北温带森林中植食昆虫的存在使得大气中二氧化碳浓度上升，从而导致更多生物质丧失，在线发表于《自然—植物》的一篇报告得出上述结论。该研究认为食草昆虫会限制这些森林在高浓度二氧化碳环境中的碳吸收作用。

大气中二氧化碳的高浓度被认为会促进某些地区的森林生产力，从而可以从大气中吸纳更多的二氧化碳。但是，许多因素会阻碍森林碳吸收的能力，比如大气对流层中的臭氧、森林养分的限制等。

John Couture等人研究了在高浓度二氧化碳和臭氧的环境中，白杨和白桦的树冠受损程度，实验环境为威斯康星州北部的白杨的空气中二氧化碳富集（FACE）设备。在浓度升高的二氧化碳中，昆虫导致的树冠受损程度显著增加，但在浓度升高的臭氧中，该程度则有所下降。研究人员通过模型推算：由食草昆虫引起的森林生产量的下降程度是高浓度二氧化碳条件下的两倍多，但低于在高浓度臭氧条件下。（来源：中国科学报 张笑）

Insect herbivory alters impact of atmospheric change on northern temperate forests

Abstract  Stimulation of forest productivity by elevated concentrations of CO₂ is expected to partially offset continued increases in anthropogenic CO₂ emissions. However, multiple factors can impair the capacity of forests to act as carbon sinks; prominent among these are tropospheric O₃ and nutrient limitations. Herbivorous insects also influence carbon and nutrient dynamics in forest ecosystems, yet are often ignored in ecosystem models of forest productivity. Here we assess the effects of elevated levels of CO₂ and O₃ on insect-mediated canopy damage and organic matter deposition in aspen and birch stands at the Aspen FACE facility in northern Wisconsin, United States. Canopy damage was markedly higher in the elevated CO₂ stands, as was the deposition of organic substrates and nitrogen. The opposite trends were apparent in the elevated O₃ stands. Using a light-use efficiency model, we show that the negative impacts of herbivorous insects on net primary production more than doubled under elevated concentrations of CO₂, but decreased under elevated concentrations of O₃. We conclude that herbivorous insects may limit the capacity of forests to function as sinks for anthropogenic carbon emissions in a high CO₂ world.

原文链接：http://www.nature.com/articles/nplants201516