The effects of fire on pollination haven’t been explored in sexually deceptive systems. Sexually deceptive plants achieve pollination by mimicking the sex pheromone of female insects in order to attract male insects. These systems are highly specialised, with the orchid often being pollinated by a single insect species.
In our new paper, we observed the frequency of pollinator visits to flowers of a sexually deceptive orchid, Caladenia tentaculata, and related it to the post-fire age class of heathy woodland in south-western Victoria.
We also related the number of the pollinator’s putative larval hosts (scarab beetles) captured at these sites to age class. At the local scale, visitation was highest in recently burnt sites. At the landscape scale, positive associations were observed between (1) putative pollinator hosts and vegetation burnt 36–50 years ago, and (2) pollinator visitation and vegetation burnt more than 50 years ago. Local- and landscape-scale effects on visitation were synergistic, such that visitation was greatest when fire age was variable within the pollinator foraging range.
Brown, J., York, A. & Christie, F. (2016). Fire effects on pollination in a sexually-deceptive orchid. International Journal of Wildland Fire. 25: 888-895.
We're offering three exciting PhD projects within the following two research programs:
Please find further information here. Within the scope of the existing research frameworks, candidates will have the flexibility to develop projects based on their interests and skills.
The projects will run between 2017 and 2020 and are based at the University of Melbourne's Creswick campus. We are committed to supporting PhD students by providing:
Applicants should send a written expression of interest, including CV and statement of results, to Julian by 30 September 2016. Julian can also be contacted with any enquiries.
Nineteen students took our two-week intensive Masters subject "Bushfire and Biodiversity" as part of the Master of Forest Ecosystem Science and Master of Environment.
The course covers the effects of fire on many aspects of biodiversity and ecological processes, and involves a three-day field trip to the Otway Ranges. Students were free to design their own field exercise in groups using a pre-defined canvas - an area near Anglesea burnt by planned fire in autumn 2015. Three groups chose to explore the effects of fire severity on plant species diversity and one group focused on birds.
Despite the intensive fieldwork, we managed to find time in the evening for table tennis and snap tournaments.
Please contact us for more information about what the subject involves.
Many thanks to Julio and Alan for photos.
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
Our 2016 fieldwork program has already kicked off with a team of seven visiting the Otways to help Hilman and Natasha measure vegetation structure and trap small mammals.
Hilman is nearing the end of a mammoth effort to deploy camera traps and measure vegetation at 130 long-term monitoring sites spanning foothills forest, forby forest, tall-mixed woodland and heathland. His Masters research examines the influence of time since fire and habitat structure on the functional diversity of ground-dwelling mammals, and will reveal the attributes of prescribed burns that are likely to enhance ecosystem function.
Natasha has recently begun fieldwork for her Masters project which seeks to test species distribution models for mammals in heathland, where several species appear to have become locally extinct or persist in very small numbers. She is using Elliott traps to target small mammals, and plans to create new models of species' current distributions.
Please contact us if you are interested in joining a field trip as a volunteer. Our Otways fieldwork is finishing shortly, but several opportunities are coming up in the Central Highlands.
Many thanks to Matt and Natasha for these photos.
Trent's article was originally published on The Conversation and is republished here with permission. Read the original article.
Last week Victoria announced a new plan to manage bushfire risk by conducting prescribed burns.
Previously, Victoria had adopted a plan to burn 5% of the state’s area each year to manage bushfire risk. The 5% target has been criticised by scientists for damaging the environment without necessarily reducing risk. But, following a review, the state is shifting to a new “risk-based” strategy.
So, how does the new strategy work and what can we learn from it?
Targets: a blunt instrument
Immediately following the devastating Black Saturday bushfires there were many questions about whether the government could have done more to either prevent such an event or at least reduce the impact of the fires.
A Royal Commission considered a range of submissions from government, the public and scientific committees. Following careful consideration of the information, the commission handed down 67 recommendations. Recommendation 56 was to adopt a long-term program of prescribed burning with a rolling average of 5% per year on public land.
A range of research has since been conducted examining the role of prescribed burning in reducing the risk to people and property (some examples here, here and here), as well as the impact on biodiversity (some examples here, here and here).
The key message is that a hectare target is not the most cost efficient way of reducing risk to people and property, and that such an approach can have negative impacts on biodiversity.
Therefore, an alternate approach is needed to achieve the two objectives in the Code of Practice for Bushfire on Public Land:
The risk of bushfires
The new risk-based approach means that the state government will be able to focus their efforts in strategic areas, such as places close to houses and infrastructure, or areas where due to landforms there is a high chance of fires starting or spreading quickly.
Reducing fuels in these areas can result in the greatest reduction in risk from wildfires to the assets, but have a much higher risk of damage if the prescribed burn escapes such as we have seen recently at Lancefield.
Risk to people and property will be measured through fire behaviour simulation using the PHOENIX RapidFire program. This allows the state to compare the risk of losing houses between maximum fuel load (and maximum risk) and fuel loads after burnoffs.
The difference between the two is known as “residual risk” and is expressed as a percentage of the maximum risk. Victoria has set a target of 70% residual risk which means that burnoffs will remove at least 30% of the maximum risk. While there may be debate about the actual value, adopting a risk-based metric represents a more outcome focused approach to developing fire management strategies.
Residual risk methods currently consider only the impacts on people and property, however equivalent methods are being developed for the environment.
As a researcher in the field, it would be remiss of me not to say that there is great scope for improving both the underlying fire behaviour model and the methods of calculating risk. There is a big difference between developing a model in the lab and applying it to public safety. In time, new methods will be developed and Victoria will need to consider whether these represent improvements over their current system before they are adopted.
Doesn’t remove risk
The new plan advocates a reduction in risk, but doesn’t entirely remove it. This is simply not possible.
Black Saturday fires could occur again in the future under either a hectares or a risk reduction approach to fuel treatment as these fires are driven primarily by catastrophic fire weather.
What is important to note is that a risk reduction approach aims to reduce the impact of such fires so that we hopefully do not see the same devastating loss of life and property.
Fire management on private land and the preparedness of communities for wildfire will remain vital. Communities in at-risk areas need to be actively involved in fire management decision making and preparedness. Some communities may elect to live with the risk while others may actively be involved in reducing risk. Regardless of the decision, it is important that all parties understand the risk they are exposed to and take actions accordingly.
Overall, Victoria’s new plan is a major step forward for fire management in the state and Australia. Explicitly adopting risk as a measure of success is a brave and positive step by the Victorian government. The success of the new policy will be assessed in time, but in my opinion, it will make fire management decisions more transparent.
Such transparency will allow for better community involvement in the planning and application of fire management. In time, the inclusion of other asset types in the estimation of risk will complicate the process, but also allow for better assessments of the extent to which both objectives for fire management can be met.
Alarmingly, it’s been two months since our last news item, so we’ve put together a collection of photos to illustrate some of our springtime activities.
Many thanks to Julio and Alan for these photos.
Fire Ecology and Biodiversity at UniMelb
Bushfire Behaviour and Management at UniMelb
Quantitative & Applied Ecology Group at UniMelb
Integrated Forest Ecosystem Research at UniMelb