Impacts of atmospheric and precipitation change on aboveground-belowground invertebrate interactions

Aboveground-belowground invertebrate interactions often operate when invertebrates (i) modify plant traits affecting behaviour and/or performance of other invertebrates, (ii) cause shifts in plant community composition that affect other invertebrates and (iii) alter patterns of deposition of plant-derived organic matter affecting soil-dwelling invertebrates. In this chapter, we show how atmospheric and climatic change has the capacity to shape both the magnitude and frequency of such interactions, often by affecting plants mediating the interaction. For example, elevated atmospheric carbon dioxide concentrations (e[CO2]) caused a 36% increase in deposition of organic matter through increased herbivory of aspen and birch trees aboveground. This input most likely affected soil-dwelling invertebrates such as detritivores. Environmental change factors also interact with one another. For instance, increased air temperatures dampened the effects of e[CO2] on legume-mediated interactions between weevils and aphids. Changes in precipitation have the strongest effects on aboveground-belowground interactions, usually mediated via plant-stress related changes in plant chemistry. Our understanding of how atmospheric and climatic change might affect aboveground-belowground invertebrate interactions is limited by the scarcity of information available. We suggest three key areas of research that should be prioritised: (i) better characterisation of belowground components to assist hypothesis development, (ii) tests of multiple environmental factors simultaneously, particularly those involving warming, and (iii) expansion of study systems to include different plant functional groups and mixed plant communities.