Tasmanian Forest Practices Authority

Hobart, Australia

Tasmanian Forest Practices Authority

Hobart, Australia
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MacGregor J.W.,Murdoch University | Holyoake C.,Murdoch University | Munks S.,Tasmanian Forest Practices Authority | Munks S.,University of Tasmania | And 5 more authors.
Australian Journal of Zoology | Year: 2016

Body condition is an important aspect of the health of any animal. The current standard method of body condition assessment in the platypus is the tail volume index (TVI). Although the tail is the largest repository of fat in the platypus, the reliability of TVI has not been adequately demonstrated. The aims of this study were, first to assess performance of the TVI, and second, to develop and evaluate performance of new techniques for routine field assessment of platypus body condition. Morphometric data were collected under anaesthesia from 137 adult wild platypuses (74 males, 63 females) captured in north-west Tasmania; ultrasound images of tail fat were also collected from 100 of these individuals (54 males, 46 females). Three new indices for platypus body condition were identified. An objective tail fat index (Relative Tail Fat Volume: RTFVTBL) was developed, based on cross-sectional area measurements taken from detailed ultrasound images compared with total body length (TBL). Two body condition indices intended for routine field use were developed - one based on body mass (mb) and bill width (BW) (Body Condition Index; BCIBW), and the other based on a single linear ultrasonographic measurement of tail fat depth and BW (Relative Fat Depth; RFDBW). Results indicated that RFDBW outperforms TVI as an index of platypus tail fat. Further work, however, is needed to determine the relationship between tail fat and total body fat in the platypus before conclusions can be drawn about the effectiveness of BCIBW as a body condition index. © CSIRO 2016.


Macgregor J.W.,Murdoch University | Holyoake C.S.,Murdoch University | Munks S.A.,Tasmanian Forest Practices Authority | Munks S.A.,University of Tasmania | And 5 more authors.
Journal of Wildlife Diseases | Year: 2017

Changes in the health of individuals within wildlife populations can be a cause or effect of population declines in wildlife species. Aspects of individual platypus (Ornithorhynchus anatinus) health have been reported. However, holistic studies investigating potential synergistic effects of both pathogens and environmental factors are needed to expand understanding of platypus individual health. We collected baseline data on the health of platypuses in two Tasmanian river catchments (including evidence of the potentially fatal fungal disease mucormycosis) and on individual, demographic, and geographic patterns associated with health data results. We examined 130 wild platypuses from the Inglis River Catchment and 24 platypuses from the Seabrook Creek Catchment in northwest Tasmania between 29 August 2011 and 31 August 2013. More than 90% of captured platypuses were infected with ticks, Theileria spp., and trypanosomes. Evidence of exposure to other infections, including Salmonella spp., Leptospira spp., and intestinal parasites, was low (<10%). Three platypuses had single fungal granulomas in the webbing of a forefoot, but no evidence of mucormycosis was found in any of the study animals. Possible subclinical hepatopathies or cholangiohepatopathies were found in six platypuses. Exposure to infectious agents did not cluster geographically, demographically, or in individuals, and there was minimal evidence of morbidity resulting from infection. This study has provided important baseline data for monitoring the effects of threatening processes, including mucormycosis, on the health of infected populations. © Wildlife Disease Association 2017.


Cawthen L.,Tasmanian Forest Practices Authority | Cawthen L.,Cooperative Research Center for Greenhouse Gas Technologies | Cawthen L.,University of Tasmania | Munks S.,Tasmanian Forest Practices Authority | And 2 more authors.
Australian Mammalogy | Year: 2011

Linen thread was built into radio-collars as a weak-link to trial its effectiveness at ensuring that radio-collars did not remain indefinitely on animals if they were not recaptured. Eighty percent of collars with weak-links broke or degraded, resulting in the collars dropping off within 12-45 days. This method may be useful for short-term studies of some species of mammal that are difficult to recapture in order to remove collars. © 2011 Australian Mammal Society.


