Modelling human impacts on the Tasmanian wedge-tailed eagle (Aquila audax fleayi)

Bekessy, Sarah A., Wintle, Brendan A., Gordon, Ascelin, Fox, Julian C., Chisholm, Ryan, Brown, Bill, Regan, Tracey, Mooney, Nick, Read, Steve M. and Burgman, Mark A. (2009) Modelling human impacts on the Tasmanian wedge-tailed eagle (Aquila audax fleayi). Biological Conservation, 142 11: 2438-2448. doi:10.1016/j.biocon.2009.05.010


Author Bekessy, Sarah A.
Wintle, Brendan A.
Gordon, Ascelin
Fox, Julian C.
Chisholm, Ryan
Brown, Bill
Regan, Tracey
Mooney, Nick
Read, Steve M.
Burgman, Mark A.
Title Modelling human impacts on the Tasmanian wedge-tailed eagle (Aquila audax fleayi)
Formatted title
Modelling human impacts on the Tasmanian wedge-tailed eagle (Aquila audax fleayi)
Journal name Biological Conservation   Check publisher's open access policy
ISSN 0006-3207
1873-2917
Publication date 2009-11-01
Sub-type Article (original research)
DOI 10.1016/j.biocon.2009.05.010
Volume 142
Issue 11
Start page 2438
End page 2448
Total pages 11
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Language eng
Formatted abstract
The wedge-tailed eagle is Australia's largest bird of prey and one of the largest eagles in the world. Aquila audax fleayi is an endemic Tasmanian subspecies isolated for 10,000 years from the nominate subspecies on the Australian mainland. The Tasmanian wedge-tailed eagle is classified nationally and at a State level as endangered due to its small number of breeding pairs, low breeding success and high rate of mortality from unnatural causes. The subspecies experiences mortality throughout its range from shooting, poisoning, trapping, road accidents, electrocutions and collisions with wind turbines, aircraft, fences and overhead wires, which we term 'un-natural mortality'. A portion of the subspecies' range is managed for timber production, which can lead to disturbance of nest sites and the loss of nest trees. We use a model of the eagle population from the Bass District in northeast Tasmania to explore the relative importance of different sources of mortality and nesting habitat loss, and the potential for mitigating impacts associated with unnatural mortality, disturbance, nesting habitat loss and human access to forests. We create a habitat map including suitable nest sites and link it to a dynamic landscape population model based on life history traits and disturbance responses. Using the program RAMAS-Landscape, we model alternative forest management scenarios, ranging from no timber harvesting and a natural wildfire regime, to scenarios prescribing native forest harvesting and regeneration and different levels of conversion of native forest to plantation under the same natural wildfire regime. The results indicate that the Tasmanian wedge-tailed eagle is sensitive to unnatural mortality, plantation establishment and native forest harvesting. The predicted decline over the next 160 years (∼65%) will most likely be driven largely by loss of current and potential future nest sites associated with harvesting activities, exacerbated by unnatural mortality in the wider landscape. Interventions that minimise unnatural mortality, reduce nest disturbance, and retain breeding habitat and nest sites may improve the prospects for the subspecies in the Bass District. If nest disturbance and unnatural mortality continue at the rates modelled here, the species appears to face a high risk of declining substantially in the region.
Keyword Wedge-tailed eagle
Population viability analysis
Forestry
Disturbance
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Geography, Planning and Environmental Management Publications
 
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