Climate matching techniques to narrow the search for biological control agents

Abstract

Climate matching can assist in exploration for biological control agents to control invasive organisms, especially when the native range of the target organism is broad, and control is required in a subset of the organism’s fundamental niche. Climate matching increases the chances that biological control agents will establish and persist in the desired part of its invaded range. Chromolaena odorata is a major invasive alien pest plant problem worldwide. Two biotypes of C. odorata have been identified. The biotype growing in southern Africa differs in several respects from the more common type invading elsewhere, including that it appears more cool-adapted. So far, biological control efforts aimed at controlling the southern African type have floundered, presumably partly because the agents were maladapted to the relatively cool conditions experienced in southern Africa. Using two different climate matching approaches (CLIMEX Match Regions and FloraMap) we identify locations in the Caribbean, Central America and South America that are most climatically similar to localities in southern Africa where the southern African biotype of C. odorata has invaded. We identify regions most likely to yield biological control agents that are able to complete their development normally on the plants in South Africa. Several higher-latitude and higher-altitude areas in South and Central America were identified by both CLIMEX and FloraMap as being similar to the region invaded by C. odorata in southern Africa. We compare and contrast the two climate matching approaches that can assist in exploration for biological control agents.