Wiersma J.,Tasmanian Forest Practices Authority | Wiersma J.,Cooperative Research Center for Greenhouse Gas Technologies | Koch A.J.,Tasmanian Forest Practices Authority | Koch A.J.,Cooperative Research Center for Greenhouse Gas Technologies | Koch A.J.,University of Tasmania
Corella | Year: 2012

A standardised protocol for surveying raptor breeding activity based on nest characteristics rather than observations of adults and chicks could reduce the cost and time required for surveys, increase sampling capacity and minimize disturbance to birds. We examined whether the breeding activity of the Tasmanian Wedge-tailed Eagle Aquila audax fleayi can be assessed indirectly by surveying nest characteristics in the late stages of breeding or after the breeding season. The presence or absence of nestlings (approximately 4-6 weeks old) in 75 nests was assessed either from the air or from the ground during the 2007-2008 breeding season. Two sources of data on nest characteristics were available and were considered separately. One set (37 nests) was collected after the breeding season by eagle biologists during aerial (helicopter) or ground-based surveys. The other set (38 nests) was collected during the breeding season, by trained forest planners during ground-based surveys. A high proportion of the nests containing nestlings that were surveyed by eagle biologists after the breeding season were in good condition, had flat tops, brown leaves, whitewash and prey remains. Nests without nestlings were more bleached than nests with nestlings. Classification tree analysis indicated that the presence of a flat top or whitewash were comparable models for data collected mid breeding season (26% misclassification). The presence of a flat top was the best predictor of the presence of nestlings for data collected after the breeding season (8% misclassification). Nest characteristics change during and after breeding activity, so survey timing is important to consider when determining the nest characteristics that best reflect breeding activity.


Koch A.J.,Tasmanian Forest Practices Authority | Koch A.J.,University of Tasmania | Koch A.J.,Cooperative Research Center for Greenhouse Gas Technologies | Baker S.C.,Forestry Tasmania | And 2 more authors.
Biodiversity and Conservation | Year: 2011

Tree hollows provide critical habitat for many species worldwide. The conservation of hollow-bearing trees presents a particular challenge for forest managers, partly due to difficulties in predicting their occurrence across a landscape. We trialled a novel approach for assessing relative hollow availability, by remotely estimating mature crown cover and senescence from aerial photographs in Tasmania, Australia. These estimates were tested against plot-based field assessments of actual occurrence of hollow-bearing trees. In dry forest we conducted ground-based surveys of hollows for all mature trees (>50 cm dbh) in 37 half-hectare plots. In wet forest, we conducted helicopter-based surveys of hollows for all mature trees in 45 oldgrowth plots (0. 29-4. 63 ha). Aerial photographs (1:10,000-1:25,000) were used to classify the senescence and cover of mature crowns in each plot. Regression analysis showed that, in dry forest, hollow-bearing tree densities were strongly related to the remote assessment of mature crown cover, with an 8% increase in variability explained if senescence was also included (R2 = 0. 50). In wet forest, mature crown cover alone was the best model (R2 = 0. 53 when outliers were removed). Assessing senescence was less important in dense wet forests than dry forest because trees take longer to form mature-shaped crowns and so mature-shaped crowns are more likely to have hollows. These results suggest that, with skilled photo-interpretation, aerial photographs can be useful for remotely assessing the relative density of hollow-bearing trees. This approach has the potential to greatly improve conservation planning for hollows and hollow-dependent fauna. © 2011 Springer Science+Business Media B.V.


Stojanovic D.,Australian National University | Koch A.J.,Tasmanian Forest Practices Authority | Koch A.J.,University of Tasmania | Webb M.,Australian National University | And 4 more authors.
Austral Ecology | Year: 2014

Tree cavities provide important habitat for wildlife. Effective landscape-scale management of cavity-dependent wildlife requires an understanding of where cavities occur, but tree cavities can be cryptic and difficult to survey. We assessed whether a landscape-scale map of mature forest habitat availability, derived from aerial photographs, reflected the relative availability of mature trees and tree cavities. We assessed cavities for their suitability for use by wildlife, and whether the map reflected the availability of such cavities. There were significant differences between map categories in several characteristics of mature trees that can be used to predict cavity abundance (i.e. tree form and diameter at breast height). There were significant differences between map categories in the number of potential cavity bearing trees and potential cavities per tree. However, the index of cavity abundance based on observations made from the ground provided an overestimate of true cavity availability. By climbing a sample of mature trees we showed that only 5.1% of potential tree cavities detected from the ground were suitable for wildlife, and these were found in only 12.5% of the trees sampled. We conclude that management tools developed from remotely sensed data can be useful to guide decision-making in the conservation management of tree cavities but stress that the errors inherent in these data limit the scale at which such tools can be applied. The rarity of tree cavities suitable for wildlife in our study highlights the need to conserve the tree cavity resource across the landscape, but also the importance of increasing the accuracy of management tools for decision-making at different scales. Mapping mature forest habitat availability at the landscape scale is a useful first step in managing habitat for cavity-dependent wildlife, but the potential for overestimating actual cavity abundance in a particular area highlights the need for complementary on-ground surveys. © 2014 Ecological Society of Australia.

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