Patrick O'Grady: Desert Dune Biodiversity
2006 Mildred Mathias Award
Sand Dunes
Small groups of highly localized insect species dwell in geographically restricted sand-dunes. Photo courtesy of Patrick O'Grady.

Patrick O'Grady, professor of environmental science, policy, and management at UC Berkeley, is interested in how the wealth of the planet's biodiversity is generated. His 2006 UC MEXUS faculty grant project, "Population genetics and statistical phylogeography of dune endemic species in northern Mexico and southwestern United States," received the Mildred Mathias Award for its unique contributions toward understanding the processes involved in generating biological diversity. The project research concentrates on island-like systems in the U.S.-Mexico borderlands where small populations of endemic species can be found in geographically restricted sand dunes.

As part of the project, O'Grady developed a cross-border collaboration with Edward Pfeiler from the Centro de Investigación en Alimentación y Desarrollo (CIAD)-Unidad Guaymas and Manuel Balcázar Lara from the Universidad de Colima. The research team also included Balcázar Lara's graduate student, Julio Rodríguez. Focusing on two genuses of sand cockroach (Eremoblatta and Arenivaga) in the Blattidae family and a genus of a large flower-loving fly (Rhaphiomidas), the researchers collected species samples to develop a model for the evolutionary path that these dune residents might have taken and a depiction of biodiversity over time and space. An understanding of these evolutionary processes may help inform conservation management decisions at a time when both urbanization and global climatic changes are affecting the remaining open space in North American deserts.

With his graduate student, Matthew Van Dam, and other collaborators, O'Grady has now generated more than 100 new DNA sequences from four different genes in species belonging to the genus Rhaphiomidas. This work represents the first molecular phylogenetic study of Rhaphiomidas and the first multigene study in the Mydidae family. O'Grady notes that the research will serve as the basis for future projects on the evolutionary relatedness of several groups of two-winged flies. Using the DNA markers and analysis as part of this project, O'Grady's research group has been able identify, for the first time, an undescribed larval form as Rhaphiomidas trochilus.

The final aspect of the project will be to complete a detailed population genetics study of the unique Rhaphiomidas acton group in Southern California. The research group is in the process of identifying a number of new species and assessing the genetic differentiation between the populations and subspecies in order to gain insight into some of the mechanisms involved in the generation of biodiversity.

The project has resulted in a description in Zootaxa of two new Rhaphiomidas species from Mexico and the United States and a study of the impact of off-road vehicle use on dune endemic plants and insects published in the Annals of the Entomological Society of America. Several additional publications are in preparation. Dr. O’Grady can be reached at ogrady@nature.berkeley.edu and additional information about his research is available at on his website.