Matching landscapes and managing habitats to enhance classical biological control of arthropods

Abstract

Landscape structure and composition are known to affect natural enemies of arthropod pests. In general, structurally complex landscapes with large areas of semi-natural habitat have been proven to often benefit natural enemies by providing them with shelter, alternative food and adequate microclimate. As agricultural landscapes are more prone to frequent changes (e.g., fragmentation), natural enemies therein may face more challenges of dealing with scarce and sparse food/shelter resources. In such cases, implementing habitat management could be pivotal to dampen the effects of landscape degradation and crop disturbances upon natural enemies, and consequently enhance biological control. It is expected that imported natural enemies will often be released in a new landscape bearing quite differences from their native region, which in turn could hamper their establishment and efficacy. Therefore, I discuss in this article the importance and necessity of carrying out a matching study of landscapes prior to natural enemy importation, which could be crucial for success of classical biological control. In this sense, better chances of natural enemy establishment would be expected when a higher similarity between the landscapes (native vs. new region of introduction) is detected. Additionally, I argue that implementing local habitat management in the new region of introduction should further facilitate the establishment of imported natural enemies. Lastly, I offer a hypothesis that habitat management will have its greatest or least/moderate positive impact on imported natural enemies when the similarity between the native and new region of introduction is low or high, respectively.