IPM strategies: Indexing difficult to monitor populations of pest species

Abstract

Author(s): Engeman, Richard M.; Witmer, Gary W. | Abstract: Monitoring populations of problem species is an essential component for integrated damage reduction programs. Tracking population size through time and space helps define the potential magnitude and geographical extent of damage. Population size at an early stage of a crop cycle can serve as a predictor of damage levels later on, indicating whether control is necessary or what forms would be economically optimal. The ability to monitor for population change also permits assessment of the efficacy of the control methods for reducing numbers of a pest species. Methods for quantifying population levels can be as diverse as the number of subject species, the objectives of an IPM program, and whether direct estimates or indices of population parameters are required. Often, indirect methods involving counts of tracks, burrows, droppings, or food removal are used. We review methods used for a variety of wildlife species, examine the desirable characteristics for useful monitoring methods, and describe some of our current research on indexing methods.