Sunday, 6 October 2019

Book review, 70 years late

Hmmm, that post title makes it look as though my To Do list is a tad lengthy, but please let me explain. Despite my curmudgeonly exterior and 'born old' ethos, I do try to keep on trend to some extent. In the dragonfly world, this sees a photo ID guide of local species loaded onto my Orkney dragonfly group in Facebook and the page also has a general gleaning of exciting Odonata news from home and abroad. I will admit that 'exciting' is defined as 'exciting to me'.

A new specialist second-hand bookshop opened up in Orkney recently, and what with the length of my To Do list, I've only just got around to visiting it. The property used to be the home of Fluke Jewellery, who we visited on our first ever holiday to Orkney back in 2006. Now the modernised and extended premises house shelf after shelf of carefully-labelled books, in a multitude of categories including science fiction, history, nature and many more.

I was not expecting to find anything which would give me a frisson of interest, but tucked away in the Nature section was a small volume entitled 'The Dragonflies of the British Isles' by Cynthia Longfield. It was a second edition from 1949 (the first edition was published in 1937), so my interest was a historical one, rather than for a current ID guide.

Cynthia Longfield was one of the outstanding dragonfly enthusiasts of the 20th Century. When the British Dragonfly Society was formed in 1983, Cynthia was elected as the first Honorary member. Sadly, she died in 1991 at the age of 94, several years before my own interest in dragonflies took to the wing.

Although Odonata have been around for more than 300 million years, and the seventy years since the publication of Cynthia Longfield's ID guide is less than the blink of an eye by comparison, there have been noticeable changes. Between 1949 and 2019, the number of species of dragonfly and damselfly in the British Isles has certainly fluctuated. In 1949, there were 44 species altogether, 27 dragons and 17 damsels. By 2019, there were 52 species altogether, 32 dragons and 21 damsels. But these changes are not as simple as may first appear.

Firstly, for dragonflies, we lost the Orange-spotted Emerald, which went extinct in the British Isles in the 1950s, most likely due to a pollution incident on the Moors River in Dorset. The Highland Darter has since been 'lumped' in with the Common Darter by taxonomists, so technically another species lost, but there have also been additions of Southern Migrant Hawker (1952), Vagrant Emperor (1970s), Green Darner (1998), Lesser Emperor (1996), Scarlet Darter (1995) and Large White-faced Darter (2012).

Then, for damselflies, we lost the Dainty Damselfly, which went extinct in the British Isles in 1953, when a storm surge on the east coast destroyed its breeding site in Essex. However, the species was rediscovered in 2010 in Kent. Another loss was the Norfolk Damselfly, not recorded since 1958, its disappearance again linked to habitat loss. New additions include Willow Emerald Damselfly (2007), Southern Emerald Damselfly (2002) and Small Red-eyed Damselfly (1999).

The overall trend, then, is upward, which looks like a biodiversity win on the face of it. But the extinctions have been due to loss of habitat and pollution, factors which still threaten much wildlife globally. The new species which have begun to colonise the British Isles, are taking advantage of climate change, as rising temperatures bring new opportunities for expansion. However, paradoxically, this factor also poses a threat to northerly-adapted species, as they will be forced further north, until they run out of British Isles.

In 1949, many of the British odonates did not yet have common names, with some of our most abundant species only being referred to by Genus with an English modifier e.g. Common Ischnura for Blue-tailed Damselfly, Ischnura elegans. Others have had their Genus changed e.g. Beautiful Demoiselle, Calopteryx virgo, was an Agrion virgo back in 1949.

One unfortunate inclusion in the book, which caught me by complete surprise, was in a useful table of the principal colours of the insects' bodies. Blues, greens, reds, purples, blacks and whites were all described with subtle descriptors for each change of hue. However, the browns included a shade which I will not reproduce here, but simply say that it was not subtle and I will acknowledge that it was written in a different time and place. As well-travelled and enlightened as she was, I guess that the author was using language which it was expected her readership would recognise. I would like to think that the world is above and beyond all that now, but sadly, we know this is still not the case.

More happily, the second edition did include 12 colour plates not in the first edition. These were illustrated by W. F. Evans and first published in 'British Libellulinae or Dragonflies' in 1845, over one hundred years beforehand. The artist's grandson gave permission for the plates to be used.


Mark said...

Impressive! As I've mentioned before, you're knowledge of Odes is inspiring. On the other side of the coin - a friend of mine assures me he has seen Large Tortoiseshells on the south coast of England. They were supposed to bd extinct in Britain decades ago!

Imperfect and Tense said...

Your friend may be correct. There were at least 6 sightings of Large Tortoiseshell in the UK in 2018. Historically, sightings have tended to be on the south coast, which possibly suggests that these individuals are migrating or dispersing from France. However, unofficially, folk do rear and release them, so this can't be discounted as the reason.