Topic: Marine Ecology
Grade Level: 6-12
Summary: Students will lay out transect lines beside a local stream or river. There they will record species of plants and insects living around the stream. By doing so, students will learn how to use transect sampling techniques, use a variety of methods to sample species, and compare species diversity and density between parallel transects.
Key Words: transect; wetland indicator plants; diversity; sampling
Introduction: Field work on local sites has many benefits. Often students are surprised to discover thriving ecosystems in the most familiar and ordinary places. This activity helps students gain experience in problem-solving, scientific processes, and communication.
What to Expect: Always visit a study site before bringing students. Check for safety, access, poison ivy or ticks, and obtain permission when necessary. Arrange to have one volunteer for every four to five students in the class.
- 6 pieces of nylon rope about 50 feet long each
- Hula-hoops or one square meter area markers
- Fine mesh nets for collecting insects
- Small containers for viewing insects while sketching
- Hand-held microscopes
- Guide books / reference books
- Hand Magnifying lens
- Streamside Transect Data Sheet
1. Before the transect, spend one or two days with the class becoming familiar with the common wetland plants in your area. Use samples for students to handle and look at; make a game of matching each plant with its name.
2. At the study site, have pairs of students use the nylon rope to lay out 6 transects approximately 10 m long, parallel to the stream or river, with three on each side. Each transect should be separated from the next by 1-5 m, depending on topography.
3. Mark sampling sites every 2-3 meters with tape or paper markers.
4. Have each pair of students start at each end of a transect and work their way toward the center, with each group sampling two of the marked sites.
5. At each sampling site, the students will place their hula-hoop so that the transect rope runs through the center of the circle. Have students describe topography and soil, then identify and count species using sampling methods (already practiced in a previous outing) and reference materials. Have students sketch plants to identify them rather than collect them unless the plant if very common. Insects can be collected, sketched, and released. A camera or digital camera is very useful. Record results on data sheet.
6. Back in the classroom, have students make large maps showing plant distribution, topography, soil.
7. Have students present reports on results.
8. Generate comparative discussion with the students:
- How does the data from transect A1 compare to transect A2? B1 to B2? C1 to C2?
- How does data from transect A1 compare to transect C1? A2 to C2?
- How do transect sites differ upstream versus downstream?
Evaluation: Class map of site, with key; group reports describing how their results fit with the class transect data.
1. Couple this exercise with a study of the stream.
2. Sites can be visited several times during the year.
Local field and reference guides (contact your local library or town hall)
Other good reference materials include:
Pond and Brook, by Michael Caduto
Wetland Plant Identification, by Ralph Tiner
Wonders of Wetlands, by Britt E. Slattery
Pond Life, by Reid, Zim, and Fichter
Trees of North America, by C.F. Brockman
STREAMSIDE TRANSECT DATA SHEET
|Transect ID #:|
|Soil Color & Texture:|
1-METER HOOP SAMPLE: Transect Line:____________ Hoop#:___
|Plant Type or Description: Number in Hoop:|
|Insect Type or Description: Number in Hoop:|
|Comments and Observations:|
Source: Jennifer Gibbs, SEA Experience 1997
Copyright 1998-2008 by Sea Education Association, all rights reserved.
Compiled and edited by Pat Harcourt & Teri Stanley.
This project was supported, in part, by the National Science Foundation (Proposals # TEI-8652383, TPE-8955214, and ESI-925324), the Henry L. and Grace Doherty Foundation, the Donner Foundation and the Pew Charitable Trusts. Opinions, findings, conclusions or recommendations expressed are those of the authors and not necessarily of the Foundations.