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Chapter 8 - Plant Demography and Dynamics: Fire Traps

from Part II - The Savanna Garden: Grassy Vegetation and Plant Dynamics

Published online by Cambridge University Press:  09 September 2021

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

This chapter is concerned with numerical changes in tree and grass populations. Size structure distributions of savanna trees vary widely, suggesting episodic recruitment is widespread. Life-history transitions of savanna trees are erratic and contingent on prevailing conditions, especially fire return intervals. Savanna trees vary widely in potential longevity, from several decades to thousands of years. Tree populations may be expanding or contracting in response to climatic variation or contingent influences. Grasses increase numerically through proliferation of either tillers, tufts or runners. Grass populations may turn over between one year and the next following drought or heavy grazing. Refuge sites enable grass species to persist through prolonged droughts.

Keywords

size structure distributionsepisodic recruitmentfire trapslottery competitiontree longevitytree mortalitytufts versus tillersgrass species turnover.
Type
Chapter
Information
Only in Africa
The Ecology of Human Evolution
 , pp. 118 - 127
Publisher: Cambridge University Press
Print publication year: 2021

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References

Suggested Further Reading

O’Connor, TG; Everson, TM. (1998) Population dynamics of perennial grasses in African savanna and grassland. In Cheplick, P (ed.) Population Biology of Grasses. Cambridge University Press, Cambridge, pp. 333–365.CrossRefGoogle Scholar
Staver, AC, et al. (2011) History matters: tree establishment variability and species turnover in an African savanna. Ecosphere 2(4):Art 49.Google Scholar

References

Bond, WJ; van Wilgen, BW. (1996) Fire and Plants. Springer, Berlin.CrossRefGoogle Scholar
Neke, KS. (2005) The regeneration ecology of savanna woodlands in relation to human utilisation. PhD thesis, University of the Witwatersrand, Johannesburg.Google Scholar
Helm, CV; Witkowski, ETF. (2012) Characterising wide spatial variation in population size structure of a keystone African savanna tree. Forest Ecology and Management 263:175–188.CrossRefGoogle Scholar
Helm, CV; Witkowski, ETF. (2013) Continuing decline of a keystone tree species in the Kruger National Park, South Africa. African Journal of Ecology 51:270–279.Google Scholar
Biggs, R; Jacobs, OS. (2002) The status and population structure of the marula in the Kruger National Park. South African Journal of Wildlife Research 32:1–12.Google Scholar
Higgins, SI, et al. (2000) Fire, resprouting and variability: a recipe for grass–tree coexistence in savanna. Journal of Ecology 88:213–229.Google Scholar
Wakeling, JL, et al. (2011) Simply the best: the transition of savanna saplings to trees. Oikos 120:1448–1451.CrossRefGoogle Scholar
Bond, WJ. (2008) What limits trees in C-4 grasslands and savannas? Annual Review of Ecology Evolution and Systematics 39:641–659.CrossRefGoogle Scholar
Wakeling, JL, et al. (2012) The savanna–grassland ‘treeline’: why don’t savanna trees occur in upland grasslands? Journal of Ecology 100:381–391.CrossRefGoogle Scholar
Edkins, MT, et al. (2008) Baobabs and elephants in Kruger National Park: nowhere to hide. African Journal of Ecology 46:119–125.Google Scholar
Bond, WJ; Loffell, D. (2001) Introduction of giraffe changes acacia distribution in a South African savanna. African Journal of Ecology 39:286–294.CrossRefGoogle Scholar
Sinclair, ARE, et al. (2007) Long‐term ecosystem dynamics in the Serengeti: lessons for conservation. Conservation Biology 21:580–590.Google 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. 7–46.Google Scholar
Anderson, TM, et al. (2015) Compositional decoupling of savanna canopy and understory tree communities in Serengeti. Journal of Vegetation Science 26:385–394.Google Scholar
Staver, AC, et al. (2011) History matters: tree establishment variability and species turnover in an African savanna. Ecosphere 2:1–12.Google Scholar
Bond, WJ; Midgley, GF. (2012) Carbon dioxide and the uneasy interactions of trees and savannah grasses. Philosophical Transactions of the Royal Society B – Biological Sciences 367:601–612.Google Scholar
Bond, WJ, et al. (2001) Acacia species turnover in space and time in an African savanna. Journal of Biogeography 28:117–128.CrossRefGoogle Scholar
Sea, WB; Hanan, NP. (2012) Self‐thinning and tree competition in savannas. Biotropica 44:189–196.CrossRefGoogle Scholar
Chase, MF, et al. (2019) Severe drought limits trees in a semi-arid savanna. Ecology 100:e02842.Google Scholar
Spinage, CA; Guinness, FE. (1971) Tree survival in the absence of elephants in the Akagera National Park, Rwanda. Journal of Applied Ecology 8:723–728.Google Scholar
Williams, RJ; Douglas, M. (1995) Windthrow in a tropical savanna in Kakadu National Park, northern Australia. Journal of Tropical Ecology 11:547–558.Google Scholar
Shackleton, CM. (1997) The prediction of woody productivity in thie savanna biome, South Africa. PhD thesis, University of the Witwatersrand, Johannesburg.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 29:585–595.Google Scholar
Fuls, A; Vogel, JC. (2005) The life-span of leadwood trees. South African Journal of Science 101:98–100.Google Scholar
Seymour, CL. (2008) Grass, rainfall and herbivores as determinants of Acacia erioloba (Meyer) recruitment in an African savanna. Plant Ecology 197:131–138.CrossRefGoogle Scholar
Patrut, A, et al. (2018) The demise of the largest and oldest African baobabs. Nature Plants 4:423–426.Google Scholar
Swemmer, AM. (2020) Locally high, but regionally low: the impact of the 2014–2016 drought on the trees of semi-arid savannas, South Africa. African Journal of Range & Forage Science 37:31–42.Google Scholar
Wilcox, KR. (2020) Rapid recovery of ecosystem function following extreme drought in a South African savanna grassland. Ecology 101:e02983.Google Scholar
Wigley-Coetsee, C; Staver, AC. (2020) Grass community responses to drought in an African savanna. African Journal of Range & Forage Science 37:43–52.Google Scholar
Abbas, HA, et al. (2019) The worst drought in 50 years in a South African savannah: limited impact on vegetation. African Journal of Ecology 57:490–499.CrossRefGoogle Scholar
Novellie, PA; Bezuidenhout, H. (1994) The influence of rainfall and grazing on vegetation changes in the Mountain Zebra National Park. South African Journal of Wildlife Research 24:60–71.Google Scholar
O’Connor, TG. (1991) Local extinction in perennial grasslands: a life-history approach. The American Naturalist 137:753–773.Google Scholar
O’Connor, TG; Pickett, GA. (1992) The influence of grazing on seed production and seed banks of some African savanna grasslands. Journal of Applied Ecology 29:247–260.CrossRefGoogle Scholar
O’Connor, TG. (1993) The influence of rainfall and grazing on the demography of some African savanna grasses: a matrix modelling approach. Journal of Applied Ecology 30:119–132.Google Scholar
Anderson, TM. (2008) Plant compositional change over time increases with rainfall in Serengeti grasslands. Oikos 117:675–682.CrossRefGoogle Scholar
Brown, PM; Wu, R. (2005) Climate and disturbance forcing of episodic tree recruitment in a southwestern ponderosa pine landscape. Ecology 86:3030–3038.CrossRefGoogle Scholar

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