Patterns of change in the herbaceous layer of a mesic savanna, South Africa

N. van Rooyen, G.K. Theron, D. Bezuidenhout, G.J. Bredenkamp, M.W. van Rooyen
1993 South African Journal of Botany  
The basal cover and presence of savanna plant species of the herbaceous stratum were monitored seven times from 1975 to 1990. The two dominant grass species, Eragrostis pal/ens and Digitaria eriantha contributed 58.5% to the overall mean percentage basal cover. A significant decrease in mean basal cover between 1977 and 1980 and a significant increase between 1986 and 1990 were observed. However, there was no significant difference between the mean total basal cover for 1975 (5.46%) and 1990
more » ... (5.46%) and 1990 (6.13%). Rainfall during the 21 months preceding sampling as well as fire may explain the trends in basal cover. The ordination trajectories of basal cover and species presence over time indicate that no clear monotonic trends were apparent; however, a cyclic pattern could be recognized. Die basale bedekking en teenwoordigheid van savanne-plantspesies van die kruidstratum is vir die tydperk 1975 tot 1990 gemonitor. Die twee dominante grasspesies, Eragrostis pal/ens en Digitaria eriantha, het 58.5% tot die gemiddelde basale bedekking bygedra. 'n Betekenisvolle afname in die gemiddelde basale bedekking tussen 1977 en 1980, en 'n betekenisvolle toename tussen 1986 en 1990, is aangeteken. Daar het egter geen betekenisvolle verskil tussen die gemiddelde basale bedekking vir 1975 (5.46%) en 1990 (6.13%) voorgekom nie. Die tendense in basale bedekking kan moontlik deur die reenval van die voorafgaande 21 maande, asook deur vuur, verklaar word. Die verloop van basale bedekking en spesieteenwoordigheid oor tyd dui daarop dat geen duidelike monotone tendense na vore getree het nie, maar dat 'n sikliese patroon wei opgemerk kan word .
doi:10.1016/s0254-6299(16)30777-3 fatcat:7s3crbporvfb3cxmd7f27xuoj4