- Title
- Investigations into the ecology and management of the invasive plant Galenia pubescens within the native temperate grasslands of Victoria, Australia
- Creator
- Mahmood, Ako
- Date
- 2016
- Type
- Text; Thesis; PhD
- Identifier
- http://researchonline.federation.edu.au/vital/access/HandleResolver/1959.17/154244
- Identifier
- vital:11069
- Identifier
- https://library.federation.edu.au/search/a?searchtype=t&searcharg=Investigations+into+the+ecology+and+management+of+the+invasive+p&searchscope=4&SORT=D
- Abstract
- Plant invasions of natural ecosystems are one of the major threats to the conservation of biological diversity across nearly all biogeographical regions in the world. This thesis focuses on Galenia pubescens (Carpet weed) as a case study of possible approaches to the potential management of environmental weed species. G. pubescens is a woody prostrate perennial plant that is becoming a serious threat to Australian temperate grasslands, surrounding agricultural areas and conservation reserves. It is indigenous to South Africa and was first recorded in Australia in the early 1900s, and it is an aggressive competitor against native species. It is difficult to control, and little information exists about its effects on natural ecosystems, and aspects of its biology and ecology. This study has investigated some important ecological characteristics of G. pubescens’ seeds and has experimented with different management strategies in combination with chemical control. It has also considered the potential for the expansion of the distribution of this species across suitable habitat in Australia under predicted elevated CO2 and drought conditions. Seeds of G. pubescens are shown to be able to germinate over a broad range of temperatures, but short bursts (5 minutes) of high temperatures (80oC to 120oC replicating possible exposures to a fire) reduced seed germination. Seed germination was positively favored by light and declined rapidly in darkness, decreasing by > 80% at a depth of only 0.5 cm in soil. This suggests that fire regimes might be useful in removing mature plants and controlling seed numbers on the surface, and that subsequent native seeding of undisturbed areas may assist in the long-term management of this noxious weed. A trial was conducted to determine the effect of treatment with a plant essential oil (pine oil) to limit the seed germination and seedling emergence of G. pubescens. This trial showed that the effects of pine oil application were significant (P<0.05). Germination was completely inhibited by application of pine oil at 5% or higher concentrations directly to seeds, and seedling emergence was reduced by between 90 and 100% in pot trials. These outcomes demonstrate the potential viability of pine oil as a long-term control option for this species. In field-based experiments, control strategies including herbicide control with glyphosate, organic herbicide control with pine oil, the application of mulch, and the addition of native seeds to the available seedbank (and all possible combinations of these techniques), were tested. The study showed that one single treatment of a G. pubescens infestation without undertaking a secondary treatment is insufficient to control the G. pubescens infestation or to encourage native regeneration, but that a combined strategy, employing all the aforementioned techniques, is more effective. It is however suggested that full regeneration of the area may not be possible unless further restoration programs are instituted after the cycle of G. pubescens’ treatment has been completed. The thesis also assessed the control effects of chemical control combined with a prescribed spring burning. Assessment of the resulting aboveground vegetation of G. pubescens has shown that a combination of chemical control and late-spring burning can reduce the cover of non-native species such as G. pubescens, suggesting that this could be a useful tool in their management. Finally, this study has supported the view that the growth of G. pubescens will be significantly enhanced in a future climate with an enriched atmospheric CO2 concentration. These climatic changes will have important implications for management of this noxious weed in the future.; Doctor of Philosophy
- Publisher
- Federation University Australia
- Rights
- Copyright Ako Mahmood
- Rights
- Open Access
- Rights
- This metadata is freely available under a CCO license
- Subject
- Plant invasions; Conservation; Ecosystems; Galenia pubescens; Carpet weed; Victoria; Australia
- Full Text
- Thesis Supervisor
- Florentine, Singarayer
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