Crop–weed competition rather than temperature limits the population establishment of two annual C4 weeds at the edge of their northern range |
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Authors: | T Hyvönen S Ramula |
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Institution: | 1. MTT Agrifood Research Finland, Plant Production Research, , Jokioinen, Finland;2. Section of Ecology, Department of Biology, University of Turku, , Turku, Finland;3. ?bo Akademi University and Novia University of Applied Sciences, Aronia Coastal Zone Research Team, , Eken?s, Finland |
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Abstract: | Climate change is predicted to affect range expansion of harmful C4 weeds into the boreal region, given that they are able to successfully colonise both C3 and C4 crops. We studied the impact of a 3°C elevation in temperature on the establishment and maintenance of populations of two annual C4 weeds (Amaranthus retroflexus and Echinochloa crus‐galli) with and without a competing C3 (barley) or C4 (maize) crop. Data obtained from field and glasshouse experiments were modelled using a periodic matrix population model. Competition of a weed with a crop appeared to be a more important factor for limiting the maintenance of weed populations than elevation in temperature, as neither of the weed species was able to maintain populations in competition with crops. Even an increase in the frequency of warm years did not result in viable weed populations establishing. However, A. retroflexus was able to form persistent populations in competition with maize when released from competition every fifth year. Simulations parameterised from glasshouse data predicted that both weed species would persist without competition in the current climate, whereas simulations parameterised from field data suggested only A. retroflexus to be able to persist. These results demonstrate that competition affects the range expansion of arable weed species more than elevation in temperature, necessitating the inclusion of crop–weed interactions in models of range shifts as a consequence of climate change. |
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Keywords: | climate change species invasion photosynthetic pathway
Amaranthus retroflexus
Echinochloa crus‐galli
boreal climate |
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