Plant and soil communities are linked via the plant and influence
each other
In terrestrial ecosystems, aboveground and soil communities are
inseparably linked via plants (Wardle et al., 2004). Such
aboveground-belowground linkages determine plant diversity effects on
ecosystem functioning (Eisenhauer, 2012). Plant species often harbor
unique rhizosphere communities and even influence the surrounding
community composition of root-associated organisms through
species-specific and context-dependent organic matter inputs (Bezemer et
al., 2010; van der Putten et al., 2013). Similarly, each plant species
has a specific herbivore community which can affect soil communities via
herbivory, either directly via frass or indirectly via induced responses
(Bardgett & Wardle, 2010). Aboveground herbivory can, for instance,
positively affect soil microbial activity by inducing the release of
carbon into the rhizosphere, and change arbuscular mycorrhizal
colonization by reducing the carbon allocation to roots (Gehring &
Whitham, 1994; Hamilton & Frank, 2001). In turn, soil biota, especially
root parasites, pathogens, and herbivores as well as mutualistic
symbionts can influence plant community structure and functioning via
soil feedback effects (Van Der Heijden et al., 2008; van der Putten et
al., 2013; Wardle et al., 2004). Root parasites, pathogens, and
herbivores generally induce a negative plant-soil feedback by directly
removing or damaging root tissues and thus reducing root uptake
capabilities. Mutualistic organisms, on the other hand, induce a
positive soil feedback effect on plant growth by improving soil nutrient
uptake (Bardgett & van der Putten, 2014; Wardle et al., 2004), and
protection against antagonists (Latz et al., 2012). The magnitude and
direction of those plant-soil feedback effects, however, is not equal
for all plant species and community contexts (Cortois et al., 2016).