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For this assignment, I sampled tree species virtually be means of three sampling techniques: simple random, systematic and haphazard. I selected an area based method for Snyder-Middleswarth natural area. The technique that was the most efficient in terms of time spent was the systematic sampling method which took 12 hours, 35 minutes. The next fastest sampling technique was haphazard sampling at 12 hours, 39 minutes, while the slowest method was random sampling which took 12 hours, 49 minutes.
The following is the percentage error calculated using (E – T)/T*100, where E = estimated value and T = true value
Most common specie – Eastern Hemlock
systematic: 6.3% error
random: 26.7% error
haphazard: 2.0% error
Second most common specie – Sweet Birch
systematic: 1.3% error
random: 24.0% error
haphazard: 27.7% error
Most rare specie – White Pine
systematic: 233.3% error
random: 49.7% error
haphazard: 48.8% error
Second most rare specie – Striped Maple
systematic: 100.0% error
random: 76.0% error
haphazard: 28.6% error
From the results, the most accurate sampling strategy for common species was systematic, while the most accurate method for rare species was haphazard. The accuracy declined substantially for rare species, especially in the systematic sampling method. Accuracy increases with greater species abundance.
I was surprised to see that the systematic sampling method had the highest percentage error for rare species. This might be due to a low species density distribution along the two y coordinates used in the systematic method. Additionally, it would be interesting to observe a change in accuracy for species in the community from using more then 24 sample points.
