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Did the elephant and giraffe mediate change in the prevalence of palatable species in an East African Acacia woodland?

Published online by Cambridge University Press:  08 December 2014

Megan K. L. Strauss  and
Craig Packer
Megan K. L. Strauss*
Affiliation:
Department of Ecology, Evolution and Behavior, University of Minnesota, 100 Ecology Bldg, 1987 Upper Buford Circle, Saint Paul, MN 55108, USA
Craig Packer
Affiliation:
Department of Ecology, Evolution and Behavior, University of Minnesota, 100 Ecology Bldg, 1987 Upper Buford Circle, Saint Paul, MN 55108, USA
*
1Corresponding author. Email: [email protected]
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Abstract:

We report on a 2009 survey of Acacia woodlands in the Seronera area of central Serengeti, Tanzania, and compare the results to previous surveys from the 1970s–1980s. We document a substantial change in woodland structure and composition. From 1978 to 2009, woody plant density (mean ± SD) declined from 255 ± 35 trees ha−1 to 147 ± 14 trees ha−1. Canopy cover declined from 15.1 ± 1.9% to 5.7 ± 0.6%. Canopy volume declined from 1810 ± 207 m3 ha−1 to 1410 ± 121 m3 ha−1. A 19% increase in the relative canopy volume of Acacia robusta, a species avoided by the giraffe, represents a sharp decline in the quality of the giraffe's food supply, which was last comprehensively assessed in 1978. We examine these changes in the context of Pellew's 1983 woodland dynamics model describing the impacts of elephant, giraffe and fire on an Acacia tortilis tree population and determine that our data are qualitatively consistent with this model. We hypothesize that selective elephant and giraffe browsing has contributed to an increase in the relative dominance of unpalatable species, consistent with Pellew's predictions.

Keywords

AcaciaAfrican elephantgiraffeSerengetivegetation impactsunpalatable species
Type
Research Article
Information
Journal of Tropical Ecology , Volume 31 , Issue 1 , January 2015 , pp. 1 - 12
Copyright
Copyright © Cambridge University Press 2014 

