Affects of Elevation on lichen and moss coverage on rocks as well as tree species.
Canann, C; Hvolboll, A; Grubb, J; Jacobson, E
Abstract: We investigated the effects of elevation on tree species and on lichen and moss coverage of rocks. Tree species changed dramatically from 100% juniper low down to Aspen and Spruce on top. Moss changed with elevation but seemed more correlated with moisture. Lichen decreased with elevation.
Introduction: In the mesas of Western Colorado, we observed thick lichen and moss on rocks and minimal tree diversity. Noticing the surrounding mountains we asked the question how these variables would change with increasing elevation.
Methods: We estimated percentages of lichen and moss cover on 20 similar sized rocks in each location. We also identified all tree species in sight and estimated the percentage of each tree species. We did this for five sites, beginning at 6200 ft and ending at about 9500 ft.
Results:
Site #1. 6200 feet. Dev’s house. Tree coverage ….100% juniper Rock coverage moss 38%, green lichen 23%
Site #2. 7000 feet. Old mine. Tree coverage ….70% juniper, 15% Oak, 15% Pinyon Pine
Rock coverage moss 26%, green lichen 9%
Site #3. 8000 feet. Birth of a structure. Tree coverage ….100% oak Rock coverage moss 7%, green lichen 7%
Site #4. 8800 feet. Lunch spot Dev’s house. Tree coverage ….50% Oak, 45% Aspen, 5% Choke cherry
Rock coverage moss 3%, green lichen 5%
Site #5. 9500 feet. Dev’s house. Tree coverage ….70% Aspen. 30% Spruce.
Rock coverage moss 36%, green lichen 6%
Conclusions: Tree species changed dramatically as elevation increased. In less than 10 miles and with about 3000 feet gain, tree species changed from 100% juniper to Oak to Aspen and Spruce.
Moss coverage decreased with elevation but then increased again at the top site, we are guessing that it has more to do with moisture than elevation.
Lichen coverage decreased with elevation. Why? We have no idea. The one guess is that maybe rocks are more mobile at higher elevations because of snow. Or maybe because fires appear more often at lower elevations where the people are.