Species distributions in response to environmental gradients in the Upper Midwest of the United States - an example using the Neotoma database

Alison Smith, Kent State University; Joan Bunbury, University of Wisconsin - La Crosse, Amy Myrbo, LacCore/CSDCO/Limnological Research Center, University of Minnesota
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Pollen and ostracode records are used here to examine the migration of the prairie-forest border during the Holocene in the Upper Midwest. Using the Neotoma database, we can explore the modern geographic distribution of prairie and forest vegetation (represented by pollen data) and freshwater ostracodes (microscopic aquatic crustaceans), and then track the shifting boundary of the prairie forest border over the most recent 10,000 years using pollen and the remains of ostracodes preserved in a lake sediment core.

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Learning Goals

By completing this exercise, students will:

  • Learn to use the Neotoma database and plot species distributions
  • Explore species distributions across the prairie-forest ecotone in Minnesota
  • Describe the major climatic gradient(s) in Minnesota
  • Explain the relationship between species distributions and climate
  • Understand the use of climate proxies to interpret the past
  • Interpret stratigraphic diagrams
  • Speculate on how the distribution of vegetation and ostracodes might change in response to future climate change

Context for Use

This college-level activity is intended for students with an introductory knowledge of biogeography. In larger, lower-level classes, it could act as an in-class lab assignment, and in smaller, upper-level courses it provides an introduction to the database, which students could then use to develop their own research question related to species distributions.

Description and Teaching Materials

Teaching Notes and Tips

Answers to some of the questions and instructions for the instructor are (bold and in parentheses). These should not be included in the student handout.

Additional Taxa - If instructors wish, here are taxa that show the same relationship to the P/F border as the pollen and ostracodes:

Diatoms: Suirirella ovata (saline); Cyclotella glomerata (dilute). Be sure to look at the distributions of the above two taxa prior to adding the following taxon. Amphora ovalis (cosmopolitan)

Mammals: Geomys bursarius (prairie dog - prairie, but present across Minnesota); Antilocapra americana (pronghorn - prairie); Glaucomys sabrinus (flying squirrel - forest). Be sure to look at the distributions of the above taxa prior to adding the following taxon. Odocoileus virginianus (white tailed deer - cosmopolitan)

If you would like to have your students be familiar with the Neotoma database before beginning this exercise, you could have them complete the Exploring the Neotoma Paleoecology Database exercise first.


Students will answer questions as they complete the exercise. Upper-level students can develop a research question that can be answered using the database.

References and Resources

Student-instructor document for exploring species distributions in the Upper Midwest (Acrobat (PDF) 101kB Aug25 16)

Ostracode stratigraphic diagram from Elk Lake, Grant Co., MN (Acrobat (PDF) 13kB Aug25 16)

Neotoma Paleoecology Database: http://neotomadb.org/

PRISM climate data: http://www.prism.oregonstate.edu/normals/

North American Non-Marine Ostracode Database Project: http://www.personal.kent.edu/~alisonjs/nanode/index.htm

The movement of the prairie/forest ecotone through Holocene time is well known in the fields of Ecology, Quaternary Studies and Biogeography. Early papers on this research include:

Cushing, E.J., 1965. Problems in the Quaternary phytogeography of the Great Lakes region, IN (The Quaternary of the United States, (H.E.Wright, Jr. and D.G. Frey, eds), Princeton U. Press, Princeton, N.J., pp. 403-416.

Webb, T. III, Cushing, E.J., and Wright, H.E., Jr., 1983. Holocene changes in the vegetation of the Midwest, IN "Late Quaternary Environments of the United States" (H.E.Wright, Jr., ed.), v. 2, The Holocene, Univ. of Minnesota Press, pp. 142-165.

Smith, A.J., 1993, Lacustrine ostracodes as hydrochemical indicators in lakes of the north-central United States, J. of Paleolimnology 8, pp. 121-134.

Smith, A.J., Donovan, J.J., Ito, E., Engstrom, D.R., and Panek, V.A., 2002. Climate-driven hydrologic transients in lake sediment records: multiproxy record of mid-Holocene drought, Quaternary Science Reviews, 21, pp. 625-646.