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References

LITERATURE CITED

AUGUSTINE, D. J. & MCNAUGHTON, S. J. 1998. Ungulate effects on the functional species composition of plant communities: herbivore selectivity and plant tolerance. Journal of Wildlife Management 62:1165–1183.Google Scholar
BELSKY, A. J. 1984. Role of small browsing mammals in preventing woodland regeneration in the Serengeti National Park, Tanzania. African Journal of Ecology 22:271–279.Google Scholar
BEN-SHAHAR, R. 1996. Woodland dynamics under the influence of elephants and fire in northern Botswana. Vegetatio 123:153–163.Google Scholar
BEUCHNER, H. K. & DAWKINS, H. C. 1961. Vegetation change induced by elephants and fire in Murchison Falls National Park, Uganda. Ecology 42:752–766.Google Scholar
BIRKETT, A. 2002. The impact of giraffe, rhino and elephant on the habitat of a black rhino sanctuary in Kenya. African Journal of Ecology 40:276–282.Google Scholar
BIRKETT, A. & STEVENS-WOOD, B. 2005. Effect of low rainfall and browsing by large herbivores on an enclosed savannah habitat in Kenya. African Journal of Ecology 43:123–130.Google Scholar
BOND, W. J. & LOFFELL, D. 2001. Introduction of giraffe changes acacia distribution in a South African savanna. African Journal of Ecology 39:286–294.Google Scholar
COTTAM, G. & CURTIS, J. T. 1956. The use of distance measures in phytosociological sampling. Ecology 37:451–460.CrossRefGoogle Scholar
CROZE, H. 1974a. The Seronera bull problem. II. The trees. East African Wildlife Journal 12:29–47.CrossRefGoogle Scholar
CROZE, H. 1974b. The Seronera bull problem. I. The elephants. East African Wildlife Journal 12:1–27.Google Scholar
DEMPEWOLF, J., TRIGG, S., DEFRIES, R. S. & EBY, S. 2007. Burned-area mapping of the Serengeti-Mara region using MODIS reflectance data. IEEE Geoscience and Remote Sensing Letters 4:312–316.Google Scholar
DUBLIN, H. T. 1995. Vegetation dynamics in the Serengeti–Mara ecosystem: the role of elephants, fire and other factors. Pp. 71–90 in Sinclair, A. R. E. & Arcese, P. (eds.). Serengeti II: dynamics of an ecosystem. University of Chicago Press, Chicago.Google Scholar
DUBLIN, H. T., SINCLAIR, A. R. E. & MCGLADE, J. 1990. Elephants and fire as causes of multiple stable states in the Serengeti-Mara woodlands. Journal of Animal Ecology 59:1147–1164.Google Scholar
ESTES, R. D., RAGHUNATHAN, T. E. & VAN VLECK, D. 2008. The impact of horning by wildebeest on woody vegetation of the Serengeti ecosystem. Journal of Wildlife Management 72:1572–1578.Google Scholar
GOHEEN, J. R., KEESING, F., ALLAN, B. F., OGADA, D. & OSTFELD, R. S. 2004. Net effects of large mammals on Acacia seedling survival in an African savanna. Ecology 85:1555–1561.Google Scholar
HERLOCKER, D. J. 1976. Structure composition, and environment of some woodland vegetation types of the Serengeti National Park, Tanzania. PhD dissertation, Texas A&M University.Google Scholar
HEYTING, A. 1968. Discussion and development of the point-centred quarter method of sampling grassland vegetation. Journal of Range Management 21:370–380.Google Scholar
HOLDO, R. M., HOLT, R. D. & FRYXELL, J. M. 2009. Grazers, browsers, and fire influence the extent and spatial pattern of tree cover in the Serengeti. Ecological Applications 19:95–109.Google Scholar
JACHMANN, H. & CROES, T. 1991. Effects of browsing by elephants on the Combretum/Terminalia woodland at the Nazinga Game Ranch, Burkina Faso, West Africa. Biological Conservation 57:13–24.Google Scholar
LAMPREY, H. F., GLOVER, P. E., TURNER, M. I. M. & BELL, R. H. V. 1967. Invasion of the Serengeti National Park by elephants. East African Wildlife Journal 5:151–166.Google Scholar
MAPAURE, I. & MOE, S. R. 2009. Changes in the structure and composition of miombo woodlands mediated by elephants (Loxodonta africana) and fire over a 26-year period in north-western Zimbabwe. African Journal of Ecology 47:175–183.Google Scholar
MCINNES, P. F., NAIMAN, R. J., PASTOR, J. & COHEN, Y. 1992. Effects of moose browsing on vegetation and litter of the boreal forest, Isle Royale, Michigan, USA. Ecology 73:2059–2075.Google Scholar
MOE, S. R., RUTINA, L. P., HYTTEBORN, H. & DU TOIT, J. T. 2009. What controls woodland regeneration after elephants have killed the big trees? Journal of Applied Ecology 46:223–230.Google Scholar
NORTON-GRIFFITHS, M. 1979. The influence of grazing, browsing, and fire on the vegetation dynamics of the Serengeti. Pp. 310–352 in Sinclair, A.R.E. & Norton-Griffiths, M. (eds.). Serengeti: dynamics of an ecosystem. University of Chicago Press, Chicago.Google Scholar
O’KANE, C. A. J., DUFFY, K. J., PAGE, B. R. & MACDONALD, D. W. 2014. Model highlights likely long-term influences of mesobrowsers versus those of elephants on woodland dynamics. African Journal of Ecology 52:192–208.Google Scholar
