User: | Open Learning Faculty Member:
In the virtual forest tutorial, I chose Mohn Mill as my community sample. I chose to do area-based sampling using haphazard, random, and systematic methods. The haphazard method of sampling had the fastest estimated sampling time at 14 hours and 48 minutes, followed by the systematic method (16 hours and 59 minutes), and the random method (18 hours and 13 minutes).
Percentage errors of the two most abundant species:
Red Maple:
- Haphazard- 2.68%
- Random- 8.20%
- Systematic-11.5%
Chestnut Oak:
- Haphazard-2.90%
- Random-2.05%
- Systematic-5.08%
Percentage errors of the two least abundant species:
White Pine:
- Haphazard- 100%
- Random- 54.4%
- Systematic-53.9%
Downy Juneberry:
- Haphazard-44.0%
- Random- 53.9%
- Systematic- 57.0%
It is clear from the data that the more abundant species were more accurate than the less abundant ones. Overall, the random method was most accurate, followed by systematic, and then haphazard. Although haphazard sampling is more time efficient, it is not as accurate as the other two methods. It surprised me to see that haphazard sampling was the most effective for common species and that random/systematic sampling was most effective for uncommon species. I would expect haphazard sampling to be more effective for less common species, as samples are chosen subjectively. I would expect systematic sampling to be most effective for common species. My surprising results are likely due to my not taking enough samples before collecting and analyzing the data or poor choices when choosing quadrants to sample.
