Description

Masses of cones of lodgepole pines (conemass) from 16 different habitat types (habitat) in western North America.

Format

A data frame with 16 observations on the following 4 variables.

habitat

a factor with levels: island absent, island present, and mainland present

conemass

mass of cone

location

island or mainland

squirrels

absent or present

Source

Edelaar, P. and C.W. Benkman. 2006. Replicated population divergence caused by localised coevolution? A test of three hypotheses in the Red Crossbill-lodgepole pine system. Journal of Evolutionary Biology 19: 1651-1659.

References

http://en.wikipedia.org/wiki/Lodgepole_pine

http://en.wikipedia.org/wiki/Red_crossbill

Examples