Friday 24 May 2019

If only .......

This spring is starting to show signs of stress in the insect world. The numbers of hoverflies I am recording have dropped alarmingly and there are some genera that are seemingly absent on my local patch (Mitcham Common). Where are the Cheilosia and Pipiza? Platycheirus and Melanostoma are extremely thin on the ground, as are Eristalines (although I did get a very odd one yesterday that I cannot identify). My instincts are that these are the impact of last year's heatwave, but it may not be possible to make the causal link.

What is needed is a decent block of data on a range of relatively widespread and abundant species across a range of taxa. I started casting my mind around and hit upon the spectacular red and black hopper Cercopis vulnerata. Surely I had recorded this in sufficient detail? It seems not! I know it was recorded from Mitcham Common in 1984 at least in two locations (by John Hollier). I don't seem to have logged it. Has it disappeared? If so, it joins Leucozona lucorum as an unexplained loss.

I don't see how these two widespread and often abundant species can be the victims of anything other than climate change. The Common has not changed so much as a result of adjacent land management but might of course have been affected by atmospheric pollution.

Unfortunately, I have rarely been around sufficiently consistently to record every year in May, but have had the opprtunity these last two years. It is now a sigh of 'if only'. So, the mantra for all field naturalists needs to be log everything all the time. That is not to say I am proposing 'pan-listing'. I am not. But, most of us can recognise some taxa beyond the narrow confines of our specialism; some of which may just be useful in developing our understanding of the impacts of climate change!