Only known from six stands in the Sierra Madre Oriental in México where it is threatened by logging
Distribution
México: Nuevo León (Sierra Madre Oriental: Montemorelos, Aramberri). Known from six stands, all less than 150km from each other. The extent of occurrence and area of occupancy are within the thresholds for Endangered and with two locations.
The most recent census estimates that the total number of mature individuals does not exceed 800. The main (southern) stand at El Butano has an estimated 350 trees.
Habitat and Ecology
One locality with this species (near La Trinidad, Montemorelos) is described as on slopes of coarse limestone talus in a sheltered canyon at 2100–2200 metres above sea-level. In montane mixed coniferous-deciduous broad-leaved forest. Picea martinezii is here associated with Abies vejarii, Pinus spp., Taxus globosa, and angiosperm broad-leaved trees such as Quercus spp., Tilia, Ostrya, Cornus, Ilex, Juglans, and Crataegus. There is no surface water, but frequent rain and fog provide ample moisture to sustain a lush mesophytic forest type.
Human Uses
This species has been logged for its timber by local sawmills and the wood has been used for construction purposes and carpentry. This use is now being discouraged for conservation reasons. It has been introduced to arboreta in Europe, Australia (Tasmania) and New Zealand; trees that still survive from this effort can be considered extremely rare. Some may be misidentified as Picea chihuahuana, which has more glaucous, shorter leaves and entire, not denticulate seed scales.
Conservation Status
Global status
Endangered B1ab(ii,iii,v)+2ab(ii,iii,v); C1
Global rationale
The extent of occurrence (EOO) and area of occupancy (AOO) are 565km² and 16km² respectively. There are two locations and an ongoing decline due to logging and fire. The total number of mature individuals is less than 800 and a continuing decline of at least 20% is likely within the next two generations. On this basis Picea martinezii is assessed as Endangered under the B1, B2 and C1 criteria. The previous Red List assessment (1998) arrived at CR based on an estimated AOO of less than 10km². This new assessment is based on complete mapping data of the localities known (4, in 2 locations) and the use of a 2km wide grid as recommended by IUCN.
Global threats
This extremely rare species is restricted to two sub-populations about 150km apart. The largest sub-population has suffered some logging in recent years from local lumber companies; the smallest population has fewer than 15 mature trees. Poor cone set and low seed viability has been noted in the two main stands. A potential threat is forest fires, which could easily destroy the smallest population in one event. Climate change is also a potential threat as subpopulations are small and occur within restricted habitats that present little opportunity for migration. The genus Picea is at or near its southernmost limit in México (only in Taiwan does it extend a little further south) and species such as Picea martinezii are probably Pleistocene relicts that were more widespread during cooler climatic periods.
Conservation Actions
According to the Secretaría de Medio Ambiente y Recursos Naturales (Mexico) (2010) this species is in danger of extinction. Awareness of the conservation issue is growing and local foresters are monitoring the situation. Protection against wildfire and logging is essential. Strategies to improve seed production within stands could involve thinning some of the associated pines and other trees. Enrichment planting is also recommended provided that the young trees can be protected and competition with other species controlled. Ex-situ conservation in the form of seed banking is also recommended: in the 1980s seed was collected and distributed to several arboreta and the Royal Botanic Gardens, Kew (Rushforth 1986) but more concerted efforts are required.
References and further reading
Ledig, T., M. Mapula-Larreta, B. Bermejo-Velasquez, V. Reyes-Hernandez, C. Flores-Lopez & Capo-Arteaga, M.A. (2000). Locations of endangered spruce populations in Mexico and the demography of Picea chihuahuana. Madroño 47(2): 71-88.
Ledig, T., P. Hodgskiss & Jacob-Cervantes, V. (2002). Genetic diversity, mating system, and conservation of a Mexican subalpine relict, Picea mexicana Martínez. Conservation Genetics 3(2): 113-122.
Ledig, T., P.D. Hodgkiss, K.V. Krutovskii, D.B. Neale & Eguiluz-Piedra, T. (2004). Relationships among the spruces (Picea, Pinaceae) of southwestern North America. Systematic Botany 29(2): 275-295.
Rushforth, K. (1986). Mexico's spruces - rare members of an important genus. Kew Magazine 3(3): 119-124.
Secretaría de Medio Ambiente y Recursos Naturales. (2010). Norma Oficial Mexicana NOM-059-SEMARNAT-2010. Protección ambiental de especies nativas de México de flora y fauna silvestres: Categorías de riesgo y especificaciones para su inclusión exclusión o cambio-Lista de especies en riesgo. Diario Oficial de la Federación: 1-78.
Taylor, R.J. & Patterson, T.F. (1980). Biosystematics of Mexican spruce species and populations. Taxon 29(4): 421-467.
Thomas, P. & Farjon, A. (2013). Picea martinezii. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.1. <www.iucnredlist.org>. Downloaded on 13 July 2013.
