I found this amusing story in the news today. Seems some university decided to make a case against worms for some reason. "The presence of earthworms in temperate hardwood forests may accelerate decomposition of forest litter, which potentially reduces habitat for forest-floor animals, (increases) soil erosion... and affects carbon and nitrogen cycles," https://www.bbc.co.uk/news/science-environment-14788783
Wonder if that's the author's idea of a joke? Seems a bit too subtle for British humour, though. Odd.
In fairness the study is really only suggesting that certain non-indigenous worm species are causing a specific problem regarding the breakdown of deep litters in forrest systems and the effect this may have on succession within the system as well as on certain indigenous species of flora and fauna found in a specific geographical location. Not that earthworms are bad. If you are not concerned with protection of a specific indigenous system and are quite happy to accept exotics which will change the system because this may in fact be more productive, resilient or whatever else then you wouldn't consider this a problem. However if your primary concern happened to be the protection or conservation of specific indigenous systems then this would be an issue to you. Below is an entry from wikipedia regarding earthworms in this context: Earthworms as invasive species From a total of around 6,000 species, only about 120 species are widely distributed around the world. These are the peregrine or cosmopolitan earthworms.[6][7] Australia Australia has 650 known species of native earthworm that survive in both rich and in nutrient-poor conditions where they may be sensitive to changes in the environment. Introduced species are commonly found in agricultural environments along with persistent natives. Most of the 75 or so exotics have been accidentally introduced into Australia. The total species numbers are predicted to exceed 2,000.[8] North America A total of approximately 182 earthworm taxa in 12 families are reported from America north of Mexico, i.e., USA & Canada, of which 60 (ca. 33%) are exotic/introduced.[9] Only two genera of Lumbricid earthworms are indigenous to North America while introduced genera have spread to areas where earthworms did not formerly exist, especially in the north where forest development relies on a large amount of undecayed leaf matter. When worms decompose that leaf layer, the ecology may shift making the habitat unsurvivable for certain species of trees, ferns and wildflowers. Another possible ecologic impact of greater earthworm numbers: larger earthworms (e.g. the night crawler, Lumbricus terrestris, and the Alabama jumper, Amynthas agrestis) can be eaten by adult salamanders, and when the salamanders do consume the earthworms they are more successful at reproduction. However, those earthworms are too large for juvenile salamanders to consume, which leads to a net loss in salamander population.[10] Currently there is no economically feasible method for controlling invasive earthworms in forests. Earthworms normally spread slowly, but can be quickly introduced by human activities such as construction earthmoving, or by fishermen releasing bait, or by plantings. United Kingdom A recent threat to earthworm populations in the UK is the New Zealand Flatworm (Artiposthia triangulata), which feeds upon the earthworm, but in the UK, has no natural predator itself. At present sightings of the New Zealand flatworm have been mainly localised, but this is no reason for complacency as it has spread extensively since its introduction in 1960 through contaminated soil and plant pots. Any sightings of the flatworm should be reported to the Scottish Crop Research Institute, which is monitoring its spread.