Effects of changes in soil moisture and precipitation patterns on plant-mediated biotic interactions in terrestrial ecosystems

摘要

Due to climate change, the amount, frequency, and intensity of precipitation worldwide are changing. There is increasing evidence that hydrological change severely affects species interactions and that these effects might overrule direct autecological responses, although this is currently understudied. Here, I synthesize published data on 405 interactions to show how changes in soil moisture affect the frequency or strength of plant-mediated biotic interactions. Despite substantial variation among published responses, general patterns have emerged. A recurrent finding in the synthesized studies is that dryness impedes beneficial interactions between plants and other organisms (decreased mycorrhization and infection with other symbiotic endophytes, less pollinator visits, less active decomposers) and increases detrimental interactions (increased performance of sucking insects, pathogen infection and competition between functionally similar plants). For increased wetness, which is far less studied, stress intensity seems to matter: Slightly increased precipitation often benefits plants and thereby associated interaction partners (increased mycorrhization and infection with symbiotic endophytes, increased herbivore performance), while extreme waterlogging or flooding impedes many interactions (decreased decomposer activity and mycorrhization). Legacy effects of changed soil moisture on plant community composition can amplify or reverse short-term effects on interactions. Although some concepts acknowledge the role of stress intensity (mild versus severe) and stress type (permanent versus pulsed) empirical research testing-related hypotheses is largely lacking, as is research on the role of soil moisture legacies for interactions.