2014) Restoration of a megaherbivore: landscape‐level impacts of white rhinoceros in Kruger National Park, South Africa. Journal of Ecology 102:566575.Google Scholar
Cromsigt, J, et al. (2017) The functional ecology of grazing lawns – how grazers, termites, people, and fire shape HiP’s savanna grassland mosaic. In Cromsigt, JPGM, et al. (eds) Conserving Africa’s Mega-diversity in the Anthropocene: The Hluhluwe-iMfolozi Park Story. Cambridge University Press, Cambridge, pp. 135160.Google Scholar
Olivier, RCD; Laurie, WA. (1974) Habitat utilization by hippopotamus in the Mara River. African Journal of Ecology 12:249271.Google Scholar
Lock, JM. (1972) The effects of hippopotamus grazing on grasslands. The Journal of Ecology 60:445467.Google Scholar
Kanga, EM, et al. (2013) Hippopotamus and livestock grazing: influences on riparian vegetation and facilitation of other herbivores in the Mara Region of Kenya. Landscape and Ecological Engineering 9:4758.Google Scholar
Verweij, R, et al. (2006) Grazing lawns contribute to the subsistence of mesoherbivores on dystrophic savannas. Oikos 114:108116.CrossRefGoogle Scholar
McNaughton, SJ. (1983) Serengeti grassland ecology – the role of composite environmental-factors and contingency in community organization. Ecological Monographs 53:291320.CrossRefGoogle Scholar
Yoganand, K; Owen‐Smith, N. (2014) Restricted habitat use by an African savanna herbivore through the seasonal cycle: key resources concept expanded. Ecography 37:969982.Google Scholar
McNaughton, SJ. (1985) Ecology of a grazing ecosystem: the Serengeti. Ecological Monographs 55:259294.Google Scholar
Anderson, TM, et al. (2010) Landscape‐scale analyses suggest both nutrient and antipredator advantages to Serengeti herbivore hotspots. Ecology 91:15191529.Google Scholar
Archibald, S, et al. (2017) Interactions between fire and ecosystem processes. In Cromsigt, JPGM, et al. (eds) Conserving Africa’s Mega-Diversity in the Anthropocene: The Hluhluwe-iMfolozi Park Story. Cambridge University Press, Cambridge, pp. 233261.Google Scholar
Sinclair, A, et al. (2008) Historical and future changes to the Serengeti ecosystem. In Sinclair, ARE, et al. (eds) Serengeti III: Human Impacts on Ecosystem Dynamics. University of Chicago Press, Chicago, pp. 746.Google Scholar
Eby, S, et al. (2015) Fire in the Serengeti ecosystem: history, drivers, and consequences. In Sinclair, ARE, et al. (eds) Serengeti IV: Sustaining Biodiversity in a Coupled Human–Natural System. University of Chicago Press, Chicago, pp. 73103.CrossRefGoogle Scholar
Roques, KG, et al. (2001) Dynamics of shrub encroachment in an African savanna: relative influences of fire, herbivory, rainfall and density dependence. Journal of Applied Ecology 38:268280.CrossRefGoogle Scholar
O’Connor, TG, et al. (2014) Bush encroachment in southern Africa: changes and causes. African Journal of Range & Forage Science 31:6788.CrossRefGoogle Scholar
Moe, SR, et al. (2009) What controls woodland regeneration after elephants have killed the big trees? Journal of Applied Ecology 46:223230.Google Scholar
Voysey, MD, et al. (2021) The role of browsers in maintaining the openness of savanna grazing lawns. Journal of Ecology 109:913926.CrossRefGoogle Scholar
Pellew, RA. (1984) The feeding ecology of a selective browser, the giraffe (Giraffa camelopardalis tippelskirchi). Journal of Zoology 202:5781.Google Scholar
Augustine, DJ; McNaughton, SJ. (2004) Regulation of shrub dynamics by native browsing ungulates on East African rangeland. Journal of Applied Ecology 41:4558.Google Scholar
Staver, AC; Bond, WJ. (2014) Is there a ‘browse trap’? Dynamics of herbivore impacts on trees and grasses in an African savanna. Journal of Ecology 102:595602.Google Scholar
Prins, HHT; van der Jeugd, HP. (1993) Herbivore population crashes and woodland structure in East Africa. Journal of Ecology 81:305314.Google Scholar
