Josh Van Buskirk. 2005. Local and landscape influence on amphibian occurrence and abundance. Ecology 86:1936–1947.

Appendix B. Results of a principal components analysis summarizing variation in landscape features measured within a 1-km radius of 83 ponds.

   Notes: The analysis was conducted on the correlation matrix, and the resulting factor pattern was subjected to oblique promax rotation to ensure that each variable loaded mostly on one factor (Harris and Kaiser. 1964. Oblique factor analytic solutions by orthogonal transformations. Psychometrika 29:347–362). Proportions were arcsin-sqrt transformed and densities were log-transformed.