Population dynamics of Ceratozamia matudai Lundell (Zamiaceae) in el Triunfo Biosphere Reserve, Chiapas, Mexico

We describe Ceratozamia matudai geographic distribution, its basic demographic parameters, and the association of these parameters with environmental factors. A species survey and a review of herbarium collections indicated that C. matudai occurs only on the pacific slopes of the Sierra Madre of Chiapas, Mexico. Two censuses (1998-1999) were performed in a Pine-Cupressus forest in the core zone of the Triunfo Biosphere Reserve, and a Montane Rain Forest in its buffer zone. Neighboring floristic composition, soil depth, and slope around marked and mapped C, matudai individuals in each site were described. This species showed a clumped local distribution on shallow soils on steep slopes. Individuals showed differences in amount of leaf production, trunk diameter, and height between sites. Neighboring species composition affected seedling mortality. Because of its low numbers and limited range we recommend a status change in its IUCN category to endangered. As with other cycads, C. matudai can reach high market values. Ex-situ propagation of this and other species may provide incentives among local peasants for conservation of the natural populations and its habitat.