Nahanni Lichen Locations
Keyword
Rhizocarpon geographicumlichenometry
lichen photogrammetry
Nahanni National Park Reserve
direct measurement of lichen growth
lichen growth
lichen mortality
repeat photography
Bologna Glacier
Butterfly Glacierlichenometric dating
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Repeat photography and photogrammetry is being used to establish lichenometric dating controls for Rhizocarpon geographicum agg. lichens in the Selwyn Mountains (62°07’57” N 128° 04’05.8”W). This is about 30 km East of the mining settlement of Tungsten in Canada’s Northwest Territories. This document has a crude map and photographs that can guide workers to the marked lichens. The lichens were photographed in the summers of 2005, 2006, 2007 and 2016. If you wish to assist in this research or access the original files, please contact D. P. McCarthy at the Dept. of Earth Sciences, Brock University, St. Catharines ON. Canada.Collections
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Lichen 40 and 24Repeated photographs of Rhizocarpon geographicum agg. lichens #40 and 24 on quartzite rocks at the Illecillewaet Glacier, BC, Canada show changes that occurred between 1996 and 2014.
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Illecillewaet Ortho Error List with Dense Cloud DataAgisoft Photoscan software is being used to construct 3D models and generate ortho-images and maps for each of the micro-plots at the Illecillewaet Glacier study site. This work began in the Spring of 2016 and was funded in large part by an Explorer’s Grant from the National Geographic Society to Daniel McCarthy. This work is ongoing.
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Measurement of growth in the lichen Rhizocarpon geographicum using a new photographic techniqueLichenologists and users of lichenometry have long used calipers or photogrammetry to measure the growth of crustose lichens. Now, digital photography and popular computer software provide methodological alternatives. This thesis developed and tested a new methodology for tracking change and growth of the lichen, Rhizocarpon geographicum. Adobe Photoshop CS3 Extended software and a photographic time series (1996,2003,2006 and 2007) were used to measure thallus diameter, area, prothallus width and areolae area in 115 small R. geographicum thalli (0.53-1049.88 mm2 ). Measures of 8 diameters per thallus showed that change in diameter was highly variable and is a weak index of growth. Thallus area was a reliable measure of growth (power correlation, R2 = 0.89). Rapid, highly irregular growth occurred in small thalli «30 mm2 ), and steady, uniform growth occurred in larger thalli (>30 mm2 ). This new methodology is tedious but can potentially generate accurate and precise measures for even the tiniest of lichens.
