COMPETITIVE EFFECT AND RESPONSE OF 10 NAMAQUALAND EPHEMERAL PLANT-SPECIES AT 2 NUTRIENT LEVELS

Competitive effect and response hierarchies between Namaqualand pionee r plant species, across two nutrient levels, were constructed. The ten species investigated were: Arctotheca calendula, Dimorphotheca sinuat a, Foveolina albida, Gazania lichtensteinii, Heliophila variabilis, Le ysera tenella, Oncosiphon grandiflorum, Osteospermum hyoseroides, Sene cio arenarius and Ursinia cakilefolia. The target species used to cons truct the rankings were Dimorphotheca sinuata, Gazania lichtensteinii, Heliophila variabilis and Ursinia cakilefolia. Competitive effect as well as response rankings were found to be concordant between the two nutrient levels, i.e. sail fertility did not have a significant effect on the competitive effect or response hierarchy, as well as between t he target species. Competitive effect and response were significantly negatively correlated only at the low nutrient level. Competition inte nsity for each pairwise interaction showed no significant difference b etween target species however, differences were found between neighbou r species and nutrient levels, competition intensity being higher at l ow nutrient levels.