The humble earthworm is vital to Britain’s biodiversity. Their population size have declined by at least 33% over the past 25 years according to a study. The decline in the number is probably as important as any other major decline in wildlife. Prof James Pearce-Higgins from the British Trust for Ornithology (BTO) said:
“We need to be concerned about what is happening to biodiversity below the ground in order to protect the biodiversity that we see above ground. We need to look after earthworms. Thrashes, starlings and many waders that rely on soil invertebrates are in long-term decline, which may partly be linked to long-term changes in their food. These declines are greatest in south-east England where hotter, drier summers may also reduce the availability of earthworms to foraging birds.”
Charles Darwin portrayed the humble earthworm as unsung heroes of the natural world. He doubted that there were many other creatures that had “played so important a part in the history of the world than the earthworm”. He described them as “nature’s ploughs”.
We know that they improve soil fertility. You should also know that they influence the storage of carbon, aerate the soil and improve drainage while boosting plant productivity.
Sadly, historically, not much work has been devoted to monitoring their population size in Britain. In order to plug this gap in knowledge the British Trust for Ornithology reviewed more than 100 relatively small studies going back a century.
They decided that the evidence was consistent with a dramatic fall in their population size by at least 33% and possibly more than 40% over the past 25 years.
Ailidh Barnes of the BTO, who led the study, said:
“Changes in the UK countryside over the last century, such as extensive drainage, pesticide use and inorganic fertiliser application, are likely to have negatively affected earthworm populations”.
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