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When a 'new' species isn't news

Posted: Friday 11th August 2017 by BrianEversham

Grass snake by David ChamberlainGrass snake by David Chamberlain

Whether you call it a species or a subspecies, good conservation helps take care of both

One of the most striking wildlife news headlines of 2017 appeared this week, New grass snake identified in the UK. When the BBC explained that this new species, Natrix helvetica, brought the number of British native snakes to four, I became suspicious. As a geeky teenager I’d learnt the names of British reptiles, and knew our grass snake as Natrix natrix helvetica (Lacépède, 1789), a western subspecies of the wide-ranging Natrix natrix. Sure enough, it turns out that new research has simply reclassified our western grass snake as a full species, because DNA analysis showed that where the western and eastern ‘subpecies’ overlapped, they rarely bred. It’s a good scientific paper, and is well explained by the Cambridge and Peterborough Reptile and Amphibian Group. So Britain’s ‘new’ species was actually described in 1789 - not very new news!

The media also garbled the description of the beasts: they differ slightly in the dark stripes that give ‘our’ species its common name of barred grass snake, but the background colour and conspicuous yellow ‘collar’ are the same. Interestingly, the genetic study did reveal a couple of eastern grass snakes in Britain, perhaps introduced through the pet trade, but it's not clear if they are established and breeding.

What species should we conserve?
As a charity which aims to conserve all wildlife in our area, we should do the right thing for all species, even if we are not sure of their scientific names. But it’s important to have a reliable system for naming wildlife or we cannot relate research to the best habitat for the species we are trying to conserve. There may be subtle differences between two snake species; one might be more tolerant of temperature extremes or water pollution, for instance. If so, best conservation practice for eastern grass snakes might be inappropriate for our western grass snakes.

Throughout my career, I’ve been influenced by one of Britain’s greatest conservation scientists, the late Derek Ratcliffe. One of his tenets was that the surest way to conserve the full genetic variability of a species should be to maintain its population throughout their geographic range. If we adopt that stance, we have a good chance of also conserving species we don’t yet recognise. 

A consequence of this approach is that we care about species in our country and in our area regardless of how well they are doing in other parts of the world. We are excited when ospreys move into our area, even though they are probably the world’s most abundant and widespread large bird of prey; and it’s wonderful to see black-winged stilts breeding in Cambridgeshire this year, even though they are common around the Mediterranean. We appreciate our local stag beetles at Totternhoe in Bedfordshire, even though there are many more in the Thames valley.

New species hidden in well-known species
Sometimes, a new name will make us look a species anew. Everyone knows the stinging nettle, Urtica dioica, one of the first plant species to be given a scientific name by Carl Linnaeus himself in 1753. So, it was a surprise to hear in the 1990s of a new species, Urtica galeopsifolia, the so-called stingless or fen nettle. In extreme forms, it’s a distinctive plant, with no stinging hairs, longer narrower leaves, and a more furry stem. It usually grows in wetlands and wet woodland on less fertile soils. Subsequent research has shown that there are intermediate plants with a few stinging hairs, and it’s currently regarded as Urtica dioica subspecies galeopsifolia. But it’s an interesting genetic variant, and the fact that it has quite different ecology makes it significant to conservationists, as well as something to point out to visitors on fenland nature reserves.

Baffling beetles
The more we get to know wildlife, the more we realise there are plenty of ecological and genetic puzzles still to solve. One of Britain’s rarest and prettiest insects is the tansy beetle. Its stronghold is on river banks near York, where it feeds on its namesake plant. But there’s also a small population in the Great Fen, feeding on water mint and gypsywort, plants unrelated to tansy which look and smell very different. The beetles look the same, but are they actually a subspecies? Or even a separate species? We want to conserve them whichever turns out to be the case, but if the handful of individual beetles in the Great Fen are the entire British population of a separate species, perhaps we must try even harder to safeguard them.

Looking at how species change their distribution over time can also provide clues to their status. The amazing bombardier beetle, which defends itself by squirting a jet of toxic chemicals and super-heated steam from its rear when provoked, used to be widespread in southern England. Since the 1970s, almost all records are within a few miles of the coast, and almost all inland populations have disappeared. Does this imply that something about its ecology has enabled it to survive climate change and modern agricultural practice better near the coast? Or might it be, as some entomologists have suggested, that we had two species in Britain, a coastal one which has not changed its range, and an inland one which is almost extinct? We are taking no changes: the biggest inland population these days is probably on and around our nature reserve at Old Sulehay in Northants, and we are monitoring our bombardiers closely!
 

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