The analysis of the national wetlands vegetation database: freshwater lowland palustrine wetlands

[摘要] The South African wetlands vegetation is not well known. Number studies wereconducted to classify vegetation focusing mostly in small areas throughout the country.Data from all studies were collated and used to build the National Wetlands Vegetationdatabase. This study was aimed at grouping the similar vegetation plots in the NWVDinto plant communities, to find what extent environmental factors can explain patternsin plant species composition, to find which species can be used as environmentalindicators in wetlands and to determine how the species respond to the environmentalvariables that drive the ecosystem. The database contains eight Main Clusters that arefurther subdivided into communities. Each of these Main Clusters is used as a startingpoint for further, more detailed analysis. Two of the Main Clusters, SclerophyllousWetlands Vegetation and Temperate Grassy Wetland vegetation w~re used for thepurpose of the study. In order to understand the various types of wetlands and theirenvironmental drivers, data analytical data analytical techniques were used to revealpatterns in species composition and their correlation with environmental factors. Themultivariate methods used for the analysis of the database were cluster analysis,indicator species analysis, ordination, group testing, and species response curves. Allof the above-mentioned methods make use of similarity measures among sampleunits. S0renson similarity measure was the measure of choice. Analysis was performedusing the two data analytical I packages PC-Ord 6 and HyperNiche 2. The mostcontrasting influential environmental variables for South African wetlands are Soiltexture, Hydrogeomorphic type and the Wetness index. This study also contributes tothe management and conservation of water resources. Recommendations are made asto how the vegetation can be used in the assessment of wetlands health/quality andmonitoring of wetlands, as well as management.

[发布机构] University of the Free State