Overview

Distribution

Range Description

Restricted to the Canary Islands (Gran Canaria, Gomera, La Palma and Tenerife) and Madeira (from Pico Arieiro to Pico Ruivo).

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Ecology

Habitat

Habitat and Ecology

Habitat and Ecology

Canary Islands:

In the Canary Islands this species has become adapted to different habitats. In Tenerife and La Palma, J. cedrus occurs at the timberline (2,200 m), which characteristically has low precipitation and great diurnal temperature variation. Here the dominant vegetation is of shrubs Spartocytisus supranubius and Adenocarpus viscosus. In contrast, on La Gomera, which is lower in altitude, (1,150 m.) the habitat is Laurel forest which has high levels of humidity as a result of the north-east trade winds. In Gran Canaria it only occurs on Montaña del Cedro, where it grows at altitudes between 800-900 m, here the temperatures are relatively warmer. At some of the locations (La Gomera and one location on Tenerife) there is evidence of regeneration but generally recruitment appears to be relatively poor. One factor that may be related to this, is the decline in ravens (Corvus corax) that are thought to have played a significant role in seed dispersal (Nogales 1999, Remeu et al. 2009). Recent research has revealed that winter visiting Ring Ouzels (Turdus torquatus) also play a key role in seed dispersal (Remeu et al. 2009). Additional research has indicated that the Canary Islands subpopulations produce seed with relatively lower viability, possibly due to lower pollination rates resulting from fragmentation of stands (Remeu et al. 2009)

Madeira

The subpopulation on Madeira occurs on exposed rock faces above the laurel forest tree-line above 1,400 m in altitude. Here it belongs to the Polysticho falcinelli-Ericetum arboreae (Capelo et al. 2004). The main components include: Erica maderinicola, Ilex perado, Laurus novocanariensis, Polystichum falcinellum, Vaccinium padifolium & Sorbus maderensis. In Madeira there have not been any studies to establish whether or not there is any regeneration, however since the removal of goats in recent years the vegetation recovery rates are very encouraging.

The current distribution pattern and the restriction to almost inaccessible sites in the Canary Islands and on Madeira reflect past human disturbance. Formerly it was more widespread.

Systems
  • Terrestrial
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Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
EN
Endangered

Red List Criteria
B2ab(ii,iii,v); C2a(i)

Version
3.1

Year Assessed
2011

Assessor/s
Rumeu Ruiz, B, de Sequeira, M, Elliot, M & Gardner, M.

Reviewer/s
Thomas, P. & Farjon, A.

Contributor/s

Justification

The total area of occupancy (AOO) is calculated to be 29 km². The AOO is based on presence within 1 km² grid cells overlaid on 1:40,000 scale maps. Presence and absence records are derived from recent, extensive surveys carried out between 2004 and 2009 (Elliot 2009, Rumeu unpublished data 2010, Sequeira pers.comm 2010). The total population (n = ca 600) consists of five subpopulations/ locations found on five islands (Gran Canaria (n =12), Gomera (n = 100), La Palma (n = 250), Tenerife (n = 200) and Madeira (n = ca 40)). Each subpopulation/location is more than 60 km from the next and no single subpopulation contains more than 50% of the total population. These subpopulations are regarded as severely fragmented. The total population is estimated to be less than 600 mature trees and no subpopulation contains more than 250 mature individuals. Regeneration in some subpopulations is poor or absent, possibly due to reduced seed set (Rumeu et al. 2009), the decline of avian dispersers (Nogales 1999, Rumeu 2009) and the effects of grazing. In some locations fires have led to the loss of mature individuals. Together, these factors contribute to a continuing decline in the quality of habitat and number of mature individuals. On the basis of these data, Juniperus cedrus meets the criteria for Endangered.


History
  • 2000
    Endangered
  • 1998
    Vulnerable
    (Oldfield et al. 1998)
  • 1998
    Vulnerable
  • 1997
    Endangered
    (Walter and Gillett 1998)
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Population

Population

The population is estimated to be c. 600 sexually mature individuals.

