open access

https://hdl.handle.net/2115/47650

Simulated warming effects on plant-insect interactions in a cold temperate region

英語

2011-10-31

Session 2.1: Biodiversity and Environmental Protection in the North

Temperature increases of global warming are predicted to be greater at higher latitudes and impact virtually all chemical and biological processes. Ecosystem responses to global warming will be complex and varied in time and space due to direct and indirect effects of them. Field ecological manipulations of global warming are conducted to determine response of whole terrestrial ecosystems to an environmental variable in a manner that mimics climate change. Recently, ecologists from around the world have begun filed manipulations of global warming. Most studies have focused on effects of experimental warming on soil respiration, net N mineralization, and aboveground productivity of understory plants. In contrast, the trophic interactions in changing climate conditions are poorly known. Researches on warming experiments focused initially on the responses of plants and, to a much lesser extent, on those of a second trophic group. Temperature is identified as the dominant abiotic factor affecting insect herbivores. In forests, most biological activities and species diversity are concentrated in the canopy, rather than in the understory. To understand how soil and branch warming affect herbivory via changes in leaf traits on canopy trees of Quercus crispula (18-20 m in height), we measured leaf traits (e.g. LMA, nitrogen, and total phenolics) and herbivory using a canopy crane. The branch warming did not affect herbivory of canopy foliage. However, the soil warming decreased herbivory of canopy foliage. The soil warming altered canopy leaf traits; nitrogen content and lignin decreased but total phenolics and condensed tannin increased. The decrease in herbivory can be explained by cellulose, total phenolics, and lignin in canopy foliage. These results suggested that plastic response of canopy leaf traits to the soil warming may decrease abundance of insect herbivores in forests. This is contrary to what would generally be expected according to mathematical modeling and laboratory investigations considering about direct effects of global warming on insect herbivores.

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