Speaker:Maurice Avent
For centuries we have been keeping records of butterflies and moths, far longer than for any other species. It is estimated that between 1690 and 2019 around 15 million butterfly records were made. The National Moth Recording Scheme has more than 26 million records. What these records show is how the changes in weather and the quality of the air have such an effect on population of so many species. As Maurice stated, “Butterflies can recover from natural problems but not man-made problems.” The Grayling and Wall Brown butterfly species have completely disappeared from the Midlands due to the detrimental effects of in diesel exhaust fume particles. These butterflies are still found on the coast, which is a key indicator of air quality.
Scottish lepidopterists have benefitted from global warming with species such as Comma arriving in their country. We can see many butterflies and moths expanding their range compared with centuries ago.
However, a major issue is that the first butterflies are generally arriving 20 days earlier than they did in the 1970s, but not all plants are doing the same, which means that when the butterflies or moths species and plants go out of rhythm it is a “signature for death”.
Maurice has kept extensive records between 1996 and 2024 on West Yatton Down (A Site of Special Scientific Interest near the Castle Combe Racing Track), which he proudly owns. The butterfly numbers in 2024 decreased by 24%. They totalled only 87% of the second lowest figure over this period when, in 1995, a harsh summer drought saw a huge reduction in butterfly numbers.
Other problems include the reduction of tree felling in woodlands since the Second World War that has resulted in far fewer Violet plants. This has had a major effect on the number of fritillary butterfly caterpillars. They need Violets in great bunches. A few will not do. Another issue is intensive farming that has reduced hay meadows to areas of, for example, rye grass. Butterflies are very sensitive to the fact that these fields are no longer the right environment for them.
The losses of butterflies and moths are far greater than those of birds and plants, highlighting their importance as key indicators of the changes in our environment.
On a more positive note, the very rare Purple Emperor which had not previously been seen on the Knepp Estate in Sussex has, since rewilding, been seen there in very good numbers.
Butterflies and moths need our help and in Maurice Avent they have a wonderful champion.
Andrew Harrison
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