Detecting Ecological Interactions in monitored Populations.

Speaker: Stephen N. Freeman (British Trust for Ornithology)

Abstract

I shall present a simple log-linear model for series of regular bird counts at a number of survey sites. The model is parameterized in terms of growth rates rather than abundance; this permits easy estimation of these parameters and allows us to model the effects upon population growth of covariates. The latter might be local presence of a competitor or predator, or some management regime, which may themselves vary in space and over time. A recursive relationship permits the expected count at a site to be functionally dependent upon the expected count at the previous visit, rather than replacing the latter with their observed counterparts, as has been used previously.