PACKER, C., HILBORN, R., MOSSER, A., KISSUI, B., BORNER, M., HOPCRAFT, G., WILMSHURST, J., MDUMA, S. & SINCLAIR, A. R. E. 2005. Ecological change, group territoriality, and population dynamics in Serengeti lions. Science 307:390–393.Google Scholar
PELLEW, R. A. 1981. The giraffe and its food resource in the Serengeti National Park. PhD dissertation, University of London.Google Scholar
PELLEW, R. A. 1983a. The impacts of elephant, giraffe and fire upon the Acacia tortilis woodlands of the Serengeti. African Journal of Ecology 21:41–74.Google Scholar
PELLEW, R. A. 1983b. Modelling and the systems approach to management problems: the Acacia/elephant problem in the Serengeti. Pp. 93–114 in Owen-Smith, R. N. (ed.). Management of large mammals in African conservation areas. HAUM Educational Publishers, Pretoria.Google Scholar
PELLEW, R. A. 1983c. The giraffe and its food resource in the Serengeti. I. Composition, biomass and production of available browse. African Journal of Ecology 21:241–267.CrossRefGoogle Scholar
PELLEW, R. A. 1983d. The giraffe and its food resource in the Serengeti. II. Response of the giraffe population to changes in the food supply. African Journal of Ecology 21:269–283.Google Scholar
PELLEW, R. A. 1984a. Food consumption and energy budgets of the giraffe. Journal of Applied Ecology 21:141–159.Google Scholar
PELLEW, R. A. 1984b. The feeding ecology of a selective browser, the giraffe (Giraffa camelopardalis tippelskirchi). Journal of Zoology (London) 202:57–81.Google Scholar
PELLEW, R. A. & SOUTHGATE, B. J. 1984. The parasitism of Acacia tortilis seeds in the Serengeti. African Journal of Ecology 22:73–75.Google Scholar
PRINS, H. H. T. & VAN DER JEUGD, H. P. 1993. Herbivore population crashes and woodland structure in East Africa. Journal of Ecology 81:305–314.Google Scholar
REED, D. N., ANDERSON, T. M., DEMPEWOLF, J., METZGER, K. & SERNEELS, S. 2009. The spatial distribution of vegetation types in the Serengeti ecosystem: the influence of rainfall and topographic relief on vegetation patch characteristics. Journal of Biogeography 36:770–782.Google Scholar
RUESS, R. W. & HALTER, F. L. 1990. The impact of large herbivores on the Seronera woodlands, Serengeti National Park, Tanzania. African Journal of Ecology 28:259–275.Google Scholar
SANKARAN, M., HANAN, N. P., SCHOLES, R. J., RATNAM, J., AUGUSTINE, D. J, CADE, B. S., GIGNOUX, J., HIGGINS, S. I., LE ROUX, X., LUDWIG, F., ARDO, J., BANYIKWA, F., BRONN, A., BUCINI, G., CAYLOR, K. K., COUGHENOUR, M. B., DIOUF, A., EKAYA, W., FERAL, C. J., FEBRUARY, E. C., FROST, P. G. H., HIERNAUX, P., HRABAR, H., METZGER, K. L., PRINS, H. H. T., RINGROSE, S., SEA, W., TEWS, J., WORDEN, J. & ZAMBATIS, N. 2005. Determinants of woody cover in African savannas. Nature 438:846–849.Google Scholar
SHARAM, G., SINCLAIR, A. R. E. & TURKINGTON, R. 2006. Establishment of broad-leaved thickets in Serengeti, Tanzania: the influence of fire, browsers, grass competition, and elephants. Biotropica 38:599–605.Google Scholar
SHAW, M. T., KEESING, F. & OSTFELD, R. S. 2002. Herbivory on acacia seedlings in an East African savanna. Oikos 98:385–392.Google Scholar
SHAW, P., SINCLAIR, A. R. E., METZGER, K., NKWABI, A., MDUMA, S. A. R. & BAKER, N. 2010. Range expansion of the globally vulnerable Karamoja apalis Apalis karamojae in the Serengeti ecosystem. African Journal of Ecology 48:751–758.Google Scholar
SINCLAIR, A. R. E. 1979a. Dynamics of the Serengeti ecosystem: Process and pattern. Pp. 1–30 in Sinclair, A. R. E. & Norton-Griffiths, M. (eds.). Serengeti: dynamics of an ecosystem. University of Chicago Press, Chicago.Google Scholar
SINCLAIR, A. R. E. 1979b. The Serengeti environment. Pp. 31–45 in Sinclair, A. R. E. & Norton-Griffiths, M. (eds.). Serengeti: dynamics of an ecosystem. University of Chicago Press, Chicago.Google Scholar
SINCLAIR, A. R. E. 1995. Equilibria in plant–herbivore interactions. Pp. 91–113 in Sinclair, A. R. E. & Arcese, P. (eds.). Serengeti II: dynamics, management, and conservation of an ecosystem. University of Chicago Press, Chicago.Google Scholar
SINCLAIR, A. R. E. & NORTON-GRIFFITHS, M. 1982. Does competition or facilitation regulate migrant ungulate populations in the Serengeti? A test of hypotheses. Oecologia 53:364–369.Google Scholar
SINCLAIR, A. R. E., MDUMA, S. A. R., HOPCRAFT, J. G. C., FRYXELL, J. M., HILBORN, R. & THIRGOOD, S. 2007. Long-term ecosystem dynamics in the Serengeti: lessons for conservation. Conservation Biology 21:580–590.Google Scholar
SINCLAIR, A. R. E., HOPCRAFT, J. G. C., OLFF, H., MDUMA, S. A. R., GALVIN, K. A. & SHARAM, G. J. 2008. Historical and future changes to the Serengeti ecosystem. Pp. 7–46 in Sinclair, A. R. E., Packer, C., Mduma, S. A. R. & Fryxell, J. M. (eds.). Serengeti III: human impacts on ecosystem dynamics. University of Chicago Press, Chicago.Google Scholar
STRONACH, N. R. H. 1989. Grass fires in Serengeti National Park, Tanzania: characteristics, behaviour and some effects on young trees. PhD dissertation, Cambridge University.Google Scholar