Hostname: page-component-cd9895bd7-gbm5v Total loading time: 0 Render date: 2024-12-27T07:52:35.507Z Has data issue: false hasContentIssue false
  • English
  • Français

The role of the elephant (Loxodonta africana) and the tree squirrel (Paraxerus cepapi) in marula (Sclerocarya birrea) seed predation, dispersal and germination

Published online by Cambridge University Press:  13 February 2012

Jeremy J. Midgley ,
Kirsten Gallaher  and
Laurence M. Kruger
Jeremy J. Midgley*
Affiliation:
Botany Department, University of Cape Town, P. Bag Rondebosch, 7701South Africa
Kirsten Gallaher
Affiliation:
Botany Department, University of Cape Town, P. Bag Rondebosch, 7701South Africa
Laurence M. Kruger
Affiliation:
Botany Department, University of Cape Town, P. Bag Rondebosch, 7701South Africa Organization for Tropical Studies, Kruger National Park, P.O. Box 33, Skukuza, 1350, South Africa
*
1Corresponding author. Email: Jeremy.Midgley@uct.ac.za
Get access Rights & Permissions [Opens in a new window]

Extract

The marula (Sclerocarya birrea (A.Rich.) Hochst., Anacardiaceae) has a strongly lignified endocarp or stone which contains several seeds, each of which is within its own locule that is sealed by an individual operculum (Figure 1). The strong casing prevents germination, not by preventing the passage of water to the seeds, but by preventing oxygen from reaching the seeds (von Teichman et al. 1985). It is well known that marula fruits taken from the dung of the African elephant (Loxodonta africana Blumenbach) have more rapid germination than those that have not been eaten by elephants (Dudley 2000, Lewis 1987). This positive impact of elephants on marula germination continues to be considered to be through acid treatment in the digestion system of the elephant (Helm et al. 2011). We hypothesize that the primary mechanism which favours germination is mastication by elephants which physically loosens the opercula, rather than digestive dissolution of the stone. If true, the relevance of this is that only elephants would be the legitimate dispersers of marula seeds, because none of the many other species that are attracted to marula fruits would have jaws powerful enough to loosen the opercula.

Keywords

dispersalelephantsgerminationLoxodonta africanamarulaParaxerus cepapiscatter hoardingSclerocarya birreasquirrels
Type
Short Communication
Information
Journal of Tropical Ecology , Volume 28 , Issue 2 , March 2012 , pp. 227 - 231
Copyright
Copyright © Cambridge University Press 2012

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

LITERATURE CITED

ALVERSON, W. S. & DIAZ, A. G. 1989. Measurement of the dispersal of large seeds and fruits with a magnetic locator. Biotropica 21:61–63.CrossRefGoogle Scholar
DUDLEY, J. P. 2000. Seed dispersal by elephants in semiarid woodland habitats of Hwange National Park, Zimbabwe. Biotropica 32:556–561.CrossRefGoogle Scholar
GUIMARÃES, P. R., GALETTI, M. & JORDANO, P. 2008. Seed dispersal anachronisms: rethinking the fruits extinct megafauna ate. PLoS ONE 3 (3):e1745. doi:10.1371/journal.pone.0001745CrossRefGoogle ScholarPubMed
HELM, C. V., SCOTT, S. L. & WITKOWSKI, E. T. F. 2011. Reproductive potential and seed fate of Sclerocarya birrea subsp. caffra in the low altitude savannas of South Africa. South African Journal of Botany 77:650–664.CrossRefGoogle Scholar
LEWIS, D. M. 1987. Fruiting patterns, seed germination, and distribution of Sclerocarya caffra in an elephant-inhabited woodland. Biotropica 19:50–56.CrossRefGoogle Scholar
MIDGLEY, J. J. & ANDERSON, B. C. 2005. Scatterhoarding in Cape fynbos. Pp 197–204 in Forget, P.-M., Lambert, J. E, Hulme, P. E & Vander Wall, S. B. (eds.). Seed fate: predation, dispersal and seedling establishment. CAB Publishing, Wallingford.CrossRefGoogle Scholar
PETERS, C. R. 1993. Shell strength and primate seed predation of nontoxic species in Eastern and Southern Africa. International Journal of Primatology 14:315–344.CrossRefGoogle Scholar
PIENAAR, U. DE V. 1968. The ecological significance of roads in a National Park. Koedoe 11:169–174.CrossRefGoogle Scholar
RANDRIANSOLO, A. & MILLER, J. S. 1999. A new species of Poupartia (Anacardiaceae) from Madagascar. Novon 9:546–548.CrossRefGoogle Scholar
VANDER WALL, S. B. & LONGLAND, W. S. 2004. Diplochory: are two seed dispersers better than one? Trends in Ecology and Evolution 19:155–161.CrossRefGoogle ScholarPubMed
VILJOEN, S. 1977 a. Behaviour of the bush squirrel, Paraxerus cepapi cepapi (A. Smith, 1836). Mammalia 41:119–166.CrossRefGoogle Scholar
VILJOEN, S. 1977 b. Feeding habits of the bush squirrel Paraxerus cepapi cepapi (Rodentia: Sciuridae). Zoologica Africana 12:459–467.CrossRefGoogle Scholar
VILJOEN, S. 1983. Feeding habits and comparative feeding rates of three southern African arboreal tree squirrels. South African Journal of Zoology 18:378–387.CrossRefGoogle Scholar
VON TEICHMAN, I., SMALL, J. G. C. & ROBBERTSE, P. J. 1985. A preliminary study on the germination of Sclerocarya birrea subsp. caffra. South African Journal of Botany 52:145–148.CrossRefGoogle Scholar
WROE, S., MCHENRY, C. & THOMASON, J. 2005. Bite club: comparative bite force in big biting mammals and the prediction of predatory behaviour in fossil taxa. Proceedings of the Royal Society B Biological Sciences 272:619–625.CrossRefGoogle ScholarPubMed