Camille A. Holmgren, Ph.D.

Camille Holmgren is a paleoecologist and biogeographer interested in changing environmental conditions in arid and semi-arid environments from the last ice age until present. Her research specializes in using plant fossils from rodent middens (their dens) to reconstruct vegetation patterns in western North America. Midden studies provide insight into plant species and community responses to changing climatic conditions over the past ~50,000 years and provide a baseline for assessing current and projected future changes.

Dr. Holmgren is also active in developing innovative teaching materials, including the NSF-sponsored Integrate course module “Changing Biosphere” in which students evaluate recent human influences on the biosphere in the context of the geologic record. She is a contributor to the Science Education Resource Center with several activities that have been awarded Exemplary Status.

Courses Taught

• GEG 101 World Natural Environments
• GEG 103 Introduction to Environmental Sustainability (New Spring 2024)
• GEG 385 Past Climates and Environments
• GEG 396 Research Methods
• GEG 423/523 Biogeography
• GEG 478 Global Change
• GES 111 Oceanography

Dr. Holmgren’s Research in the Media:

Arizona Illustrated - Arizona Public Media/PBS, July, 2023, Pack Rat Time Machine

Smithsonian Magazine, Nov. 2019. From Ancient Seeds to Scraps of Clothing, Rats’ Nests are Full of Treasures

Der Spiegel (Germany), April, 2010, Warum Rattenurin ein wahrer Schatz ist (Why Rat Urine is a Real Treasure)

National Geographic Magazine, Sept. 2004, Global Warming: Bulletins from a Warmer World – Signs from Earth pp. 56-75.

Selected Publications

Becklin, K., Betancourt, J.L., Braasch, J., Dézerald, O., Díaz, F.P., González, A.L., Harbert, R., Holmgren, C.A., Hornsby, A.D., Latorre, C., K.M., Matocq, M.D., Smith, F.A. 2024. New uses for ancient middens: bridging ecological and evolutionary perspectives. Trends in Ecology and Evolution. https://doi.org/10.1016/j.tree.2023.12.003

Holmgren, C.A., Hornsby, A.D., Becklin, K.M., Betancourt, J.L., Díaz, F.P., González, A.L., Latorre, C.L. 2023. Best Practices for Ancient Rodent Midden Collection, Processing, and Curation. Protocols. Io. dx.doi.org/10.17504/protocols.io.4r3l224q4l1y/v1

Holmgren, C.A., Bream, G.J., Duran, K.L., Briles, C.E. 2022. Paleoenvironment: The Woodrat Midden Record. In Multidisciplinary Research at the La Botica Site, Conejos County, Colorado (M.D. Mitchell, Ed.), Research Contribution 115, Archaeological Investigations in the San Luis Valley 8. History Colorado – State Historical Fund, Denver, CO.  pp. 43-56. https://paleocultural.org/wp-content/uploads/2022/06/Mitchell-2022-Multidisciplinary-Research-La-Botica-Site-low-res.pdf 

Smith, A.D., Kaminski, M.J., Kanda, K., Sweet, A.D., Betancourt, J.L., Holmgren, C.A., Hempel, E., Alberti, F., Hofreiter. M. 2021.  Recovery and analysis of ancient beetle DNA from subfossil packrat middens using high-throughput sequencing. Scientific Reports 11, 12635. https://doi.org/10.1038/s41598-021-91896-8

Butterfield, B.J., Holmgren, C.A., Anderson, R.S., Betancourt, J.L. 2019. Life history traits predict colonization and extinction lags of desert plant species since the Last Glacial Maximum. Ecology. https://doi.org/10.1002/ecy.2817

Butterfield, B.J., Anderson, R.S., Holmgren, C.A., Betancourt, J.L. 2019. Extinction debt and delayed colonization have comparable but unique effects on plant community-climate lags since the Last Glacial Maximum. Global Ecology and Biogeography 28, 1067-1077. https://doi.org/10.1111/geb.12915 

Holmgren, C.A., Hunter, K.L., Betancourt, J.L. 2019. Creosote bush (Larrea tridentata) ploidy history along its diploid-tetraploid boundary in southeastern Arizona-southwestern New Mexico, USA. Journal of Arid Environments 164, 7-11.https://doi.org/10.1016/j.jaridenv.2019.02.002 

Holmgren, C.A. 2017. The biodiversity crisis—Are humans causing a sixth mass extinction? Published online as part of Integrate’s Changing Biosphere module for undergraduate instruction. http://serc.carleton.edu/integrate/teaching_materials/biosphere/student_materials/unit1_read.html

