Conservation Officer Caroline Kelly reveals a breakthrough for one of the UK's rarest butterflies.
The highly threatened Heath Fritillary has recovered this year after struggling following a series of cold springs to record a fantastic 2015, Butterfly Conservation (BC) are delighted to reveal.
The butterfly has responded well to targeted management at a number of its UK strongholds with high numbers reported.
Since 2011 the Heath Fritillary has been in decline at all four of the landscapes it occupies in England. In some areas these declines have been aggravated by poor weather. The butterfly struggles in low temperatures and needs sunny conditions in which to thrive.
One of this year’s particular Heath Fritillary highlights was the high numbers recorded in West Blean and Thornden woods in the Blean area of Kent.
In this environment the fritillary lives up to its traditional nickname of the ‘woodman’s follower’ as it occupies freshly coppiced areas of woodland as soon as they become suitable as a breeding habitat. More than 260 Heath Fritillaries were recorded in just one small patch of freshly coppiced woodland during one survey this summer.
Mike Enfield, who monitors the butterfly at Kent Wildlife Trust reserves in the Blean, explained: “There is little doubt the recent conservation work here has helped the upturn in the fortunes of the butterfly, especially by making sure coppiced woodland is linked together by a network of well-managed rides. Good new habitat has been found very quickly by egg-laying females and colonies are now spread over a wider area than for many years.”
The butterfly also thrived at its West Country stronghold, the Duchy of Cornwall-owned Greenscoombe Wood near Luckett on the Cornwall and Devon border. Heath Fritillary eggs were recorded in the wood’s freshly coppiced areas where the butterfly has been declining since 2011. A total of 63 adults were recorded flying this year in comparison to only one individual in 2014.
BC’s Lydford Old Railway reserve recorded the highest numbers of Heath Fritillary since the butterfly was re-introduced in the early 1990’s. This site is relatively small and the annual management undertaken by BC Devon Branch volunteers is a credit to their dedication and hard work.
The butterfly has showed initial success at Hawkescombe Wood on Exmoor after it was moved to the site in 2014. This year’s surveys revealed that the Heath Fritillary successfully over-wintered with more than 15 adults recorded suggesting that the woodland management work by Exmoor National Park has been a success in creating suitable breeding habitat and host plants.
But it wasn’t all good news for the butterfly. Heath Fritillary struggled at the RSPB’s site, Blean Woods National Nature Reserve in Kent. RSPB volunteer, Michael Walter said: “Disappointingly, numbers on the Blean Woods NNR were the lowest since 2005 and all six of last year’s best sub-colonies (with a peak count of 30 or more) declined drastically. But, targeted management planned for some of the most likely sites this autumn and winter should see a marked improvement over the next couple of years.”
Management for this species differs in the few areas of England where it occurs. Moorland sites need management including burning, grassland sites require appropriate cutting and woodland sites need annual coppice cutting and ride management. Difficulties can arise for the butterfly if habitat is not maintained annually.
There is nothing more satisfying than getting an email and an image which shows how well this little beauty is responding to all the hard work that is going on around the UK. What is even better is walking through a site and being overwhelmed by the sheer numbers of these beautiful creatures as they delicately glide around you, it is so magical and a feeling that I can’t put into words.
Without the targeted management for this rather fussy species I wouldn’t have the pleasure of writing this blog. Woodland management and the decline in the coppiced wood product industry affected this once common visitor to the woods. This year’s surge in the number of adults is a result of a huge effort from all of our partners who have this butterfly on their sites.
Hopefully the heartening results of this year’s surveys across England will demonstrate that all of the hard work and determined effort of land managers and volunteers is worth the wait.
Caroline is BC's Conservation Officer (Species and Regions)
Follow her on Twitter @arionathaliaBC