Resumo

FERRER, Merari et al. Population dynamic of genets and ramets in an endemic cactus of Yucatan Mammillaria gaumeri. Bol. Soc. Bot. Méx [online]. 2011, n.89, pp.83-105. ISSN 0366-2128.

We analyzed the population dynamics of genets and ramets of Mammillaria gaumeri, an endemic cactus of Yucatan in order to generate demographic information that supports the change in status of species of "special protection" to "endangered species" in the Norma Oficial Mexicana. A matrix model was used to analyze the population dynamics of eight populations for a period of four years (2004-2007). The results indicate that the populations are comprised mainly of adults, with a density in 2007 from 300 to 3,737 ind/ha. We obtained a low percentage of field germination and seedling establishment as reported for other globular cacti. The mortality rate was higher in the first categories of size, and when there was high mortality of adults due to disturbance events (illegal looting, fires). The population growth rate (λ) ranged from 0.6255 to 1.2629. Elasticity values indicated that the stasis of adults had the greatest contribution to population growth rate, so that protection of these individuals, and its habitat conservation are priority actions for the survival of this species.

Palavras-chave : demography; elasticity; Mammillaria; Matrix models.

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