Blue butterflies return after sowing wild flowers

Some threatened blue butterfly species are making a comeback as a direct result of grassland habitat restoration schemes which included sowing seed of key wild flowers.

In 2018 we were delighted to receive feedback from two very successful habitat restoration schemes using wild flower seeds that Emorsgate Seeds had had past involvement with.

Both case studies resulted in species recovery of threatened blue butterfly species: the small blue butterfly in Warwickshire, and turquoise blue butterfly in the Czech Republic.

Although the two schemes are far apart geographically, in other respects their history and progress are very similar.

In both cases populations of blues had declined to critical levels; the few remaining colonies were fragmented, isolated and close to extinction.

Key to turning their fortunes around was creating new species rich grassland using seeds.  The aim being to reverse past habitat losses which were the cause of their catastrophic decline.

Small blue butterfly


Small blue butterfly (Cupido minimus)

Warwickshire is the only county in the West Midlands region where the small blue butterfly has not already become extinct. By 2009 however, there were only 3 colonies left; a decline of 87%. This was a butterfly teetering on the brink of total regional extinction.

The Small Blue Project was launched in March 2009 by the Warwickshire branch of Butterfly Conservation.

Kidney vetch, the foodplant of small blue, was introduced using seed supplied by Emorsgate Seeds on to a number of key restoration sites, many of which were former small blue sites.

Butterfly restoration site 1

Restoration and habitat creation involved significant landscape works and clearance before seeding and planting kidney vetch. Devising a sustainable long-term management plan is also essential for success.

Southam Bypass restoration site

Southam Bypass road verge is now wall to wall kidney vetch with active small blue colonies. In recent years this site has produced the earliest sightings of small blues in the county.

Ten years later small blue butterflies are up from 3 to 23 colonies in Warwickshire as shown on the map below.

(Information and photos kindly supplied by Mike Slater, Butterfly Conservation Warwickshire https://www.warwickshire-butterflies.org.uk/small-blue.asp )

Small blue map

 

Turquoise blue (Polyommatus dorylas)

Like the small blue in England, the turquoise blue in the White Carpathian region of Czechia was just about surviving as a few isolated colonies in the SE part of the country.

The fortunes of the turquoise blue, and other wildlife, are now also looking up thanks to a grassland restoration projects initiated by the Czech Union for Nature conservation an NGO working in the Bile Karpaty Protected Landscape Area (PLA) of the White Carpathians.

Arable reversion in Czechia

One project involved the expansion of species rich grassland out across 13 ha of arable land adjacent to a remnant of dry grassland habitat of only 1 hectare in a protected site called Zerotin. This hilltop site was important as it was home to a turquoise blue colony that was just about able to hang on there.

I was able to visit this notable grassland reversion site in May 2018. It had been sown with a seed mix which included kidney vetch (which is also the food plant of the Turquoise blue). I saw for myself the colourful diversity of wild flowers that had established from both sown seed and natural regeneration. I also saw the turquoise blue butterfly colonies which had expanded out into their new enlarged territory, and whose future was now more secure as a result.

Emorsgate seed did not directly supply seed in this instance, but did share our brush harvesting technology freely with Ivana Jongepierova of the Czech Union for Nature conservation. This machine was then used to harvest seed locally for use in these grassland restoration projects.

The projects have been a great success and the distribution of turquoise blue is expanding into the newly created grasslands.

 


Posted on 08 January 2019,
Category: News