Catalina Arias Agudelo

Landscape Connectivity and Genetic Structure of the Neotropical Oak (Quercus Humboldtii Bonpl.) in Colombia

Working in Cachalu.

Worm eating Q humboldtii 's leaves.

Frog of virolin.

Q. humboldtii 's worm.

Central and Latin America, Habitat25 Feb 2008

Habitat loss and fragmentation are important and recurrent issues in conservation biology. It is known that diverse populations are better able to resist environmental variation and disease outbreaks. For small and isolated subpopulations random events become more important because there is less random mating and less migration. This results in a reduction in the number of heterozygotes and a higher probability of allele fixation. Thus, the chances of surviving stochastic environmental changes become more difficult and the extinction risk higher for the small populations.

The Guantiva - La Rusia – Iguaque "conservation corridor" is a large area dominated by Quercus humboldtii Bonpl. The World Wildlife Federation (WWF) recognizes it as a strategic area for Q. humboldtii ecosystem conservation. It was designated "conservation corridor" by the Fundación Natura of Colombia as a protection space where they have been developing different biological and social research programs for at least twelve years. The main focus has been on oak ecosystem conservation, rather than efforts to connect the subpopulations via true "corridors".

My research aim is to identify relationships between genetic diversity and landscape features of Q. humboldtii populations in order to suggest strategies for its protection. By using both Geographical Information System (GIS) tools and molecular genetic analyses it will be possible to provide detailed information about the population structure and to identify the historical impact of the landscape changes on the genetic structure. It then will be possible to propose regions to maintain the connectivity within the species in order to foster population size increases, reduce inbreeding depression, and to promote gene flow by connecting isolated subpopulations.

I will also integrate my study of genetic diversity of Q. humboldtii in the Guantiva - La Rusia – Iguaque "conservation corridor" with analyses of other Colombian oak populations (map 1) to investigate larger patterns of landscape characteristics, genetic structure, and gene flow within and between Q. humboldtii populations. I will be testing if fragmentation has had a negative effect on the genetic diversity of the population, if subpopulations that are near to one another have more similar genetic structure than ones that are far apart, and finally, if there is higher genetic diversity in larger and connected subpopulations than in small and isolated subpopulations.

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Project Update: June 2008

During the field work I was in different oak populations of Boyacá and Santander in the eastern mountain range of Colombia. The high hills were a constant to get to the forests since, although oaks distribution is between 1500 to 3300 meters high, the forest have been marginalized to spaces with difficult access.

There where oak forests fully dominated by oaks and other with more plant diversity. Also, anthropogenic fragmentation (livestock principally) is evident in all the places. The more fragmented populations are in the southern part of the Guantiva - La Rusia – Iguaque "conservation corridor" populations in Arcabuco, Gachantiva, and Oiba.

Actually, I am doing the laboratory part of the project in the International Center for Tropical Agriculture (CIAT) into the laboratory of the Institute of Biological researches Alexander von Humboldt (IAvH) where by now I am extracting DNA.

Final Report

Read about the activities undertaken and findings of this project in the final report and Thesis below.

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Final Report572.97 KB
Thesis861.17 KB

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