Email: Roosevelt Garcia
Phone: +44 (0)131 248 2899
Fax: +44 (0)131 248 2901
My research interests focus on understanding the origin and maintenance of tree species diversity in Amazonian forests. For the past few years I have been studying the floristic diversity of the Peruvian Amazon trying to determine how environmental variation influences patterns in plant diversity. In my doctoral dissertation I am using a combination of molecular techniques and extensive fieldwork to try to understand the origin of Amazonian white-sand forests, a distinctive forest type with many endemics and soil-specialists, and its biogeographic relationships with the Guiana Shield area.
Characteristic structure of lowland Amazonian white-sand forest with densely packed, thin-trunked trees, Peruvian Amazon.
White-sand forests occur on quartz-rich sandy soils patchily distributed like habitat-islands in the lowlands of Amazonia. They are more common in the Guiana Shield region of northern South America, which is thought to have served as source for this type of soil in Amazonia. Despite being species poor, these forests support a distinctive flora with many habitat-specialists and endemics. The phytogeographic affinities between western Amazonian white sands and the Guiana Shield region have been suggested by taxonomic studies but not thoroughly evaluated.
Exposed white-sand soils covered by non-white-sand soils (clay-loam soils) at the Iquitos-Nauta road, Peruvian Amazon.
Geological evidence suggests that white-sand soils in the western Amazon originated 6-8 million years ago, whereas Guiana Shield white-sand forests might be much older. Distributional data shows that white-sand plant taxa can be found in: a) neighbouring non-white sand forests and hence are either broad habitat generalists, cryptic species or are present in white-sand forests simply via mass effects; b) are not present in neighbouring forests, yet are found in white-sand forests elsewhere in the Amazon, including those of the Guiana Shield; and c) those that are endemic to the white-sand forests of the western Amazon or the Guiana Shield. I will use a molecular approach in well resolved monophyletic groups of selected species with shared distributions between western Amazonian white-sand forests and the Guiana Shield white-sand flora to investigate the divergence time between taxa and its congruence with current geological knowledge of the region and the hypothesized origin of white-sand. An ancestral area reconstruction analysis will further shed light into the origin of Amazonian white-sand forests.
Landsat TM satellite image of the Upper section of the Nanay River, Northern Peruvian Amazon showing patches of white-sand forests.
Fine P., García-Villacorta R., Mesones, I., & N. Pitman. 2009. A floristic study of the white-sand forests of Peru. Annals of the Missouri Botanical Garden. 97: 283-305.
García-Villacorta, R. & Hammel B. 2004. A noteworthy new species of Tovomita (Clusiaceae) from Amazonian White Sand Forests of Peru and Colombia. Brittonia 56 (2): 52-55.
García-Villacorta, R., M. Ahuite Reátegui & M. Olórtegui Zumaeta. 2003. Classification of the white sand forests of the Allpahuayo Mishana Reserve (ZRAM), Peruvian Amazonia. Folia Amazónica 14 (1-2): 11-28.
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