1) estimate local density (q+/+) from a species presence absence grid based on the work of Hui et al. (2006) and Hui (2009)
Hui, C., M. A. McGeoch, and M. Warren. 2006. A spatially explicit approach to estimating species occupancy and spatial correlation. Journal of Animal Ecology 75:140-147.
Hui, C. 2009. On the scaling patterns of species spatial distribution and association. Journal of Theoretical Biology 261:481-487.
(last content added: 04/15/10)