Cooper, SM; Owen-Smith, N. (1985) Condensed tannins deter feeding by browsing ruminants in a South African savanna. Oecologia 67:142146.CrossRefGoogle Scholar
du Toit, JT; Owen-Smith, N. (1989) Body size, population metabolism, and habitat specialization among large African herbivores. The American Naturalist 133:736740.Google Scholar
Owen‐Smith, N, et al. (2019) Megabrowser impacts on woody vegetation in savannas. In Scogings, PF; Sankaran, M (eds) Savanna Woody Plants and Large Herbivores. Wiley, Oxford, pp. 585611.CrossRefGoogle Scholar
Chafota, J; Owen-Smith, N. (2009) Episodic severe damage to canopy trees by elephants: interactions with fire, frost and rain. Journal of Tropical Ecology 25:341345.CrossRefGoogle Scholar
Cromsigt, JPGM; Kuijper, DPJ. (2011) Revisiting the browsing lawn concept: evolutionary interactions or pruning herbivores? Perspectives in Plant Ecology, Evolution and Systematics 13:207215.Google Scholar
du Toit, JT; Olff, H. (2014) Generalities in grazing and browsing ecology: using across-guild comparisons to control contingencies. Oecologia 174:10751083.Google Scholar
Asner, GP; Levick, SR. (2012) Landscape‐scale effects of herbivores on treefall in African savannas. Ecology Letters 15:12111217.Google Scholar
Pellegrini, AFA, et al. (2017) Woody plant biomass and carbon exchange depend on elephant–fire interactions across a productivity gradient in African savanna. Journal of Ecology 105:111121.CrossRefGoogle Scholar
Sinclair, ARE, et al. (2008) Historical and future changes to the Serengeti ecosystem. In Sinclair, ARE, et al. (eds) Serengeti III: Human Impacts on Ecosystem Dynamics. University of Chicago Press, Chicago, pp. 746.Google Scholar
Morrison, TA, et al. (2016) Elephant damage, not fire or rainfall, explains mortality of overstorey trees in Serengeti. Journal of Ecology 104:409418.Google Scholar
Trollope, WSW, et al. (1998) Long-term changes in the woody vegetation of the Kruger National Park, with special reference to the effects of elephants and fire. Koedoe 41:103112.Google Scholar
Laws, RM, et al. (1975) Elephants and Their Habitats. Clarendon Press, Oxford.Google Scholar
Dublin, HT, et al. (1990) Elephants and fire as causes of multiple stable states in the Serengeti–Mara woodlands. The Journal of Animal Ecology 59:11471164.CrossRefGoogle Scholar
Dublin, HT. (1991) Dynamics of the Serengeti–Mara woodlands: an historical perspective. Forest & Conservation History 35:169178.Google Scholar
Agnew, ADQ. (1968) Observations on the changing vegetation of Tsavo National Park (East). African Journal of Ecology 6:7580.Google Scholar
Leuthold, W. (1977) Changes in tree populations of Tsavo East National Park, Kenya. African Journal of Ecology 15:6169.Google Scholar
Leuthold, W. (1996) Recovery of woody vegetation in Tsavo National Park, Kenya, 1970–94. African Journal of Ecology 34:101112.Google Scholar
Mosugelo, DK, et al. (2002) Vegetation changes during a 36‐year period in northern Chobe National Park, Botswana. African Journal of Ecology 40:232240.Google Scholar
Skarpe, C, et al. (2014) Plant–herbivore interactions. In Skarpe, C, et al. (eds) Elephants and Savanna Woodland Ecosystems. Wiley, Oxford, pp. 189206.Google Scholar
Teren, G, et al. (2018) Elephant‐mediated compositional changes in riparian canopy trees over more than two decades in northern Botswana. Journal of Vegetation Science 29:585595.Google Scholar
Makhabu, SW. (2005) Resource partitioning within a browsing guild in a key habitat, the Chobe Riverfront, Botswana. Journal of Tropical Ecology 21:641649.CrossRefGoogle Scholar
Chamaillé‐Jammes, S, et al. (2007) Managing heterogeneity in elephant distribution: interactions between elephant population density and surface‐water availability. Journal of Applied Ecology 44:625633.Google Scholar
