Research in my lab focuses on the evolution and conservation of biodiversity. Students investigate forces responsible for creating and maintaining genetic and community diversity in freshwater ecosystems. Our study organisms include invertebrates inhabiting springs in the Chihuahuan Desert of west Texas and southeastern New Mexico, and freshwater mussels (the most imperiled group of animals in North America) from throughout North America. The evolutionary forces we study are natural selection, isolation and dispersal among populations, and random changes in genetic diversity and community composition. Springs in the Chihuahuan Desert provide ideal systems for this work because they contain unique assemblages of invertebrates. Stark landscapes, wide-open spaces, and beautiful sunsets are added bonuses for working in this part of the world. Our work with freshwater mussels has focused on the geographic distribution of genetic diversity within species. We are interested in understanding the mechanisms by which populations of mussels re-inhabited northern rivers following the recessions of Pleistocene glaciers. We also are estimating the degree of gene flow among declining populations when isolation of such populations becomes greater due to habitat fragmentation and loss of intermediate populations.
In addition to basic research, we are examining the use of molecular genetic tools for answering questions of conservation interest. The National Science Foundation has funded our surveys of desert springs to uncover cryptic biodiversity, new species that are genetically distinct from, but outwardly similar to, known species. We are testing the effectiveness of DNA barcoding, a rapid technique for identifying such diversity. The premise for this technique is that certain genes are similar among members of the same species, but differ significantly among species. If this is the case, these gene sequences can be "read" like a bar code in order to identify species.
Because most of our study organisms are at risk of extinction - largely due to human alteration of habitat - our research is of interest to agencies and organizations that manage endangered species. The U.S. Fish and Wildlife Service, the New Mexico Department of Game and Fish (NMDGF), the World Wildlife Fund, and other agencies and NGOs have provided funding. We are collaborating with NMDGF and The Nature Conservancy to protect freshwater invertebrate populations throughout the Chihuahuan Desert.
Environmental Biology (BIO 121)
Fundamentals of Ecology (BIO 209)
Invertebrate Zoology (BIO 312)
Conservation Biology (BIO 467/567)
Inoue, K., E. M. Monroe, C. L. Elderkin, and D. J. Berg. In press. Phylogeographic analyses reveal Pleistocene isolation followed by high gene flow in a wide-ranging, but endangered, freshwater mussel. Heredity.
Inoue, K., B. K. Lang, and D. J. Berg. 2013. Development and characterization of 20 polymorphic microsatellite markers for the Texas hornshell, Popenaias popeii (Bivalvia: Unionidae), through next-generation sequencing. Conservation Genetics Resources 5: 195-198.
Levine, T. D., B. K. Lang, and D. J. Berg. 2012. Physiological and ecological hosts of Popenaias popeii (Bivalvia: Unionidae): laboratory studies identify more hosts than field studies. Freshwater Biology 57: 1854-1864.
Elderkin, C. L., L. D. Corkum, C. Bustos, E. L. Cunningham, and D. J. Berg. 2012. DNA barcoding to confirm morphological traits and determine relative abundance of burrowing mayfly species in western Lake Erie. Journal of Great Lakes Research 38: 180-186.
Seidel, R. A., B. K. Lang, and D. J. Berg. 2010. Salinity tolerance as a potential driver of ecological speciation in amphipods (Gammarus spp.) from the northern Chihuahuan Desert. Journal of the North American Benthological Society 29: 1161-1169.