Category: Mammals

Another PhD completion! Congratulations to Kate Parkins!

24/4/2018

Kate presented her PhD completion seminar last week and is a (possum) whisker away from submitting her thesis. Her research focussed on edges, which are ecologically important environmental features that have been well researched in agricultural and urban landscapes but remain poorly understood in natural systems.

Fire is an agent of edge creation and a globally important driver of biome distribution and community composition, yet little is known about how fire edges affect ecological processes in flammable ecosystems. While edge effects and faunal-fire responses have been well studied independently, how animals respond to fire edges remains poorly understood.

Kate's thesis explores this knowledge gap focusing on the influence of fire edges on fauna, and discusses some methodological advances for ecological field studies. Her study sites were in Victoria's beautiful Central Highlands where she invested enormous energy installing remote cameras, trapping bush rats and agile antechinus, and fitting pesky-but-cute mountain brushtail possums with GPS collars. The possums in particular played very hard to get, but Kate's persistence paid off and she's currently putting the finishing touches on her analyses.

Congratulations Kate on your epic achievement!

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Congratulations to Manuela Fischer on her PhD completion!

8/4/2018

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Manuela gave her completion seminar on Friday and is moments away from submitting her thesis. Her exciting project involved use of GPS data and experimental exclosures to investigate resource selection, road crossing behaviour and browsing impact of the abundant native swamp wallaby. Her study took place on Phillip Island, a landscape of natural and human-modified patches, dissected by roads.

She found that wallabies modulate their selection of resources on a circadian basis to optimise the use of resources under anthropogenic disturbance. Although natural vegetation patches are likely to be used, patches of high anthropogenic disturbances are tolerated at night, when disturbances are less. She also showed that roads are avoided, especially during the day and that crossings are more likely when tree cover is high and water further away from the crossing location. Further, she demonstrated that in vegetation patches, wallabies suppress weed diversity, but do not influence native species diversity.

Her work has shed substantial light on the behaviour of Phillip Island's booming wallaby population. Well done Manuela on your inspiring work!

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Volunteer opportunity: microbats and fire in the Otway Ranges

9/10/2017

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Sandra is looking for volunteers to join her on short field trips between now and Christmas. She'll be working with bat detectors and invertebrate traps at various sites in the beautiful Otway Ranges.

A reasonable level of fitness is required for walking short distances through the bush to sites without established walking tracks.

All food, accommodation, coffee etc. will be provided. Upcoming dates are:

October
Sun 15 – Mon 16

November
Sun 5 – Mon 6
Sat 11 – Sun 12

December
Sun 3 – Mon 4
Sun 10 – Mon 11
Sun 17

If you’d like to join in or find out more, please contact Sandra.

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New PhD opportunity with our research group

12/7/2017

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We're offering an exciting PhD opportunity within the Fire & Fragmentation Project. The aim of project will be to determine the arrangement of fires that maximises habitat suitability, movement capacity and gene flow for mammals or invertebrates in a fragmented landscape.

Please find further information here.

The project will run between 2018 and 2021 and is based at the University of Melbourne's Creswick campus. We are committed to supporting PhD students by providing:

an experienced supervisory team
a collaborative research environment
fieldwork support
project operating expenses
computing resources
a top-up scholarship of $24,500 ($7,000/year for 3.5 years)

Applicants should send a written expression of interest, including CV and statement of results, to Holly by 25 September 2017. Holly can also be contacted with any enquiries.

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Congratulations to Kirsten Langmaid on completing her Masters research project!

29/6/2017

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Kirsten worked with Kate in the Central Highlands to investigate the responses of Mountain Bobucks (Trichosurus cunninghami) to fire. She measured the home range sizes of animals fitted with GPS collars, and examined the response of home range size to fire severity and vegetation diversity.

She found that home ranges were smaller in areas burnt by high-severity fire in 2009 than in long-unburnt areas. Smaller home ranges reflect high quality habitat, and it's likely that regenerating acacia in burnt areas provides bobucks with an abundant food supply. Within areas burnt by high-severity fire, there was a positive relationship between home range size and vegetation-type diversity, indicating that riparian vegetation is particularly resource-rich.

These results will help researchers and land mangers better understand the implications of changing fire regimes for bobuck populations.

Well done Kirsten, and thanks to Julio, Kate and Kirsten for the photos!

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Conservation of the threatened brush-tailed phascogale in a degraded landscape

14/5/2017

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Brush-tailed phascogale. © Jerry Alexander

Degraded woodland in Central Victoria. © Cara Mansfield

A phascogale being wrangled. © Cara Mansfield

Cat Nield weighing an animal. © Cara Mansfield

Habitat loss and degradation have contributed significantly to the decline of many species worldwide. To address this loss, we first require a comprehensive understanding of habitat requirements and resource-use patterns of the species under threat.

In our new paper, we aimed to quantify variation in the habitat of a the threatened brush-tailed phascogale (Phascogale tapoatafa tapoatafa), by measuring several physical characteristics of trees and ground cover. We surveyed phascogales in Central Victoria over a 13-year period from 2000 to 2012, and measured habitat variables characterising tree communities, ground cover and coarse woody debris.

The highest overall animal abundance was at sites characterised by red stringybark, red box, grey box and broad-leaved and narrow-leaved peppermints. At these sites, red stringybark and grey box trees were of small diameter and tended to have small hollows.

