Groupings by locality in community ecology and paleoecology: tests of significance

Harper, Charles W. Jr. 1978 07 15: Groupings by locality in community ecology and paleoecology: tests of significance. Lethaia , Vol. 11, pp. 251–257. Oslo. ISSN 0024–1164.
Ecologic sample localities are commonly classified into groups on the basis of their species content; distinctive groups of localities are then commonly used to define discrete biofacies or communities. Yet, such locality groups and, by extension, the communities or biofacies inferred from them are almost never tested for statistical significance. Two approximate randomization tests are proposed as a step in this direction. One evaluates whether or not a given data set on which one or more locality groups are based exhibits a degree of clustering by locality that is statistically significant. The second evaluates the statistical significance of the degree of mappability exhibited by a given collection of inferred locality groups.