Insects are dying off – except those living in fresh water.

The Guardian has grim news for bugs (which include critters like the bees that pollinate our crops) with a little flash of hope. Insect populations have dropped by 25% over the last 30 years, they say – but they’re rebounding in freshwater

The analysis combined 166 long-term surveys from almost 1,700 sites and found that some species were bucking the overall downward trend. In particular, freshwater insects have been increasing by 11% each decade following action to clean up polluted rivers and lakes. However, this group represent only about 10% of insect species and do not pollinate crops.

Insects are by far the most varied and abundant animals, outweighing humanity by 17 times, and are essential to the ecosystems humanity depends upon. They pollinate plants, are food for other creatures and recycle nature’s waste.

Recent analyses from some locations have found collapses in insect abundance, such as 75% in Germany and 98% in Puerto Rico. The new, much broader study found a lower rate of losses. However, Roel van Klink, of the German Centre for Integrative Biodiversity Research in Leipzig, who led the research, said: “This 24% is definitely something to be concerned about. It’s a quarter less than when I was a kid. One thing people should always remember is that we really depend on insects for our food.”

The research, published in the journal Science, also examined how the rate of loss was changing over time. “Europe seems to be getting worse now – that is striking and shocking. But why that is, we don’t know,” said van Klink. In North America, the declines are flattening off, but at a low level.

Losses of insects are driven by habitat destruction, pesticides and light pollution. The impact of the climate crisis was not clear in the research, despite obvious local examples. Van Klink said changes in heat and rain could harm some species while boosting others, even in the same location.

But he highlighted another study showing that rising carbon dioxide levels are reducing the nutrients in plants and significantly cutting grasshopper abundances on prairies in Kansas, US. ”That is absolutely shocking, because that could be happening all over the world.”