Understanding variation in traits within species is critical to predict plant performance, community assembly, and ecosystem function. Roots contribute to key functions of grassland ecosystems, including the sequestration of carbon, cycling of nutrients and water, and anchoring of soil, however, variation in root traits remains poorly understood. Our main research questions were: 1) Does the root system, morphology, and architecture of dominant plants change over the course of restoration to resemble a native prairie? 2) Do changes in the diversity and structure of soil nematodes reflect changes in root traits of dominant plants?; and 3) Do changes in root traits and soil nematodes reflect changes in the structure and function of restored grasslands? To answer these, we relate changes in root traits of dominant plants (Bouteloua gracilis and Pascopyrum smithii) to the diversity and feeding structure of soil nematode communities across a chronosequence of mixed-grass prairie restoration in Grasslands National Park, Saskatchewan, Canada.
Results/Conclusions
Root architecture and morphology of dominant grasses changed with restoration and soil food webs in recently restored prairies were structured around resources provided by roots. In contrast, food webs in the native prairie were structured around decomposition and were characterized by a high proportion of bacterial feeding nematodes. Our study demonstrates that changing root traits following restoration can cascade through soil foodwebs, changing 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 not be sufficient for explaining the causal relationship between root feeding nematodes and their resources.