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Tetraclinis articulata

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Taxonomy [top]

Kingdom Phylum Class Order Family
PLANTAE TRACHEOPHYTA PINOPSIDA PINALES CUPRESSACEAE

Scientific Name: Tetraclinis articulata
Species Authority: (Vahl) Mast.
Common Name(s):
English Sandarac, Sandarac Gum Tree
French Bois de citre, Thuya de Barbarie
Spanish Alerce
Synonym(s):
Thuja articulata Vahl

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2011
Date Assessed: 2009-11-25
Assessor(s): Sánchez Gómez, P., Stevens, D, Fennane, M, Gardner, M. & Thomas, P.
Reviewer(s): Farjon, A. & Knees, S.
Justification:
Due to its extensive distribution in North Africa, this species is assessed as Least Concern although some small subpopulations (Malta and Spain) are highly threatened and there some evidence of decline in the main parts of its range.
History:
1998 Lower Risk/near threatened (Oldfield et al. 1998)
1997 Rare (Walter and Gillett 1998)

Geographic Range [top]

Range Description: Tetraclinis articulata is widespread in northern Morocco, Algeria and Tunisia and also has two small relictual subpopulations in Malta and near Cartagena in Spain. In Morocco it is found in six zones: 1-Rif mountains; 2-Eastern Morocco; 3-Eastern middle Atlas; 4-Valleys of the central plateau and eastern Meseta; 5-Western Middle Atlas and High Atlas; 6- Anti Atlas. Across North Africa Tetraclinis woodlands are estimated to cover almost 1 million hecatres of which more than 600,000 are in Morocco.
Countries:
Native:
Algeria; Malta; Morocco; Spain; Tunisia
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: In Morocco, Algeria and Tunisia, Tetraclinis can form extensive open woodlands. The Spanish subpopulation is restricted to an area of about 500 ha near Cartagena while the Maltese subpopulation consists of less than 130 trees scattered in several very small localities.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: Tetraclinis ranges from near sea level to 1,800 m asl. In Spain it occurs from 30 to 500 m asl and between 30 and 200 m asl in Malta. In most parts of its range precipitation ranges from 300-500 mm  per year. It occurs with a range of other species, depending on where it is growing. Adult trees usually respond to fires by coppicing; repeated fires prevent regeneration from seed and may eventually kill adults.
Systems: Terrestrial

Use and Trade [top]

Use and Trade: Tetraclinis has a range of uses involving its leaves, fruits, wood, resin and oil. The burls that are formed after repeated coppicing are particularly valued for craftwork.

Threats [top]

Major Threat(s): North Africa: Overgrazing and overexploitation are potential threats in many parts of its extensive range in North Africa.

Spain: The principle threat comes from urbanization, including the establishment of sport facilities such as golf courses. Historically, human-set fires have had the greatest impact on the populations. The most notable fire occurred in September 1992 when 55 ha were burnt affecting a significant proportion of the population (Nicolás et al. 2004). Regeneration after fire can be rapid although it is estimated to take 10-20 years for burnt areas to recover (López-Hernández et al. 1995). A serious fire in the main part of the population (e.g. Cenizas-Peña de Aguila) has the potential of eradicating up to 80% of the population. Post-fire regeneration of competing species such as Pinus halepensis is a problem until the plants of Tetraclinis reach maturity. Mining has been a cause for concern in the past. The extensive heaps of spoil have caused serious fragmentation of the population. In some parts of its range (El Sabinar), regeneration is hampered by grazing for sheep and goats. Competition from invasive species is also of concern; the most detrimental species being Pinus halepensis (Martinez 2008). Tetraclinis is frequently cultivated in southern Spain in gardens and as a plantation species. Some of these plantations are located close to the native population. It is thought that the origin of this germplasm is the North African (Morocco) population. Genetic contamination could be a problem although to date no studies have been carried out to investigate its potential impact.

Malta: Tetraclinis articulata was once much more common in Malta and the various places called Ghar-ghar, Ghar-ghur etc. point out to the existence of a wider distribution, and possibly small forests (Borg 1927). It apparently disappeared centuries to decades ago, mostly due to habitat alteration and land reclamation (Stevens and Baldacchino 2000). The main threats today include habitat modification and/or destruction (including land reclamation and the clearance of the vegetation) and human-induced disturbance, including the introduction of alien species such as Acacia saligna and Eucalyptus spp. Afforestation and reforestation programmes in its distribution range with indigenous and alien trees, which do not form part of its biotope are also important threats. Competition from invasive species such as exotic Pinus spp. and particularly the native P. halepensis are also seen as threats.


Conservation Actions [top]

Conservation Actions: Subpopulations in Malta and Spain are currently listed as Regionally Endangered due to their very restricted distributions and small population sizes. In each locality they were formerly more widespread but have declined to their current sizes as a result of historical over-exploitation, fires, urbanisation  and the expansion of agricultural activities. In North Africa, many woodlands have become degraded as a result of over-grazing. However, the total area is still so extensive that it falls outside of the thresholds for listing under the IUCN's categories and criteria. If the decline continues, then it may qualify as Near Threatened in the future.

Citation: Sánchez Gómez, P., Stevens, D, Fennane, M, Gardner, M. & Thomas, P. 2011. Tetraclinis articulata. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 30 October 2014.
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