Moths in Crisis

If you are a developer wanting to build houses, a new supermarket, or erect a wind turbine, you will know all about the Wildlife and Countryside Act 1981. Even if your opinion of it is ‘irritating and costly green crap/red tape’, you will be aware that in order to get planning permission, the services of an ecologist must be engaged. They will then survey the land for various species which might be affected by your proposals, and suggest ways in which the impact can be mitigated or, ideally, eliminated altogether.

Depending on what exactly you are proposing, this might include checking for the presence of breeding birds which might be disturbed, Great Crested Newts, Dormice, or any of Britain’s 18 resident species of bat. In the case of wind turbine applications, special attention is paid to the flightlines of raptors and wild geese. But in almost no cases will those ecological surveys include moths.

Currently, in contrast with all of Britain’s bats and the vast majority of birds, hardly any moths have any protection at all. Only eight species, in fact, out of the 2500 or so that are found in the UK. That’s about 0.3% which are fully protected, compared with around 10% of our breeding butterflies, 50% of Amphibians, 100% of bats and almost 100% of birds, apart from the few species on Schedule 2 which can be killed or taken at certain times of year or by an ‘authorised person’. The remaining 99.7% of moth species are not taken into consideration at all when it comes to planning decisions.

Historically, this state of affairs was perhaps justified. When the lists were being drawn up for the landmark legislation in 1981, far less was known about the distribution and numbers of moths in the UK, and their populations were in significantly better shape than they are now. I’ve been moth trapping for nearly 30 years and can see the declines of many common species in my own records. There are yearly ups and downs, mostly weather-related, but the long term trends are generally downwards. Speak to anyone who’s been trapping longer than that, since the 1950s, say, and they will tell you that catches at light today are but a fraction of what they used to see 60 years ago.

It isn’t just anecdotal evidence though. Two recent studies – The State of Britain’s Larger Moths 2013 and Long-term changes to the frequency of occurrence of British moths are consistent with opposing and synergistic effects of climate and land-use changes have proved that this is the case. And the declines are staggering. Two thirds of common and widespread moth species in the UK declined between 1968 and 2007. The total abundance of all larger moths declined by 28% in the same period. Some of the individual species statistics are frightening: the V-Moth, which I used to get in my Leicestershire garden, declined by 99% in that 40-year period. This species is now much rarer in the UK than the Great Crested Newt, yet has no protection whatsoever. Sixty other moth species have all declined by over 75%. Why aren’t they protected? No species can sustain this rate of decline for long. In another 40 years many of these moths will be gone for good if we don’t act now.

Heath RusticGarden TigerHeath Rustic & Garden Tiger, both trapped in my garden in 2002, declined nationally by 95% & 92% respectively between 1968 & 2007.

So what needs to be done? The 2013 report points out that ‘understanding of the major factors that are driving the changes revealed in this report remains limited’ and that ‘there is little direct evidence linking moth population (or distribution) trends to particular drivers of change.’ It does, however, suggest that habitat loss is most likely a major cause of moth declines, which takes us back to my starting point…

As an occasional ecological surveyor, I’ve seen at first hand how the system works, and a lot of it is, of necessity, ‘box-ticking’. Developers are bound by law (though maybe not for much longer if the Tories carry out their threat to ‘get rid of all the green crap’) to check for the presence of certain species. Pond on site? Survey for Great Crested Newts. Wind turbine application? Survey for raptors and bats. Destroying a bit of decent woodland in southern England? Dormouse survey.

For the vast majority, that’s all they do, the absolute minimum required of them by law. You can’t really blame them for that, but it is the law that is at fault, not the developers, and certainly not the ecologists who do the best they can within the time and money constraints under which they are placed. So, if there are no Great Crested Newts in your pond – congratulations, you can legally fill it in during the winter when there are no birds breeding around it, even though it may well support many invertebrates which are now considerably rarer and less widespread than the Great Crested Newt (not hard, since they are pretty much everywhere in southern Britain!). No Dormice in the wood? Go ahead and fell it, even though you might well be destroying thousands of eggs or larvae of moth species that now have a more restricted distribution than the Dormouse.

The trouble with allowing wholesale destruction of supposedly ‘common’ species is that, over time, the populations of even the commonest can become reduced to the point where they are themselves threatened. And it can happen in the blink of an eye. To give an ornithological analogy, 30 years ago the Turtle Dove was a common breeder across the southern half of Britain. You saw them everywhere during the summer and didn’t think anything of it. Now they are almost completely gone, and could become extinct as a British breeding bird within the next ten years.

And the same is happening with our moths, although largely unnoticed by most people. But if you have even the slightest grasp of ecology, the knock-on effects are obvious. At the most basic level, fewer moths equals fewer caterpillars for birds to eat. If the moths disappear, so ultimately do your garden Blue Tits.

There is some hope though, as interest in moths has soared in the last few years. I don’t want to harp on about the old days, but when I started ‘mothing’ (as no-one ever called it then), it was still a relatively oddball hobby compared with birdwatching. References were hard to come by and expensive, especially for the micro-moths. Now there are plenty of readily available books and websites showing you how to identify almost everything. The number of people at least moth trapping in their gardens has risen enormously, and continues to increase every year.

What is needed now is to convert that interest into more hard evidence, and then to use that evidence to force a change in the law regarding the protection of our moths and butterflies. Far more species should be on the protected list, and developers should have to commission long term surveys, not just a couple of nights’ trapping, to establish exactly what is using a site they wish to destroy, just as they currently have to with birds, amphibians, bats etc.

For far too long we have fetishized the same few species and groups of animals when it comes to ecological surveying rather than looking at the whole picture. And of course all of what I’ve said applies to other invertebrate groups. So much depends on having healthy and diverse populations of invertebrates, and yet they are almost entirely overlooked when it comes to making decisions that affect whether their habitats survive or not. If we don’t protect biodiversity at the bottom of the food chain, what’s the point of trying to protect it higher up?

One of the concluding paragraphs from the Butterfly Conservation report sums it up perfectly:

‘The substantial decline of Britain’s larger moths is one of the clearest signals yet of potentially catastrophic biodiversity loss caused by human impacts on the environment, which is of great conservation concern and potentially threatens some of the ecosystem services upon which the human race depends’.

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