Dept. of Biological and Environmental Sciences
BIO L229 – GENERAL ECOLOGY LAB
- Plot Sampling of Woody Vegetation
Many techniques have been developed for sampling vegetation. In this laboratory exercise we will use a belt transect to collect data in two wooded areas. The belt transect method uses multiple sample units to gather abundance and frequency data. Ecologists often utilize sampling techniques to gather information about a population or community in which it is difficult to take a census of all individuals in the area of interest. From the data collected, inferences can be made about the entire population or community. The data collected during this exercise can be used to compare species composition and distribution found for the two different areas
- To become familiar with a method commonly used to survey plants.
- To learn how to use basic field data to calculate ecological measurements that can be used to compare populations, communities, or areas within the same habitat.
- To gain familiarity with tree species found in the Troy University Arboretum.
Terminology and sample calculations
- Species richness (s): the number of species
- Abundance (N): the number of individuals of a species in a given area.
- Frequency (f): the proportion of the total number of sample units taken that contains the species in question.
For example: If a species is found in 7 out of 10 sample units surveyed, it would have a frequency of 7/10. If a species is found in 3 out of 10 sample units surveyed, it would have a frequency of 3/10.
Sorensen’s coefficient of community (CC) is based on species presence or absence (equation from Elements of Ecology, p.354)
CC = 2c/(s1 + s2)
- c = number of species common to both samples
- s1 = species richness in sample 1
- s2 = species richness in sample 2
Plot 1 Plot 2
Red maple Red maple
Southern red oak Water oak
Water oak Sweet gum
Loblolly pine Loblolly pine
CC =2(3)/(5+4) = 6/9 = 0.67 The closer the CC value is to 1.0, the more the samples are alike.
Field site: TROY Arboretum.
Materials: (per group)
- 30 meter tape measure
- flags to secure tape measure and to mark out belt transect
- Work in assigned groups. At the designated locations within the woodland, each group will complete a sampling of the woody vegetation composition by plotting out a belt transect.
- Fill out the requested information at the top of your data sheet: location, name of group, plot size, and date. Identify all trees to species, you may use common names on your data sheet.
- Record your data on the data sheet. You will need a total count of all individuals of each species found in your plot. Only count and record trees ≥ 9cm DBH (palm width).
NOTE: record the data for each of the observational units separately on your data sheet.
- Repeat the belt transect sampling in your second assigned wooded area and record your data.
Use tables to display abundance and frequency for each species; you should have separate tables for the two areas (Table 1 and Table 2).
Compare the abundance N for each species in the two different areas by using a column chart to display side-by-side abundance (Figure 1).
Calculate CC comparing the two areas.
- Compare and contrast presence and abundance of tree species for the two different areas
- Explain the significance of the different frequencies seen in each belt transect in regards to distribution of each species, i.e. does the species show clumped, uniform, or random distribution.
- Discuss a peer-reviewed journal article that describes a similar study done in a forested area. You should mention where the study was done and what the researchers were hoping to accomplish.
Woody Vegetation Sampling Data Sheet
Belt Transect, dimensions in meters _____________5 x 50___________________________
Area 1 Area 2
Species Name Abundance, N Species Name Abundance, N
|Sample unit 1|
|White Oak||2||Darlington’s Oak|
|Sample unit 2|
|Sample unit 3|
|Sample unit 4|
Sample unit 5
Sample unit 6
Sample unit 7
|Loblolly Pine||5||Darlington’s Oak|
Sample unit 8
|White Oak||2||Loblolly Pine||1|
Sample unit 9
|Loblolly Pine||2||Darlington’s Oak|
Sample unit 10
|White Oak||1||Loblolly Pine||3|