Sunday 17 November 2013

BDS 30th Anniversary meeting

The Oxford Natural History Museum is famous for many things:
  • it has the most complete remains of a single Dodo anywhere in the world;
  • it displays a 1651 painting of a Dodo by Jan Savery, which is likely to have influenced the character of the Dodo in Lewis Carroll's Alice's Adventures in Wonderland;
  • in 1894, it was the site of the first public demonstration of wireless telegraphy;
  • in 1860, it was the site of the 'Great Debate' on evolution between Samuel Wilberforce, Bishop of Oxford, and Thomas Huxley, a supporter of Darwin.
Whilst the latter event occurred at the 30th annual meeting of the British Association for the Advancement of Science, I am sure it was purely coincidental that the 2013 British Dragonfly Society Members' Day, celebrating the society's 30th anniversary, was held at the same venue.

In what is usually the curtain-closing finale of the dragonfly year (though mild Autumns can scupper the assertion), this heady blend of the science and the art of these spectacular insects is much anticipated by Yours Truly, as we begin the long wait until the next flight season.

I guess it was a little more poignant for me this year, as I'm unlikely to be attending the next few and I doubt if Kirkwall is on the list of possible contenders to host it.

As mentioned above, the day was a mixture of talks covering academic research, recording /monitoring initiatives and personal odo travelogues. This made for a varied programme which, for me, led to education (a new word!), fascination (amazing slo-mo footage) and appreciation (lots of stunning photographs).

And cake...

The day began with a talk by Mark Tyrrell, the Northamptonshire dragonfly recorder, who explained how two species are colonising the county: Beautiful Demoiselle from the south west; Scarce Chaser from the north east. Northamptonshire's extensive river system is also linked to the Grand Union Canal network, which is enabling the expansion in ranges of these dragonflies.

As befits a significant anniversary year, there was then a personal review of the Society's history from a former President, Andy McGeeney. Andy is an ecotherapist, which must be one of those jobs that the careers officer inexplicably forgot to mention when I was a lad.

After a short tea break, we were given the lowdown on the next recording and monitoring project, which will take over from the Atlas work that has occupied much of the last five or so years. DragonflyWatch is the scheme that hopes to pull together the data from all levels of recorder expertise and use it to produce information and advice on population trends.

The final talk of the morning was given by Prof. Georg Rüppell & Dr Dagmar Hilfert-Rüppell and looked at sexual conflict in dragonflies, asking the question "Is it a pacemaker of evolution?" This talk was accompanied by some stunning slow motion footage of male aeshnids attacking each other as they fought over territory and females. I certainly learnt a few things, as I hadn't realised that in low density populations, clear-winged species are the ones most likely to  engage in battle, whereas colour-winged species will use their wings to signal their intentions without actual physical contact with an adversary.

After lunch, the afternoon session kicked off with an update from David Clarke on the translocation project for White-faced Darter in Cumbria. Following three years of translocations from an established site in the north of the county to a new site in the south, there were encouraging results. The new site was obviously viable and no detrimental effect was measured at the existing site.

Then, Dr Vicky Nall of the Cheshire Wildlife Trust explained about a similar project in Cheshire, where the White-faced Darter was being reintroduced to an area of Delamere Forest, from which it had been lost. Much rewilding and habitat maintenance had been carried out by the site owners to make the area viable for the species once again.

Next up was a talk entitled 'A farm buzzing with pond life' by Dr Carl Sayer of University College London. In a tour de force of science and humour, Carl took us to the forgotten ponds of Norfolk, where nearly every field used to have a marl pit pond. Of the 22,000 remaining (from an estimated 60,000), 95% are now just small circular overgrown copses, any water remaining being an oxygen-poor murk, unfit for life. As part of his research, Carl and his team opened up a few ponds and monitored the return of all manner of wildlife, from seeds remaining dormant in the sediment at the bottom of the pond, to dragonflies turning up within hours of the restoration of open water. In a similar project, several 'ghost' ponds (ponds that had been deliberately filled in, leaving only a ghostly image in aerial photographs) were re-excavated, revealing the original sediments still in situ. Carl promised to return to a future BDS Members' Day to report on the progress of these.

The final talk of the day was delivered by Dave Chelmick and entitled 'Emeralds'. Dave is an excellent raconteur, and we were entertained by various stories of trips to Spain to figure out the strange life cycle of Emerald damselfly species inhabiting ephemeral ponds and lakes in an endorheic region. This was a new word for me, but as I understand it, 'endorheic' refers to water bodies that are purely rain-fed and if it doesn't rain for long periods, the lakes disappear in a catastrophic evaporation event. Catastrophic for any creature attempting to complete their life cycle, that is. Dave was able to witness mass emergences of damselflies from water bodies that had been totally dry within the larval life cycle of the insects! We are all aware of eggs remaining unhatched until conditions are suitable, but aestivation of aquatic larvae in the absence of water? That's just plain weird. As Dave summarised, more research is needed to fully understand the processes at work here.

I must mention the tongue-in-cheek fire safety briefing at the beginning of the day. This was delivered by the Collections Manager, Darren Mann, who is responsible for the entomological collections at the museum. He quipped that in the extremely unlikely event of a fire, BDS members should form an orderly queue in the Entomological department, where they would be given trays of priceless specimens from the collections to carry outside to safety. Humans are expendable!

At least, I think he was joking.


Martin said...

It all sounds like a thoroughly enjoyable day with plenty of interest for the scientific or naturally minded person.

Endorheic must translate into English as Dew Pond, such as those atop the South Downs... but the processes of completing the lifecycle without water is fascinating. Maybe people should observe the southern ponds and see if the same thing occurs in a cooler climate.

Imperfect and Tense said...

I always thought that ANY water on top of a chalk hill was on borrowed time!