Original Research

Herbivores shape woody plant communities in the Kruger National Park: Lessons from three long-term exclosures

Benjamin J. Wigley, Herve Fritz, Corli Coetsee, William J. Bond
Koedoe | Vol 56, No 1 | a1165 | DOI: https://doi.org/10.4102/koedoe.v56i1.1165 | © 2014 Benjamin J. Wigley, Herve Fritz, Corli Coetsee, William J. Bond | This work is licensed under CC Attribution 4.0
Submitted: 07 May 2013 | Published: 11 March 2014

About the author(s)

Benjamin J. Wigley, School of Natural Resource Management, Nelson Mandela Metropolitan University, George campus, South Africa; UMR CNRS 5558 LBBE, University Claude Bernard Lyon 1, France
Herve Fritz, UMR CNRS 5558 LBBE, University Claude Bernard Lyon 1, France
Corli Coetsee, School of Natural Resource Management, Nelson Mandela Metropolitan University, George campus, South Africa
William J. Bond, Department of Biological Sciences, University of Cape Town, South Africa

Abstract

The role of grazers in determining vegetation community compositions and structuring plant communities is well recognised in grassy systems. The role of browsers in affecting savanna woody plant communities is less clear. We used three long-term exclosures in the Kruger National Park to determine the effect of browsers on species compositions and population structures of woody communities. Species assemblages, plant traits relating to browsing and soil nutrients were compared inside and outside of the exclosures. Our results showed that browsers directly impact plant species distributions, densities and population structures by actively selecting for species with traits which make them desirable to browsers. Species with high leaf nitrogen, low total phenolic content and low acid detergent lignin appeared to be favoured by herbivores and therefore tend to be rare outside of the exclosures. This study also suggested that browsers have important indirect effects on savanna functioning, as the reduction of woody cover can result in less litter of lower quality, which in turn can result in lower soil fertility. However, the magnitude of browser effects appeared to depend on inherent soil fertility and climate.


Conservation implications: Browsers were shown to have significant impacts on plant communities. They have noticeable effects on local species diversity and population structure, as well as soil nutrients. These impacts are shown to be related to the underlying geology and climate. The effects of browsers on woody communities were shown to be greater in low rainfall, fertile areas compared to high rainfall, infertile soils.


Keywords

Browsers; herbivore exclosures; plant communities; plant traits

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Crossref Citations

1. A thorny issue: Woody plant defence and growth in an East African savanna
Benjamin J. Wigley, Corli Coetsee, David J. Augustine, Jayashree Ratnam, Dawood Hattas, Mahesh Sankaran, Giselda Durigan
Journal of Ecology  vol: 107  issue: 4  first page: 1839  year: 2019  
doi: 10.1111/1365-2745.13140