• Abstract and Figures
• Public Full-text

Dwarf Rush Project from Deutschlands Flora in Abbildungen. Author: Johann Georg Sturm. Painter: Jacob Sturm. Juncus capitatus Weigel (synonyms can be found in Appendix 1) Common names – dwarf rush and leafybract dwarf rush, there is no known Welsh name for this species. Description & Background Juncus capitatus is native to Europe, Asia and North Africa. It is also an introduced species in parts of North America such as California and the Gulf Coast, Australia and New Zealand. It grows in moist areas, such as wet sand, vernal pools, and ditches. J. capitatus is a small annual herb not exceeding ten centimetres in height. The stems are erect and threadlike, flat or somewhat corrugated. The leaves are basal and up to 3 or 4 cm long. The plant is green to red or brownish in colour. Each stem bears an inflorescence of up to six clustered flowers. The pointed bracts at the base of the Dwarf Rush Project 1 inflorescence are often over a cm long, longer the flower cluster itself, and are somewhat leaflike, giving the species its common name. Each flower has pointed outer tepals and thinner, shorter, oval- shaped inner tepals. There are three stamens. The fruit is a tiny oval-shaped capsule one to two mm long. (URL: https://species.nbnatlas.org/ Accessed 24/06/2020) Threat Status Juncus capitatus is considered vulnerable on a UK wide basis (JNCC, 2005) and is found only at a limited number of sites in Cornwall, on the Channel Islands and on Anglesey, North Wales. It reaches the northernmost edge of its UK range in Anglesey, Wales, which holds 57% of the UK population and an estimated population of 800 to 1000 plants (Dines. T., 2008). It is becoming increasingly important to identify the status of species such as J. capitatus in order to select priorities for conservation and for monitoring the impacts of climate change. Small, edge-of- range populations of species that might be vulnerable to change are particularly important as they are often genetically distinct. Welsh Vascular Plant Red List Category Endangered B1ac(iv) Year Published: 2008 Date Assessed: No date given Assessor(s): Dines, T. Reviewer(s): N/A Map 1 UK distribution (from https://bsbi.org/maps?taxonid=2cd4p9h.fdb) Dwarf Rush Project 2 J. capitatus in North Wales J. capitatus was first recorded on Anglesey by Bolton King in August 1918 from near Rhosneigr "in good quantity over a limited area, but assuredly native, growing with the usual damp heath vegetation". He subsequently gave details of the locality as "the extreme northern edge of Towyn-Trewan, close to the S. corner of the encircling wall round a rocky mound called Carnau". A few years later a further Anglesey specimen of J. capitatus by Lady Kathleen Stanley who wrote on 25 June 1925 that "there was quite a lot of it at Tywyn Trewan quite close to Rhosneigr". Specimens of both observations are held at the Oxford University Herbarium (OXF). In the 1940s the construction of RAF Valley airfield had a huge impact on the dune system and its heath at Tywyn Trewan and as this development encroached up to the wall of the Carnau mound J. capitatus was presumed extinct in the area. Searches of the site had no success. J. capitatus was subsequently re-found nearby to Tywyn Trewan by Tim Blackstock while he was recording bryophytes on 31 March 1995. Subsequent records have been made for the species at the site up until 2019. Elsewhere in Anglesey, there are records from three other dune systems. It was observed on a field excursion of the Botanical Exchange Club in June 1937 from "S.W. side of Newborough Warren"" it has not been recorded again from this locality where its habitat may have been destroyed by the establishment of a conifer plantation. It has also been reported from Tywyn Aberffraw by J. G. Duckett and J. N. B. Milton, and a specimen was gathered in August 1983 "on damp sand", more recent searches at this site by R. H. Roberts and others have been unsuccessful. An additional record for Tywyn Gwyn, at SH295815, was made by Andy Jones in 1998. J. capitatus has thus been recorded only very sporadically and locally in Anglesey from four sand dune systems. Viable seed of this species can remain dormant for at least 29 years. and its reappearance at Tywyn Trewan demonstrates that it can persist unnoticed for over 50 years. (Blackstock, T & Jones, R., 1997) Current Status of J. capitatus at Cwmran Tywyn Trewan common at Cymyran is an area of common land managed by the Tywyn Trewan Board of Conservators. Cymyran is part of the much larger Beddmanarch Cymyran SSSI, which encompasses the shallow waters of the strait which separates Holy Island from mainland Anglesey, Juncus capitatus is one of the designated features of this site. Cymyran