Olea europaea | UAE National Red List of Vascular Plants

Taxa
Olea europaea | L.
Publication
UAE National Red List of Vascular Plants
Location
Countries in Assessment
United Arab Emirates
Country ISO code(s)
ARE
Does the assessment cover a marine EEZ area(s)?
Off
Scope (Assessment)
National
Taxon
Taxonomic Group
Plants
Taxonomic Group Level 2
Flowering Plants
Assessed taxon level
Species
Taxonomic Notes
Olea taxonomy is far from being clearly understood. Some molecular studies (Balboni et al. 2006, Besnard et al. 2009, Besnard et al. 2013) strongly suggest that there have been successive episodes of cross-breeding among wild, feral and cultivated forms of Olea europaea, throughout the Mediterranean region for several centuries. As the cultivated forms were brought from the eastern to the western Mediterranean, they also crossbred with spontaneous Olea subspecies and then became feral. As centuries passed, this process resulted in the gradual dilution of oriental haplotypes into the western haplotypes. However, it is considered that some of the conclusions presented in the above molecular studies are not robust, since they may lack some taxonomic accuracy regarding the sampled taxa (with different taxa sampled as the same taxon) (J. Capelo pers. comm. 2016) and therefore molecular studies are not yet conclusive in terms of the taxonomy of this species; we follow the classical taxonomic treatment from Green (2002). Four subspecies and one variety of Olea europaea L. are considered native to Europe (WCSP 2016):<ul><li>O. europaea subsp. cerasiformis G.Kunkel & Sunding</li><li>O. europaea subsp. europaea</li><li>O. europaea subsp. guanchica P.Vargas, J.Hess, Muñoz Garm. & Kadereit</li><li>O. europaea var. sylvestris Brot.</li></ul>These taxa are related to cultivated Olive.
Taxon distribution as listed in assessment
The species is found at higher elevations along connected high elevation ridges in the 'Olive Mountains' of the UAE. This species was first recorded for the UAE in 1997 at sites including the summit of Jebel Qitab (at c. 1,000 m asl), and above Wadi al-Iyeli; at each of these localities approximately two dozen specimens were present in adjacent ravines, and observations suggested that limited numbers were present in the intervening area (Feulner 1997). In general, it is restricted to the highest ridges of the Hajar Mountains southwest of Fujairah above 600 m (G.R. Feulner, in litt, MEW 2010, Feulner 2014). Records from the ""Olive Highlands"" area include the higher ridges above Wadi Mayy, Wadi Hayl and Wadi Saham, on north-facing cliffs of Jebel Al-Iyeli and on the northern slopes and ravines of Jebel Sfai (Feulner 2014). Individual small specimens have been found at wadi level in Wadi Hayl (M.A.R. Khan pers. comm. in Feulner 2014). The only other records are of two small trees (&lt;1.5 metres tall) on the northern slopes of Jebel Jabsah, and north of Wadi Ham on the outskirts of Fujairah city (Feulner 2014). The species is absent from Wadi Wurayah National Park (Feulner 2016) and from the Ru's al-Jibal (Feulner 2011). The EOO is less than 200 km<sup>2</sup>. The AOO has not been measured as detailed locality records are not available, but it is likely to also be 200 km<sup>2</sup>. It is considered to be native to the UAE. The species has been very widely cultivated so it is difficult to determine its full native range, but currently it is considered native to parts of Africa, Europe and western Asia.
Habitats and Ecology
Ecological system type
Terrestrial system
No
Freshwater system
No
Marine system
No
Habitat
Habitat details as listed in assessment
A tree that grows to at least 3-4 m in height in the UAE (G.R. Feulner pers. comm. 2019). The species is generally found along ridge tops, summit cliffs, and north and east-facing slopes and ravines of the Hajar Mountains above 800 m as well as, occasionally, in ravine beds in wadi bottoms at Wadi Hayl and Wadi Mayy (Feulner 2014).
Is there a map available in assessment?
Yes
Assessed status
Asessment status in full
Vulnerable
Assessment status abreviation
VU
Assessment status criteria
D1
Assessment rationale/justification
This species was first recorded for the UAE in 1997 and is now known to be largely restricted to the 'Olive Highlands' area of the Hajar Mountains in eastern UAE, with additional records from northern slopes of Jebel Jabsah and north of Wadi Ham on the outskirts of Fujairah city. The extent of occurrence (EOO) is less than 200 km<sup>2</sup>. The area of occupancy (AOO) has not been measured as detailed locality records are not available, but it is likely to be less than 200 km<sup>2</sup>. The impact of current and potential threats are not known, however grazing by livestock and feral animals may account for the poor regeneration that was observed in the early 2000's. The species is assessed as Vulnerable (VU D1) because there are thought to be c. 500 mature individuals. No rescue effect is applied as, although the species occurs in Oman, no young trees have been seen. Conservation action and research is required for this species in order to protect significant subpopulations, and to understand the impacts of hybridisation and climate change in the mountains.
About the assessment
Assessment year
2019
Assessors/contributors/reviewers listed
UAE National Red List Workshop
Affliation of assessor(s)/contributors/reviewers listed on assessment
Government
IGO
Assessor affiliation specific
Government|IGO
Criteria system
Criteria system specifics
IUCN v3.1 + Regional Guidelines v4.0
Criteria system used
IUCN
Criteria Citation
IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1, Second edition. IUCN, Gland, Switzerland and Cambridge, UK. iv + 32pp pp. And IUCN. 2012. Guidelines for Application of IUCN Red List Criteria at Regional and National Levels: Version 4.0. Gland, Switzerland and Cambridge, UK: IUCN. iii + 41pp.
Endemism
Endemic to region
Not_assigned
Endemism Notes
Is an endemic?: Not_assigned
Conservation
Threats listed in assessment
The species is at the northern extent of its range in these mountains. Individuals in wadi beds and the lower parts of ravines are vulnerable to grazing, development (housing, roads etc), and other threats. Grazing by livestock and feral animals might be the cause of the poor regeneration observed by G.R. Feulner (in litt, MEW 2010). There has been localised loss of individuals as a result of development (radio mast construction). In parts of the Olive Highlands, introduced (e.g., from Spain and Italy) olive plantations have been developed. Hybridisation between wild olives and planted olive trees is highly likely by pollinators and wind pollination.
Conservation Measures

Conservation measures:
Conservation measures notes:
Required conservation measures:

Further information
History
Same population size, although the individual trees were in better condition as a a result of higher rainfall.
Scientific Name Kingdom Phylum Class Order Family Genus
Olea europaea Plantae Tracheophyta Magnoliopsida Lamiales Oleaceae Olea