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Appendix B 
Selected Data on Lichens, Mosses, 
and Vascular Plants on the Prudhoe Bay Tundra 
MICHAEL E. WILLIAMS*, EMANUEL D. RUDOLPH, 
and EDMUND A. SCHOFIELD** 
Institute of Polar Studies and Department of Botany 
The Ohio State University 
Columbus, Ohio 43210 
Vegetation study plots were established at 
Prudhoe Bay 5-14 July 1972 in eight sites 
selected for their apparent homogeneity in rep- 
resenting various floristic communities (Fig. 1 
and Table 1). Six plots were 10 m on each side, 
while the remaining two were 5m on each side. 
Samples of aboveground plant material, with the 
exception of loose vascular plant litter, were 
separated into moss, vascular plant, and lichen 
components, the latter by species. Ten 48 cm? 
samples were collected in each of the larger 
plots, and five samples in each of the smaller 
plots. The values for several abiotic parameters 
were also determined. Using random cores 7.2 
cm in diameter and 10 cm deep, soil moisture, 
depth of thaw, and humus thickness were 
measured. Soil pH was obtained using the solu- 
tion from a 5:1 dilution of air-dried soil in 
deionized water, which was filtered 18 to 19 hrs 
later through a No. 120 soil sieve (115 mesh, 
125 um opening). The pH was also determined 
for runoff water (i.e., the surface water nearest 
the study site to which the draining water would 
naturally flow). Conductivity was measured for 
both runoff water and aqueous extracts of soil. 
The results of these determinations are present- 
ed in Table 1. 
No clear correlation exists between standing 
crop of mosses or vascular plants and soil mois- 
ture. Lichens showed a direct relationship with 
substrate water content, with the exception of 
plots IV and V. The presence of a large number 
of tussocks in plot IV, which were considerably 
drier than the surrounding wet depressions, 
formed a suitable base for lichen colonization. 
The bryophyte standing crop was also relatively 
low here, as compared to other sites with high 
moisture. The apparent reason for the absence 
of lichens in plot V, in spite of the relatively low 
soil moisture that normally favors lichen growth, 
was the extremely dense moss stand. The close 
proximity to the Prudhoe Bay coastline (ca. 
75 m), however, does not permit the exclusion 
of direct marine effects, which are no doubt 
responsible for the barrenness of nearby plot IV. 
The presence of lichens in high moisture sites 
with low moss biomass (plot IV), and the 
absence of lichens in a site with favorably low 
substrate moisture but a dense moss stand (plot 
V), lead to the conclusion that, at least in 
certain. sites, competition for space with 
bryophytes may be a limiting factor for lichen 
growth. Such competition was also observed in 
the case of adjacent high-center polygons in 
“Current address: School of Public Health, Harvard University, Cambridge, Massachusetts 03128 
**Current address: Ohio Department of Natural Resources, Columbus, Ohio 43224 
