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In this exercise I used a virtual forest tutorial to test the accuracy of estimating species abundance using three different sampling techniques: area, random or systematic; distance, random or systematic and finally, Haphazard.
The distance, random or systematic would have been the most efficient model as its estimated time to sample is only 4 hours 43 minutes compared to the other two ranging around 12-13 hours. This is most likely influenced by how spread apart the sample sites are as there are equal sample sites in each method.
Percent error for each sampling technique for the most abundant and most rare species was:
- Area, random or systematic: Eastern hemlock- 14.9% error. White Pine = 8.3% error
- Distance, random or systematic: Eastern hemlock = 30.2% error and White pine= 100% (none found)
- Haphazard, are: Eastern Hemlock= 4.7% and White pine = 90%
The most accurate for abundant species was the Haphazard method at 4.7% error rate. It estimated 448 out of the 469.9 total Eastern Hemlocks in the area. However, this technique over-estimated by double the amount of White Pine. The most effective at the rare species of White Pine was the area, random-sampling technique which had a small error rate of 8.3%. It estimated 7.7 of the 8.4 total White Pine trees. The accuracy trend between abundant and rare species was dependent on the method used. The most constant technique was area, random or systemic where the percent error decreased with the rare but only slightly. The least reliable was the distance, random or systematic which had a high error rate for both species; finally, the haphazard technique had an accurate estimation for abundant species but unreliable estimations for rare species.
24 sampling points allow fairly reliable sampling results for area, random or systematic sampling, but if using the other techniques it would be useful to add more sampling sites to improve estimations of rare species.