Borrelli, M.P. and Holmgren, C.A. 2016. Dietary modifications of packrats in response to changing plant communities: Evidence from fossil plant cuticles spanning >55,000 years in Sonoran Desert packrat middens. Journal of Arid Environments 138, 1-8. https://doi.org/10.1016/j.jaridenv.2016.08.004 

Holmgren, C.A., Betancourt, J.L., Peñalba, M.C., Delgadillo, J., Zuravnsky, K., Hunter, K.L., Rylander, K.A., Weiss, J.L. 2014. Evidence against a Pleistocene desert refugium in the lower Colorado River Basin. Journal of Biogeography 41, 1769-1780. https://doi.org/10.1111/jbi.12337 

Zinniker, D.A., Holmgren, C.A., and Simoneit, B.R.T. 2013. Enterolactone and Other Lignan Metabolites as Taxon-Specific Markers in Modern and Ancient Woodrat Middens. Zeitschrift für Naturforschung C. 68c, 327-335.

Holmgren, C.A., Betancourt, J.L., and K.A. Rylander. 2011. Vegetation history along the eastern, desert escarpment of the Sierra San Pedro Mártir, Baja California, Mexico. Quaternary Research 75, 647-657. https://doi.org/10.1016/j.yqres.2011.01.008 

Holmgren, C.A., Betancourt, J.L., and K.A. Rylander. 2010. A long-term vegetation history of the Mojave/Colorado Desert ecotone at Joshua Tree National Park. Journal of Quaternary Science 25, 222-236. https://doi.org/10.1002/jqs.1313 

Placzek, C., Quade, J., Betancourt, J.L., Patchett, P.J., Rech, J.A., Latorre, C., Matmon, A., Holmgren, C.A., and English, N.B. 2009. Climate in the dry, central Andes over geologic, millennial, and interannual timescales. Annals of the Missouri Botanical Gardens 96, 386-397.http://dx.doi.org/10.3417/2008019 

Holmgren, C. A., Rosello, E., Latorre, C., and Betancourt, J. L. 2008. Late Holocene fossil rodent middens from the Arica region of northernmost Chile.  Journal of Arid Environments 72, 677-686. https://doi.org/10.1016/j.jaridenv.2007.09.003 

Holmgren, C.A. 2007. Paleoenvironmental response of the northern Chihuahuan Desert to the Bølling/Allerød-Younger Dryas climatic oscillation. Invited paper for Current Research in the Pleistocene 24, 7-10.

Holmgren, C.A. 2007. Book review of Dry Borders: Great Natural Reserves of the Sonoran Desert. Felger, R. S. and Broyles, B. The Quarterly Review of Biology 82, 304. https://www.journals.uchicago.edu/doi/abs/10.1086/523203 

Holmgren, C.A., Norris, J., and Betancourt, J.L. 2007. Inferences about winter temperatures and summer rains from the late Quaternary record of C4 perennial grasses and C3 desert shrubs in the northern Chihuahuan Desert. Journal of Quaternary Science 22, 141-161. https://doi.org/10.1002/jqs.1023 

Holmgren, C. A., Betancourt, J.L., and Rylander, K. A. 2006. A 36,000-yr B.P. vegetation history from the Peloncillo Mountains, southeastern Arizona, USA. Palaeogeography, Palaeoclimatology, Palaeoecology 240, 405-422. https://doi.org/10.1016/j.palaeo.2006.02.017 

Latorre, C. L., Betancourt, J. L., Rech, J. A., Quade, J., Holmgren, C.A., Placzek, C. P., Vuille, M., and Rylander, K. A. 2005. Late Quaternary History of the Atacama Desert.  In M. Smith & P. Hesse, Eds., 23° South: Archaeology and Environmental History of the Southern Deserts. National Museum of Australia Press, Canberra.

Holmgren, C. A., Peñalba, M. C., Rylander, K. A. and Betancourt, J. L. 2003. A 16,000 14C yr BP packrat midden series from the U.S.A.-Mexico Borderlands.  Quaternary Research 60, 319-329.https://doi.org/10.1016/j.yqres.2003.08.001 

Holmgren, C. A., Betancourt, J. L., Rylander, K. A., Roque, J., Tovar, O., Zeballos, H., Linares, E., and Quade, J. 2001.  Holocene vegetation history from fossil rodent middens near Arequipa, Peru. Quaternary Research 56, 242-251. https://doi.org/10.1006/qres.2001.2262