Associate Professor David L. Fox
My research has three broad focuses. The first is using stable isotope measurements of biogenic and sedimentary materials to answer questions in paleobiology and paleoclimatology. A selection of planned and on-going stable isotope projects include: tracking changes in North American deer ecology from the Late Pleistocene to the Recent using carbon, oxygen, and nitrogen isotope measurements of teeth and bones; studying the ecology of Late Pleistocene North American mammoths and mastodons and Eurasian mammoths, including the latest surviving population from Wrangel Island north of Siberia, using carbon, oxygen, and nitrogen isotope measurements of tusks and teeth (in collaboration with Dan Fisher at the University of Michigan); and tracking the expansion of grasslands and concurrent changes in ecology among Miocene mammals of the Great Plains using carbon and oxygen isotope measurements of soil carbonate nodules and herbivore teeth. Future work may include development of compound-specific techniques for application to paleontological material.
A second focus is exploring the role of stratigraphic data in phylogenetic analysis through the use of computer simulated evolutionary histories. Stratocladistics, which incorporates stratigraphic range data into the logic of traditional cladistic analysis, is still a controversial method. However, stratocladistic analysis of simulated character data sets and stratigraphic ranges has been shown to lead to more accurate estimates of simulated phylogenies than traditional cladistic analysis of simulated character data sets alone (see Fox et al., 1999). On-going simulation studies focus on the sensitivity of both stratocladistics and cladistics to tree shape, variable preservation probability, variable character evolution probabilities through time, taxon sampling, stratigraphic resolution, and missing data.
The third focus of my research (in collaboration with Catherine Badgley at the University of Michigan) is on the ecological biogeography of modern North American mammals in relation to the spatial variation in climate. The frequency of modern mammal species in body size and dietary categories shows striking correlations with climatic variables and, in parts of the continent formerly covered by the Laurentide (continental) ice sheet, the time since deglaciation. Continuing work on the biogeography of mammals will include development of transfer functions to estimate paleoclimatic variables from the ecological characteristics of fossil mammalian faunas and comparisons between the modern mammalian faunas of North American and Africa, continents with quite different faunal and climatic histories over the last several million years.
*designates a student author
- Marcot, J.D. and Fox, D.L., 2008. StrataPhy: a new computer program for stratocladistic analysis. Palaeontologia Electronica 11.5.5A, 16 pp., http://palaeo-electronica.org/2008_1/142/index.html.
- Martin, R.A., Pel?ez-Campomanes, P., Honey, J.G., Fox, D.L., Zakrzewski, R.J., Albright, L.B., Lindsay, E.H., Opdyke, N.D., and Goodwin, H.T., 2008. Rodent community change at the Pliocene-Pleistocene transition in southwestern Kansas and identification of the Microtus immigration event on the Central Great Plains. Palaeogeography, Palaeoclimatology, Palaeoecology 267: 196-207.
- Matson, S.D. and Fox, D.L., 2008. Can oxygen isotopes from turtle bone be used to reconstruct paleoclimates? PALAIOS 23: 24-34. DOI: 10.2110/palo.2006.p06-049r.
- Fox-Dobbs, K., Bump, J.K., Peterson, R.O., Fox, D.L., and Koch, P.L. Carnivore specific stable isotope variables and variation in grey wolf foraging ecology: case studies from Isle Royale, Minnesota, and La Brea. Canadian Journal of Zoology 85: 458-471.
- Fox, D.L., Fisher, D.C., Vartanyan, S., Tikhonov, A.N., Mol, D., and Buigues, B., 2007. Paleoclimatic implications of oxygen isotopic variation in late Pleistocene and Holocene tusks of Mammuthus primigenius from northern Eurasia. Quaternary International 169-170: 154-165.
- Rountrey, A.N., Fisher, D.C., Vartanyan, S., and Fox, D.L., 2007. Carbon and Nitrogen Isotope Analyses of a Juvenile Woolly Mammoth Tusk: Evidence of Weaning. Quaternary International 169-170: 166-173.
- Angielczyk, K. and Fox, D.L., 2006. A new role for stratigraphic data in phylogeny reconstruction? Exploring an alternative use of stratigraphic data in phylogeny reconstruction. Paleobiology 32: 147-165.
- Cowan, C.A., Fox, D.L., Runkel, A.C., and Saltzman, M.R. Terrestrial-marine carbon cycle coupling in ~500 million year-old phosphatic brachiopods. Geology 33(8): 661-664. (authorship is alphabetical)
- Fox, D.L. and Koch, P.L., 2004. Carbon and oxygen isotopic variability in Neogene paleosol carbonates: constraints on the evolution of the C4-dominated grasslands of the Great Plains, USA. Palaeogeography, Palaeoclimatology, Palaeoecology 207: 305-329.
- Fox, D.L. and Fisher, D.C, 2004. Dietary reconstruction of Gomphotherium (Mammalia, Proboscidea) based on carbon isotope composition of tusk enamel. Palaeogeography, Palaeoclimatology, Palaeoecology 206: 311-335.
- Fox, D.L. and Koch, P.L., 2003. Tertiary history of C4 biomass in the Great Plains, U.S.A. Geology 31: 809-812.
- Fisher, D.C. and Fox, D.L., 2003. Season of death and terminal growth histories of Hiscock mastodons. In: Laub, R.S. (ed.), The Hiscock Site: Late Pleistocene and Holocene Paleoecology and Archaeology in Western New York State. Bulletin of the Buffalo Society of Natural Sciences 37: 83-100.
- Fisher, D.C, Fox, D.L., and Agenbroad, L.D., 2003. Tusk growth rate and season of death of Mammuthus columbi from Hot Springs, South Dakota, USA. DEINSEA 9: 117-133.
- Fisher, D.C., Foote, M., Fox, D.L., and Leighton, L.R., 2002. Stratigraphy in phylogeny reconstruction--Comment on Smith (2000). Journal of Paleontology 76(4): 585-586.
- Fox, D.L. and Fisher, D.C., 2001. Stable isotope ecology of a late Miocene population of Gomphotherium (Mammalia, Proboscidea) from Port of Entry Pit, Oklahoma: diet, climate and diagenesis. PALAIOS 16: 279-293.
- Fox, D.L., 2000. Growth increments in Gomphotherium and implications for late Miocene climate change in North America. Palaeogeography, Palaeoclimatology, Palaeoecology 156: 327-348.