Distributed in the Sierra Madre Oriental of Mexico where the main threat is over-grazing
Distribution
Native to Mexico where it occurs in the Sierra Madre Oriental in the States fo: Coahuila, Hidalgo, Nuevo León, Queretaro, San Luis Potosí, Tamaulipas. The extent of occurrence (EOO) is estimated to be more than 90,000km² but the estimated area of occupancy (AOO) is estimated to be between 500 to 1000km². It is known from more than 10 locations but subpopulations are severely fragmented.
Scattered individuals are the rule in many areas, so the population is more limited than its EOO might suggest. Mature trees are uncommon, especially in ranchland with free grazing animals.
Habitat and Ecology
In open shrubland or in Pinyon-Juniper woodland, associated with Pinus cembroides, Juniperus flaccida and sclerophyllous shrubs; on rocky slopes and along intermittent streams. Also found in open pine forest with P. montezumae. The altitude range is based on data from herbarium collections and is possibly incomplete.
Human Uses
This species is being used for fence posts.
Conservation Status
Global status
Vulnerable B2ab(iii,v)
Global rationale
Data are lacking to estimate rates of decline both in the past and for the future, but a continuing decline is inferred from the situation that much of the population occurs on land that is increasingly under pressure from grazing livestock. The EOO is large, but the AOO probably limited, although more precise figures could not be calculated due to a paucity of herbarium collections with geo-reference data available (20, giving 14 localities).
Global threats
The main threats to this species would come from overgrazing, which makes it difficult for seedlings to establish. Adams (2011) asserts that it “may become threatened in future” by general degradation of the environment by clearing land, and goats browsing is a problem. Habitat for Juniperus angosturana can be converted to agriculture.
Conservation Actions
No specific conservation actions are known for this species. Monitoring of habitat and population trends is required.
References and further reading
Adams, R. P. (1994). Geographic variation and systematics of monospermous Juniperus (Cupressaceae) from the Chihuahuan Desert based on RAPD's and terpenes. Biochem. Syst. Ecol. 22(7):699-710.
Adams, R.P. (2011). Junipers of the World: The genus Juniperus. Trafford Publishing Co., Bloomington, Indiana.
Farjon, A. (2005). A Monograph of Cupressaceae and Sciadopitys. The Royal Botanic Gardens, Kew.
Farjon, A. (2013). Juniperus angosturana. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1. <www.iucnredlist.org>. Downloaded on 06 July 2013.
