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.

Monday, 31 December 2012

Keeping up-to-date in ecological research

It's hard to keep up-to-date with all the new ecology that is being conducted across the globe. Not only is there precious little time to read scientific papers, scan journals for interesting work, and do research, but the sheer volume of material being published means that many interesting research papers will slip by. This is a shame, because it forces us to narrow our search focus when we do read papers.

So, I have started to use Blogs to keep up to date with ecological developments. I started my own Blog because I wanted to communicate about the research we do in my Lab, and to comment on ecology more generally. It's been almost two years since I started, and I've had 15,000 page views. So, I guess someone finds this stuff interesting! Assuming that others share the same philosophy, I started to scan for Blogs that summarised new papers in the general area of Ecology and Evolutionary Biology and came across The EBB and Flow: blogging all things ecology and evolutionary biology. This is a really neat Blog. It's big on reporting about papers that focus on ecological theory (which we should use as the basis for all our investigations) - under the 'Research Focus' tab. The most recent Blog on a new paper by Jonathon Levine about how coexistence theory can help inform community assembly makes a difficult/challenging topic palatable.

EBB and Flow also has excellent sections on 'Conservation Focus', 'Academic Life' (which PhD students will find really informative, 'Career Corner' (ditto), 'Meeting Dispatches', 'Recent Papers of Interest' and the excellent 'Researcher Spotlight' that send the reader off into weird and wonderful (and more importantly, relevant) ecological territory. It's well worth bookmarking!

Happy New Year!

Saturday, 22 December 2012

Ecology Apps.....for Christmas?

I've just upgraded my mobile phone and got myself a smartphone. My Grad Students would perhaps say it's about time I got into the year 2012 (which is not so great given it'll be 2013 in a little over a week). It's not that I don't like technology; rather, I'm a slow adopter. My current phone works fine, and I do hate the idea of consumerism.

But, I've bitten the bullet. One of the reasons was that Nick Bell, a Summer Research Student working on our long-term ecological plots examining alpine vegetation change, recently showed me how useful smartphones can be for the average field ecologist. While he was talking to me about technology stuff that seemed to be based on the English language, he showed me two simple Apps that I might find useful.
Nick talking to John
(thanks to Calvin & Hobbes)

One was an app to help measure tree heights (Smart Measure). Having recently done this with Nick in the field the old fashioned way - tape measure, compasses, pythagoras' calculations - this seemed really simple and effective. Then, he showed me how you could ghost an image on the screen while trying to re-take the same image. This would be awesome for my re-photography work that I am currently undertaking, comparing photos from the 1930s with the current day.

Measuring tree height is easy. Right?
Source: http://www.nativetreesociety.org/measure/tree_measuring_guidelines.htm

I went away and started to do some research. Not on getting a smartphone, but on the apps that I could use in ecology. Very quickly, I was thinking "hmmm, there's a lot of technology available that is cheap, accessible, and that I've totally overlooked".

One of the sites I found was Emilio Bruna's excellent 'Mobile Ecology' webpage. This page lists a bunch of apps for research, teaching and outreach (with a US emphasis, so I guess I'll have to look for the Australian equivalent). If you're interested in such things, it is well worth a look. My favourite was the app called RInstructor - this looks like something that will really facilitate my learning and use of R, particularly how to customise plots.

So, with Christmas coming up, I might just have to treat myself and upload (or is that download) a couple of these apps to see whether my investment in a new phone was actually worth it! In any case, I can see great potential in this technology to help me facilitate my data collection and efficiency in the field.

Merry Christmas, and best of wishes for the New Year. I look forward to writing more about plant ecology in southern Australia in 2013.  JOHN

Friday, 7 December 2012

Fire in south-east Oz - 'new' things to observe

I've just returned from the annual meeting of the Ecological Society of Australia, this year held in my home town of Melbourne. As usual, there was a great mix of student presentations, challenging plenary talks, and ample time for discussion during the breaks.

One thing that struck me was the number of talks I saw on fire. There was a whole symposium dedicated to fire, which was very well-attended. I also saw talks scattered through the programme that dealt with the impacts of individual fires, the regeneration biology of key species, the importance of fire return interval, why fire severity matters, etc, etc.

