Grazing response in the vegetation communities of the Kamiesberg, South Africa: Adopting a plant functional type approach

• Published in: Journal of arid environments Vol. 75; no. 3; pp. 255 - 264
• Main Authors: Anderson, P.M.L., Hoffman, M.T.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-03-2011; Elsevier
• Subjects: accuracy; altitude; Animal and plant ecology; Animal, plant and microbial ecology; Biological and medical sciences; botanical composition; cacti and succulents; communally owned land; experimental design; flowers; functional diversity; Fundamental and applied biological sciences. Psychology; Grazing; grazing intensity; growth habit; height; leaves; methodology; plant architecture; plant communities; Plant functional types; range management; rangelands; Succulent karoo; Synecology; Terrestrial ecosystems; vegetation; woody plants; South Africa; Africa; South Africa, Karoo; Grazing; Plant functional types; Succulent karoo; Plant community; Arid environment; Approach
• ISSN: 0140-1963; 1095-922X
• DOI: 10.1016/j.jaridenv.2010.10.012

Potential grazing impacts associated with the sustained heavy grazing of a communal rangeland are explored through a plant functional type approach. An informative typology is derived that shows grazing responses. An examination of plant functional types within growth forms does not provide any additional insights, whereas looking at traits alone does demonstrate a grazing response with increases in the traits of large basal and erect leafy growth forms and losses in the traits of medium height, simple leaves and few flowers. There is also evidence of a biogeographic shift, with an increase in a succulent-dominated plant functional type at higher altitudes on the heavily grazed communal rangeland. This is attributed to the fact that in adopting the proposed universal language advocated by plant functional type practitioners some of the subtleties of this particular vegetation type are lost. For example growth form height classes are too coarse for the shorter vegetation of the Succulent Karoo. In the resultant ‘fuzzy’ groups, responses are lost. While the method adopted is informative a stronger case is made for a more simple growth form analysis traditionally adopted in rangeland analysis.
► Plant functional traits demonstrate a grazing response with increases in the traits of large basal and erect leafy growth forms and losses in the traits of medium height, simple leaves and few flowers in a semi-arid rangeland. ► Heavy grazing gives rise to a biogeographic shift, with an increase in a succulent-dominated plant functional type at higher altitudes on the heavily grazed communal rangeland. ► Findings suggest the proposed universal language advocated by plant functional type practitioners means that some of the subtleties of some vegetation types are lost.