Coding Spreadsheets for Intervention Decisions in Wildlife Damage Management

Sterner (In press) described the use of a priori, theoretical analyses of crop/resource savings and benefit:cost ratios as a way of making intervention decisions in wildlife damage management. Iterative (1-variable-changed-at-a-time) calculations of these economic indices were computed for the use of zinc phosphide baits to control vole (Microtus spp.) populations in alfalfa (Medicago sativa). Results showed that indices displayed transitive effects -- greater net savings and benefit:cost ratios were related to larger field-size, crop-damage and bait-effectiveness variables, but smaller bait-application fees. Ratios varied between 0.40 and 6.45, with -5-10% vole-caused damage required to produce returns on investments equal to the costs of control (benefit:cost ratio = 1.0). This paper presents the detailed Lotus® 1-2-3®, 9.5 code used to derive the results of Sterner (In press). Adaptation of the code to the study of other wildlife damage management problems is straightforward.