Vegetation Sampling Techniques

Topics: Arithmetic mean, Standard deviation, Biodiversity Pages: 7 (1622 words) Published: December 6, 2010
Backround Info
Weeds are nature’s most widely dispersed group of plants, and their job is to insure that the soil always has the protection of a green blanket. Without weeds, the fertile soil which took Nature centuries to build, would erode away without the protection of a plant cover. The objective of this experiment is to determine whether an undisturbed habitat will yield a higher species diversity and density than a disturbed habitat. The experiment will investigate the sample area’s using the method of Quadrant sampling. Quadrants are placed in a grid pattern on the sample area. The occurrence of organisms in these squares is noted. It is used to estimate population parameters when the organisms present are too numerous to count in total. In this case, Quadrant sampling will be used to estimate and compare population species diversity and density of a abandoned lot and a city pathway using the Simpson’s index and Jaccard coefficient. The procedure is to count all the individuals in 3 quadrants per habitat and to use this information to work out the abundance or percentage cover value for the whole area. The quadrant is square and covers 0.25 m2 (0.5m x 0.5m). The grid will be 2 m by 2 m. Which results in 4M2.

Estimated Total number of individuals counted average density = Number of quadrants X area of each quadrant

Purpose: Investigate the effects of human disturbance on species diversity.

Research Question
Does an undisturbed habitat yield a higher species diversity versus a disturbed habitat?

Null Hypothesis (Ho)
Ecosystem B will not have a higher or lower species diversity than Ecosystem A. They are not statistically different.

Alternate Hypothesis: The disturbed area will have a higher species abundance, but the undisturbed area will have a larger species diversity

Assumptions: Ecosystem A is completely undisturbed by humans

Independant Variable: Human Disturbance

Dependant Variable: Species Diversity Index
Controlled: The Sampling size will be the same for both Ecosystems. The area being sampled will not be chosen on a bias-standpoint. Both sample areas of each ecosystem will be chosen randomely, as to prevent favourable results. Uncontrollable: The range of human disturbance and undisturbance.

1. Find an area of forest floor in Ecosystem A which is is suitable for a 4m2 Quadrant sample through random selection. 2. Grid the 4m2, mark the corners with rocks.
3. Apply the quadrant to the predetermined grid by randomely choose 1/16 possibilities using a random number table. 4. Carefully examine each selected quadrant and count the number of individuals of each species present. 5. Using the random number table, apply a second quadrant to the grid. 6. Examine, count and record the species present for the second quadrant. 7. Once again, randomely apply a third quadrant to the grid. 8. Examine, count and record the species present for the second quadrant. 9. Repeat steps 1-8 for Ecosystem B.

10. The species diversity will be measured using the Simpsons Index. 11. The sample size for each Ecosystem is 3 quadrants.
12. The data will be analysed by calculating the mean number of species of each sample (quadrant), then the mean number of species in the the total sample (3 quadrants). 13. Estimate the mean number of species in the entire grid.

Raw Data: Quantitive Discreet
Number of species per ecosystem, per quadrant Ecosystem AEcosystem BEcosystem AEcosystem BEcosystem AEcosystem B
Quadrant # 1Quadrant # 2Quadrant # 3
Henbit: Lamium Amplexicaule
Ivy leaved morning glory Ipomoea Hederacea
Oak-leaved goosefoot:C. Salinum Stand
Field Bindweed:...
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