Research Interests
Plant Systematics—The páramo ecosystem, located above the tree line in the tropical Andes of Colombia, Ecuador and Venezuela, has been the setting for some of the most dramatic recent rapid plant radiations. With an estimated age of 2–4 million years, the páramo is the world’s most diverse high-elevation ecosystem. Today 141+ species of frailejones (subtribe Espeletiinae Cuatrec., Asteraceae) dominate this ecosystem. Frailejones have intrigued naturalists and botanists, not just for their appealing beauty and impressive morphological diversity, but also for their remarkable adaptations to the extremely harsh environmental conditions of the páramo. For my dissertation I reconstructed the phylogenetic relationships within Espeletiinae, using multiple molecular markers (sequence data (2,954 bp): nrDNA (ITS and ETS) and cpDNA (rpl16); and fragment data (1,665 bins): 28 primer combinations of AFLPs). I am currently interested in using next generation sequencing to study more in detail speciation and hybridization mechanisms within the group. In addition to Espeletiinae, I have ongoing projects on the phylogenetic and biogeographic relationships of Chiliotrichum (Asteraceae), Gochnatia (Asteraceae), Ludwigia (Onagraceae), Sideritis (Lamiaceae), Werneria (Asteraceae) and fungal mitochondrial genomes (some manuscripts in preparation).
Niche Modeling and Climate Change—The biological impacts of climate change are widespread and are likely to be as dramatic in the high elevations as in the high latitudes. Massive extinctions are predicted to happen in the Andes, an area well known for its extraordinary biodiversity. Climate change can also push entire lineages (i.e. groups of related species) to the verge of extinction, with irreversible losses of genetic information, unique to those lineages. Based on empirical evidence, scientists have proposed a general trend of change: with the increase of temperatures, climate envelopes of species will be displaced toward the poles and upward in the mountains. To test this hypothesis, I modeled the habitat suitability for 133 species of Espeletiinae under various scenarios of climate change. I am designing a pipeline in R to run the Maxent Entropy (Maxent) algorithm on High-Performance Computing (HPC) clusters: Herdon at the Smithsonian Institution (VA), and Rocks64 and Silicon Mechanics HPC cluster in Saint Louis University (MO). I am expanding the modeling of climate change impacts to two additional clades of Andean Asteraceae: the Werneria sensu lato clade and the Chiliotrichum group (219 species and 22 genera in total). All these plants are found in the high elevations of the Andes, and cover the Andes from Venezuela to Patagonia. In addition, I am incorporating high-resolution (5 m) satellite (RapidEye) and radar images (RADARSAT-2), to model narrowly distributed species.
Evolutionary Ecology—Over decades scientists have been debating over the validity of deterministic theories in community ecology, versus more stochastic theories. Deterministic theories suggest that local, niche-based processes largely determine patterns of species diversity and composition. Stochastic theories rest relevance to niche and give more importance to processes such as colonization probability, random extinction and ecological drift. One way to address this problem is studying the two general types of β diversity in a landscape: directional turnover along a gradient and non-directional variation. I am investigating species variation and directional species turnover along latitudinal, longitudinal and elevational gradients in the Guiana Shield. I am using more than 160,000 geo-referenced collections, obtained over more than two decades of studies in the area. Future directions include incorporating niche modeling and phylogenetic signal to study phylogenetic community ecology in this area.
Historical Biology—Jose Cuatrecasas (1903-1996) is considered one of the greatest explorers and scientists of the New World. He gave his life to the study of the tropical flora of South America and his splendid work represents an example of devotion, consecration, perfectionism and accomplishment. This emeritus scientist left an everlasting trace in the field of Botany. However, most of his archives cannot be accessed by the community. In 2005 Dr. Funk and I initiated a project to document and study the life and expeditions of Cuatrecasas, to make them available for the general public and the scientific community. I supervise the internship program, which has brought dozens of undergraduate and graduate students, some of them from abroad, to learn and collaborate in the project. A current subproject includes developing a prototype of an online tool for dynamically connecting content between Cuatrecasas’ specimens and archival information (photos, maps, journals, etc.) or other sources, with a user-friendly interface.
Taxonomy and collections—Since my appointment as director of the HPUJ Herbarium in the Pontificia Universidad Javeriana (2001–2006) I have been interested in taxonomy and botanical collections. As part of my dissertation I conducted a thorough revision of the nomenclature (published) and built and interactive digital identification key (available online at http://espeletia.org/Espeletia/Key.html). I am also contributor for the Virtual Key for the Compositae project (http://www.vkcomp.org/) and curator of Compositae (a.k.a. Asteraceae) for the LifeDesks (http://compositae.lifedesks.org/). I recently proposed using QR Codes in specimens of biological collections to facilitate linking electronic information such as photographs, maps, associated collections, ecosystem notes, citations, and GenBank sequences (paper submitted).
Mauricio Diazgranados, PhD. Post-doctoral Researcher, Department of Botany, National Museum of Natural History, Smithsonian Institution, PO Box 37012, Washington, DC 20013-7012. E-mail: DiazgranadosM@si.edu / espeletias@gmail.com
Office Phone: (202) 633-0951
Last Update: Apr. 22 2013