Sianga, K, et al. (2017) Spatial refuges buffer landscapes against homogenisation and degradation by large herbivore populations and facilitate vegetation heterogeneity. Koedoe 59:a1434.Google Scholar
Ben-Shahar, R. (1998) Changes in structure of savanna woodlands in northern Botswana following the impacts of elephants and fire. Plant Ecology 136:189194.Google Scholar
Rutina, LP, et al. (2005) Elephant Loxodonta africana driven woodland conversion to shrubland improves dry-season browse availability for impalas Aepyceros melampus. Wildlife Biology 11:207213.Google Scholar
Stevens, N, et al. (2017) Savanna woody encroachment is widespread across three continents. Global Change Biology 23:235244.Google Scholar
Gosling, CM, et al. (2012) Effects of erosion from mounds of different termite genera on distinct functional grassland types in an African savannah. Ecosystems 15:128139.Google Scholar
Goudie, AS. (1988) The geomorphological role of earthworms and termites in the tropics. In Viles, H (ed.) Biogeomorphology. Blackwell, Oxford, pp. 4382.Google Scholar
Davies, AB, et al. (2014) Spatial variability and abiotic determinants of termite mounds throughout a savanna catchment. Ecography 37:852862.CrossRefGoogle Scholar
Mobæk, R, et al. (2005) Termitaria are focal feeding sites for large ungulates in Lake Mburo National Park, Uganda. Journal of Zoology 267:97102.Google Scholar
Davies, AB, et al. (2016) Termite mounds differ in their importance for herbivores across savanna types, seasons and spatial scales. Oikos 125:726734.Google Scholar
Holdo, RM; McDowell, LR. (2004) Termite mounds as nutrient-rich food patches for elephants. Biotropica 36:231239.Google Scholar
Loveridge, JP; Moe, SR. (2004) Termitaria as browsing hotspots for African megaherbivores in miombo woodland. Journal of Tropical Ecology 20:337343.Google Scholar
Ferrar, P. (1982) Termites of a South African savanna. IV. Subterranean populations, mass determinations and biomass estimations. Oecologia 52:147151.Google Scholar
Deshmukh, I. (1989) How important are termites in the production ecology of African savannas? Sociobiology 15:155168.Google Scholar
Borer, ET, et al. (2019) More salt, please: global patterns, responses and impacts of foliar sodium in grasslands. Ecology Letters 22:11361144.Google Scholar
Seagle, SW; McNaughton, SJ. (1992) Spatial variation in forage nutrient concentrations and the distribution of Serengeti grazing ungulates. Landscape Ecology 7:229241.Google Scholar
Griffith, DM, et al. (2017) Ungulate grazing drives higher ramet turnover in sodium‐adapted Serengeti grasses. Journal of Vegetation Science 28:815823.Google Scholar
Stock, WD, et al. (2010) Herbivore and nutrient control of lawn and bunch grass distributions in a southern African savanna. Plant Ecology 206:1527.Google Scholar
Weir, JS. (1972) Spatial distribution of elephants in an African National Park in relation to environmental sodium. Oikos 23:113.Google Scholar
Bond, WJ. (2005) Large parts of the world are brown or black: a different view on the ‘Green World’ hypothesis. Journal of Vegetation Science 16:261266.Google Scholar
Zimov, SA, et al. (2012) Mammoth steppe: a high-productivity phenomenon. Quaternary Science Reviews 57:2645.Google Scholar
Owen-Smith, N. (1987) Pleistocene extinctions: the pivotal role of megaherbivores. Paleobiology 13:351362.CrossRefGoogle Scholar
Mueller-Dombois, D. (1972) Crown distortion and elephant distribution in the woody vegetations of Ruhuna National Park, Ceylon. Ecology 53:208226.Google Scholar
Karanth, KU; Sunquist, ME. (1992) Population structure, density and biomass of large herbivores in the tropical forests of Nagarahole, India. Journal of Tropical Ecology 8:2135.CrossRefGoogle Scholar
Cardoso, AW, et al. (2020) The role of forest elephants in shaping tropical forest–savanna coexistence. Ecosystems 23:602616.Google Scholar

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