Journal archives for January 2020

January 21, 2020

A less negative view on changing moth populations

There have been a few news stories discussing declines in insect populations in the last two years or so, and some of those have come under criticism for methodological issues or "extrapolating beyond the data". The headlines about 'insect armageddon' following the release of the German study in 2017 became topical and were concerning for many. I just learned about a recent UK study that was profiled in the Guardian newspaper that offers a less alarming conclusion.

The UK study is interesting and possibly unique because of the timeframe, it covers 50 years of moth sampling at over 30 sites across the UK. It has a much longer reference period that the German study that got so much attention. The UK study actually points to an increase in biomass over the first portion of the study (roughly 1967 to 1982), followed by a decline. However, over the entire study period, biomass increased, which is interesting given that we are still in the period of decline. Starting points are important as the German study covers only the second part of the timeframe, and only documents a decline. The conditions could be very different in the two countries, but it is in instructive to note that the trends reversed dramatically in the UK. And that may have been the case in Germany, but we don't know because the German data series doesn't go back as far.

You can request a free copy of the UK study from the author at the following link if you are interested in some of the details. Different moth families have different trajectories, and the data is also segregated by land use type (agricultural, forest, urban etc)

Further commentary on the topic is also available on iNat's discussion forum

Posted on January 21, 2020 03:33 by dkaposi dkaposi | 1 comment | Leave a comment