Abstract

Grazing, fire and selective tree cutting are major disturbances that shape species diversity in savanna ecosystems, yet their effects are highly variable. We carried out a factorial experiment with two levels to examine the effects of grazing, fire and selective tree cutting on herbaceous species richness, abundance and diversity on two sites in the Sudanian savanna-woodlands of Burkina Faso for 10 years (1994-2003). The results showed significant inter-annual variation in species richness, abundance and diversity at both sites (p<0.001), while main or combined effects of fire, grazing and selective cutting were very limited and varied between life forms and sites. Grazing tended to favour the diversity of perennial grasses; fire tended to influence the richness of annual grasses and abundance and diversity of perennial grasses while selective tree cutting had no effect on any of the vegetation attributes assessed. The combined effect of grazing, fire and selective cutting tended to increase the diversity of forbs. In many cases, the responses of herbaceous species to treatments were clearer on the site with deeper soils than the one with shallow soils. Depending on the site and treatments, the inter-annual variation in vegetation attributes was partly related to amount and/or frequency of rainfall and partly to inter-annual variation in grazing or fire intensity. It can be concluded that both disturbances and climatic condition influence the structure and diversity of herbaceous flora in the Sudanian savanna-woodland ecosystem. The responses were site-specific, which accentuates the importance of landscape-scale approaches to understand the impacts of disturbances on composition, structure and diversity of savanna ecosystems. (C) 2008 Rubel Foundation, ETH Zurich. Published by Elsevier GmbH. All rights reserved.

Keywords

Burkina Faso; conservation; disturbance; diversity; herbivory; species richness

Published in

Perspectives in Plant Ecology, Evolution and Systematics
2008, Volume: 10, number: 3, pages: 179-195

SLU Authors

• Savadogo, Patrice

  • Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences
    

• Tigabu, Mulualem

  • Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Forest Science


Publication identifier

DOI: https://doi.org/10.1016/j.ppees.2008.03.002

Permanent link to this page (URI)

https://res.slu.se/id/publ/28246