Thursday 20 June 2019

Common species matter


I return to that perennial chestnut – whether there is any value in records of common species? New recruits to recording schemes often wonder whether their very limited repertoire has any value, whilst more experienced recorders are perhaps less excited by common species and therefore ignore them. I think it is essential that scheme organisers continue to emphasise the benefits of recording commoner and more easily identified species.

I am reminded of the fate of the House Sparrow. Ringers tell me that when they started they were actively discouraged from ringing house sparrows. So, when these cheeky little chaps started to decline nobody had any data! Even now, I’ll bet the data are incomplete but at least these days BirdTrack asks for full lists and the way it is designed makes you feel obliged to try to compile a full list. So, an opportunity was missed but future issues are now addressed by a hugely successful data-capture system.

With invertebrates we have an even bigger problem. There have been several stages in the decline of our wonderful insect populations. Firstly we had the development of more intensive agriculture post WW2. By the 1950s farmers were being actively encouraged to drain and plough and ‘improve’ previously fallow land. We lost vast areas of grassland and wet pasture. No more orchid fields, just a green monoculture of grass and cereals. That must have had a devastating effect on invertebrates but we don’t have any data to consider it.

Then came the pesticide revolution. DDT and a wider range of Organo-phosphates laid waste to our insect populations in the 1960s and 1970s. I can still remember a field in France in 1970 that had been treated – it was awash with the corpses of so many lovely animals. The shock has stayed with me for the following 50 years (I was 11 or 12 at the time). So, by the mid-1970s a lot of damage had been done, but still we had no decent recording system.

Then came the onset of recording schemes. The HRS started in 1976 – just in time for the first devastating heatwave and drought. Again, we have precious little data! There is a theme developing here. So, today, we have had a sequence of extreme heatwaves and droughts but can we analyse their effects? Probably not. The data are just too patchy. Yet, if every field naturalist had simply noted all the ‘common’ and readily identifiable species for the past 50 years we would have a fighting chance of picking up some signals.

So, the issue of insect decline is not going to go away! Indeed this spring we have witnessed some pretty worrying shortages of all manner of insects. It is time we addressed the data shortfall and valued records of ‘common’ species. After all, they could become the modern equivalent of the passenger pigeon!

So, if you have just joined the recording process, don't worry if your records are of a narrow suite of species. The data are useful. Similarly, if you are experienced please submit full lists. They really do count.

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