Transects and Quadrats
To census biodiversity and to compare it between different ecosystems
- Paper and pencil, if needed
In transect surveys, students stretch a string across a piece of ground, stake each end, and count the living things that are either underneath the string or within arm’s length of it. In quadrat surveys, students map out a square piece of ground and survey the living things lying within the square.
For transect studies of trees and shrubs, the students use a piece of string perhaps 5–10 yards long, depending on how dense the plant growth is, and survey all the items within arm’s length of the string. For finding small creatures and herbs, the students can use a piece of string perhaps 1 yard long (a mini-transect) and count everything underneath it. Or they can map out a square 3 feet by 3 feet, get down on their knees, and count everything lying within. These can be great ways for students to discover a whole new world of living things that they didn’t know existed. In tallying their results on a piece of paper, kids will probably not know the names of the trees, herbs, insects, and other living things they encounter. Instead, they can come up with simple descriptions: e.g., two little yellow flowers, three black beetles, and two clumps of moss.
Transect and quadrat studies can reveal the differences in varied habitats. Have the students compare the life found in such environments as grasslands, eroded landscapes, patches of forest, streamsides, and backyards. After the students are finished, gather them together and tally their results on a blackboard or flip chart paper.
1. Which ecosystem had the most diversity and which had the least? What might explain these results? (e.g., grazing, livestock, compacting soil, moisture, human foot traffic.)
2. How do human-modified or livestock-modified ecosystems compare with non-modified examples?
3. What do you think we could do to protect and increase biodiversity in these ecosystems?
This lesson plan is an activity from the Environmental Activities for Youth Clubs and Camps, a resource developed by the Peace Corps Office of Overseas Programming and Training (OPATS). It was contributed by Peace Corps/Paraguay.