We investigated the effects of enhanced plant species diversity on prairie restoration on arthropod community assembly in a restored tallgrass prairie of the U.S. Midwest. Despite weak correlation with the arthropod taxon, enhanced plant species diversity in the restored prairie (RP) promoted the evenness and diversity of arthropod functional groups and led to a divergence of arthropod assemblage in comparison to the ones in old field (OF) and monospecific stand (reed canary grass [RCG]) of exotic reed canary grass (Phalaris arundinacia). Pollinators were most and least abundant in RP and RCG, respectively, and exhibited a positive correlation to plant species diversity. Herbivore abundance, highest in RP, also increased with plant species diversity. The diversity of arthropod functional groups was likely facilitated by structural complexity of the RP vegetation that resulted from the enhanced plant species diversity, particularly flowering and nectar-producing forbs. Predator abundance, highest in RCG, decreased with plant species diversity and increased with C 3 grass cover. The presence of small-body sized herbivores seemed to attract predators in the RCG site, which has a monospecific vegetation structure of C 3 reed canary grass. Our results demonstrate a positive effect of prairie restoration on the diversity of arthropod functional groups. We recommend increasing the diversity of native plant species and reduction (or eradication if possible) of exotic plants in the OF and RCG sites.

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