Advanced exploration of the ecological consequences of trophic downgrading in mixed/short grass prairies in North America

Dennis Ruez, University of Illinois at Springfield
Megan Styles, University of Illinois at Springfield
Felisa Smith, University of New Mexico
Eric Grimm, Illinois State Museum
Author Profile


North American ecosystems have fundamentally changed over the late Pleistocene and Holocene; from a system dominated by mammoths, to bison, to domestic livestock. Given the very different body size and herd formation of these 'ecosystem engineers', it is likely that animals influence soil structure, water tables, vegetation and other animals in the ecosystems. What has been the ecological influence of the continued 'downsizing' of the largest animals in the ecosystem?

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Learning Goals

  1. Students will understand
    • that ecosystems are dynamic and change is continual.
    • significant patterns in and impacts of climate change during the late Pleistocene and Holocene in North America.
    • how climate change, human action, and alterations in species distribution have collectively influenced the distribution and abundance of grassland ecosystems in North America.
  2. Students will be able to use the Neotoma database and ArcGIS to investigate the role that "ecosystem engineers" play in driving ecosystem change. In particular, they will be able to generate distribution maps and compute the overlap of geographic ranges among multiple taxa.
  3. Students will develop hypotheses about the role played by top consumers in shaping observed variations over time in grassland ecosystems.
  4. Students will think critically about the possibilities and limitations of using a multi-proxy database such as Neotoma to investigate questions about climate change, ecology, and human action in North America.

Context for Use

This activity is intended for undergraduates and can be done over several class periods. Before beginning, students need to know how to use the Neotoma database to find data about the distributions of species in a given time period. The activity What are the ecological consequences of trophic downgrading in mixed/short grass prairies in North America? is designed to introduce those skills, in preparation for this activity.

Following this activity, students could be encouraged to conduct independent or small group research into a variety of related questions. See the document with a few suggested research topics in the Teaching Materials section, below.

Description and Teaching Materials

In this activity, students explore the potential interactions between different species by computing the area of the geographic range and overlap within and between species over time.

Download the student handout in PDF or Word format:

As a follow-up activity, you could encourage students to conduct independent or small group research into a variety of related questions. Download a few suggested research topics (Microsoft Word 2007 (.docx) 19kB Apr14 16).

Teaching Notes and Tips

The activity What are the ecological consequences of trophic downgrading in mixed/short grass prairies in North America? was designed as an introduction to this one. In that exercise, students i) generate distribution maps and ii) analyze changes in the distributions of species over time.

Because there are multiple reasonable ways to draw the geographic range of taxa in the ArcGIS component, instructors should expect there to be variation within results.

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