Restoration ecology in the semi-arid woodlands of north-west Victoria
- Authors: Murdoch, Fiona
- Date: 2005
- Type: Text , Thesis , PhD
- Full Text:
- Description: Arid areas are often overgrazed and dysfunctional with poor recruitment of desirable species, diminished control over resources and altered soil properties. Restoration ecology re-establishes these valued processes. State-and-transition models summarise knowledge of vegetation dynamics and tools for restoration, and encourage the incorporation of new information. The model developed here for semi-arid woodlands of north-west Victoria highlighted the unknown cause of observed, natural recruitment and the need for a technique, other than direct seeding and handplanting, for enhancing the recruitment of desirable species. I pursued these knowledge gaps for two dominant, woodland trees: Allocasuarina luehmannii and Casuarina pauper. Natural recruitment of juvenile C. pauper was found to be limited and primarily from root suckers. Extensive recruitment of A. luehmannii was shown to be mostly seedlings established following substantial reductions in grazing pressure since 1996. Seedlings were associated with areas devoid of ground flora near a female tree. The importance of competition between seedlings and ground flora, spatial variation in soil moisture and individual variation in the quantity of seed produced deserves further investigation to enhance future restoration success. Root suckers of both C. pauper and A. luehmannii can be artificially initiated, albeit in low numbers and this was found to be a feasible, new tool for restoration. Suckers are preceded by the growth of callus tissue on exposed or damaged, living, shallow roots. Both male and female trees can produce suckers and spring treatments may be more successful. Genetic fingerprinting of mature A. luehmannii and C. pauper trees in six populations did not identify any clonal individuals indicating that recruitment in the past has been from seedlings. Despite this, the high level of gene flow suggests that the impact of introducing small numbers of root suckers into existing populations is unlikely to impact negatively on the population genetics of these species.
- Description: Doctor of Philosophy
Vegetation change in Hattah Kulkyne National Park: A state-and-transition model
- Authors: Murdoch, Fiona
- Date: 2006
- Type: Text , Journal article
- Relation: Proceedings of the Royal Society of Victoria Vol. 118, no. 2 (2006), p. 305-312
- Full Text: false
- Reviewed:
- Description: Many arid landscapes worldwide are degraded. Restoration ecology offers a variety of tools to enable managers to restore valued processes to landscapes. One such tool is state-and-transition (S-T) modelling which provides a way to summarise knowledge of vegetation dynamics, tools for restoration and the impact of restoration activities. A theoretical S-T framework was developed and used to organise the history of degradation and restoration in the semi-arid woodlands of Hattah Kulkyne National Park, north-west Victoria. This process highlighted four main opportunities to enhance restoration success including: exploring where, when and why natural recruitment of key species was occurring, utilising the artificial stimulation of root suckers as an alternative tool to enhance the regeneration of desirable species, understanding and developing techniques to enable regenerating or partially restored woodlands to move to the desirable state of a self-perpetuating, restored woodland and a need to monitor and manage the threat posed by emerging weeds.
- Description: C1
- Description: 2003004781
Seed colour indicates germinability of Buloke (Allocasuarina luehmannii)
- Authors: Murdoch, Fiona
- Date: 2007
- Type: Text , Journal article
- Relation: Ecological Management and Restoration Vol. 8, no. 3 (2007), p. 234-237
- Full Text: false
- Reviewed:
- Description: C1
- Description: 2003004793
Ecology of the common marsupial tick (Ixodes tasmani Neumann) (Acarina: Ixodidae), in eastern Australia
- Authors: Murdoch, Fiona , Spratt, David
- Date: 2005
- Type: Text , Journal article
- Relation: Australian Journal of Zoology Vol. 53, no. 6 (2005), p. 383-388
- Full Text: false
- Reviewed:
- Description: Ixodes tasmani is one of the most common and widespread of the Australian species of Ixodes and a vector of zoonotic rickettsial diseases. The tick was reared successfully in the laboratory; the entire life cycle was completed in 4 months. A diurnal rhythm of detachment from captive hosts (laboratory Rattus norvegicus) was observed for all stages and, combined with other evidence, suggests that I. tasmani is nidicolous. The prevalence and intensity of tick infestation on wild-caught, common brushtail possums (Trichosurus vulpecula), was least during the summer months. To investigate questing activity, laboratory-reared nymphs were held in enclosures in one sheltered (tree hollows) and three exposed (vegetation) microhabitats. Questing was continuous but at low intensity in tree hollows, and nocturnal and at an increased (higher) intensity in vegetation. The observed questing activity appeared to maximise host contact with T. vulpecula, which is nocturnal but retires by day to tree hollows. Field and laboratory observations suggest that the risk for humans of tick-bite from I. tasmani and consequent transmission of zoonotic diseases may be low compared with the risk from other tick species. © CSIRO 2005.
- Description: C1