Cupressus guadalupensis
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| Cupressus guadalupensis | ||||||||||||||||
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| Cupressus guadalupensis S.Watson |
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Cupressus forbesii |
Cupressus guadalupensis is a species of cypress native to Guadalupe Island off Baja California, Mexico, and scattered north to southernmost California in the United States; it is always found in small, scattered populations.
It is an evergreen tree with a conic to ovoid-conic crown, variable in size, with mature trees reaching 10-20 m tall. The foliage grows in dense sprays, dark green to gray-green in color. The leaves are scale-like, 2-5 mm long, and produced on rounded (not flattened) shoots. The seed cones are globose to oblong, 12-35 mm long, with 6 to 10 scales, green at first, maturing gray-brown to gray about 20-24 months after pollination. The cones remain closed for many years, only opening after the parent tree is killed in a wildfire, thereby allowing the seeds to colonise the bare ground exposed by the fire. The male cones are 3-5 mm long, and release pollen in February-March.
There are two varieties, treated as distinct species by some botanists:
- Cupressus guadalupensis var. guadalupensis – Guadalupe Cypress
- Foliage dark green, cones large (25-35 mm long).
- Guadalupe Island, at altitudes of 800-1280 m. It had a population of numerous but old and weak trees in 2000[1]. They disappeared rapidly from the late 19th century onwards, as hordes of feral goats ate any seedling that germinated after the mid-late 19th century. One major subpopulation was destroyed entirely, and the isolated stands were all but wiped out. Also, by the animals destroying vegetation cover wholesale and especially the cloud forest, the water table dropped, jeopardizing the existence of the remaining two main subpopulations.[2]
- The long-awaited removal of goats being effectively completed by 2005 and habitat being fenced in in 2001, the first young plants since 150 years or so can now grow up[3]. However, it appears as if the cypress is more vulnerable to droughts than for example the Guadalupe variety of Monterey Pine (Pinus radiata var. binata), and hence the population might decline further in the future.[2] In any case, it cannot be assumed that presently more than a few 100 trees exist that are viable in the long term.
- Cupressus guadalupensis var. forbesii – Tecate Cypress
- Foliage gray-green, cones smaller (12-25 mm).
- 5 major subpopulations in northern mainland Baja California, and San Diego and Orange Counties, California, at altitudes of 450-1000 m. One of the main populations, on Tecate Mountain, is within the area burnt in the October 2007 California wildfires.[4]
The species as a whole is rated as Vulnerable (VU B1+2a) by the IUCN. The Tecate Cypress is rated as Imperiled (G2) by NatureServe. The Guadalupe Cypress is considered Critically Endangered by the IUCN.[5]
[edit] Footnotes
- ^ 200 according to CSG (2000), some 4000 according to León de la Luz et al. (2003). The cause(s) for this discrepancy are elusive.
- ^ a b León de la Luz et al. (2003)
- ^ Junak et al. (2003)
- ^ San Diego: Fire Map
- ^ Farjon, A. (2005). Monograph of Cupressaceae and Sciadopitys. Royal Botanic Gardens, Kew. ISBN 1-84246-068-4
[edit] References
- Conifer Specialist Group (CSG) (2000). Cupressus guadalupensis. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 11 May 2006.
- Junak, S.; Keitt, B.; Tershy, B.; Croll, D. & Sánchez, J.A. (2003): Recent conservation efforts and current status of the flora of Guadalupe Island, Baja California, Mexico. Presentation at Taller sobre la Restauración y Conservación de Isla Guadalupe ["Workshop on restauration and conservation of Guadalupe Island"]. Instituto Nacional de Ecología, November 13-14, 2003. HTML abstract.
- León de la Luz, José Luis; Rebman, Jon P. & Oberbauer, Thomas (2003): On the urgency of conservation on Guadalupe Island, Mexico: is it a lost paradise? Biodiversity and Conservation 12(5): 1073–1082. doi:10.1023/A:1022854211166 (HTML abstract)
