Our research focuses on the population dynamics of plants and how they are influenced by impacts of natural disturbances and global environmental change. We are particularly interested in the interactive effects of fire, grazing and drought in grasslands and woodlands in southern Australia, and how climate change, fragmentation and shrub encroachment affect ecosystems.

Thursday, 27 June 2013

Management burns and refuges for animals

Chris Helzer has an excellent Blog called The Prairie Ecologist. Check it out if you're interested in land management and nature conservation in grasslands. Chris has a fabulous writing style (and beautiful photos) and makes prairie conservation sound super-exciting.

A couple of weeks ago, something he wrote really caught my attention:

In the aftermath of any prescribed fire, there are winners and losers.  Fire rapidly and dramatically alters habitat and growing conditions in ways that favor some plant and animal species and put others at a disadvantage.  Fires also kill some insects and other animals outright.  For example, dormant season (late fall through early spring) fires burn up a lot of invertebrates that overwinter in prairie thatch.  Growing season fires, of course, can kill numerous small animals – especially slow-moving non-flying ones.  We usually don’t see the evidence of those impacts, but when we do, it’s no fun.  Over the years, I’ve seen way too many fried snakes and scorched nests, in addition to animals who suffered injuries from our fires.  It can be tough to deal with the knowledge that I made the decision to light the fires that killed or maimed those animals.

I was interested in this insight because I'm sure it's also very relevant to the fires we light for management purposes, particularly in native grasslands and grassy woodlands in southern Australia. Some of you may grapple with exactly the same issues.
Burnt grassland near Horsham
May 2013
Fires in temperate, productive grasslands are necessary to allow native plant species to coexist at high density, and have a role in maintaining animal habitat via manipulation of sward structure. This is pretty well-known and has been the basis for developing management burn plans in grasslands for many years now.
I've always accepted that some animals will die in fires, unpalatable as this may be, and that for the long-term function of the system, such losses are both inevitable and acceptable. After-all, we know that fires kill plants and their propagules, but this event also creates the necessary conditions for seedling regeneration and species turnover. Indeed, I know this better than most. My PhD was looking at exactly the issue of recruitment by native forbs in grasslands under different fire regimes.
If timed correctly, fire need not cause excessive animal mortality, knowing full well that no mortality is highly unlikely. There is very little data, however, that I know of that quantifies when the 'best' time to burn is to reduce animal deaths.
Intuitively, it is likely that summer burns will have the least effect on animals because they occur when there are cracks in the soil where reptiles, frogs and ground dwelling invertebrates can escape, and bird and invertebrate breeding is largely over. Summer burns, however, are very difficult (if not impossible) to implement so an alternative time to burn needs to be found.
Spring burning, I suspect, likely impacts on breeding in many species as it coincides with the most productive phase of temperate grasslands. Very late autumn burning (even stretching into winter) often occur after cracks have disappeared as soils re-wet with the autumn rains; it's also a time of emergence of many invertebrates after the summer drought and hence, likely to be sub-optimal if the aim was to reduce animal mortality.
Early dry season burning in Darwin. Note low flame height.
There is one place I had never though of as a refuge from fire that I recently observed while burning savannah in the Top End. Last week, as part of the CSIRO Burning for Biodiversity project that I help out on (with Dick Williams and friends), we observed something very curious. Something I'd never considered before, but that might be very relevant to fires in grassy woodlands in southern Australia.
After fire ignition, but well before the fire front approached, frogs, geckoes, lizards and invertebrates started moving up tree stems into the canopy. I presume that many of these were in the grassy sward initially. Jumping up the trunk must be hard work for frogs, in particular, (and dangerous, because it probably exposes them to predators), but in early season savannah fires, this is probably an excellent refuge. Flame heights are rarely more than 2-3 m at this time of year (and tree canopies are 8-12 m high, well away from the flames). Residence time of the fire at any point is mostly only 30-90 seconds as the fire passes, and smoke clears quickly once the fire front has moved on. Hence, moving up to escape fire seems to me a very logical thing to do for an animal to survive the fire event. As a refuge from fire, it shouldn't be under-estimated given the probability of canopy fire is exceedingly low.
Early season savanna fire in Darwin.
Flames rarely reach the lower tree canopy.
I, nor my invertebrate ecologist friend Michael Nash who observed this phenomenon with me, have little idea what the cues are for this behaviour. Apparently there is some research that says frogs respond to the sound of fire (and they make their way into the ground). I'd also think that smoke (or some chemical cue in smoke) likely triggers this response. It's like a siren has gone off, and the critters are well-drilled to respond. One thing I think we could rule out is that these critters were responding to heat generated by the fire itself. They began moving well before any fire was near, and besides, waiting for it to get hot before responding is probably a strategy fraught with too much danger to be successful in the long-term.
So, if you manage a system with trees and grasses in it, think about the role that individual trees might play on creating refuges for animals from the fire event itself. And document this if it does occur. There is so much still to be learnt about fire response by animals yet simple observations, like the one I have described above, could be crucial for understanding how plants and animals coexist with fire.

