McCauley, Ross A. , Cortés-Palomec, Aurea C. , Oyama, Ken .
Distribution, genetic diversity, and conservation of a rare microendemic hardwood species, Guaiacum unijugum (Zygophyllaceae) in the Cape Region of Baja California, Mexico.
Guaiacum unijugum Brandegee is a rare shrub to small tree endemic to an approximately 70 km stretch of coastline extending east from San JosÃ© del Cabo in the Cape Region of Baja California, Mexico. Very little is known regarding the number of populations, size of populations, or genetic structure of G. unijugum. To develop a baseline of data for species conservation we initiated a survey of the species range to determine the extent of occurrence and surveyed the genetic structure and diversity present within and among the identified populations. A detailed investigation of herbarium material identified approximately five specific collection localities and our survey was able to locate four distinct populations of G. unijugum with a total of 29 individuals. Seed production was observed in almost all individuals although successful reproduction as evidenced by seedlings was only observed in one population. A genetic analysis using 17 microsatellite loci showed very low levels of genetic diversity with a mean expected heterozygosity (HE) of 0.07. Most loci were found to be monomorphic across the four populations. Genetic divergence was small and maintained solely by the presence of rare private alleles in widely-separated populations. Our analysis additionally suggests that selfing is likely maintaining the populations. To assist in conservation we provide a series of recommendations for listing on national and international endangered species lists and outline a potential for increased seedling recruitment via ex-situ propagation.
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1 - Universidad Nacional Autónoma de México, Centro de Investigaciones en Ecosistemas, Antigua Carretera a Pátzcuaro No. 8701, Col. Ex-Hacienda de San José de la Huerta, Morelia, Michoacán, 58190, México
Presentation Type: Oral Paper:Papers for Topics
Date: Monday, July 28th, 2008
Time: 8:00 AM