Mind the gap: when the news article run ahead of the science

This is a quick post on a blatant example on how careful and prudent interpretation in scientific articles are over-simplified in news article.

Scrolling through lemonde.fr website I found this article about a long-term study that looked at the long-term changes in insect biomass. In this article one can reads:

‘Le facteur majeur permettant d’expliquer un effondrement aussi rapide, avancent les auteurs, est l’intensification des pratiques agricoles’

In english this gives (more or less): ‘According to the authors, the major driver explaining this swift collapse is the agricultural intensification’.

Woaw, this topic being dear to me I tracked down the article: ‘More than 75 percent decline over 27 years in total flying insect biomass in protected areas’ by Hallmann et al. Which is a very cool one with a nice dataset based on 27 years of observations in protected areas in western Germany. The data has been collected using standardized sampling method by the entomological society of Krefeld (will expand in a later post on the invaluable role these societies have been and will be playing in documenting biodiversity and its changes). So all very nice, except, that the study provides no information regarding the effect of changing agricultural practices on insect biomass. Read that least sentence again. Got it? The authors state: ‘Agricultural intensification (e.g. pesticide usage, year-round tillage, increased use of fertilizers and frequency of agronomic measures) that we could not incorporate in our analyses, may form a plausible cause’, that’s it. This study reports that insect biomass have been declining by around 76% over 27 years but when the authors tried to model this decline, residual variations was way larger than the contribution of the tested covariates. So basically, insect biomass is strongly declining but we do not why.

This does not diminish the importance of this study which is super important in reporting temporal trends in biomass (remember this article?) for taxa that are currently understudied. So thumbs up to the authors and the entomological society of Krefeld, but thumbs down to the speedy journalists that are looking for some catchy title and fast conclusion. I found a couple of nicer and more balanced press coverage of this article, like this one, or that one that focus way more on the fact that this study is a first step towards a better understanding of the temporal dynamics of insects.