XVI International Botanical Congess

Pinus maximartinezii is a rare, endemic, and threatened species known from a single, small population in the state of Zacatecas, Mexico. It bears one of the largest and nutritious seeds among the edible pine nuts. The seeds are harvested directly from the trees and illegally sold in the market. To assess the impact of different rates of seed harvesting over the species, a two-year study of the population dynamics was conducted over three 0.1ha plots. Demographic data were collected for the species and an eight stage-structured matrix model was used to simulate population dynamics over time. A sensitivity analysis was performed to determine the maximum number of seeds, which could be harvested on a sustainable base. Population growth rate was 1.18 and relatively insensitive to changes in fecundity. The species tolerates a seed harvesting intensity of 99% before it decreases to the equilibrium level of 1.0.