Britain's Moth Population Declined by a Third in the Past 50 Years [Study]

Moths play a vital role in the ecosystem. With the steep decline by a third of Britain's moth populations, scientists worry about the adverse effects of the disappearance of the pollinators in their ecosystems.

The Decline of Britain's Moths

A report published in the Butterfly Conservation entitled "The State of Britain's Larger Moths 2021 Report" reveals the decline of a third in Britain's moth abundance only in the last 50 years.

The report highlights a 39% decline in larger moth species abundance over southern Britain and a 22% fall across northern Britain. This further stresses the devastating decline in flying insects in the industrialized world.

Among the reported species, the most rapidly declining species in Britain's over 900 larger moth species are the stout dart that's declining by 81% over a 10-year period; the golden plusia declining by 58%; and, the garden dart declining by 54%.

Richard Fox from the Butterfly Conservation who produced the report in collaboration with the UK Centre for Ecology & Hydrology and the Rothamsted Research, says that the decline is harrowing since moths play a key role in the ecosystem. Adding that moths are pollinators of many plants and some wildflowers such as orchids that rely on visiting moths for reproduction.

Moths are also essential food for thousands of animal species such as familiar birds and bats.

Reporting the Steep Decline of Moths

The report gathered millions of moth records by Rothamsted Insect Survey in collaboration with National Moth Recording Scheme from 1968-2017. The data was last analyzed in 2007, revealing a 40% decline in southern Britain's moth populations although no overall change to the abundance of moths in northern Britain.

Fox explains that a 22% decline in the abundance of moths is now recorded in northern Britain in a 50-year-period which is a cause for concern for researchers.

He adds that moth species are spreading northward due to climate change, with northern Britain reaping most of the benefits. However, he stresses that the significant decline in overall moth abundance in the north is worrisome.

Fox explains that the primary drivers behind the steep decline in the moth population are likely due to intensive agriculture, significant habitat loss, chemical farming, chemical change, increased nitrogen deposition, and light pollution.

He stresses that no species is immune to the said different factors. Even moths living high up the Scottish mountains will be impacted by nitrogen depositions especially climate change.

The increase in nitrogen deposited via rainfall due to pollutants and car emission are causing the robust plants to crowd more delicate flowers and plants that moth caterpillars heavily depend on.

Dan Blumgart, a moth ecologist at Rothamsted Insect Survey, says that comparing the report on the latest State of Britain's Larger Moths 2006 edition is a disappointing situation that hasn't improved. It's clear to researchers that bolder policies on habitat restorations and protections need to take effect to safeguard British moths' future.