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  • Writer's pictureSim Elliott

Ashcombe Bottom, East Sussex. Relict ancient woodland on the South Downs. Birds, vascular plants, bryophytes, lichen & fungi. 01.04.21

Ashcombe Bottom, 4km west of Lewes, is one of the very few ancient woodlands left on the East Sussex Downs. Owen Johnson (1998) The Sussex Tree Book p.24.




To reach Ashcombe Bottom by bus take the 28, 29 or 29A from Brighton to Housedean Farm Regency 28 - Brighton - Hailsham and Eastbourne | Brighton & Hove Buses Regency 29 - Brighton - Tunbridge Wells and Heathfield | Brighton & Hove Buses (journey time 20 mins) From the Housedean Farm Bbus stop walk up the South Downs Way path until the "Field System" on the map, then turn left onto anpth marked footpath. This path will take you to the bottom of Ashcombe Bottom and then up through the wood, joining the South Downs Way again at Black Cap Blackcap | East Sussex | National Trust



... the hazel coppice supports a colony dormice - an exclusively arboreal rodent - to which for millennia this wood must have been a kind of ark in an ocean of open fields. Among the hazels grow many spreading oaks, their branches festooned with polypody and harts tongue ferns. Oaks dislike chalk but thrive here because the acid clays deposited on top the chalk have not been dispersed by ploughing or erosion. Owen Johnson (1998) The Sussex Tree Book p.24.


All sections of text in italics are quotations, sources sited.


Ashcombe Bottom is part of the Clayton to Offam Escarpment SSSI, but Nature England's citation only mentions Ashcombe Bottom with regard to its importance to animals: Breeding birds in Ashcombe Bottom include nightingale, all three British woodpeckers, tawny owl and a variety of warblers and tits. Thrushes and finches winter in large numbers and passage birds recorded include buzzard and merlin. Over one hundred and eighty species of moth occur and thirty three species of butterfly including the white admiral Ladoga camilla. Glow worms, dormice, harvest mice and adders are some of the other less common animals found in Ashcombe Bottom 1002124 (naturalengland.org.uk). The only vascular plants mentioned in the SSSI specification related to grassland and scrub flora; its seems a little odd not to mention the presence of ancient oaks and polypody ferns, which are both rare on South Downs.


I am only an amateur naturalist; thus all identifications in this post are provisional; if you note a mistake in identification please feel free to tell me. If you want to contact me about any aspect of this blog, email me at simeon[underscore]elliott[at]gmail[dot]com.


Please note this post is not a systematic survey of the this location (I do not have the level of knowledge, nor did I have sufficient time, to do that); this post discusses just the things I happened to notice.


Approaching Ashdown Bottom from the south west:




Birds


Outside the woodland, Skylarks debating territory and making song flights, and Corn Buntings making their scratchy (jangling key) call atop Hawthorns and fence posts, could be heard and seen on/over grassland surrounding the Ashcombe Bottom. Both birds are ground nesters and are Red Listed by the RSPB, due to reduction in nesting habitat. The corn bunting is not a migratory bird in the UK; it is so sedentary, in fact, that males who are just 30km apart sing with different 'dialects'. Corn bunting | The Wildlife Trusts


The short grass of calcareous downland and arable fields provides a nesting habitat for Skylarks, Alauda arvensis and Corn Buntings, Emberiza calandra. However, the conversion of historic grazed short grassland ( a very rare and special habitat) to the arable land has destroyed much of the grazed short grassland, although ididoes provide a food source for Corn Buntings. Unfortunately the largest decline [in grasslands] detected ..... was in calcareous grassland which apparently declined 91% from 600 hectares to 60 hectares between 1990 – 2000. SLR Report Template_Blank (plantlife.org.uk). In the South Downs [calcareous grasslands] now covers just 4 per cent of the National Park’s area. Over one-third of the sites are less than one hectare in size. Ideally a site of at least 20 hectares is needed to secure the future of this important habitat. Our Chalk Grassland - South Downs National Park Authority


Skylarks


A Corn Bunting


Within the woodland, I saw Goldfinches, Carduelis carduelis, and Long-tailed Tits, Aegithalos caudatus and heard Buzzards, Buteo buteo. All three of these species are common now on the Downs.


