Density-impact functions for terrestrial vertebrate pests and indigenous biota: Guidelines for conservation managers

摘要: Abstract The relationship between the density of a pest and its impact on valued resource is critical for cost-effective management. Despite their simplistic representation dynamic often complex systems, density-impact functions (DIFs) are appealing because they provide managers with tangible goals control. Historically, these relationships have focused agricultural resources: relatively few been quantified conservation assets. We empirical evidence six theoretical forms DIF. Linear default condition based notion that some benefit will result from any level control, but comprised less than one fifth DIFs reviewed. More half were strongly non-linear, substantial benefits indigenous species when pests suppressed to low levels. Recovery species, however, usually function multiple processes, not just removal pests, recovery tends be place- time-specific. Thus, guidelines help derive use in ways maximise value without overextending utility are: 1) minimise influences factors other pests; 2) where necessary, undertake site-specific experiments, rather generalising studies; 3) time scales recognise delays biota adjust control; 4) measure instantaneous responses (e.g. demographic rates) as early indicators; 5) guide short-term management, trophic-interactive modelling longer-term derived used this way significant improvement over unguided biodiversity an base decision-making.