lies at the southern end of the SSSI on the Anglesey mainland, adjacent to the RAF Valley airfield. Running along the shore of the strait, Tywyn Trewan is a narrow low-lying site. The terrain is relatively flat with a series of low dunes. The small area of dune heath is located in the northern part Tywyn Trewan and straddles the track to Plas Cymyran. The Anglesey Coastal Path passes through the site along the track to Plas Cymyran. In addition, a number of small paths crisscross the dunes giving access to the shore. Cymyran has one of the largest remaining sites for dune heath in Anglesey and is considered of high conservation value, it supports the majority of the population of Juncus capitatus. The lack of management is of considerable concern as bramble and scrub are invading the entire dune system. Whilst the lichen – rich areas tend to be on areas of bare sand, which are less likely to become scrub encroached, these areas are becoming shaded by surrounding scrub and the total area of dune heath is threatened, as is the J. capitatus. Grazing management would appear to be extremely difficult on this site due to the open boundaries along the shore and at the entrance to the track. The proximity to RAF valley and the Coastal Path Dwarf Rush Project 3 may also present barriers to grazing livestock due to regular disturbance. Cutting and removing scrub and bramble needs to be undertaken as a priority to protect the remaining areas of heath. In addition, it might be possible to open up pathways to allow more access across the dunes to promote disturbance of sand, although this should be considered alongside concern in the local community regarding the level of access to the site. Whilst we would like to see more access (and localised disturbance) along tracks and paths this will need to be presented carefully to the site managers and locals. The cutting of the heathland vegetation a number of years ago had some success, but it may well be better to strip some areas back to bare sand to allow re-colonisation. As this is a small site this could be done by hand. In the long-term it may also be worth considering some form of shepherded grazing (Sherry, J., 2015). A site visit to Cwmran undertaken by R. Blackhall-Miles and N. Brown on 26/06/2020 found no plants present at any of the recently recorded coordinates for the species. Map 2 – Distribution of Juncus capitatus in the heath at Cwmran – grid refs obscured for site protection Dwarf Rush Project 4 Map 3 – BEDDMANARCH-CYMYRAN SSSI showing location of Juncus capitatus records (map taken from http://lle.gov.wales/)Project details Project details Ex-situ Juncus capitatus is held ex-situ in 8 collections worldwide although only 4 have shared their data regarding this species via the BGCI PlantSearch database. Only one of these 4 ex-situ collections is held in the UK at the Millennium Seed Bank. The MSB holds 6 accessions of seed from Portugal, Switzerland, Australia and the UK. There is no location data available for the UK seed accession at the MSB. This project plans to collect seed of this species from its Anglesey populations, alongside herbarium vouchers for each sub-population collected, to be lodged at the Natural History Museum, London, FossilPlants and the National Museum of Wales. Seed will be collected either directly from extant plants or through soil sample collection in order to germinate any seed existing in the soil seed bank. With no more than <10% (ideally <5%) of available seed or soil surface area of recently known J. capitatus depressions collected. Seed collections will be germinated and cultivated at FossilPlants’ conservation research nursery with seed produced being used to supplement the population of the species upon the creation of suitable habitat, restoring the species to previous locations at Cymyran. Should restoration to other sites on Anglesey be considered this should be undertaken through discussion and approval by NRW and other stakeholders. Soils at the J. capitatus sites at Cwmran have a pH of between 5 and 5.5 and a consistency of sandy peat in equal parts, this should be considered in the ex situ management of the species. Seed collection will also allow the species to be maintained in cultivation and stored as seed at FossilPlants, with additional seed, collected from cultivated plants, potentially being distributed to both the MSB and the National Botanic Garden of Wales. Accurate location data will be collected alongside seed and herbarium specimens. Dwarf Rush Project 5 In-situ The proximity to RAF valley and the Coastal Path present barriers to grazing livestock at Cwmran and thus is not a viable management option unless a form of shepherded grazing could be utilised.

Load more

  7

Copy Link