Bastow Wood YWT
Recorders: Ian Powell and Ian Court Distance: 3008 Walk Time: 1.5hours
Lea Green lies just to the east of Bastow Wood and is the site of quarrying for lead and limestone that needed a ready supply of timber for charcoal from the woods. It is also very close to Grass Wood and lies in Wharfedale. This transect covers an area of Carboniferous Limestone near Grassington, Wharfedale that supports flora typical of limestone grassland including Common Rock Rose Helianthemum nummularium. The transect route passes through a Northern Brown Argus colony before entering Bastow Wood, one of only two Ash-Hazel woodland pastures in the YDNP. The very thin unimproved limestone grassland and scree with some bracken
S1 is perfect for the Small Heath and the Northern Brown Argus abounds . S2 becomes more limestone pavement and then down into a very favoured gully of S3 Thes soils are at their thinnest in S1-3 perfect for Northern Brown Argus but also Dark Green Fritillary and Green Hairstreaks. You then descent down the slope towards Bastow Woods and longer grasses and scrub and encroaching birch with patchs of Rock rose The longer grasses are perfect for the Scotch Argus and Meadow Brown. By S7 you enter woodland with grassy glades and the grasses longer and the Speckled Wood and Vannesids favour. S9 is a green lane and hedgerow
Small Heath favour S2 and S3. Scotch Argus preferes S4 -5. Northern Brown Argus along with Meadow Brown prefer S1-3 The Fritillaries favour S3-4 . Green Hairstreak is mostly S1-2 . Common Blue S3. The Vannesids favour woodland of S7-9 .Speckled Wood S7 Wall was spotted in S9 this year
The best year since the 2013-14 big peak and numbers half nearly doubled in twenty years with teh site becoming more calacareous grassland. Northern Brown Argus has nearly doubled along with other grassland species with meadow Brown near trebling. Brimstone was seen for teh first time this year and Orange tip looks like it is trying hard with a big jump in numbers this year . Small Skipper doubled over last year and had a good summer and large skipper seemed to suffer in teh drought as it did back in 2018-19. Northern brown argus dropped back from its average after an exceptional year last year and follows teh pattern elsewhere of suffering from drought. we should expect to drop even lower next year as a consequence, Although Small Tortoieseshel held its own while it has been near universally down elsewher Peacock halved in line with teh county, again suffering under the drought. Dark green fritillary has dropped back in numbers in teh last 10 years and was quite low this year at about a fifth of the peak which reflects teh changing habitat.
last year speckled wood boomed but fell back thsi summer under less good moist conditions. Its great to see teh wal lback these last two years after a gap of nearly 10 years. Scotch Argus has been seen spasmodicallly since 2013 but becake resident in 2019 with this year alos being quite good. The Meadow Brown and Ringlet both boomed doubling or treblling on last years numbers enjoying the warm June weather and reaching numbers not seen since 2013-14 while Small heath, as it did almost universally, fell back slightly.
2021 sees a improvement over 2020 but not quiet as good as 2019 an exceptional year. The biggest improvemnt have been in Northern Brown Argus and Scotch Argus having bumper years . Small Heath along with Meadow Browns were up and it was great to see the Wall returning browns
A pretty good year with the scarcer species holding up well with only Ringlet showing a decrease after the long hot summer of 2019 and drought of spring 2020 . Common Blue and particularly Small Tortoiseshell had a very good year. NB alot of the data is based on estimates as walk frequency was low.