Can root traits predict communities of soil nematodes in restored northern prairies?

Abstract

We examined how restoration affects the structure and function of grasslands belowground by relating changes in the morphology and architecture of root systems of dominant plants to the structure of soil food webs. We measured changes in root traits of dominant plants (Bouteloua gracilis and Pascopyrum smithii) and related them to the diversity and feeding structure of soil nematodes across a restoration chronosequence in a mixed-grass prairie in Grasslands National Park, Saskatchewan, Canada. Root architecture and morphology of dominant grasses changed with restoration, and soil food webs in recently restored prairies centred around resources provided by roots. In contrast, food webs in a native prairie centred around the decomposition of soil organic matter and plant litter. Our study demonstrates that changes in root traits following restoration can cascade through soil foodwebs, altering the function of restored prairies. Our study also highlights that the diversity and structure of soil nematodes can reflect changes in root traits of dominant plants. However, traits that generalize the whole root system may be insufficient to explain the causal relationship between root feeding nematodes and their resources.