The butterflies of Cambridgeshire: past, present and future
Caroline Fitton, of the Wildlife Trust in Cambridgeshire, explains the work being done to protect and encourage species, as a new exhibition gets under way at the Museum of Zoology.
With flamboyant pale yellow and black wings, a black margin around them, hindwings with ostentatious tails and a blue and red fake eye, the largest and most charismatic native British butterfly, the swallowtail, was once found across the fens of Cambridgeshire, East Anglia and beyond.
The draining of these natural wetlands for arable agriculture caused its loss from the area, and it is now confined to the Norfolk Broads: when global warming causes the Broads to be inundated with sea water - widely expected within 100 years - the swallowtail will become extinct unless successfully relocated to suitable inland sites.
These new sites will have to be meticulously created to cultivate a single wetland plant used by this notoriously picky butterfly species – milk parsley, the larval food plant of choice.
Swallowtails are central in a new exhibition at the University of Cambridge’s Museum of Zoology, tracing the fate of British butterflies from the time of Leonard Jenyns, a contemporary of Darwin’s, to the present day.
Butterflies are struggling: more than three-quarters of the Britain’s 59 butterfly species have declined over the past 40 years, due to habitat loss, climate change and pesticide use.
In meticulously kept notebooks, Jenyns records that the swallowtail was once found “in the greatest plenty, throughout the Fens between Ely and Cambridge”.
The large copper butterfly, now extinct in the UK, was once also found in Cambridgeshire’s fens and “not uncommon” in Jenyns’ time.
Even before his death in 1893, Jenyns was already concerned about the impact that fenland draining was having on rare species and in the intervening years natural fenland has been absorbed by expanding farms, with chemicals used on soils and CO2 emissions contributing to rising temperatures and unstable seasons.
Since 2001 the Wildlife Trust in Cambridgeshire has successfully been re-wetted 3,700 hectares of wetland at the Great Fen, and the work continues: this fenland and peatland restoration means the return of some species.
Brian Eversham, the trust’s CEO says: “In my time at WTBCN we’ve introduced landscape-scale conservation, championing the need for adaptation to climate crisis. Purple emperors are among the largest and, for me, most elusive British butterfly: in the past their numbers declined to a point that they could only be seen locally at a single site in Northamptonshire. Then, earlier this century, they began to spread – it’s now an annual highlight to see males jousting over the tallest oaks at Woodwalton Fen, the natural heart of the Great Fen.”
Rebekah O’Driscoll, communities officer at the Great Fen, echoes the importance of conservation work: “The large copper was once common here on the fens, but driven to extinction by drainage and habitat loss in 1851. However, guided walks certainly help keep the history of the species alive – and it’s important for new generations to know and understand what has been lost and preserve those species that we still have.”
Informing modern-day conservation, Jenyns’ 150 year-old notebooks provide a window into the wildlife of the past, as Ed Turner, curator of insects at the museum, explains: “They have allowed us to time travel. Matt and I have been able to go back in time and show us how much things have changed.”
Matt Hayes, PhD researcher and curator of the exhibition adds: “Jenyns recorded an entry for every species he saw in the county, noting where he found it and how common it was - that means 200 years later we have data we can use today.”
Dr Gwen Hitchcock, BCN senior research and monitoring officer, adds: “It’s really exciting in this exhibition to see how past records can help with the current, and future, conservation of these beautiful and important species. It highlights the importance of biological recording and how, by working together, we can ensure a future for our wildlife. We‘re collaborating with Matt and Ed and the Zoology department on an exciting project in Bedfordshire where we’ve created special banks for butterflies looking at mitigating impacts of climate change for temperature sensitive butterflies, based on research going back 15 years.”
Jenyns’ prophetic words carry a stark warning which we need to heed today more than ever. Prior to 1850, he wrote of Cambridgeshire: “A county which through drainage and enclosure, has lost of late years so many of its rarer species.”
For more on the exhibition, which runs at the Museum of Zoology until September 18.
Wildlife Photography Competition 2022
The trust’s wildlife photography competition 2022 is open until May 17: entry is for all ages, and the theme for this year’s competition is Nature from Every Angle (climb a tree, lie on the grass, float on a pond...). The top three winning photographers will bag prizes generously supplied by Canon UK and Opticron and the top 24 images will be published in the trust’s 2023 calendar.
Find out more at www.wildlifebcn.org/get-involved/photo-competition.
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