Canary Islands - 572 individuals: Gran Canaria 12; La Palma 250; Tenerife 200; La Gomera 100 (Elliot 2009).

Madeira - one population with c. 40 individuals (Sequeira 2010, unpublished data).

Population Trend
Decreasing
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Threats

Major Threats

Canary Islands

There are a variety of threats, the most severe of which is fire. In 2007 a fire on Tenerife (El Teide National Park) destroyed 30 old-growth trees. Other threats, which are detrimental to recruitment, include goats and the release of Barbery sheep (La Palma) and Muflón (Tenerife) for hunting purposes. Global warming could affect the amount of seasonal rainfall and moisture from coastal fog.

Madeira

Historically over-grazing, cutting and burning have been significant threats to the population. Although these threats are less today, the fast expansion of Cytisus scoparius following grazing is certainly a potential threat as it greatly increases the fire risks.

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Management

Conservation Actions

Conservation Actions

Juniperus cedrus is a protected species in the Canary Islands and occurs in three National Parks; Parque Nacional del Teide, Tenerife; Parque Nacional de Garajonay, La Gomera; Parque Nacional de la Caldera de Taburiente, La Palma. The area affected by fire in Parque Nacional del Teide is being restored by using local provenance material (seed). In Gran Canaria, the subpopulation in Montaña del Cedro is included within the Reserva Natural Especial de Güigüi. This sub-population is considered as 'in danger of extinction' in the Regional Catalogue of Threatened Species (Ministerio de Medio Ambiente 2009). On Madeira it is protected within the Parque Natural da Madeira (Natura 2000) where all goats have been removed above 1,400 m under the authority of Direcção Regional de Florestas. This has had a positive effect on the general vegetation, but as J. cedrus is a slow growing tree, any benefits are unlikely to be seen for several years.

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Wikipedia

Juniperus cedrus

Juniperus cedrus (Canary Islands Juniper) is a species of juniper, native to the western Canary Islands (Tenerife, La Palma, Gran Canaria, Gomera) and Madeira (J. cedrus Webb & Berthel. subsp. maderensis (Menezes) Rivas Mart et al.), where it occurs at altitudes of 500–2400 m. It is closely related to Juniperus oxycedrus (Prickly Juniper) of the Mediterranean region and Juniperus brevifolia (Azores Juniper) of the Azores.

It is a large shrub or tree growing to a height of 5–20 m (rarely 25 m). The leaves are evergreen, needle-like, in whorls of three, green to glaucous-green, 8–23 mm long and 1–2 mm broad, with a double white stomatal band (split by a green midrib) on the inner surface. It is usually dioecious, with separate male and female plants. The seed cones are berry-like, green ripening in 18 months to orange-red with a variable pink waxy coating; they are spherical, 8–15 mm diameter, and have six fused scales in two whorls of three; the three larger scales each with a single seed. The seeds are dispersed when birds eat the cones, digesting the fleshy scales and passing the hard seeds in their droppings. The male cones are yellow, 2–3 mm long, and fall soon after shedding their pollen in February–March.

It is endangered in its native range due to a combination of historical felling for the valuable wood, and overgrazing by goats. It has been fully protected since 1953 and populations are very slowly recovering. Historical reports suggest trees up to 30 m tall occurred in the past; trees over 10 m are very rare now and confined to inaccessible cliffs.

It is occasionally grown as an ornamental tree in warm temperate climates, including New Zealand, the British Isles and California, but is not common in cultivation. There are also some small experimental plantations on the Canary Islands, where it has shown fast growth in good conditions, reaching about 14–15 m tall in 40 years.

Extraction of the wood with acetone, followed by analysis of the extract, indicate that the essential oil of Juniperus cedrus is particularly rich in thujopsene, which comprises around 2.2% of the weight of the heartwood.[1]

References[edit]

General references and external links[edit]

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