Variation in Microtopography Measurements in Freshwater Wetlands in Central Pennsylvania
Open Access
- Author:
- Gallagher, Ryan P
- Area of Honors:
- Geography
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Robert P Brooks, Thesis Supervisor
Roger Michael Downs, Thesis Honors Advisor - Keywords:
- Microtopography
Measurements
Variation
Freshwater
Wetlands
Disturbance - Abstract:
- Microtopography measurements are valuable when monitoring wetlands. One question in this type of field measurement is, “how much of the variation (difference) between microtopography measurements and observations of the same site are due to human error?”. To learn more about this, six wetlands sites in central Pennsylvania were selected for analysis of microtopography measurements. Microtopography measurements were performed on each site every week for three consecutive weeks. The measurements and observations were recorded each week using the coarse measurement method of measuring elevation, taking note of soil condition, vegetation, and debris occurrence every 1-m interval. Additionally, measurements and observations were recorded using the fine measurement method of doing the same procedure every 10 cm along a 3-m transect. This resulted in the accumulation of a large amount of data with many different patterns and even some inconstancies. Ultimately, it appears that roughly, a 0.0 to 10.0 cm range of variation could be expected between fine measurements of the same site due to error and about a 0.0 to 30.0 cm range of variation could be expected between coarse measurements of the same site due to error. However, much of this variation was fairly consistent across each individual transect, and the microtopography pattern was often similar. Further study is required to better understand what is causing the variation in the measurements that occurs even when the pattern is the same or similar. General ranges for the expected variation in certain microtopography statistics as well as soil and vegetation observations were also produced in this study. Additionally, the results suggest that the “lumpiness” of a wetland site does seem to decrease as the disturbance increases, but this was only seen in the coarse microtopography measurements. However, limitations in the study could have affected results. Further studies should be conducted to increase confidence in the amount of variation that should be expected between microtopography measurements of the same site, and to better understand what causes this variation so that more accurate microtopography measurements can be made in the future.