Year

1997

Degree Name

Doctor of Philosophy

Department

Department of Biological Sciences

Abstract

There is little known about the ecology of the freshwater wetlands on the south coast of NSW. Yet wetlands in the area continue to be lost, while others face increasing levels of human induced disturbance. At the same time there is an increasing local demand for information on wetland restoration and creation. Coomonderry Swamp (34°48' S, 150°44' E) is, at 670 ha, the largest freshwater, coastal wetland in southern NSW, Australia. Partial National Park protection of the wetland followed recognition of its ecological significance in various inventories, although comprehensive surveys of the flora and fauna had yet to be carried out. In this study the floristic composition and plant communities at Coomonderry Swamp were described. Comparisons were then made with a diversity of other local wetlands in order to investigate the distribution and abundance of key plant species over a broad range of conditions, to analyse characteristics of the environment responsible for determining plant species composition, and to assess the importance of Coomonderry Swamp as a reference site. The study progressed to an examination of vegetation change in response to the disturbance regime in Coomonderry Swamp and finally to an experimental investigation of the propagation and establishment characteristics of some key wetland species. Data from the various facets of research were used to compile ecological profiles of some important herbaceous wetland species. Seven communities were defined by cluster analysis at Coomonderry Swamp with 11 'local variants' recognized within these. Plant community differentiation was considered to be related to the structure of vegetation, drainage and nutrient status of soils, and to disturbance and stress derived from anthropogenic influences and/or from flux in water levels. Cluster analysis of communities from eight other local wetlands resulted in the identification of a further four community types, with salinity being the major additional environmental component differentiating these groups from those described for Coomonderry Swamp.

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