Doctoral Thesis
Ecological effects of urbanisation on woodland plant communities of the Swan Coastal Plain, Western Australia.
Doctor of Philosophy (PhD), Murdoch University
2024
Abstract
Life on earth is in a period of rapid anthropogenic driven environmental change. The human population is eight billion and most people live in cities. Urbanisation impacts on native vegetation include loss through clearing, altered disturbance regimes, soil nutrient change, interruption of life cycle processes, introduction of weeds or disease, and species loss.
Using a multi-faceted approach, I investigated impacts of rapid urbanisation in two threatened woodland plant communities over a 25-year period in Perth, Western Australia. I remeasured sites quantifying species composition and soil nutrients. I reviewed extinction debt (delayed species loss) globally and quantified extinction debt locally coupled with quantification of soil and plant community change alongside land use drivers.
The global-scale meta-analysis showed extinction debt was detectable for up to a century post-fragmentation. For the two woodlands I measured, I estimated an average future loss (extinction debt) of 28% of species per patch in banksia woodlands, but no debt in tuart woodlands. Soils of banksia woodlands were more acidic and possessed lower amounts of major plant nutrients than tuart woodlands. Native plant richness was highest where soil phosphorus was lowest and over time total nitrogen and phosphorus had increased, particularly in portions of the landscape with altered land use. The comparison of contemporary and historical datasets revealed an overall decrease in native species richness and increase in exotic species richness, with the most species-rich woodlands impacted most. Compositional shifts included increased exotic herbaceous and grass species and decreased woody native species.
Capturing change over 25 years, my research provides evidence on response of two woodland communities to rapidly urbanising landscapes, like many cities globally. Communities and species at risk, as well as their drivers, highlight pro-active management measures for mitigation and conservation.
Details
- Title
- Ecological effects of urbanisation on woodland plant communities of the Swan Coastal Plain, Western Australia.
- Authors/Creators
- William M Fowler
- Contributors
- Joe Fontaine (Supervisor) - Murdoch University, Centre for Terrestrial Ecosystem Science and SustainabilityRachel Standish (Supervisor) - Murdoch University, School of Environmental and Conservation Sciences
- Awarding Institution
- Murdoch University; Doctor of Philosophy (PhD)
- Identifiers
- 991005649569407891
- Murdoch Affiliation
- School of Environmental and Conservation Sciences
- Resource Type
- Doctoral Thesis
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