For the virtual forest tutorial I sampled the Mohn Mill site using area based methods. The most efficient way to sample data was the systematic technique, taking 10.5 hrs and the other methods taking approximately 12.5 hrs each.
I have calculated the percent errors for each sampling technique below:
Systematic Percent Errors:
Red Maple (Common): 0.0027 %
Eastern Hemlock (Common): 0.79%
American Basswood (Rare): 5.33%
Yellow Birch (Rare): 10.0%
Random Percent Errors:
Red Maple (Common): 0.094%
Eastern Hemlock (Common): 0.36%
American Basswood (Rare): 10.0%
Yellow Birch (Rare): 10.0%
Haphazard Percent Errors:
Red Maple (Common): 0.053%
Eastern Hemlock (Common): 2.02%
American Basswood (Rare): 10.0%
Yellow Birch (Rare): 10.0%
The accuracy of these techniques is subject to the experimenter(s) running the study. For common species, each technique gave similar errors. The most accurate technique for the common and rare species is based on the lowest average of percent errors. In this case, the lowest average for common species was the random technique calculated as 0.227%.
For rare species the most accurate technique was the systematic sampling technique, calculated as 7.6%. The accuracy for rare species declined from using the systematic to haphazard approaches. Even though the Yellow Birch percent error never changed over the study.
In this case, the sample size of 24 was not enough for some components of the study. The 24 sample points were sufficient to identify the number of species in the community. This study captured 16 species including Sweet Birch, Witch Hazel, Hawthorn and White Oak in addition to the 4 above. I do not think the sample size of 24 was sufficient to accurately estimate the abundance of each species as for some species the estimated densities were 0.0.