Grass-feeding butterflies defied the second wettest year on record to enjoy a bumper 2012 across the UK countryside, according to a new scientific survey, although there was bad news for other species. Last year’s rain prompted substantial grass growth and provided good conditions for some grassland species such as the Meadow Brown, Ringlet and Gatekeeper.
The Wider Countryside Butterfly Survey (WCBS) revealed that the Meadow Brown enjoyed its best year since the start of the scheme in 2009 with almost twice as many counted than in 2011. But overall 2012 proved to be a washout with recorders seeing 43% fewer species on average than in 2011 during survey counts.
The WCBS is run by Butterfly Conservation, the British Trust for Ornithology (BTO) and the Centre for Ecology & Hydrology (CEH) as part of the United Kingdom Butterfly Monitoring scheme (UKBMS). It involves counting butterflies in more than 700 randomly generated 1km squares across the UK countryside and helps assess the health of butterfly populations across the wider countryside, rather than specially managed hotspots such as nature reserves.
Last year, recorders saw on average 44 butterflies of four species per survey made over July and August, compared with 2011 when 47 butterflies from seven species were seen on average. In 2009 an average of 80 butterflies and eight species were recorded per survey.
A relatively dry start to 2012 followed by near continual rain saw bumper grass growth, which provided some species with an abundance of their favoured food plants. The Meadow Brown thrived as a result with more than 18,500 counted, almost twice as many as in 2011. This was the most widespread butterfly for the third successive year being seen in 89% of squares surveyed.
The Ringlet also enjoyed a good year and was found in almost two-thirds of squares compared to half of squares in 2011. Another grass-feeder, the Gatekeeper, was also more widespread than 2011.
But months of unseasonable wet weather proved problematic for many other species - there were 38 visits when recorders saw no butterflies at all. Garden favourite the Small Tortoiseshell suffered further declines, with less than half the number counted than in 2011. This once widespread species was present in less than half of the squares sampled.
The Common Blue also struggled and was found in 50% fewer squares than in 2011, while the Wall butterfly continued a series of declines and was found in just 4% of squares compared to 9% in 2009.
WCBS Co-ordinator Dr Zoë Randle said: “Last year was fantastic for the Meadow Brown - however the overall picture is that butterfly populations are suffering in the wider countryside and this needs to be addressed urgently.”
Kate Risely, who co-ordinates the BTO butterfly surveyors, said record-breaking rainfall during the summer months had affected birds and butterflies alike, with many species suffered a disastrous season. However credit was due, she said, to all the volunteer recorders who braved the weather and collected the valuable data on butterfly populations.
Butterfly Conservation issued a press release for this story.
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