Soil Macro-Invertebrates: Their Impact on Plants and Associated Aboveground Communities in Temperate Regions

Abstract

Soil macro-invertebrates, the so-called soil macrofauna, belong to different functional groups such as ecosystem engineers, detritivores, root herbivores, and predators. They have often profound impacts on physical, chemical, and biological soil characteristics. Effects of soil macrofauna on plants are mediated by direct (trophic) and indirect interactions with roots. The objective of this chapter is to summarize the knowledge and identify knowledge gaps on the connection between soil macrofauna, plants, and aboveground arthropod communities. Above–belowground interaction studies involving soil macrofauna mainly focused on insect root herbivores or earthworms, while other taxa of the soil macrofauna have been widely neglected. Root feeding insect larvae can induce defense mechanisms in the whole plant, while earthworms affect plant performance mainly indirectly by changing resource availability, soil structure, and/or impacting other soil biota. The resulting systemic changes in plant traits can further affect aboveground plant interactions with herbivores and higher trophic levels. Other, little studied aspects are legacy effects of soil macrofauna that may alter future plant performance and interactions mediated by changes in soil characteristics and plant traits. Global change factors, such as climatic or land use changes, have also been shown to alter the strength of interactions between soil macrofauna and aboveground organisms. We conclude that more realistic insights in the role of soil macrofauna on plant performance and ecosystem functions could be achieved by more encompassing multispecies interactions under different climatic conditions and at different temporal and spatial scales.