|Scientific Name:||Pinus rzedowskii|
|Species Authority:||Madrigal & M.Caball.|
|Red List Category & Criteria:||Vulnerable D1+2 ver 3.1|
|Reviewer/s:||Thomas, P. & Perez de la Rosa, J.|
Discoveries of several new localities with mostly very small subpopulations since the late 1990s have not greatly altered the range of this species. It’s extent of occurrence and area of occupancy are very small, and had there been evidence of continuous decline it would easily have met the criteria for listing as Endangered or perhaps Critically Endangered. Risk of extinction by major fires is especially high in the very small subpopulations and most individuals could be impacted by a single fire. However, the study by Delgado et al. (1999) seems to imply that there is no current decline of the population. This species therefore meets the criteria under D for listing as Vulnerable.
|Range Description:||Endemic to Mexico, where it is found in western Michoacan (Cerro de Chiqueritos, Cerro Ocotoso, Puerto del Pinabete, Fresno, Alberca and seven other more recently discovered localities within the municipality of Coalcomán).|
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The population is small and consists of 12 more or less separate localities, in each ranging from 1 to 3,500 individuals, totalling 6,000-6,500 individuals (Delgado et al. 1999). Regeneration is quite abundant at some of the sites. From this it is inferred that the total of mature trees is probably around 1,000. There is considerable genetic diversity, indicating a larger population in the (geological?) past (Delgado et al. 1999).|
|Habitat and Ecology:||
The two smaller ‘classical’ subpopulations, Cerro de Chiqueritos and Cerro Ocotoso, are on steep talus of large, eroded limestone blocks, near the summits of small mountains in the mainly volcanic Sierra Madre del Sur. Each have only from 10 to a few score trees, from old to saplings. Some subpopulations are on more level ground, also with limestone boulders, but inter-spaced with other rocky substrates. In the two former areas, the trees remain small, less than 15 m tall; in some of the larger subpopulations trees to 30 m have been found. The altitudinal range is 1,714-2,480 m a.s.l. Annual precipitation is ca. 1,500 mm, most of it occurs from July to October. The climate is warm-temperate, with a minimum of -5° C (December) and a maximum of 30° C (April). Although surrounded by extensive mixed pine forest with species like P. pseudostrobus, P. herrerae and P. oocarpa, these species do not grow on the limestone talus. There, Quercus and shrubs, e.g. Clusia salvinii, form an understorey with Agave and tall herbs. Fires occur frequently, but regeneration seemed good at least at Cerro Chiqueritos visited by the author of this assessment in 1994, where young saplings were observed.
|Major Threat(s):||The greatest threat to this species would appear to be a forest fire, as it is not a fire-adapted pine. Its occurrence amidst extensive pine forests make it vulnerable to this hazard. There is evidence in several of the scattered stands of ground fires having occurred (Perry 1991).|
|Conservation Actions:||No logging seems to take place of this rare pine, probably because of the inaccessibility of its populations in remote locations and the poor form of most trees from a lumber man's viewpoint. A fire-lookout post is established near one of the localities of P. rzedowskii, as it is located on the upper slope of a small peak in the area. Studies in population dynamics related to environmental factors, especially fire and reproduction, are much wanted to ensure proper management of this evolutionarily interesting pine. Pinus rzedowski is listed as Endangered on the official 2010 Mexican National Red List (the Mexican Red List categories are similar but not equivalent to the IUCN system).|
|Citation:||Farjon, A. 2013. Pinus rzedowskii. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 06 December 2013.|
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