examining the relationship between moss communities and ... · examining the relationship between...
TRANSCRIPT
Examining the Relationship between Moss Communities and the
Cartographic Depth-to-Water Index
Prepared by: Monique Goguen
November 2013
1
Plume moss (Ptilium crista-castrensis)
Objective • The main objective of this project is to examine the
relationship between moss communities and LiDAR-derived cartographic depth-to-water (DTW) index.
• Study aims to determine whether the DTW mapping process could be useful as a tool for predicting the spatial distribution of moss species on a landscape level.
3
Study Area • Regent Bog, a wetland
complex in Fredericton, New Brunswick.
4
• Study area approx. 20 hectares in size.
Bryophyte Ecology • Bryophytes are small non-vascular plants.
• Geospatial distribution influenced by microclimate and suitable substrate, including soil moisture regime.
5
Sphagnum moss (Sphagnum sp.)
Schreber’s moss (Pleurozium schreberi)
Haircap moss (Polytrichum commune)
Wavy Dicranum (Dicranum polysetum)
Plume moss (Ptilium crista-castrensis)
Step moss (Hylocomium splendens)
Bazzania (Bazzania trilobata)
Geomatic Procedures • GPS on-foot tracking of inner and outer moss boundaries:
• Sphagnum moss
• Schreber’s moss
• GPS-locating plots along upland-wetland transitions
• Mapping flow accumulation, flow channels, and depth-to-water using LiDAR-derived elevation data (bare-ground, full-feature) and surface images at 1 m resolution
• Correlating plot data with raster data
6
Vegetation Plots
• 180 sample locations
• 1m x 1m plots
• Visual estimate of abundance (%) for each moss species
7
Wet Areas Mapping • Data derived from the bare ground digital elevation model of
digitally processed LiDAR data at 1 metre resolution:
• Predicted Stream Channel Lines (D8 Algorithm for flow accumulation – 0.5 to 4 hectare flow initiation threshold)
• Channels may not be wet during every season, but they are predicted to have a high potential for being wet during a heavy rain event or wet season.
• Cartographic Depth-to-Water
• Informs about the depth to water index (elevation rise) between the bare ground surface and the cartographically referenced water table surface below.
9
Sphagnum Boundary Conformance
20
DTW (m) Sum Shape Length (m)
Percent Total
0-0.1 2388.21 0.41
0.1-0.25 1704.69 0.29
0.25-0.5 897.15 0.15
0.5-1 508.98 0.09
Abundance vs. DTW: Sphagnum
22
R² = 0.9586
R² = 0.9807
R² = 0.9294
R² = 0.9521
0
10
20
30
40
-1.5 -1.0 -0.5 0.0 0.5 1.0
Avg
. Ab
un
dan
ce (%
)
log10 of DTW
0.5 ha
1 ha
2 ha
4 ha
Dry Wet
Stream Flow-Initiation Area
Abundance vs. DTW
23
Schreber’s moss Wavy Dicranum
Stream Flow-Initiation Area
0.5 ha
1 ha
2 ha
4 ha
Bazzania Plume moss Step moss
Common Haircap moss
Log10 of DTW
Avg
. Ab
un
dan
ce (%
)
Summary
• DTW mapping useful as a tool for predicting the spatial distribution of moss species in a wetland ecosystem.
• The GPS tracked moss boundaries aligned well with the DTW map (the 4 ha flow initiation worked best).
24
• However, these borders straddle DTW classes depending on actual soil moisture conditions.
• Of all the moss species, Sphagnum moss showed the strongest correlation with DTW.
Sphagnum moss
Acknowledgements
• Dr. Paul A. Arp, University of New Brunswick
• Jae Ogilvie, University of New Brunswick
25