Geochemical and mineralogical characteristics of elephant geophagic soils in Udawalawe National Park, Sri Lanka
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Geophagy or deliberate ingestion of soils was observed among Asian elephants (Elephas maximus) in the Udawalwe National Park, Sri Lanka, for several years. The geochemical and mineralogical composition of the clayey soil layers which are purposefully selected and eaten by elephants in the park were studied, in order to identify the possible reasons for elephant geophagy. The concentrations of major and trace elements were determined by means of X-ray fluorescence spectrometry in 21 soil samples from eight geophagic sites and six soil samples collected from four non-geophagic sites. The mineralogical composition of selected soil samples was investigated using X-ray diffractometry (XRD). These geochemical analyses revealed that geophagic soils in the study areas are deeply weathered and that most of the elements are leached from the soil layers under extreme weathering conditions. The XRD data showed that the soils of the area consisted mainly quartz, feldspar, and the clay minerals kaolinite, Fe-rich illite, and smectite. Although no significant geochemical differences were identified between geophagic and non-geophagic soils, a clear difference was observed in their clay mineralogical content. Soils eaten by elephants are richer in kaolinite and illite than non-geophagic soils, which contain a higher amount of smectite. It is suggested that elephants in Udawalawe National Park ingest soils mainly not to supplement the mineral contents of their forage but to detoxify unpalatable compounds in their diet.
KeywordMammalian herbivores Geophagy Soils Asian elephants Elephas maximus Clay minerals Udawalawe National Park
The authors wish to thank Chamitha de Alwis, Sarath Rajapakse, Deepchandi Lekamge, and Sanath Hewage for their assistance in the field, and Dr. Stefan Krum and Mr. Peter Lausser in the Chair of Geology, Erlangen for their assistance with X-ray diffractometry. Logistic and technical support provided by the park warden and his staff of Udawalawe National Park is acknowledged. We are also grateful to Mr. H.D. Ratnayake, Dr. K.B.Ranawana, and his team Prof. S.W. Kotagama and Dr. David Lohman for their numerous help. Financial support received for the field work from the Biodiversity and Elephant Conservation Trust (BECT), Sri Lanka is gratefully acknowledged. RC acknowledges the fellowship received from the Alexander von Humboldt Foundation which enabled him to carry out the chemical and mineralogical analysis at Erlangen. This research was conducted under the kind permission from the Director, Department of Wildlife Conservation, Sri Lanka.
- Bowell, R. J., Warren, A., & Redmond, I. (1996). Formation of cave salts and utilization by elephants in the Mount Elgon region, Kenya. In J. D. Appleton, R. Fuge, & G. J. H. McCall (Eds.), Environmental geochemistry and health Geological Society special publication no. 113 (pp. 63–79). London: Geological Society.Google Scholar
- Hettiarchchi, N. N., Rajapakse, I. K., & Padmalal, U. K. G. K.(2005). Food habits of Asian elephant (Elephas maximus maximus) in handapanagala, south east Sri Lanka. 10th Annual Forestry and Environment Symposium of the Department of Forestry and Environment Science, University of Sri Jayewardenepura, 2–3 December 2005Google Scholar
- Holdø, R. M., Dudley, J. P., & McDowell, L. R. (2002). Geophagy in the African elephant in relation to availability of dietary sodium. Journal of Mammalogy, 83(3), 652–664. doi: 10.1644/1545-1542(2002) 083 ≤ 0652:GITAEI ≥ 2.0.CO;2.CrossRefGoogle Scholar
- Johns, T., & Duquette, M. (1991). Detoxification and mineral supplementation as functions of geophagy. The American Journal of Clinical Nutrition, 53, 448–456.Google Scholar
- Kreulen, D. A., & Jager, T. (1984). The significance of soil ingestion in the utilization of arid rangelands by large herbivores, with special reference to natural licks on the Kalahari pans. In F. M. C. Gilchrist & R. I. Mackie (Eds.), Herbivore nutrition in the subtropics and tropics (pp. 204–221). Johannesburg: Science Press.Google Scholar
- Mahaney, W. C., Augreiter, S., & Hancock, R. G. V. (1995). Mountain Gorilla geophagy: a possible seasonal behaviour for dealing with the effects of dietary changes. International Journal of Primatology, 16, 475–488.Google Scholar
- Mee, A., Denny, R., Fairclough, K., Pullan, D.M., & Boyd-Wallis, W.(2005). Observations of parrots at a geophagy site in Bolivia Neotropica. Biota Neotropica, 5(2), http://www.biotaneotropica.org.br/v5n2/pt/abstract?short-communication+bn 02805022005 (assessed on 26.08.2007)
- Panwar, H.S., & Wickramasingha, W.R.M.S.(1997). Management Plan – Udawalawe National Park. Department of Wildlife Conservation and Protected Area Management; Department of Wildlife Conservation Sri Lanka, 76 ppGoogle Scholar
- Ranawana, K.B. (2007). Seasonal variation in availability and palatability of food plants for herbivores in Udawalawe National Park. Final report of the Protected Area Management and Wildlife Conservation Project (PAM & WCP), Department of Wildlife Conservation, Sri Lanka, 76 ppGoogle Scholar