Journal article

Publication year: 1997

Pages: 459-474

Journal: Journal of Arid Environments

Volume number: 36

Issue number: 3

ISSN: 0140-1963

DOI Link: https://doi.org/10.1006/jare.1996.0209

Publisher: Elsevier

Abstract: 

Classification of the herbacous vegetation of a heavily grazed rangeland in northern Kenya revealed four communities and a complex of extremely disturbed vegetation units. According to the ordination of releves, two of these communities, the Chrysopogon-Hibiscus and the Sporobolus-Indigofera association, represent a continuum that graded from stone covered and moderately grazed sites to smooth and heavily grazed pastures. From these, a Setaria acromelaena-Digera muricata association and an Achyranthes-Commelina association were distinctly separated. Whereas the former reflects moderately grazed pastures on day soils, the latter occurs in shaded livestock resting places and in gallery woods. Finally, the releves of the extremely disturbed vegetation originate from cattle tracks, watering places and livestock enclosures.

On light-textured soils, herbivore pressure caused a change in dominance among perennials and an increase of annual grasses. The bunch grass Chrysopogon plumulosus was replaced by the hemicryptophytic grass Sporobolus nervosus and the dwarf shrub Indigofera spinosa. Annual grasses, such as Tetrapogon cenriformis, increased in cover and frequency, or invaded i.e. Tragus berteronianus. On clay soils the perennial grasses were completely replaced by Setaria acromelaena and annual forbs. The latter achieved dominance on extremely disturbed and heavily defecated sites. Here, many of the therophytes are widespread weeds or species found on roadsides and waste grounds. The herb layer was far more sensitive to herbivore pressure than the shrub and the tree layer investigated in a previous paper. (C) 1997 Academic Press Limited.

Harvard Citation style: Cornelius, R. and Schultka, W. (1997) Vegetation structure of a heavily grazed range in northern Kenya: Ground vegetation, Journal of Arid Environments, 36(3), pp. 459-474. https://doi.org/10.1006/jare.1996.0209

APA Citation style: Cornelius, R., & Schultka, W. (1997). Vegetation structure of a heavily grazed range in northern Kenya: Ground vegetation. Journal of Arid Environments. 36(3), 459-474. https://doi.org/10.1006/jare.1996.0209