Faculté des sciences

Biological control opportunities of ragweed are predicted to decrease with climate change in East Asia

Sun, Yan ; Zhou, Zhongshi ; Wang, Rui ; Müller-Schärer, Heinz

In: Biodiversity Science, 2017, vol. 25, no. 12, p. 1285-1294

The control of invasive alien plants (IAP) that jeopardize our ecosystems and economy constitutes a significant challenge for natural resource management. Classical biological control referring to the introduction of specialist antagonists from the native range has proven to be a highly cost-effective management tool against IAP. A critical issue in biological control research is to guide... Plus

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    Summary
    The control of invasive alien plants (IAP) that jeopardize our ecosystems and economy constitutes a significant challenge for natural resource management. Classical biological control referring to the introduction of specialist antagonists from the native range has proven to be a highly cost-effective management tool against IAP. A critical issue in biological control research is to guide informed decision-making on the potential spread and distribution and thus impact of biological control candidates, especially under climate change. Here we propose a biogeographic modeling approach to predict the cover of the suitable area of a plant invader in East Asia (EA) by two biological control agents and their combinations. Our study system is Ambrosia artemisiifolia, native to North America and invasive worldwide, and two North American biological control agents, Ophraella communa and Epiblema strenuana that were accidentally and deliberately introduced into East Asia (EA) in the late 20th century, respectively. Specifically, we ask: (1) what percentage of the suitable A. artemisiifolia area is also suitable for the two agents in EA, and (2) which part of the suitable A. artemisiifolia area in EA is likely to remain uncovered by these two agents, both under current and future climatic scenarios; and (3) which particular biotypes would be needed to fill in the yet uncovered part of the suitable A. artemisiifolia range in East Asia? For this, we simultaneously modelled the species distributions based on worldwide occurrences and important bioclimatic variables for the target invasive plant and its two biological control agents. Ordination techniques were used to explore climatic constraints of each species and to perform niche overlap and similarity tests with A. artemisiifolia between its native North American and introduced EA range. Our results show that O. communa has a larger overlap with the geographic range of A. artemisiifolia than E. strenuana, both under current (40.3% vs. 21.6% for O. communa and E. strenuana, respectively) and future climatic scenarios (29.8% vs. 20.3% for O. communa and E. strenuana, respectively). Importantly, climate change is expected to reduce the total geographic overlap of A. artemisiifolia by the two agents combined (42.9% vs. 29.8% for current and future climate conditions, respectively), with a higher reduction by O. communa than by E. strenuana. Our analyses also identified for which abiotic conditions to select in order to develop climatically adapted strains for particular regions, where A. artemisiifolia is presently unlikely to be covered.