Wheldrake Ings YWT

Lower derwent Valley

York

Site Description

Recorders:  Sarah Robinson , Emily Clarke,  Fiona Bruce,  Terry Ram,  Richard Leathley              Distance:  2689m                Walk Time Approx:  1hour 30mins

Part of the lower Derwent valley reserve and its treasured MG5  grassland the site is  often flooded  in winter. 

In summer its meadows are awash with  Great burnet, Meadowsweet, and Meadow vetchling. 

Sections:

S1, relatively low counts of  common species

S2  generally has  one of the highest counts and along  with S4 tends to be the favourite area for Orange Tip  and Small White S2-S3 is also teh area favoured by occasional Dingy Skipper, Common Blue,  Gatekeeper and Wall, Small Copper and Small Heath

S3 along with S4 tend to be the favoured area for the Vanessids

S4  in more shady areas with Speckled Wood appearing and is also favoured by Meadow Brown and Ringlet

S5 Meadow Brown can be  most numerous 

S7 has a low count 



Results 2024:  Insufficient data

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

Results 2023:

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%.

Transect reports

At Wheldrake Ings overall numbers were down on the average  largely due to the very poor performance of Peacock and Small Tortoiseshells  which are often the two most abundant species on this site.  Even so they were marginally up on last year and the first signs of recovery after big fall in 2022.  Across the other species there is a good deal in common with county trends with  Ringlet dropping back on last year universally. The big winners were Comma, Red Admiral, Meadow Brown, Gatekeeper Speckled Wood and Brimstone all of which had record breaking numbers across the county.  It could have so easily been a record breaking year here only held back by the vanessids!

Results 2022:

A big increase on the last two years but still quite a way behind the good summers of 2018/19 which stand out at a modern day highpoint and 11% behind teh 5 year average there were lost of ups and down in common with most sites as a consuence of the heat and drought.  There is a surprising big difference between years at this site which seems to be not unusual on floodplain habitats .. every species either does extrememly well or extrememly poorly .  This is certainly true amongst the whites however this year as with most localities both the Brimstone and Orange Tip are up average . Small Skipper counts are always very low which is a surprise for such a grassalnd  site but  the majority of the site is cut for hay.  Dingy Skipper is likely visiting occasionally from surrounding sites like the North Selby mine close by.  Holly Blue returned after a absence of two years but not quite back to average and this species has been seen returning to many sites in the spring generation.  Small Tortoiseshell was well down on the recent years boom but no nearly as much as other sites  with good numbers in June  and then zero in August and the second generation failed completely.  Similarly with peacock just low numbers seen in  July and then nothing and was responsible for much of the losses for teh year. In contrast Comma boomed almost everwhere  and a very strong showing here  but then again nothing later.  Similar to other sites speckled wood had an excellent year particularly in September. Gatekeeper also thrived as with other sites and was almsot universally up . Meadow brown was a tad down on average buit stil way up on teh previous two years nearly doubling as did Ringlet.

Results 2021:

This riverside route is subject to much annual variations  of water levels but also of butterfly species with  ocassional explosions of some in good years like 2017-2019  foloowed by crashs.

There were  huge peaks of Peacocks and Meadow Browns  in 2019; then  Whites in 2018 so the regular floods do seem to be the key factor. For example Meadow Brown 448 in 2019 and just 15 in 2020 but there was extensive floods in February 2020 and you can guess the larvae were drowned

 Following the riverbank and  does mean there is often good quantities  food plants  for Orange tip  and Small White both of which are occasionally in very high numbers.   Comparison with the  5 year shows 2021 in a bad light  of almost eveything down  but there are exceptions which fit very well with Yorkshire trends. Small Tortoiseshell continues to boom  and Small Heath is showing a strong upwards trend.  Biggest loosers are Comma and Peacock.  Also missing in 2021  are the occasional visitors/breeders  of Small Skipper, Dingy Skipper, Holy Blue, Brown Argus, Painted Lady, Common Blue, Wall and Gatekeeper.