Cupressus arizonica var. nevadensis (Abrams) Little

Cupressaceae

Endemic to the USA in southern California and threatened mainly by fire

Distribution

Endemic to the USA: California where it is found in the Counties of Kern, Los Angeles and Tulare. Most of the population is in the Kern River drainage. The population is probably between 3000 and 5000 mature trees, but must fluctuate due to devastating fires and a required regeneration time to re-establish mature trees.

Habitat and Ecology

In mixed conifer/ broadleaved woodland with Pinus sabiniana, Quercus spp., Juniperus californica, Fremontia californica, Yucca whipplei, and in valley scrub-grassland. On dry hills, ridges and in ravines.

Conservation Status

Global status

Endangered B1ab(iii,v)c(iv)

Global rationale

This taxon meets the criteria B2 a and c for Endangered, where destructive fires can wipe out entire subpopulations (“groves”) and thereby drastically reduce the number of mature individuals in the population. If this should happen in the largest subpopulation, more than half of all mature trees might be destroyed. Regeneration usually follows fires making the population subject to extreme fluctuations. Changes in fire frequencies (either too frequent or too infrequent) can work negatively on the successful regeneration to mature trees.

Global threat

This variety has a limited distribution in ca. 12 sub-populations (groves) of different size in 4 localities, the largest being on the N slope of Bald Eagle Peak south of the little town of Bodfish, covering more than 200 ha with several thousand trees. These subpopulations occur both on private and public lands. Fire, cutting or clearing of 'brush' to extend pasture, and competition by shrubs and trees are some of the major factors that negatively influence the abundance of Cypresses. A major burn all but destroyed the Cannell Creek grove several years ago (J. A. Bartel, e-mail comm. May 2000).

Conservation Actions

Proper management of bush fires is by far the main factor to be addressed in the conservation of this variety. It would also be recommended to include at least the major subpopulation in a protected area under the system of State Parks of California, to ensure this management will be implemented.