Rare moth reintroduced in England

From Wildlife Extra:

Rare moth reintroduction a success – with cows help

08/12/2008 09:32:00 December 2008. One of the rarest moths in the UK has returned to Derwentwater in the Lake District – after an absence of nine years – thanks to the cows which graze the land. The netted carpet moth (Eustroma reticulatum) was last recorded at this National Trust site in 1999 and is listed as a species of great concern on the UK Biodiversity Action Plan (BAP).

The strikingly patterned netted carpet moth was first recorded in the UK in 1856 at woodland near Windermere in Cumbria. Since then it has been found at only a handful of sites in the Lake District and north Wales. In the 1980s there was widespread concern about a severe decline in numbers, which led to its listing as a national priority on the BAP list.

Dependent on rare plant

The conservation challenge with the netted carpet moth relates to its total dependence on a scarce plant; touch-me-not balsam. Without sufficient balsam the future of the moth would be in serious doubt.

Research over the last 15 years by the National Trust, the University of Reading and Butterfly Conservation, with funding from Natural England, has found that the balsam does not form a long-lived seed bank in the soil and will disappear from a site within two years if unable to set seed.

Reliant on grazing

Traditional hardy cows have played a crucial role in creating the right environment for the balsam to flourish. The cattle have reduced competition from perennial plants by grazing and trampling, creating more open ground which encourages the annual germination of balsam seeds. Balsam seeds have also been transported by the cattle’s hooves, helping to creating new colonies.

John Hooson, National Trust Nature Conservation Adviser for the North West of England, said: “We’ve been working closely with a farmer to introduce controlled winter cattle grazing, targeted in selected areas of woodland. This has really helped maintain and expand the Balsam colonies, particularly in areas where we know that there are moth colonies. As a result the moth population is now more robust and able to weather natural fluctuations.”

Netted carpet moths and Touch-me-not Balsam

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Netted carpet caterpillars only feed on Touch-me-not, which is the UK’s only native balsam and is found naturally in damp, shaded woodland. It’s essential to create the right environment to ensure that there is enough balsam for the caterpillars to survive.
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The life cycle of the netted carpet moth effectively runs from July to July. The eggs are laid singly on the foodplant, the touch-me-not balsam, in July and the caterpillars develop through four stages and are fully grown by early to mid-September. By October the larvae have pupated in the soil, where they spend the winter and spring. The adult moths will then emerge in the following July, mate and lay eggs. Adults can be found until mid-August.
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The touch-me-not Balsam, which is essential for the netted carpet moth, is an annual plant of moist, nutrient-rich soils and usually occurs in damp open woodlands, especially along stream sides and where there is regular ground disturbance.

Wildflowers in Cumbria’s hay meadows are “thriving”, thanks to a restoration project by volunteers: here.