ECOLOGICAL MANAGEMENT OF VERTEBRATE PESTS IN AGRICULTURAL SYSTEMS

Managing vertebrate pests has been a neglected topic of research in su stainable agriculture. Conventional approaches, often reactionary rath er than preventative, have failed to provide sustainable solutions. in deed, conventional control through density reduction often involves ba ttling natural ecological processes. Agricultural practices may improv e habitat quality for vertebrates that then become pests. Density redu ction, but without a concomitant reduction in carrying capacity, may s timulate density-dependent reproduction and survival, rapid recoloniza tion, or both; thus, vertebrate pests often show remarkable resilience in recovering from density reduction. Effective management of vertebr ate pests in agricultural systems should incorporate knowledge of temp oral and spatial dynamics of pest species. We review several approache s for managing vertebrate pests that might be successful in sustainabl e agriculture. Habitat quality, and thus carrying capacity, for pests might be reduced by modifying cultural systems; repellent or diversion ary crops also can be effective. Predators, either real or simulated, might reduce the density or alter the behaviour or distribution of pes ts. A variety of scaring devices may protect crops or commodities, alt hough protection is usually temporary and is ineffective for some pest species. Chemical repellents, either synthetic or naturally-occurring , can discourage pests. Physical exclusionary devices can protect indi vidual plants or entire fields, although expense often is high. Pest d amage, especially from birds, can be reduced by relatively modest chan ges in crop phenology, and pest-resistant cultivars have been develope d for several agricultural crops. Preventative pest management should employ forecasting, use a landscape approach, and incorporate cost-ben efit analyses.