This is not surprising given that south-eastern Australia is one of the most fire-prone areas on the globe. It is a recurrent feature in many ecosystems, and is projected to increase in frequency because of climate warming over the coming century. Additionally, it is also a contentious issue - the management of bushfire threat in SE Oz revolves around policies that mitigate risk by hazard reduction burning.

Two important issues arise - how often should it occur in an ecosystem (both as a tolerable event and as a desirable disturbance to cue important ecological processes such as seed germination). Second, what type of fire event is likely to have positive or negative impacts on these outcomes.

I've been musing about these questions for the last few weeks, but from a different perspective. And it returns me to one of my favourite pasttimes: observations in ecology.

While fire is a recurrent event throughout much of SE Oz, there are indeed very long fire-free intervals for some parts of the landscape. We intuitively know this. In the rainforests of eastern Victoria, fire is probably fairly rare - perhaps in the order of hundreds of years apart. But what is probably less appreciated is that in the drier, less productive parts of central Victoria, perhaps fire is also equally as rare.

How can I make such a statement?  What evidence do I have for one of the most fire-prone areas of the world having very long fire-free intervals. Well, that is where observation comes in. In the dry, eucalypt-dominated woodlands of north-central Victoria, around Rushworth to Wangaratta, there is a clue on the upper slopes and rocky outcrops. It's a pretty obvious clue when you think about it.

Here, there is a plant that is born to burn (or so it would seem). Grasstrees, in the genus Xanthorrhoea, are arborescent monocots, developing tall stems that allow them to grow to great heights. We know they grow very slowly. Let's focus on X. glauca. For the first 50 yrs, plants consist of leaves but no stem. The stem then emerges and height growth is about 10-25 mm per annum. My old PhD student Peter Curtis measured growth rates over 10 years, so this seems a pretty reasonable estimate. So, a plant 3 m tall might be anywhere up to 350 years old. Each year, the leaves die but are held appressed to the stem rather than shed. In unburnt grasstrees, this 'skirt' can extend all the way along the 'trunk' to the ground. When a fire occurs, the 'skirt' is a ready-made fuel source to rapidly burn the plant - a quick fire where most heat is carried rapidly away from the meristem by convection. Plants generally survive burning, although Peter's work does show that mortality of grasstrees can be quite substantial in the decade after fire. But that is another story..........

Burnt Grasstrees, Rushworth State Forest, October 2012
(Photo: Michele Kohout)
I've been wandering around the bush, observing something recently. In the last few years, many tall grasstrees have been burnt as part of new 'targets' set by the State Government - hazard reduction burns. This, in itself, is notable because many areas of bush being burnt clearly have not been burnt for centuries. How do I know this?

Well, old photos tell us so! Here are some images of grasstrees in the Warby Ranges - taken in the early 1980s by the well-known fire ecologist David Cheal - that are notable for (a) their enormous height (up to 8 m perhaps) and (b) the fact that they have grass skirts that extend all the way to the ground. This suggest that this part of the landscape has not been burnt for upwards of 600 years. Hence, we are not talking about fire suppression since european settlement. And it is not just one or two individuals, but entire slopes, suggesting that fire is very uncommon here. On recent inspection, it is hard now find examples of these great unburnt plants. Low intensity fire has seen to that.

Grasstree in the Warby Ranges, 1983. Note the scale (approx. 1.75 m)
and dead leaves all the way to the ground. The trees in the background
have not been burnt. Rather, they are dying from intense drought.
(Photo: David Cheal)
Grasstrees, all with skirts that indicate long intervals between fires, across a slope at
the Warby Ranges, 1983. Plants are approx. 2.5 m tall.
(Photo: David Cheal)
Long unburnt Grasstrees, Rushworth State Forest, 2012. Scale approx. 40 cm.
(Photo: Michele Kohout)

The lesson here, if there is any, is to observe patterns in nature. The simple observation that grasstrees in some parts of the range (low productivity, rocky) have not experienced frequent fire is probably very important, particularly when thinking about fire return intervals. While low intensity fires may seem ecologically benign, this needs to be put in the context of the fire history of the site.

It also challenges our notion that dry forests burn frequently simply because they occur in a part of the continent where fire is known to occur regularly!