During the virtual forest sampling tutorial, I used the distance-based sampling method for all three trials. Of the three sampling methods the systemic method had the fastest estimated time to sample (4 hours 7 minutes). This was followed by the haphazard sampling method (4 hours 39 minutes) and the random sampling method had the longest estimated time (4 hours 42 minutes).
This is important information to have as an ecologist may choose to a shorter sampling method, such as the systemic method, if it is likely to be as accurate and an appropriate method for the specific study.
As seen in Table 1 below the two most common species were the Eastern Hemlock and the Red Maple, they had an actual density of 469.9 and 118.9, respectively. The two rarest species were the White Pine and the Striped Maple they had an actual density of 8.4 and 17.5, respectively.
For the most common species the overall most accurate sampling method was the systemic method, as it had the lowest percent error when examining both the Eastern Hemlock and Red Maple species. During the systemic sampling method, the percent error for the Eastern Hemlock was 9.6 % and 10.7% for the Red Maple (Table 1). The random sampling method seems to produce mixed accuracy for the most common species as the percent error for the Eastern Hemlock was only 5.2% but the Red Maple had a percent error of 56.6% (Table 1). Likewise, the haphazard method produced mixed results as the Eastern Hemlock had a percent error of 10.7%, while the Red Maple had a percent error of 36.9 % (Table 1).
For the rarest species the haphazard sampling method seemed to produce the most accurate results, however all the percent errors from the three sampling methods of the rarest species were relatively high. The haphazard method produced a precent error of 78.6 % for the White Pine and 57.1% for the Striped Maple (Table 1). The random sampling method seemed to be the second most accurate method for estimating rare species as the White Pine had a percent error of 100% and the Striped Maple had a percent error of 44.6 % (Table 1). The Systemic Sampling method was the least accurate for estimating rare specie’s density, as it produced a 321.4 percent error for the White Pine and a 49.1 percent error for the Striped Maple (Table 1).
As indicated by the results from this specific tutorial abundance of species does impact the accuracy of sampling methods. Overall, rare species were more likely to have higher percent errors compared to more common species, this was true for all sampling methods. Also, species abundance affected which sampling method was most accurate for that species. For example, overall systemic sampling was most accurate for estimating the density of the most common species. However, the haphazard method was most accurate for estimating the density of rare species. With these results it is hard determine which sampling method is most accurate overall, especially considering systemic sampling was most accurate for common species but least accurate for rare species and the haphazard method was the most accurate for rare species but produced mixed results for the most common species. Perhaps looking at the range of percent errors for all sampling methods would be a good way to determine which method is most accurate. The systemic method had a range of 9.6% to 321.4%, the random method had range of 1.1% to 100% and the haphazard method had a range of 10.7%- 78.6% (Table 1). If this method is used the haphazard sampling method is the most accurate method to estimate overall species density.
