Chihuahuan Desert Biotic Study

Introduction

The Chihuahuan Desert is the easternmost, southernmost, and largest North American desert. Today you will be studying living conditions in the Chihuahuan Desert. This activity will help you understand the living environment of the desert.

Task

In groups, set up a 10 meter transect line with rope and stakes. Carefully examine the plants and ground along this line. Keep records of what animals you actually see and any evidence of other animals. Keep records of what plants you see and describe the soil along the transect line. Using the data you collect, prepare a presentation on what you found.

Materials

Each group will need the following materials:

• 10 m rope
• meter stick
• animal log
• plant log
• clipboard, paper and pencils
• hand lens

Procedures

1. Form groups of four or five students.
2. Have the groups negotiate where to lay down the transect.
   TIP: The transect must be by a Creosote bush as this is an indicator plant of the Chihuahuan Desert.
3. Laying out the transect:
   a) place one stake at one point, measure out 10 meters, and place another stake;
   b) connect the 2 stakes with the rope.
   TIP: Remember to count only those plants and animals, or evidence of them, that are actually touched by the transect, or found lying under and/or over it.
4. Identify all the plants along the transect:
   a) count the number of wildflowers, trees, shrubs, cacti and grasses;
   b) try to identify each one by using the identification books;
   c) total up all your plants;
   d) divide this total by the total number in each group to determine percentage;
   e) record this information on the Plant Transect Data Record;
   f) draw and label the plants you find.
5. Identify all the animals along the transect:
   a) count the number of reptiles, amphibians, insects, spiders, mammals and birds;
   b) try to identify each one by using the identification books;
   c) look for tracks, holes dug, scat;
   d) look for insects on the surface;
   e) dig holes to find burrowing insects or other animals;
   f) record this information on the Animal Transect Data Record;
   g) draw and label the animals you find evidence of or actually see.

Questions

Working in your small groups, get ready to present to the larger group. You should have drawings for each of the plants and animals you found. Be ready to report on the number of plants and animals you have found. Once all the groups have reported to the larger group, contrast and compare the information. Here are some questions to get you started. Come up with some of your own.

• Which transect had the least/most plants and animals?
• Which transect had the largest numbers of individuals within a species?
• What species could be found in only one of the transects?
• Why do you think there were more plants and animals in some areas than others?

Online Resources

• The Chihuahuan Desert
• An Introduction to the Chihuahuan Desert
• Chihuahuan Desert Resources on the Web
• El Paso Online Bio Project
• The Chihuahuan Desert through time

Offline Identification Guides:

• Bowers, Janice Emily.100 Desert Wildflowers. SW Parks and Monuments Association, 1989.
• Fischer, Pierce C. 70 Common Cacti. SW Parks and Monuments Association, 1989.
• MacMahon, James A. Deserts. New York: Alfred A. Knopf, 1994.
• Pearce, Q.L. Animal Footnotes:A Nature's Guide.
• Taylor, Dave. Endangered Desert Animals. Crabtree Publishing Co., 1993.

Extension

Do this activity along with an abiotic study.
Do this activity along with a journaling activity.
For frequent visits to the same study area, set up insect traps.

Publish

Keep very good notes and illustrations. Collect your findings in a spreadsheet for the class.