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Overview

Distribution

Range Description

Endemic to Mexico: S Zacatecas (Sierra de Morones near Juchipila). A second location, La Muralla in Durango, has recently been reported (Gonzalez-Elizondo et al. 2011). It was discovered in December 2010. The extent of occurrence is estimated to be about 376 km2 with an actual area of occupancy estimated to be about 35 km2.

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Physical Description

Type Information

Isotype for Pinus maximartinezii Rzed.
Catalog Number: US 2518546
Collection: Smithsonian Institution, National Museum of Natural History, Department of Botany
Verification Degree: Original publication and alleged type specimen examined
Preparation: Pressed specimen
Collector(s): J. Rzedowski
Year Collected: 1964
Locality: Cerro de Pinones, 4 km. W of Pueblo Viejo., Juchipila, Zacatecas, Mexico, North America
Elevation (m): 2000 to 2000
  • Isotype: Rzedowski, J. 1964. Ciencia (Mexico). 23: 17.
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Ecology

Habitat

Habitat and Ecology

Habitat and Ecology
The rock of the mountain in Zacatecas where P. maximartinezii occurs is in part sandstone or limestone and also metamorphic, the soils are very rocky and shallow. In Durango it grows on rocky soils of igneous origin. Precipitation is probably ca. 700-800 mm annually, virtually restricted to four months in the summer. Pinus maximartinezii is virtually the only pine here, but a few scattered individuals of P. leiophylla var. chihuahuana have been seen. Its altitudinal range is 1,750-2,400 m a.s.l. Abundant are various large leaved species of deciduous Quercus, e.g. Q. macrophylla, which are bare during the long dry season from September to May. Fires occur regularly in the region in all vegetation types; it is not known whether this species is adapted well to reseed itself after fire. Pollen dispersal is usually in May-June; the ovuliferous cones take 18-24 months to reach maturity, and perhaps longer for the seeds to ripen fully, which mostly remain in the cones. Squirrels are capable of biting off the apohyses to reach the seeds and probably store them. They, and probably also birds, may play a crucial role in effective seed dispersal, but this has not been investigated to date.

Systems
  • Terrestrial
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Molecular Biology and Genetics

Molecular Biology

Barcode data: Pinus maximartinezii

The following is a representative barcode sequence, the centroid of all available sequences for this species.


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Source: Barcode of Life Data Systems (BOLD)

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Statistics of barcoding coverage: Pinus maximartinezii

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 6
Specimens with Barcodes: 14
Species With Barcodes: 1
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Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
EN
Endangered

Red List Criteria
B1ab(ii,iii)+2ab(ii,iii)

Version
3.1

Year Assessed
2013

Assessor/s
Farjon, A.

Reviewer/s
Thomas, P. & Perez de la Rosa, J.

Contributor/s

Justification

Based on current knowledge, both the extent of occurrence (376 km2) and the area of occupancy (35 km2) are within the thresholds for Endangered. Two disjunct locations are known although it is possible that other subpopulations exist in the intervening areas. A recent decline in at least the quality of habitat has been observed in the main subpopulation in Zacatecas due to grazing and erosion. Discrepancies between the published counts for the Sierra de Morones subpopulation (2,000-2,500 mature individuals over 400 ha - Ledig 1999 and 60,548 'individuals' over 3,500 ha - Lara Rodriguez 1997) reflect different sampling strategies. The total size of the population is likely to be more than 10,000 mature individuals. On the basis of this information Pinus maximartinezii is assessed as Endangered under the B criterion.



History
  • 1998
    Endangered
  • 1997
    Endangered
    (Walter and Gillett 1998)
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Population

Population

The population in the Sierra de Morones has ca. 2,000-2,500 mature individuals scattered on ridges and E-facing slopes, covering approximately 400 ha (Ledig et al. 1999). There is regeneration, but it is under threat from seed collecting, roaming cattle and fire. On genetic grounds, Ledig et al. (1999) concluded that the species had gone through “an extreme bottleneck perhaps four to five generations ago, which is less than 1,000 years in this species." Fires of more recent times have destroyed parts of the population, so in IUCN terms of three generations, here estimated to be around 150 years, there has probably been a decline in number of mature individuals.

In another attempt at counting trees, the vastly larger figure of 60,548 individuals was reported (Lara Rodriguez 1997). This count presumably included all trees and was conducted by sampling over a larger area within the area of occupancy (AOO) in Zacatecas. The AOO was estimated to be 3,500 ha.

The new subpopulation in Durango has in excess of 900 mature trees with an AOO of ca. 110 ha (Gonzalez-Elizondo et al. 2011).

Population Trend
Decreasing
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Threats

Major Threats
The main threats are fire and over grazing and subsequent erosion which result in few seedlings that succeed in establishing themselves. Intensive harvesting of cones and seeds may also diminish its chances of reproduction although recent studies indicate that this can be sustainable provided that grazing, erosion and fire are controlled (Lopez Mata and Galván Escobedo 2011). Seed collections have been made in recent years to ensure ex situ conservation programmes. The land on which these pines grow is privately owned by villagers, who have an interest in the seed harvests as well as cattle grazing.
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Management

Conservation Actions

Conservation Actions
The local landowners (the stands on Sierra Morones are on private land) and villagers have a stake in the long term survival of this species, as its seeds have a (local) market value. Efforts are being made first and foremost to prevent forest fires, by limiting access and prohibiting camping, etc. Some restoration work has been initiated. Control of grazing is less certain, as these constitute conflicting interests. The situation in the new locality in Durango is as yet unknown.
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Wikipedia

Big-cone pinyon

Pinus maximartinezii, called Martinez pinyon or big-cone pinyon,[1] is a pine in the pinyon pine group, native to central Mexico. The range is highly localised, confined to a small area of the southern Sierra Madre Occidental in southern Zacatecas. It occurs at moderate altitudes, from 1800-2400 m and 21° North latitude, in warm and temperate, dry climate conditions.

It is a small tree, reaching 5-15 m tall and with a trunk diameter of up to 50 cm. The bark is brown, thick and fissured at the base of the trunk. The leaves ('needles') are in fascicles of five, slender, 7-13 cm long, and deep green to blue-green, with stomata confined to a bright white band on the inner surfaces. The cones are ovoid, massive, 15-27 cm long and 8-14 broad and up to 2 kg weight when closed, green at first, ripening yellow-brown when 26–28 months old, with very thick, woody scales, typically 30-60 fertile scales. The cones open to 10-15 cm broad when mature. The seeds are 2-3 cm long, with a thick shell, with a vestigial 1-2 mm wing; the seedlings have 18-24 cotyledons, the highest number reported for any plant.

Because of its isolation in a remote area, it escaped discovery until 1964, when the Mexican botanist Jerzy Rzedowski noticed some unusually large pine nuts (piñones) sold in the markets of local villages, and investigated the area to find their source. It differs from all other pinyon species in that it has very massive cones and large seeds. Like other pinyons, the seeds are edible; this represents a threat to the species' survival, as the majority of the seeds produced are harvested, limiting natural regeneration of the pines.

It has started being cultivated recently and is a very attractive tree as ornamental. The Mexican government has declared this species endangered.

References[edit]

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