Title Potential negative effects of atmospheric CO₂-enrichment on insect communities in the canopy of a mature deciduous forest in Switzerland
Author/s Florian Altermatt
Year 2003
Journal Mitt Schweiz Entomol Ges 76:191-199
Abstract Whole forest canopy CO₂-enrichment, Fagus sylvatica and Quercus petraea. A total of 1253 arthropods (1155 of them insects) in at least 59 morphospecies were found which belong to five different feeding guilds. Heteroptera (bugs, 31 %), Coleoptera (beetles, 24 %) and Auchenorrhyncha (cicadas, 18 %) were the largest taxonomic groups. On both tree species there was a significant decrease of the insect diversity under elevated CO₂. This reduction might result from shifts in the composition of the feeding guilds: chewing phytophagous (on beech) and sap-sucking insects (on oak) profited over-proportionally from CO₂-enrichment. Guild composition (percentage of chewing phytophagous insects) correlated with plant quality data (specific leaf area SLA, content of non structural carbohydrates NSC). I conclude that the atmospheric CO₂ increase will affect forest canopy insect diversity, and is likely to change the insect impact on forsts too. Cause may be the disproportional increase of chewing phytophagous insects. The most abundant herbivores become more abundant. Sap-sucking insects are used to high C:N ratios. They might be pre-adapted to such a change in food quality. Chewing phytophagous insects profited, but this was due to a huge increase of one single curculionid species.
Research project The Swiss Canopy Crane Project (SCC)
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