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, 30 May 2013

Signs of life???????

I'm not one for holding on to old 'stuff'. Spring cleaning is my thing.

But in science, it pays to never throw things out.

Old data might be useful at some stage in the future. I have learnt this the hard way.

I'm still doing point quadrats. And yes, this data is being used!
I once collected four years of point quadrat data (at 3 month intervals) to assess growth cycles of grasses and forbs in grasslands. I never used the data, let alone even crunched it into a nice graph. I decided to toss out the original data sheets not more than a year ago. What was I going to do with all this hard copy?

Turns out that I REALLY need this sort of data now - there is very little data in grasslands about timing of growth of C3 grasses, forbs and C4 grasses. Indeed, for grasslands near Melbourne, the only data I can find comes from Richard Groves who assessed biomass changes across a couple of seasons in 1965!!

Just the other day I was ferreting around in my cold room at Uni. In the back corner is a cupboard. Hmm, I wonder what's in there. I don't think I've ever looked. My cold room is set at 2 deg C, and is dark. Why would I go into the back corner and see what is shoved into a small, innocuous cupboard?

To my amazement, and surprise, were two cardboard boxes. And they were full of little glass jars. Full of seeds. Written neatly on labels placed in the jars were little jems.
'Rutidosis leptorrhynchoides, Manor Railway Reserve, 6th January 1986, DaT'
'Senecio macrocarpus, Bannockburn Railway Reserve, 5th October 1985, NHS'
'Diuris punctata var. albo-violacea, Tottenham, 4th November, 1986, DaT'
This won't mean much to many of you. But to me, this was like finding $100 in the pocket of a jacket you haven't worn for ages.
Airtight jar full of seeds of an endangered grassland plant.
Here, seeds of Senecio squarrosus, collected from
Rokewood Cemetery in 1987 by Neville Scarlett. This
population no longer exists in the wild.
Seeds of Senecio macrocarpus after 25 yrs of storage - they look OK.
These are seeds of highly endangered grassland plants that have been stored away, un-noticed, for 25 years. That alone is remarkable. But perhaps more telling is what has happened in the intervening 25 years.
The Rutidosis population at the Manor Railway Reserve, from direct counts, was about 330 plants in 1984. Today, no plants exist. A lack of frequent fire for the last 20 yrs saw the population decline rapidly in the 2000s. Like many small populations, conservation action began too late to arrest the decline.
But I have several glass jars full of seeds from this population. These may be the remaining genetic material of the species from that area.
In many respects, these airtight containers, stored in the dark at low temperatures, might be seen as a precursor to the modern seed storage facilities (or 'seed banking' as Kew Gardens in the UK calls it). But, of course, the seeds were collected and stored long before protocols for such activities were developed.
I'm sure there are many people, however, who have collected seeds from their local remnant and placed them in a paper bag and stored them in a dry spot. Is this a valuable thing to do? Or should we really collect seed and then ensure it is propagated/sown so that we don't lose that propagule forever?
Despite my delight at finding these seeds, I'm not hopeful many will germinate. The basic seed biology of Rutidosis hints that long-term storage of seed may not be a particularly viable option. In the wild, Rutidosis has a transient soil seed bank, and seed germinates rapidly upon wetting. From seed burial experiments I did in my Honours year, I know that seeds are lucky to persist in the soil for more than 5-6 months. They are not 'wired' like Cyperaceae, Acacia and Juncaceae for long-term soil persistence. Nor are Senecio.
But I will try and germinate them nonetheless. To learn about long-term seed viability. And to try and recover a locally extinct population of a species now on the brink of extinction in the Melbourne area. I'll give you an update in a few months about the species whose little seeds have persisted through time and, just as importantly, those that haven't.