Long-tailed Tit on the branch of an Oak hunting for invertebrates in the moss and in the bark. Long-tailed Tits are often seen in family groups



Goldfinches are specialist seed eaters particularly those of thistle, teasel, dandelion and other similar plants, of which there were many in Ashdown Bottom ; although they will insects too



Goldfinches are very gregarious



In my childhood in the 1960s and 1970s my grandfather was a farmer on the downs and I walked on the downs frequently; I never saw a Buzzard. I heard several Buzzards in Ashdown Combe; their call is very characteristic:




and I saw Buzzard later in the day (in Stanmer Great Wood, which I walked through to get the 25 bus back home from Stanmer)



Buzzards were lost from many parts of the UK due to ongoing persecution, a crash in prey populations and the impacts of pesticides in the 1960s and 70s. Since then, the UK has improved its wildlife conservation, banning organochlorine pesticides and increasing public awareness. This has all led to a significant rise in Buzzard population size and range, and they are now recolonising many areas of the UK, as shown by our recent research by our Conservation Biologist, Dr Matt Stevens, and Head of Conservation and Research, Dr Campbell Murn, published in the British Trust for Ornithology’s scientific journal, Bird Study. How many Buzzards are there? - research by Hawk Conservancy Trust - Hawk Conservancy Trust (hawk-conservancy.org)


However, the population size is lower than in mid-Wales and significantly lower than in a similar habitat in central Europe indicating that there are factors limiting population growth of Buzzards in southern England. These factors include:

  • illegal persecution

  • secondary poisoning from consumption of rodenticides

  • ingestion of spent lead ammunition in scavenged carcasses

  • reduced rabbit prey as a result of Viral Haemorrhagic disease

There may also have been a potential increase in illegal persecution in response to the perceived predation pressures on game bird populations from increasing Buzzard abundance. Matthew Stevens, Campbell Murn & Richard Hennessey (2019): Population change of Common Buzzards Buteo buteo in central southern England between 2011 and 2016, Bird Study, DOI: 10.1080/00063657.2019.1693960. Can be read at Full article: Population change of Common Buzzards Buteo buteo in central southern England between 2011 and 2016 (tandfonline.com), cited in How many Buzzards are there? - research by Hawk Conservancy Trust - Hawk Conservancy Trust (hawk-conservancy.org)



Vascular Plants


A fallen Oak, Quercus robur, at the bottom of the wood



with Polypodium sp. ferns growing on it



I saw Polypodies growing on Oak, Quercus robur, Elder, Sambucus nigra and Hazel, Corylus avellana in these woodland; hundreds of them. All of these Polypodies had the appearance of P. vulgare, P. intejectum or the hybrid Polypodium × mantoniae ( P. vulgare & P. interjectum.). It is not possible to separate these species without examining the spores microscopically.


I took two spore samples from two polypodies and examined them with a dissecting microscope. The differentiation between vulgare and interjectum is by nature of their spores in their sori: the spore cases [sori] can be seen to consist of two halves, held together by a ribbed 'strap'. In Intermediate Polypody, this strap has on average 7-9 (extreme 4-13) ribs or bands, while Common Polypody has on average 10-14 (extreme 7-17) ribs. Polypodies & Hard Ferns (webidguides.com)


Theses not too great micrograms suggest that the ferns I saw were P. interjectum, but because identification is undertaken by the average number of cell walls in the sori it is not possible to say definitively. Moreover, there were hundreds of polypodies in the woodland. However, in Sussex, the majority of epiphytic polypodies turn out to be intejectum. The only places where I have seen polypodies which seem reliable to be vulgare are on the dunes of East Head, West Wittering an Climping in Wets Sussex



A tiny polypody



Quercus robur English Oak



Polypodium sp. on Oak




Bryophytes


Hypnum cupressiforme, Cypress-leaved Plait-Moss



Possibly Orthotrichum diaphanum White-tipped Bristle-Moss



Probably Lewinskya affinis Wood Bristle-Moss, on Hazel



Myriocoleopsis minutissima Minute Pouncewort and Metzgeria fucata, Forked Veilwort with Physcia sp. lichen



Fissidens taxifolius Common Pocket-Moss, on the soil of the woodland floor with leaf litter



Brachythecium rutabulum Rough-stalked Feather-Moss



Lichen


Normandina pulchella Elf Ears Lichen with Fruliana Dilatata, Dilated Scalewort



Parmotrema perlatum, Black Stone Flower and Fruillana dilatata , Dilated Scalewort. growing on an Oak



An Usnea sp, possibly Usnea cornuta s. l., high up on the branches of the fallen oak above



Usnea cornuta s.l. has an unusual distribution; being a Western Atlantic woodland lichen, and a lichen of woodland of southern counties


Xanthoria parietina Golden Shield Lichen



Probably Lepraria finkii Fluffy Dust Lichen



Flavoparmelia caperata Common Greenshield Lichen; common on may trees in Ashcombe Bottom



Ramalina farinacea Farinose Cartilage Lichen, a very common lichen on Hawthorn and other trees



Fungi


Wood stained with the mycelium of Chlorociboria sp., Elf Cup fungi



Probably Exidia glandulosa Witches' Butter



Probably Stereum rugosum Bleeding Broadleaf Crust on Oak



Probably Auricularia auricula-judae Jelly Ear, with Cryphaea heteromalla, Lateral Cryphaea -(moss)



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