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Scarce and threatened, right?

We do like reading the various works with titles that begin something like ‘A Review of the Scarce and Threatened...’ and continue with a family or other group of beetles. Many of them are out of date now, but we wonder whether any of them were ever what might be called up to date. Lots of these reviews cover the known records or distributions of rarely-recorded species, and some give information about ecology or other aspects of the species included, and so they are obviously very useful. But whether they live up to their titles is another matter. Obviously these works can only deal with records from literature and various data bases and so they are necessarily limited in scope. With most groups there are only a few dedicated workers travelling around and recording the species, or maybe collating records from other people that are active in the field. Depending upon the number of records etc, species are classified as threatened or endangered or categorized as Notable A or Notable B etc, and there is a long list of such categories as any site survey will painstakingly and at great length point out. But this is a rather academic exercise because the real number of occurrences of many scarce species will be far greater than the historical and modern data would suggest. There are only so many people active in the field and they can only cover so much ground, and so many areas will either not be worked or only done so superficially. Think of a ground beetle that occurs under hedgerows, you might work a site fairly thoroughly and not find it but that does not mean that it is not there; it simply means that you have not found it. So reading about a species that has only been found in the UK half a dozen times means virtually nothing and it may simply imply that a change in sampling methods might be a good idea. Then there are other really annoying considerations such as a species being rarely recorded despite its foodplant being common everywhere and in apparently suitable habitats, and more so when said species is common everywhere on the continent, or things like the Thistle Weevil, Rhinocyllus conicus (Frölich, 1792), which was very local and rare and restricted to a few sites on the south coast, but then the range suddenly expanded a few years ago and now it’s common everywhere. Every Coleopterist knows that if a site is worked very thoroughly over a decade or two it will continually produce new species and some of these will be very rare, some even new to the UK, and that the longer a site is worked then the longer the list of beetles will grow. This is for many reasons; species disperse and the site will change over time in many ways, but the bottom line is that the longer it is worked then the greater the list will become, scarce and threatened and all. Another very obvious aspect of recording is that the more people that take part then the less likely these species are to be classified as threatened or Notable and all the rest of it. The great problem here is that not enough people know how to identify what they have found. But this, at least in some measure (but it’s a great start), has been accommodated by some of those fantastic identification groups on face book; here a complete novice can send in photos and get them identified, and at the same time there will be a few experts ready to evaluate the significance of their finds. Thus the generally very scarce ground beetle, Polistichus connexus (Geoffroy in Fourcroy, 1785), which was previously very rare and known from only a few records, has proved to be widespread by people sending pictures into face book. Add to all the above the little matter of climate change, and it seems rather pointless making judgements about scarcity and conservation values of species because so many things are in flux at the moment (and yes, they always have been but things seem to have be warming up in recent decades). The various recording schemes seem to be doing a fantastic job of monitoring distributions and movements, and this is very interesting and useful, but it should always be borne in mind just how useful this data will be, other than in some historical context, because we are not monitoring a static situation, and insects being what they are, the situation for many species will probably change quicker than a recording scheme will be able to analyze the data. And some species are naturally rare and don’t disperse much, but that does not make them scarce and threatened, at least if their sites are left alone. And the last point we should like to make on this subject, at least for now (we intend to moan on about this in more detail later), is this: from a personal point of view, and having had the privilege of doing field work and running moth traps in the mid-1970s, I think I would be saddened and horrified if I were to really understand just how much our insects have declined since that time. And if we ever manage to get a really good idea about the distribution and abundance of our present-day fauna, then I sincerely hope that young entomologists of today will not have reason to look back as I do now and weep for things past. We recently wrote about a Noetropical longhorn beetle and in doing so found out something of the disgusting environmental abuse occurring in that region, it was a very upsetting experience, and although the scale is very different, we can only admit to doing the very same thing here over the last seventy years or so.


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