Our study has provided new information concerning spatial patterns of phascogale abundance and resource use within a forested area that has been subjected to multiple disturbances. Currently, the composition and age structure of tree communities and ground habitats are a response to severe disturbance due to past mining and harvesting activities.

Successful conservation of this threatened species could be enhanced through active management of this forest to maintain the ongoing supply of nesting hollows and foraging resources.

Mansfield, C., Arnold, A., Bell, T.L. & York, A. (in press). Habitat characteristics and resource use of a threatened arboreal marsupial in a degraded landscape: the brush-tailed phascogale (Phascogale tapoatafa tapoatafa) in central Victoria, Australia. Wildlife Research. DOI

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Possum Magic in the Central Highlands

23/1/2017

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Kate and a team of volunteers have recently returned from several weeks of field work out in the forests of the Central Highlands, where they have been attempting to catch Mountain Brushtail Possums (Bobucks) as part of Kate’s PhD research.

This study aims to understand how fire affects resource use and movement patterns of the possums at sites burnt during the 2009 Black Saturday bushfires. Kate is particularly keen to understand if this species alters its movement patterns and energy use between areas of differing burn severities.

For this project Kate has built her own GPS collars, which contain: a VHF for relocating the possums, a GPS to record horizontal movement patterns, an altimeter to measure changes in height, as well as a three-axis accelerometer to measure energy use. This device will enable us to look at resource selection and movement patterns in three-dimensions, across a range of different burn severities.

If you’d like to volunteer to come along on an upcoming field trip with Kate, please get in touch with her by email.

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Contrasting responses of small mammals to fire and topographic refugia

29/4/2016

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Bush rat

Agile antechinus

Unburnt patches are expected to provide an important resource for fauna, potentially acting as a refuge from the direct effects of fire, and allowing animals to persist in burnt landscapes. Nevertheless there is little information about the way refugia are used by fauna and how populations may be affected by them.

In our new paper, we tested three alternative hypotheses relating to the abundance of two small mammal species, bush rat (Rattus fuscipes) and agile antechinus (Antechinus agilis), after a planned fire at Henderson Creek in the Otway Ranges:

Active refugia – increased abundance in unburnt patches due to a post-fire shift of individuals from burnt to unburnt areas
Passive refugia – abundance in unburnt patches would remain similar to pre-fire levels, and,
Limited or no refugia – reduced abundance in unburnt patches related to the change induced by fire in the wider landscape.

We surveyed small mammals using Elliott Traps, and found that the two species responded differently to the presence of unburnt refugia in the landscape. Whilst fire resulted in reduced abundance of bush rats on burnt slopes, there was no change in gullies, suggesting that their use of refugia is passive. In contrast, agile antechinus abundance increased in gullies immediately post-fire, consistent with a shift of individuals from burnt parts of the landscape and suggesting active use of refugia.

Our work highlights that different species' responses to patchy disturbances are likely to be influenced by factors such as site fidelity, habitat use and intraspecific competition.

Find the paper in Early View:

Swan, M., Galindez-Silva, C., Christie, F., York, A. & Di Stefano, J. (in press). Contrasting responses of small mammals to fire and topographic refugia. Austral Ecology.

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How does planned fire affect bush rat movement and resource selection?

1/3/2016

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Small mammals select resources based on their requirements for food, shelter and protection from predators. Understanding the influence of fire on resource selection can help to guide species conservation and management.

Our new paper investigates the effects of a planned fire on resource selection, abundance, body condition, and movement pathways of a native rodent, the bush rat (Rattus fuscipes). This work formed Amber Fordyce's Honours thesis, and involved gathering data from 60 individuals fitted with spool-and-line tracking devices at Breakfast Creek in the Otway Ranges.

After the fire, rats selected patches of unburnt vegetation, and no rats were caught at a trapping site where most of the understory had been burnt. The fire also reduced bush rat abundance and body condition and caused movement pathways to become more convoluted. After the fire, some individuals moved through burnt areas but the majority of movements occurred within unburnt patches.

Our findings suggest the influence of planned fire on small mammals will depend on the resulting mosaic of burnt and unburnt patches and how well this corresponds to the resource requirements of particular species.

Thanks to Amber, Bronwyn and Julian for the photos. Find the paper here:

Fordyce, A., Hradsky, B.A., Ritchie, E. & Di Stefano, J. (2016). Fire affects microhabitat selection, movement patterns and body condition of an Australian rodent (Rattus fuscipes). Journal of Mammalogy. 97(1): 102-111

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Wimmera Biodiversity

15/9/2015

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Bronwyn recently travelled to Great Western to present her GPS fox tracking research at the 18th Wimmera Biodiversity Seminar. It was a fascinating day, filled with bitterns, red gums, climate change and passionate people:

"Great Western? Do you know what’s happening with the trees out there?’ ask Lyn and Kathy at the office as I collect the uni car keys. ‘I heard they’re taking them all out, right along the highway. 400 year old redgums, just so the trucks don’t have to go round some bloody corner.’

I keep my eye out for stumps as I drive but just find trails of milk cartons, sheltering the roadside remnants of tomorrow. And strings of flags, marking off sections with trees, sections with drains, sections of paddock; at 110 km an hour it’s not clear whether they indicate the protected plants or the ones destined for removal."

Read more at Bronwyn's blog or listen to the ABC interview.