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Widdringtonia cedarbergensis

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Taxonomy [top]

Kingdom Phylum Class Order Family
PLANTAE TRACHEOPHYTA PINOPSIDA PINALES CUPRESSACEAE

Scientific Name: Widdringtonia cedarbergensis
Species Authority: J.A.Marsh
Common Name(s):
English Clanwilliam Cedar, Cape Cedar, Clanwilliam Cypress

Assessment Information [top]

Red List Category & Criteria: Critically Endangered A2acd ver 3.1
Year Published: 2013
Date Assessed: 2011-07-11
Assessor(s): Farjon, A., February, E., Higgins, S., Fox, S. & Raimondo, D.
Reviewer(s): Thomas, P. & von Staden, L.
Justification:
Intensive exploitation in the past, accompanied by changes in intensity and frequency of fires, has resulted in an estimated and observed decline in area of occupancy and quality of habitat of more than 80%. The causes of this decline, while understood, are not reversible and have not ceased. Consequently, Widdringtonia cedarbergensis is assessed as Critically Endangered under the criteria for A2.
History:
1998 Endangered
1997 Endangered (Walter and Gillett 1998)

Geographic Range [top]

Range Description: Endemic to South Africa: Western Cape Province, Clanwilliam District, Cedarberg Mountains. Higgins et al. (2002) produced a fine scale model of suitable habitat for this species. The modelled range was then ground-truthed through field surveys, and based on these surveys the extent of occurrence (EOO) of the Clanwilliam Cedar was calculated to be 660 km2. The survey also revealed that only 6% of suitable habitat is occupied by the species with an actual area of occupancy (AOO) estimated to be 39.6 km2. While there are several localities, the number of locations (sensu IUCN) is difficult to determine as the severity and extent of fires (the main threat) can vary depending on their origin or cause.
Countries:
Native:
South Africa (Western Cape)
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population:

Historical reports indicate that the species was formerly abundant within the Cedarberg Mountains, and that the first and most severe population decline occurred after European colonizers settled in the area in the late 18th century. The vegetation of the Cedarberg is very poor in tree species, and the Clanwilliam Cedar was heavily exploited for timber. In 1879 alone more than 7,000 trees were cut down for use as telephone poles (Andrag 1977). This overexploitation caused a significant population reduction, which is corroborated by the pollen record (Meadows and Sugden 1991). By 1883 no accessible trees of commercial value remained (Mustart 2008). Although it is not possible to quantify exactly the population reduction as a result of timber harvesting, it is suspected that harvesting caused an 80-90% reduction in the population.

Although timber harvesting has ceased, the population has never recovered: it would be impossible to find even a hundred telephone pole-sized trees in the Cedarberg today (Mustart 2008). Attempts to increase the population through seeding and introduction of ex situ grown plants have been largely unsuccessful.

A synthesis of long-term monitoring data of trees in four permanent plots records a 94% population decline between 1977 and 2003 (Fox 2003). This decline has been attributed to too frequent and intense fires.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: Remnant populations of this species are restricted to rocky ridges and cliffs ('krantzes' or 'kranse') of Table Mountain Sandstone, avoiding other formations below and above it. The altitudinal range is (915-)1,000-1,500(-1,650) m a.s.l. The trees are often protected by large boulders from frequent brush fires in the surrounding (secondary) fynbos vegetation. The annual rainfall is between 500-1,000 mm and occurs mostly in the cold winter months, while summers are dry and hot.
Systems: Terrestrial

Use and Trade [top]

Use and Trade: Clanwilliam Cedar has been extensively logged for its dense, easily workable and durable timber by European settlers. It was used for fence posts, construction of farm houses and sheds and later for carpentry, furniture, and cabinet making, until the resource dwindled and the last stands were almost destroyed by fires. In the nearby town of Clanwilliam beautifully worked examples can be seen in the Anglican church (doors, pews, carved altar) and Courthouse.

Threats [top]

Major Threat(s): Historical exploitation for its valuable timber during the 19th centry led to a reduction of up to 95%. One consequence of this was the expansion of fynbos, a highly flammable vegetation formation. More frequent and more intense fires prevent regeneration; surviving trees are restricted to rocky ridges, ledges, and outcrops mostly beyond reach of the flames. Natural regeneration is also hampered as a result of granivory and herbivory by native rodents.

Conservation Actions [top]

Conservation Actions: Today the few remaining trees are protected from cutting for any purposes. Cultivation is now undertaken primarily with a view of population restoration and the species is consequently grown in local nurseries as well as in several botanic gardens. Attempts at replanting are continually being made with low rates of success (Mustart et al. 1995) and extensive ex situ conservation efforts are under-way in South Africa, backed by smaller scale plantings elsewhere.

Citation: Farjon, A., February, E., Higgins, S., Fox, S. & Raimondo, D. 2013. Widdringtonia cedarbergensis. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 23 October 2014.
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