|Scientific Name:||Crambe arborea|
|Species Authority:||Webb ex Christ|
|Taxonomic Notes:||Crambe arborea Webb ex Christ is a wild relative of the oil producing and fodder crop, C. abyssinica R.E. Fr., as well as being related to other brassica crops as a member of the subtribe Brassicinae (tribe Brassiceae) (Maxted et al. in prep.). Two varieties are native to Europe: C. arborea var. arborea and C. arborea var. indivisa Svent. (Euro+Med PlantBase 2006).|
|Red List Category & Criteria:||Vulnerable D2 ver 3.1|
|Assessor/s:||García Gallo, A., Cruz Trujillo, G.M., Marrero Gómez, M.V. & Rodríguez Delgado, O.|
|Reviewer/s:||Bilz, M., Kell, S.P. & Nieto, A.|
Crambe arborea is listed as Vulnerable because its area of occupancy (AOO) is only 3 km² and the number of locations is three. The population is stable and all sites are in protected areas. However, there are potential threats from landslides, which are frequent in the area, prolonged periods of drought and plant competition.
|Range Description:||Crambe arborea is endemic to the southeastern part of Tenerife in the Canary Islands, Spain. The extent of occurrence (EOO) is 300 km² (Commission of the European Communities 2009) and its area of occupancy (AOO) is only 3 km². This species is located in several canyons and cliffs of the municipalities of Candelaria and Güímar, with two main localities at Bco. of Chacorche and Ladera of Güímar, and a third minor locality at Bco. del Madroño.|
Native:Spain (Canary Is.)
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The population has been estimated to comprise 4,027 individuals (Commission of the European Communities 2009). It has two main subpopulations of more than 2,500 individuals each, separated by about 10 km by various towns and agricultural lands. However, there may be individuals scattered between the two although this has not been observed yet. The third subpopulation comprises 250 individuals. It occupies twelve 500 x 500 m grid squares and the population has been stable in the last decade (Bañares et al. 2008).|
|Habitat and Ecology:||
C. arborea grows in crags and old basaltic cliffs with a certain degree of shade and which are north-facing, from 300 to 850 m above sea level. A characteristic association of this species is Pericallido lanatae-Sonchetum gummifer.
It belongs to the semi-arid, thermo-Mediterranean association characterized by Sonchus gummifer and Pericallis lanata, and other local endemics such as Crambe arborea and Monanthes minima. They usually grow on cliffs and foothills, accompanying other species from the class Greenovio-class Aeonietea in addition to Aeonium arboreum var. holochrysum, Hypericum reflexum, Micromeria teneriffae, Parietaria filamentosa, Sonchus acaulis, Tinguarra cervariaefolia, etc. This plant can also flourish on anthropogenic slopes and in the beds of gullies, often accompanied by Bituminaria bituminous, Carlina salicifolia, Cistus monspeliensis, Euphorbia lamarckii, Kleinia neriifolia, Rumex Lunaria and Opuntia maxima, among others.
C. arborea is a hermaphrodite plant with insect pollination.
There are no anthropogenic threats to this species. Grazing abandonment in the area has notably improved the conservation status of populations (Commission of the European Communities 2009).
Landslides, common in the ravines and hillsides where the species grows and prolonged drought are significant natural threats. Plant competition, both with alien and native species is a large problem.
Crambe arborea is listed on Appendix I of the Convention on the Conservation of European Wildlife and Natural Habitats (Bern Convention) and as a priority species on Annex II of the EU Habitats Directive. It is classed as Vulnerable D2 on the Spanish red list (Moreno 2008). The genus Crambe is listed in Annex I of the International Treaty on Plant Genetic Resources for Food and Agriculture as part of the brassica complex.
The conservation status for the three populations is good. All are within the Parque Nacional de la Corona Forestal, an in the SCI with the same name.
EURISCO reports only six germplasm accessions of C. arborea held in European genebanks (EURISCO Catalogue 2010). Further germplasm collection and duplicated ex situ storage is a priority for this species.
|Citation:||García Gallo, A., Cruz Trujillo, G.M., Marrero Gómez, M.V. & Rodríguez Delgado, O. 2011. Crambe arborea. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 12 December 2013.|
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