Aho and Weaver (2010) examined the effect of environmental characteristics on alpine vascular plant species richness on Mount Washburn (3124m) a volcanic peak in north-central Yellowstone National Park.
data(wash.rich)
A data frame with 40 observations on the following 7 variables.
site
Site identifier.
Y
Species richness.
X1
Percent Kjeldahl (total) soil N.
X2
Slope in degrees.
X3
Aspect in degrees from true north.
X4
Percent cover of surface rock.
X5
Soil pH.