Malham Tarn NNR

Dales National Park  

Field Studies Centre

Site Details: 

Recorders:     Peter Walsh 2013-16      Denis Lord 2017-                  Distance:  3175          Altitude 393m                 Walk time : 1 hour   

The National Trust’s National Nature Reserve at Malham Tarn is a very special place with an amazingly rare and dramatic array of plants and animals from the really unusual Tarn Fen (unique assemblage of fen plants and insects) to raised bog, orchid-rich wet flushes and limestone pavement and the tarn itself with crayfish, otters and many breeding birds. 


S1 takes you from Home farm to the northern edge of the estate.  S2 has the highest butterfly counts and  follows the road verge  with good numbers of Common Blue, Dark-green Fritillary and Small Heath  plus Ringlets and Green viened White in  the damper areas. Northern Brown Argus is also seen here. S3-S5 have low numbers with Green-viened White being dominant in the damp areas. S6-S8  score almost none. S9  across heathland sees Green hairstreak  and Green-viened Whites  and occasional Orange Tip.  S10 through woodland sees only Green-viened whites.  S11 enters the fine grassland in front of the field centre and a good array of the common grassland species with Meadow Borwn predominant along with Small Skipper, Ringlet and Small Heath. S12 scores zero but S13 climbing the bank to Highfolds Scar has very high numbers of grassland species but also Northern Brown Argus and Dark-green Fritillary occu . Returning past the Field centre, garden plants attract large numbers of Vanessids and even a Brimstome.

Results 2022

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%.

Malham was  down in overall numbers and like pretty much universally elsewhere the damp loving species were badly hit by last years heat. Numerically the biggest losers were Green-viened white, Ringlet and Small Heath . This was somewhat counteracted by a 80% increase in Meadow Brown again this was pretty much universal and  good numbers again this year of Small Skipper who tend to love the dry and heat  The other big loser  was Small Tortoiseshell which again has almost universally declined but Peacock which tanked countywide for a second year, here in the hills shows very strong signs of recovery up into the hundreds.  Its important to note this is a remarkable year in that Holly Blue appeared for the first time and Speckled wood has been present as singletons these last two years.. signs of things to come. All the whites tanked apart from Orange Tip.  Dark-green Fritillary recovered somewhat from last last years big dip but this is against the trend this year apart from  on sites at the highest altitudes Malham being the highest at 400m. 

Transect reports

Results 2022

Counts over the last decade have near enough doubled  mostly due  large increases in the grassland species, in particular, Ringlet , Small Heath and Common Blue.  Even the warmth lover small skipper has now made it to 400m altitude in the last  4 years and numbers this year  are double last.  Brimstone has also been seen for the first time last year . The whites had a poor year  although Orange tip staged a come back after a very poor 21  and its trend long term is very much upwards. Brown Argus is only seen spasmodically and not this year as  it has been a poorer  year on most upland sites due to drought.  Green Hairstreak  peaked in 2018-19 and was somewhat down against the average. Meadow Brown had a very good year while the other browns were down. Small Heath had a exceptional 2020 but this has been followed by two poorer years. Vanessids had a terrible year as they did in most locations due to the drought and heat.

Results 2021

After three very good years 2021 was a bit of a fall 22% down . 2019 standing out as exceptional in the last 5 years.  Small Skipper and Small Copper are showing a significant  increases  over the 5 year term in contrast to much of Yorkshire . The Whites have steadied down after the boom years 2018-19 as have Oraneg Tip. Brimstone made an appearance in 2021 which is encouraging for this spreading species. Common Blue had a very significant rise last year and is a little down this year back to their pre peak numbers. Peacock numbers have dropped back in common with most transects  and Comma has not been seen for 2 years and had a exceptionally bad year on most transects . Dark-green Fritillary numbers  peaked in 2019 and have dropped back a little while elsewhere they had a good year . Ringlet had a poorer year while Small Heath wasnt bad with second highest year and has been one of the exceptional  winning species in Yorkshire in 2021.   The  Small Tortoiseshell boom continues as elsewhere but in contrast to other areas Red Admiral did well. Northern Brown Argus fluctuiate in numbers with no clear trends while in most of Yorkshire they increased substantially.