Thursday, 20 June 2013

2012 Impact Factors

For those of you interested in the Impact Factor of Journals, the 2012 numbers have been just released. While Impact Factors are just one measure of research 'quality' - the number of citations is arguably a much more important indicator of research 'uptake' - it is clear that IF's affect where we publish our scientific work, and how it is perceived by funding bodies.

There are no surprises in the Top 10 (which include three review type journals), but some big movers up the list in 2012 include Global Ecology and Biogeography, Methods in Ecology and Evolution, Applied Vegetation Science.

Here's a selection of ecology journals that I follow (of the 136 classified under Ecology), and their IF for 2012:

1. Ecology Letters - 17.494
2. Trends in Ecology and Evolution - 15.389
3. Annual Review of Ecology, Evolution and Systematics - 10.375
5. Ecological Monographs - 8.085
6. Frontiers in Ecology and Environment - 7.615
8. Global Ecology and Biogeography - 7.223
9. Global Change Biology - 6.910
11. Diversity and Distributions - 6.122
12. Methods in Ecology and Evolution - 5.924
14. Journal of Ecology - 5.431
15. Ecology - 5.175
16. Ecography - 5.124
18. Journal of Biogeography - 4.863
19. Functional Ecology - 4.861
21. Journal of Applied Ecology - 4.740
23. Conservation Biology - 4.355
26. Ecological Applications - 3.815
27. Biological Conservation - 3.794
31. Biology Letters - 3.348
32. Oikos - 3.329
35. Ecosystems - 3.165
37. Oecologia - 3.011
46. Journal of Vegetation Science - 2.818
51. Basic and Applied Ecology - 2.696
54. Biological Invasions - 2.509
60. Biodiversity and Conservation - 2.264
61. Applied Vegetation Science - 2.263

Friday, 7 June 2013

"Birds are to woodlands what kittens are to Facebook!"

That was my favourite quote (by Ian Lunt) from the recent Biodiversity Across the Borders conference held at the University of Ballarat. I think I know what he meant!

This one-day conference is held every two years and has a really simple aim: to communicate ecological science to ecosystem managers. Over 550 people turned up to this excellent event, from a variety of organisations (Landcare, CMAs, local & state government, committees of management, universities, ecological consultancies, policy), hinting that land managers and conservationists want to hear about the research we do, as well as to swap stories and catch up with old friends. On the later point, I ran into no fewer than seven! ex-Honours students. It's great to know my students are in the field of their choice making a great contribution.

Science communication is something that is at the core of what research aims to do.

Of course, that sounds all very formal. Getting out and telling people what we've been studying, why we think it's important, and how this information might be of use to land managers should be something we embrace as ecological scientists. I find it amongst the most satisfying of things I do. I give several talks a year to local groups, Field Nats, land management agencies, etc because there is a huge hunger for information amongst passionate people. My university doesn't really value this type of thing (unless it leads to grant applications), but I clearly see the need.

So, when science meets management, what is it that makes for effective communication.

Sitting in the audience, it is pretty clear what makes a good talk. In order of importance, as I see it:

- Be Positive! Conservation biology is full of negative stories. Indeed, Richard Hobbs has just written an interesting piece in the journal Restoration Ecology about conservation grief (where he suggests many people in the conservation field are really down about all the losses and this translates to a kind of depression and negativity). Positive messages engender hope. The keynote speakers, particularly David Lindenmayer (what is needed to restore a landscape), Mike Clarke (managing fire in the mallee) and Ian Lunt (how regrowth is transforming the box-ironbark regions of Victoria) all spoke of the positive outcomes of their research and identified a 'way forward'. Sure, they don't have the answers to all the questions, but they sure as hell had some really practical outcomes that could be used right now to improve landscapes for biodiversity and ecosystem function.

- Evidence-based Science. Managers can be a tough lot. If they are going to change their management and, by extension, commit lots of time and resources to a conservation activity, they need a good reason to do so. It strikes me that managers actually love hearing about science - it gives them the confidence to make decisions. But they don't have time to read all the papers. Making science digestible (whether that is in a Blog, a Newsletter, a seminar) should be something we never forget to do as conservation scientists.

- Use Examples. The best talks I saw illustrated their work with identifiable examples. Powerpoint can be the worst way to present science - lots of text, lots of data, lots of terminology. But if the Powerpoint is used as a slideshow - in the old fashioned way - then science jumps out as tangible. Ian Lunt showed us beautifully (using a Google Earth tour) just how much regrowth has occurred on private property in the tree-change belt of north-central Victoria (heaps). Rodney van der Ree showed us that rope bridges actually work as connecting corridors across major roads! Goanna's, possum's and other critters were captured on film using the bridges, which is far more compelling than some decent histograms showing mean (+/- 1SE) utilisation rates per day!

Biodiversity Across the Borders is testament to the need for conservation science to converse with conservation practice. I am sure everyone who attends gets an enormous amount out of the day, and leaves (as I did) with renewed enthusiasm, ideas and confirmation that what we do is vitally important work. In many respects, this conference is becoming an institution in SE Australia. I can't wait for 2015.