Biodiversity and Conservation

, Volume 17, Issue 4, pp 911–923 | Cite as

Plant and small mammal richness correlate positively in a biodiversity hotspot

  • Christina Keller
  • Carsten Schradin
Original Paper


Hotspots of biodiversity are important areas in facilitating an understanding of species richness and its maintenance. Herbivores can increase plant richness by reducing dominant plant species thus providing space for subdominant species. As small mammals are abundant in the Succulent Karoo and therefore might affect plant richness by means of herbivory, we tested if this mechanism might exist in the Succulent Karoo in southern Africa, a biodiversity hotspot due to its extraordinary plant richness. At ten ecologically different study sites we measured plant and small mammal richness and diversity and determined 11 abiotic factors including soil composition, altitude and rainfall. We found positive correlations between plant richness and the number of small mammal species. A general linear model revealed that the number of small mammal species was more important than abiotic factors in explaining variation in plant richness. To test whether small mammals might directly influence plant richness, we studied the influence of the bush-Karoo rat Otomys unisulcatus, a central place forager, on the plant community. The immediate surroundings of occupied O. unisulcatus nests showed significantly higher plant richness than control areas. We conclude that small mammals can have a positive effect on plant richness in the Succulent Karoo. While experimental data are needed to support these correlative results, the results of our study indicate that areas of high small mammal richness should be included in conservation programs of the Succulent Karoo.


Macroscelidae Otomys unisulcatus Predation-hypothesis Small mammals Succulent Karoo 



We would like to thank N. Sachser, N. Pillay, the Northern Cape Department of Agriculture, Land reform, Environment and Conservation and the staff of Goegap Nature Reserve for their support during the study. We are especially thankful to M. Schubert, C. Schneider, A. Wiedon, P. Widmann and M. Scriba for field assistance. Comments by N. Pillay and H. Rödel and two unknown referees significantly improved the manuscript. We are thankful to S. Krackow for statistical advice. The University of the Witwatersrand and the Frauenförderung of the University of Münster (for CK) provided financial support. CS was supported by a fellowship of the Claude Leon Harris Foundation, South Africa. Animal ethical clearance number: 2004/1/2A (University of the Witwatersrand). We declare that all experiments comply with the laws of South Africa.


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Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  1. 1.Department of Behavioural BiologyUniversity of MuensterMuensterGermany
  2. 2.School of Animal, Plant and Environmental SciencesUniversity of the WitwatersrandJohannesburgSouth Africa
  3. 3.Research Group Cognitive EthologyGerman Primate CenterGoettingenGermany
  4. 4.Department of Animal BehaviorUniversity of ZuerichZuerichSwitzerland

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