A first formal classification of the H ardeveld vegetation in N amaqualand, S outh A fricaстатья из журнала
Аннотация: Abstract Questions The S ucculent K aroo is a winter‐rainfall desert in southern A frica with a highly diverse flora. Which environmental factors differentiate vegetation composition at the plot level: How can compositional pattern be best represented by a formal phytosociological classification. Location Soebatsfontein communal area and surroundings in the N amaqualand H ardeveld B ioregion of the S ucculent K aroo B iome, N orthern C ape P rovince, S outh A frica. Methods We recorded vascular plant species composition, together with a range of structural and soil parameters as well as grazing intensity, in 355 plots of 100 m² size. This sample covered all vegetation types of the study area except those of river beds and anthropogenic sites. Vegetation classification was carried out using modified TWINSPAN followed by manual re‐arrangement of a subset of plots with the aim of increasing floristic distinctiveness of the vegetation units. For the final vegetation units, we determined diagnostic species and environmental parameters, according to phi‐values and ANOVA , respectively, and translated these into a phytosociological classification. Results The major factor influencing species composition and richness was soil salinity. At a broad scale, the less saline sites could be differentiated into sandy plains and rocky hills, and the saline sites into quartz fields, the centres of heuweltjies (termitaria) and the matrix between. We translated these patterns into two phytosociological classes with four orders, six alliances and 16 associations. Most of the syntaxa are very well defined in floristic terms, and all except the O thonnion cylindricae are new to science. The H ermannio trifurcae‐ Z ygophylletea morgsanae represents the zonal vegetation of marginally saline soils, the D idelto carnosae‐ C ephalophylletea inaequalis the vegetation of saline soils. The vegetation of the extremely saline quartz patches probably belongs to a third class not described here due to the scarcity of representative plots. Conclusions Our phytosociological approach allowed the various degrees of ecological and floristic similarity to be represented by syntaxa of different ranks. A comparison with previous classifications from the S ucculent K aroo revealed a high spatial turnover, with only two of our alliances and none of our associations coinciding with those found in previously studied areas of the S ucculent K aroo. Our formal classification has the potential to be a powerful tool for local land use, ecological comparison and conservation, and to contribute to a future national phytosociological classification of S outh A frica.
Год издания: 2012
Авторы: Jona Luther‐Mosebach, Jürgen Dengler, Ute Schmiedel, Inga Ute Röwer, Timo Labitzky, Alexander Gröngröft
Издательство: Wiley
Источник: Applied Vegetation Science
Ключевые слова: Ecology and Vegetation Dynamics Studies, Botany and Plant Ecology Studies, Plant Diversity and Evolution
Открытый доступ: bronze
Том: 15
Выпуск: 3
Страницы: 401–431