Resource selection by grazing herbivores on post-fire regrowth in a West African woodland savanna
Erik Klop A B , Janneke van Goethem A and Hans H. de Iongh AA Institute of Environmental Sciences, Leiden University, PO Box 9518, 2300 RA Leiden, The Netherlands.
B Corresponding author. Present address: Thorbeckestraat 160, 6702 BW Wageningen, The Netherlands. Email: eklop@cs.com
Wildlife Research 34(2) 77-83 https://doi.org/10.1071/WR06052
Submitted: 13 May 2006 Accepted: 2 March 2007 Published: 24 April 2007
Abstract
The preference of grazing herbivores to feed on grass regrowth following savanna fires rather than on unburnt grass swards is widely recognised. However, there is little information on which factors govern patterns of resource selection within burnt areas. In this study, we attempted to disentangle the effects of different habitat and grass sward characteristics on the utilisation of post-fire regrowth by nine species of ungulates in a fire-dominated woodland savanna in north Cameroon. We used resource-selection functions based on logistic regression. Overall, the resource-selection functions identified the time elapsed since burning as the most influential parameter in determining probability of use by ungulates, as most species strongly selected swards that were recently burned. This pattern might be related to nutrient levels in the grass sward. In addition, most species selected areas with high grass cover and avoided grass swards with high amounts of dead stem material. This is likely to increase bite mass and, hence, intake rates. The avoidance of high tree cover by some species may suggest selection for open areas with good visibility and, hence, reduced risk of predation. Body mass seemed to have no effect on differential selection of post-fire regrowth, irrespective of feeding style.
Acknowledgements
This study was supported by the Directoraat Generaal Internationale Samenwerking of the Dutch government and the Institute of Environmental Sciences of Leiden University. In Cameroon we were greatly assisted by many people, most notably Stephen van der Mark, Assan Gomse, Kadri, Moussa, and Amadou Yadji. Marjan van de Weg did an excellent job in monitoring grass quality. Herbert Prins and Helias Udo de Haes provided valuable comments on earlier drafts of this paper. To all these people and organisations we are immensely grateful.
Archibald, S. , and Bond, W. J. (2004). Grazer movements: spatial and temporal responses to burning in a tall-grass African savanna. International Journal of Wildland Fire 13, 377–385.
| Crossref | GoogleScholarGoogle Scholar |
Edwards, G. R. , Newman, J. A. , Parsons, A. J. , and Krebs, J. R. (1994). Effects of the scale and spatial distribution of the food resource and animal state on diet selection: an example with sheep. Journal of Animal Ecology 63, 816–826.
| Crossref | GoogleScholarGoogle Scholar |
Fryxell, J. M. (1991). Forage quality and aggregation by large herbivores. American Naturalist 138, 478–498.
| Crossref | GoogleScholarGoogle Scholar |
Laca, E. A. , Ungar, E. D. , Seligman, N. G. , and Demment, M. W. (1992). Effects of sward height and bulk density on bite dimensions of cattle grazing homogeneous swards. Grass and Forage Science 47, 91–102.
| Crossref | GoogleScholarGoogle Scholar |
McNaughton, S. J. (1984). Grazing lawns: animals in herds, plant form and coevolution. American Naturalist 124, 863–886.
| Crossref | GoogleScholarGoogle Scholar |
Spalinger, D. E. , and Hobbs, N. T. (1992). Mechanisms of foraging in mammalian herbivores: new models of functional response. American Naturalist 140, 325–348.
| Crossref | GoogleScholarGoogle Scholar |
Van de Vijver, C. A. D. M. , Poot, P. , and Prins, H. H. T. (1999). Causes of increased nutrient concentrations in post-fire regrowth in an East African savanna. Plant and Soil 214, 173–185.
| Crossref | GoogleScholarGoogle Scholar |
Verweij, R. J. T. , Verrelst, J. , Loth, P. E. , Heitkönig, I. M. A. , and Brunsting, A. M. H. (2006). Grazing lawns contribute to the subsistence of mesoherbivores on dystrophic savannas. Oikos 114, 108–116.
| Crossref | GoogleScholarGoogle Scholar |
Wilsey, B. J. (1996). Variation in use of green flushes following burns among African ungulate species: the importance of body size. African Journal of Ecology 34, 32–38.