Thesis
Vegetation dynamics over two decades in wetland fringing zones on the Swan Coastal Plain, Western Australia
Honours, Murdoch University
2019
Abstract
The groundwater dependent wetlands of the Swan Coastal Plain, Western Australia are subject to multiple stressors including regional climate drying, groundwater abstraction, clearing of surrounding buffer zones, fire and a host of local scale factors. These stressors can reduce the capacity of wetlands to maintain ecological function and their social and cultural values. This study aimed to: 1) investigate evidence of change in fringing zone plant species assemblages of wetlands over two decades on the Bassendean Dune System, Swan Coastal Plain; and 2) associate the vegetation dynamics with potential drivers over the same period including changes to the extent of groundwater levels, hydric soil properties, buffer widths, and time since last fire. In the contemporary year (2018), vegetation composition and topsoils were sampled at 14 wetlands. Changes in hydric soil properties were assessed over the spatial gradient at the historic wetland boundaries. Univariate and multivariate statistical analyses were used to compare contemporary plant assemblages with historic plant assemblages (1996 to 2000), and relate these to observed stressors. Community plant diversity was highly dynamic over time, yet greater assemblage differences were found among wetlands than over the time period, and hydric soil properties were unchanged. The high degree of diversity in wetlands and their highly variable experience of the multiple stressors meant we were unable to identify a suite of factors that adequately explained their patterns of change over time. However, in total over the 20 years and across all wetlands, these stressors increased homogeneity of species and favoured generalist species tolerant of a wide variety of environmental conditions. The high plant diversity found in wetland fringing zones in this study highlight the necessity to conserve the unique wetlands of the region.
Details
- Title
- Vegetation dynamics over two decades in wetland fringing zones on the Swan Coastal Plain, Western Australia
- Authors/Creators
- Brody Loneragan
- Contributors
- Jane Chambers (Supervisor) - Murdoch University, Centre for Terrestrial Ecosystem Science and SustainabilityRachel Standish (Supervisor) - Murdoch University, Centre for Terrestrial Ecosystem Science and Sustainability
- Awarding Institution
- Murdoch University; Honours
- Identifiers
- 991005546867607891
- Murdoch Affiliation
- College of Science, Health, Engineering and Education; School of Environmental and Conservation Sciences
- Resource Type
- Thesis
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