Alien Plant Invasion: A Field Study project at Saguaro National Park
II. Background Skills and Techniques for Field Work
In this unit students conduct research that is used by the Park Service. Prepare the students for the field work by having them practice setting up a plot, learn the names of common plants, and distinguish between native and non-native species. Introduce these activities by telling the students that they are park rangers who have just been transferred to Saguaro National Park. Have them brainstorm about what they would need to know to effectively manage a national park. Record their ideas on the board. They should include that they need to be able to identify the plants, tell if they are native or non-native, study the area to determine the number, range and location of alien species, and know how best to remove the non-native plant species.
Identification of Plants
Before leaving the classroom, students will review common local plants such as: mesquite, catclaw, cholla cactus, prickly pear cactus, palo verde, barrel cactus, hedgehog cactus, saguaro cactus, desert broom, tamarisk, fountain grass, deergrass, triangle-leaf burr sage, white thorn acacia, Bermuda grass, etc. A pressed collection can be used to show characteristics used to identify plants, especially grass seedheads and leaf characteristics. These characteristics can be learned from the books listed in the teacher's resource section or from herbarium staff. Audobon identification books should be taken on the field trip to help students identify cactus, trees, shrubs, and perennial grasses. Small centimeter rules and magnifying loops will also assist students with identification. Any plants not identified should be taken back to class to compare to pressed specimens collected by the teacher. Only one plant of any one species will be collected to match with the classroom collection. A special collecting permit must be obtained from Saguaro National Park staff in order to remove any thing from the park. A list of the plants with native or alien status will be provided to the students. Additional resources are available in the Resource List. The more information you can provide students about the names and uses of the common plants the more they will remember about them. Slide shows and nature walks may also be helpful for the students.
They can practice the skills they need through the following activities:
The University of Arizona
Department of Biochemistry and Molecular Biophysics
General Biology Program for Secondary Teachers