An ever-changing climate, urban sprawl, forestry and modern farming techniques have all affected the butterfly world in the last fifty years, according to National Trust naturalist Matthew Oates.
Celebrating his 50th season of butterflying, Matthew Oates has reviewed the winners and losers of the butterfly world since the 1960s while taking a look at their future in the decades ahead.
Matthew Oates, who received his first butterfly net for his birthday on 7 August 1964 and is now the UK’s leading expert on the iconic Purple Emperor, said: “Nearly all butterfly species have seen dramatic changes over the last 50 years and for some it seems their ecology has changed almost entirely.
“Sadly, there have been more losers than winners during my career, with Dutch Elm disease, woodland clearance, intensive agriculture, urbanisation and a changing climate all playing their part.
“It’s been a massive rollercoaster ride for me. Some butterflies have done remarkably well and in some districts new species have appeared. At the National Trust’s Arnside Knott, a top butterfly site in south Cumbria, five new species have colonised during the last two decades.
“There have been many great personal highs too, notably the long hot summer of 1976 when butterflies boomed and the wonderful Painted Lady invasions of 1996 and 2009.”
At this career milestone, Matthew Oates, who continues his butterfly research with support from the National Trust, predicts more unforeseen and significant change to come for butterflies in the UK.
The last 50 years
- The Large Blue was reintroduced in the UK from Sweden after being declared extinct here in 1979. The National Trust’s Collard Hill played a key role in this success story, which was achieved by the dedicated work of a couple of top scientists.
- Adonis Blue and Silver-spotted Skipper declined severely when closely-cropped chalk grassland disappeared following the loss of rabbits to Myxomatosis. However, they are now recovering well due to conservation work and the recovery of rabbit populations: the Adonis Blue returned suddenly to the Cotswolds in 2006 after 40 years of extinction. Within 3 years there were 25 colonies, mainly on National Trust hillsides around Stroud.
- The Essex Skipper saw a sudden expansion in central southern England during the early 1980s in a run of good summers.
- The Brown Argus, Gatekeeper, Marbled White and more recently Silver-washed Fritillary have also increased and are expanding their range across the UK, and there are signs that the Purple Emperor is too.
- The Comma has also made a comeback in the UK, with a stronghold now in Northern Ireland, particularly at the National Trust’s RowallaneGarden.
- Butterflies are now very well monitored and promoted by the dedicated charity, Butterfly Conservation.
The Adonis Blue has made a comeback
- The White-letter Hairstreak, which breeds on elms and was formerly common in elm landscapes, collapsed as a result of Dutch Elm Disease in the 1970s. It has since staged a low key comeback in many areas but remains a shadow of its former self.
- The Wall Brown used to be common along road verges, woodland rides and rough grassland, but started to disappear, mysteriously, in the mid 1980s and is now rarely seen away from the coastal fringes of England and Wales.
- The Small Heath, one of the UK’s commonest butterflies, has virtually disappeared from woodland, though it still occurs in open grassland.
- The Duke of Burgundy and High Brown Fritillary are also struggling, with few of the colonies Matthew found while surveying them in the 1980s and early 1990s remaining.
- The ‘Spring Fritillaries’ (Pearl-bordered Fritillary, Small Pearl-bordered Fritillary and Duke of Burgundy) were once found in woodland clearings all across central southern England but are now very rare there.
- Surviving butterfly habitats are now often isolated fragments which makes natural spread very difficult.
- Above all, 50 years of butterflying has seen massive highs and lows, often associated with weather. Butterfly populations are hugely affected by weather, and overall climate change will affect them radically long term.
The next 50 years
- The Large Tortoiseshell, extinct for many years, could recolonise southern England from mainland Europe. There are early signs this may be happening already, with several sightings on National Trust land on the Isle of Wight this spring.
- Milder winters, associated with the less adverse side of climate change, might allow the continental Swallowtail, European Map and the Queen of Spain Fritillary to colonise from across the Channel.
- Urban spread, farming and to some extent forestry remain the big issues: yet we could have whole landscapes teeming with butterflies if society supports the work of conservationists.
Matthew Oates added: “In the next 50 years, climate change is likely to affect butterflies massively. There will be even more winners and losers, with new species likely to colonise from abroad and established UK species forced to adapt to survive.
“If the work of dedicated and passionate conservationists continues and butterflies keep growing in importance within British culture, the challenges of the next 50 years can be overcome.
“A big social revolution is taking place: old-fashioned butterfly collecting has died out and been replaced by harmless photography and more people are growing butterfly-friendly plants in their gardens. Butterflies need friends and are gaining many new converts.”
The three week recent heatwave across much of the UK is likely to boost the butterfly population in the short term, with Oates anticipating a butterfly boom for his anniversary year. This comes on the back of some very challenging times for butterflies due to recent bad summers.