Cupressus arizonica var. montana (Wiggins) Little

Cupressaceae

Endemic to Baja California in Mexico where the main threat is likely to be from an increase in the severity and frequency of fires due to fire suppression policies, coupled with the likely impacts of climate change.

Associated Names:

San Pedro cypress and San Pedro Martír cypress

Distribution

Endemic to Mexico: This variety is confined to steep slopes in San Pedro Martír Mountains, Baja California Norte, Mexico. Within that area it has been recorded from the following localities: Canon del Diablo (down to 1150 m), Arroyo de la Grulla, Cerro La Encantada (type locality ‘‘upper end of the meadow 2300 m’’), to summit of Picacho del Diablo (3095 m), E of Corral Meadow on E escarpment and S along N-facing gullies on granite exposures to the primary population on Picacho del Diablo above Vallecitos, Los Llanitos, 2400 m, locally on ridge extending out into E escarpment 5 km E of the northern end of La Encantada (2400–2600 m), and Cerro la Botella Azul, 2840 m (Thorne et al. 2010).
The extent of occurrence is estimated to be about 250 km² with a much smaller area of occupancy of arbout 30 km². These estimates reflect the occurrence of the main vegetation types in which it occurs. Its elevation ranges from 1150 to 3025 m with most stands above 1900 m asl. Previous estimates of EOO and AOO used for IUCN assessments have been based on a limited number of herbarium specimens.The primary population is located on Picacho del Diablo where it is frequent and locally abundant. In other areas it is less common.

Habitat and Ecology

Montane coniferous forest or clearings on dry slopes or in canyons, sometimes in or near creek beds. In association with Abies concolor, Pinus jeffreyi, P. lambertiana, and Populus tremuloides;

Human Uses

Rarely cultivated

Conservation Status

Global status

Near Threatened (Endangered B1ab(iii,v))

Global rationale

The San Pedro Cypress has an estimated extent of occurrence of less than 250 km². Its area of occupancy is considerably less, and has been estimated to be around 30 km², with about 100 groves occurring in several locations. The total population is unknown but certainly beyond any IUCN threshold. Recent surveys and visitors have indicated that it is locally abundant and regenerating. No decline has been observed or reported. However potential interelated threats such as climate change and an increase in the frequency and intensity of fires due to continuing fire suppression, could have a significant impact in the near future. Considering its limited distribution and the potential threats an assessment of Near Threatened is precautionary as it could rapidly meet the criteria for Endangered (B1ab(iii,v)). Currently this species is assessed as Critically Endangered by the IUCN but this assessment is due for revision in the light of better information

Global threats

Summer grazing may have a limited impact in some areas but the majority of the vegetation type in which this taxon occurs appears to be unaffected (Bojorquez-Tapia et al. 2004). A more significant threat comes from climate change with changes in precipitation regimes forecast and an increase in extreme temperatures and droughts (Meko et al. 2013). This could be amplified as fire suppression policies within the National Park lead to an increse in frequency and severity of fires (Minnich 2000, Rivera-Huerta et al. 2015).

Conservation Actions

The remaining trees are found within a national reserve.