David J. Berg


University Distinguished Professor

548 Mosler Hall, Hamilton Campus
89 Pearson Hall, Oxford Campus

Biographical Information

Research in the Aquatic Biodiversity & Conservation (ABC) Laboratory focuses on the evolution and conservation of biodiversity, and the geographic distribution of this diversity across freshwater ecosystems. Our study organisms include amphipods, snails, and other invertebrates inhabiting springs in the Chihuahuan Desert of west Texas and southeastern New Mexico, and freshwater mussels (the most imperiled group of animals in the United States) 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.  In fact, we recently described four new species within the amphipod genus Gammarus from these ecosystems.  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, climate change, and other anthropogenic causes.

In addition to basic research, we are using molecular genetic tools to answer 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. 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 provide funding for research that informs their efforts at conservation. Our research has provided critical information leading to decisions to list four species of invertebrates under the US Endangered Species Act.

We are now using next-generation sequencing tools for investigating the population genomics, evolution, and distribution of diversity in target organisms.This approach genotypes organisms at thousands of loci per individual via Restriction site-Associated DNA Sequencing (RADseq). We are developing these tools for both freshwater mussels and a variety of desert spring invertebrates. Our research will focus on the use of this information for development of conservation strategies, and on the evolution of traits such as salinity tolerance in desert spring invertebrates.

Courses Taught

  • Conservation Biology (BIO 467/567)
  • Invertebrate Zoology (BIO 312)
  • Fundamentals of Ecology (BIO 209)
  • Environmental Biology (BIO 121)

Recent Publications

  • Walters, A. D., A. G. Cannizzaro, D. A. Trujillo, and D. J. Berg.  2021.  Addressing the Linnean shortfall in a cryptic species complex.  Zoological Journal of the Linnean Society 192:  277-305.
  • Walters, A. D., K. N. Taynor, and D. J. Berg.  2021.  Genetic diversity in the threatened freshwater mussel Lampsilis powellii.  Freshwater Mollusk Biology and Conservation 24:  26-33.
  • Inoue, K., A. L. Pohl, M. Sei, B. K. Lang, and D. J. Berg.  2020.  Use of species delimitation approaches to assess biodiversity in freshwater planaria (Platyhelminthes: Tricladida) from desert springs.  Aquatic Conservation:  Marine and Freshwater Ecosystems 30:  209-218.
  • Jones, M., D. J. Berg, and N. Strenth.  2019.  Texas freshwater amphipods.  pp 70-72 in:  Chapman, B. R. & W. I. Lutterschmidt (eds). Texans on the Brink. Texas A & M University Press, College Station.
  • Walters, A. D., M. A. Brown, G. M. Cerbie, M. G. Williams, J. A. Banta, L. R. Williams, N. B. Ford, and D. J. Berg.  2019.  Do hotspots fall within protected areas? A Geographic Approach to Planning analysis of regional freshwater biodiversity.  Freshwater Biology 64:  2046-2056.
  • Stanislawczyk, K., A. D. Walters, T. J. Haan, M. Sei, B. K. Lang, and D. J. Berg.  2018.  Variation among macroinvertebrate communities suggests the importance of conserving desert springs.  Aquatic Conservation:  Marine and Freshwater Ecosystems 28:  944-953.
  • Adams, N. E., K. Inoue, R. A. Seidel, B. K. Lang, and D. J. Berg.  2018.  Isolation drives increased diversification rates in freshwater amphipods.  Molecular Phylogenetics and Evolution 127:  746-757.
  • Morningstar, C. R., K. Inoue, B. K. Lang, and D. J. Berg.  2018.  A comprehensive status, phylogenetic, and anatomical review of Stagnicola caperata (Say, 1829) in the south-west United States.  Aquatic Conservation:  Marine and Freshwater Ecosystems 28:  527-534.