Plant trait-based approaches for interrogating belowground function

Trait-based approaches, which focus on the functional characteristics of organisms rather than their taxonomic identity, offer a means to explain how plant communities and ecosystem functions respond to environmental change. Here I review recent developments in the use of plant trait-based approaches for interrogating the functioning of soil responses to global change. Plant traits impact soil functioning via multiple routes with feedback consequences for biogeochemical cycles and plant community dynamics. They also display a high degree of plasticity in response to global change; as such, there is much potential for global change induced shifts in trait spectra, both aboveground and belowground, to impact soil functions with feedbacks to biogeochemical cycling across multiple scales. Recent research reveals that root traits play a particularly important role in influencing the soil environment, with strong impacts on a host of soil physical, chemical and biological properties. Although a fast moving topic, many challenges regarding the use of trait-based approaches to interrogate soil functioning remain. I identify three. First, there is a need for improved understanding of genotypic and species level variation in plant traits, especially of root traits that have the strongest potential to influence soil function. Second, there is a need to incorporate new understanding of links between plant traits and soil processes into terrestrial biogeochemical and dynamic vegetation models, in order to enhance their predictive power. Finally, there is a need to harness new understanding of plant traits and their impact on soil functions in sustainable food production systems, in particular to enhance resource acquisition by crop plants. This last point is especially important given the extent that soils are degraded worldwide, and the need to develop sustainable ways of managing soil to prevent further degradation whilst also increasing the production of food.