|Scientific Name:||Pinus nelsonii|
|Red List Category & Criteria:||Endangered B2ab(ii,iii,iv,v) ver 3.1|
|Reviewer(s):||Thomas, P. & Perez de la Rosa, J.|
Pinus nelsonii is a rare species of which most localities / subpopulations do not cover more than one km², so the area of occupancy (84 km2) estimated here, based on 57 herbarium collections from 21 localities and using a grid of two km wide for each locality is probably optimistic and is in reality probably much smaller. With continuing decline this species meets the B2 criterion for listing Endangered.
|Range Description:||Endemic to Mexico: Coahuila (Mont. del Carmen), Nuevo León, San Luis Potosí, and Tamaulipas.|
Native:Mexico (Coahuila, Nuevo León, San Luis Potosí, Tamaulipas)
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Subpopulations are localized and severely fragmented.|
|Habitat and Ecology:||
Pinus nelsonii is a rare pine occurring in the semi-arid foothills and on mesas of the Sierra Madre Oriental; the most extensive populations are found around the Sierra Peña Nevada in Nuevo León-Tamaulipas. It is restricted to sites on rocky limestone with shallow soils. Its altitudinal range is 1,600-2,300(-2,450) m a.s.l. Annual precipitation ranges from 300-600 mm, falling mostly in the summer during brief thunderstorms. Associated conifers are P. cembroides, P. remota and Juniperus spp. It occurs in a scrubland zone with deciduous woody taxa, e.g. Quercus, Mahonia, Comarostaphylis, Brahea, and Sophora, and arborescent monocots, such as Yucca and Dasylirion. At higher altitudes it may grade into Pinyon-Juniper woodland, while lower down it is bounded by a hotter and drier semi-desert scrubland often dominated by Cactaceae and Yucca spp. Like several other narrow endemic conifers, P. nelsonii is probably an edaphic relict on limestone.
|Use and Trade:||There is no commercial exploitation of this species due to its low stature and its rarity in remote and inaccessible locations. Its seeds resemble those of the true pinyon pines (Pinus subsect. Cembroides) and are edible like these, but the seed crop is usually low compared with these species. Apart from a few specimens in botanic gardens and other dendrological collections, this interesting pine is not known in horticulture.|
|Major Threat(s):||Pinus nelsonii is by all accounts a rare pine with a scattered occurrence largely limited to limestone outcrops. Its total population almost certainly numbers fewer than 10,000 mature trees, mostly in (sub)populations of a few hundred individuals. It is thought to be in decline due to habitat disturbance and loss associated with increased cattle ranging and incidence of destructive fires associated with this type of land use. Several localities with this little tree reported in the literature or with older herbarium collections have not been retraced in recent years and the subpopulations may have disappeared.|
|Conservation Actions:||This species is in urgent need of protective measures, probably best achieved by the creation of reserves containing substantial subpopulations, and by excluding activities related to “range improvement” for cattle in such areas.|
|Citation:||Farjon, A. 2013. Pinus nelsonii. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 02 October 2014.|
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