Upper Dunsforth YWT
York
Site Details
Recorders: Alistair Taylor, Ian Craig , Amy Lax and Rosy Jamieson Distance: 1540m Altitude: Walk Time= 1 hour
A series of wet meadows and areas of wet woodland, supporting a wide variety of wetland plants and an interesting and diverse range of insects.
Sections
S1 +S2 low counts with Speckled Wood dominant
S3 the old meadow has the higest counts next to S5 and best for the Browns, Whites and the occasional Brown Argus.
S4 + S5 is favoured by Green Viened white and G
S5+ 6 are best for Vannesids and Brimstone.
S7 Speckled Wood favours the wooded areas of 1+7 along with Holy Blues.
2024 Results
Countywide, after a warm winter April turned cold, very wet and dull and everything just about stopped and it was near impossible to transect walk all month. By May there were already losses among our spring species being down a third in numbers. June brought Arctic winds, a complete reversal of the Hot June of 2023 when nine species reached all time highs here and across the UK. For the first two weeks of this June temperatures were 8’C cooler than in 2023 around a frigid 9’C with only 5 good days of sun at the end of the month. The first three weeks of July had the same theme of cool and damp with 5 warm sunny days at the end. Transect walking for many was very difficult. The persistence of the cold and damp over such a long period had a devastating effect with numerically two thirds of our butterflies in the critical later stages of their development; mortality was very high. It was also one of the longest June ‘Lulls’ lasting from late May to the beginning of July. When the main flight season did arrive it was slow to build up and there was no usual peak. Better weather in August helped save the second generation and very unusually numbers actually went up at the start of September.
Losers
For many species it was a triple whammy after the heat and droughts of the previous 2 years and last July’s poor flight period this year made it a perfect storm. Overall, annual numbers were down 41% against the average and 45% down on last year. Half our species were down more than 50% and a quarter down more than 70%. The Lycaenids, Vannesids and the Fritillaries were amongst the worst affected. Many transect walkers did not see a single Common Blue, Small Copper, Holly Blue, or Brown Argus until late into their 2nd broods.. Four of our long term declining species Common Blue, Small Heath, Small Skipper and Green-veined White had their worst year ever recorded.
The Winners and less bad losers
Northern Brown Argus had an exceptional year up near 50% Other species bucking the trend were Brimstone and Marbled White. The damp loving Ringlet on many limestone/dry sites were up a half while on most wet sites they fell by a half. However if it wasn’t for Ringlet holding up the overall numerical losses, this year would have been significantly worse. It often happens when Meadow Brown has a very poor year, like this one, Ringlet does proportionally better, and vice versa in a warm year.
It has all happened before… many times.
It was our worst year since 2016 but nearly as bad as 2009 when numbers were down 50%. 2024 comes after a run of 6 relatively good years since 2018 along with rapidly rising temperatures including 2 of our hottest summers which were followed by two of our best butterfly years in 2019 and 2023. It is likely 2024 was a blip
Upper Dunsforth was somewhat down on the county results but similar to other damp lowland sites. It is significantly worse than the previous worst year in 2016 and sadly zero Small Tortoiseshells were seen.
2023 Results
County wide 2023 results reflect the 2022 Heat and drought with Small Tortoiseshell and Peacock nearly halved for the second year against their 5 year average. Red Admiral arrived in force in July and took advantage of soft nettle growth of the rains and had their best year ever. Drought sensitive species on thin soils were badly hit, particularly Dark -green Fritillary and Northern Brown Argus but also Ringlet, Green-viened White and Small Heath. Less drought affected species along with the hottest June on record built even more on gains last year leading to Comma, Brimstone, Holly Blue and most Browns having a fantastic year reaching all time highs. A increase of 9% overall was mostly due to sheer numbers of Meadow Browns and Gatekeepers ment 2023 nearly pipped 2014 as best year in modern times. Most noticeable was the large differeces between moisiture retaining mineral soils of the valleys and thin, dry limestone or sandy soils. A large number of damp grassland, hedgerow and woodland dominated sites benefitted hugely with 3 sites seeing more than 50% increase . A smaller number of thin, chalky, sandy or craggy sites did badly some down up to 25%.
Upper Dunsforth saw a similar increase in Overall numbers to teh county average. It also follows pretty closely the county trends across the species. The big losers were those sensitive to drought namely Ringlet and Green Viened white. On teh other hand after last year heat numbers really built up for Meadow Brown, Gatekeeper, Holly Blue , Speckled Wood , Comma and of course Red Admiral all of which had their best year ever here and across the county. Wall Brown wasnt seen this year but be assured it is having a good time and still spreading in the Vale of York although due to drought numbers were down. Its lots of respects a spectacular year but not universally.
2022 Results
A poor year in the drought with many species suffering in particular big falls in the Vanessids but also the Whites,
Peacock and Small Tortoiseshell really suffered and none were seen after early July.
Comma in common with the county trend boomed on the summer (hutchinsoni) generation
Although Speckled Wood and Ringlets suffered the rest of the browns in a large part made up for the other losses particularly Gatekeeper which tripled.
Overall -12% down was not so bad!
Its great to see the Wall back and trying to establish of which can be seen in other localitiees too
In the long term numbers are decreasing slowly of the more common grassland species which does suggest some deteriation
2021 Results
A poor year 27% down on teh average Almost all species down on the average by 30-50% . Large Skipper was absent for the first year.
Biggest loosers werepeacock and speckled wood. Winners were Ringlet up slightly and gatekeepr boomed as it didi in almost all locations .
The Tortoishell boom has fizzled out! but continues apace eleswhere
Great to see the Wall back
2020 Results
A close to average year although lower than 2019 with its invasion of Painted Ladies. There was some reduction in Smal Skipper and Ringlet but the wet site seems to have come through the drought of spring 2020 pretty well. As with many other areas there was a considerable booom in Small Tortoiseshell.
Some adjustement were made for the first weeks missed during lockdown: Brimstone +4. GVW +5, Orange tip +52, Peacock +15,