|Scientific Name:||Sorbus vexans E.F.Warb.|
|Taxonomic Source(s):||The Plant List. 2017. The Plant List. Version 1.1. Available at: http://www.theplantlist.org/.|
|Red List Category & Criteria:||Critically Endangered D ver 3.1|
|Assessor(s):||Beech, E., Rich, T.C.G. & Rivers, M.C.|
|Reviewer(s):||Salvesen, P.H. & Allen, D.J.|
Sorbus vexans is a shrub or small tree with a restricted distribution in South West England. It qualifies as Critically Endangered (CR D) as it has a population of about 35 mature individuals. There is a need for a full survey of the area to determine accurate population numbers. It is also a range-restricted species with an extent of occurrence of 16 km2, however the threats to this species are not fully understood and there is no evidence of continuing decline.
|Range Description:||This species occurs along a small corridor of coast between Culbone in Somerset and an area just west of Trentishoe in Devon (Rich et al. 2010) in southwestern England. It has an estimated extent of occurrence (EOO) of 18.4 km2. The area of occupancy has not been estimated but is also likely to be restricted.|
Native:United Kingdom (Great Britain)
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There are several small populations of this species which are spread across its range. The number of individuals in each population ranges from 1-28. The total known population is 70 individuals, however it is likely there are more in surrounding habitat (Rich et al. 2010). The number of mature individuals is about 35. The population is thought to be stable although appears to be dynamic (Rich et al. 2010).|
|Current Population Trend:||Stable|
|Habitat and Ecology:||A shrub or small tree, to at least 10 m which is often multi-stemmed from the base. The species grows mainly in open oak woodlands but is also found on open rocks and heathland. It grows to its tallest in the woodland, and in more exposed areas is often found as a shrub of 2 m. It is apomictic. It has erratic fruiting and there are frequent young saplings (Rich et al. 2010).|
|Continuing decline in area, extent and/or quality of habitat:||No|
|Use and Trade:||The species is not utilised.|
|Major Threat(s):||There are no obvious widespread threats to the populations, although inappropriate woodland management and the spread of Rhododendron are potential hazards (Anon. 2009). Deer grazing and woodland closure threaten some subpopulations.|
Sorbus vexans is reported as held in 11 ex situ collections (BGCI 2015) some of which need verification. It is recorded as present in an ex situ seed bank collection (ENSCO 2015). The species occurs within several protected areas across its distribution e.g., the Watersmeet and Exmoor Coastal Heaths Sites of Special Scientific Interest (SSSI).
This species is listed as Endangered in The vascular plant Red Data List for Great Britain (Cheffings and Farrell 2005) and The Red List of England (Stroh et al. 2014). It was listed as Vulnerable in Oldfield et al. (1998). It is listed as a UK BAP priority vascular plant species (JNCC 2010). There is a need for a full survey of the area to determine accurate population numbers (Rich et al. 2010). A PhD studying its conservation is nearing completion (T. Hamston pers. comm. 2016).
Anon. 2009. Devon whitebeam and related species. Devon Biodiversity and Geodiversity Action Plan.
BGCI. 2017. PlantSearch. Available at: www.bgci.org/plant_search.php.
Cheffings, C.M. and Farrell, L. (eds). 2005. The vascular plant Red Data List for Great Britain. Species status No. 7. Joint Nature Conservation Committee, Peterborough.
ENSCO. 2015. ENSCOBASE: the ENSCONET Virtual Seed Bank. Available at: http://enscobase.maich.gr/. (Accessed: 2015).
IUCN. 2017. The IUCN Red List of Threatened Species. Version 2017-2. Available at: www.iucnredlist.org. (Accessed: 14 September 2017).
JNCC. 2010. UK Priority Species data collation Sorbus vexans. Species Pages for 2007 UK BAP Priority Species. Joint Nature Conservation Council, Peterborough.
Rich, T.C.G., Houston, L., Robertson, A. and Proctor, M. 2010. Whitebeams, Rowans and Service Trees of Britain and Ireland. Botanical Society of the British Isles, London.
Stroh, P.A., Leach, S.J., August, T.A., Walker, K.J., Pearman, D.A., Rumsey, F.J., Harrower, C.A., Fay, M.F., Martin, J.P., Pankhurst, T., Preston, C.D. and Taylor, I. 2014. A Vascular Plant Red List for England. Botanical Society of Britain and Ireland, Bristol.
|Citation:||Beech, E., Rich, T.C.G. & Rivers, M.C. 2017. Sorbus vexans. The IUCN Red List of Threatened Species 2017: e.T34725A80736740.Downloaded on 21 November 2017.|
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