Annual variation in habitat selection: patterns concealed by pooled data

The author reviewed 43 papers published in The Journal of Wildlife Management (1988-91) that examined habitat selection of terrestrial vertebrates by comparing habitat use with availability. Most studies (84%) recognized the potential for variation in habitat selection on a seasonal scale, by either restricting investigations to one season or analyzing data separately for individual seasons. In contrast, 72% of the 29 studies that spanned over one year pooled data on habitat use among years, evidently without testing for annual variation and without presenting use data for individual years. Most studies (56% of 43) lasted two years. An example for female black bears Ursus americanus illustrates the misleading inferences that can result from pooling data among years. -from Author