Agriculture, urban development, and woody encroachment have reduced the North American
tallgrass prairie ecosystem to less than 1% of its historical extent. The remnants of this now rare
habitat are currently challenged not only by ongoing human disturbance but by the anticipated
ecological regime shifts from anthropogenic climate change. In response, active restoration of
tallgrass prairie is ongoing, aiming to re-establish native vegetation communities, often on former
croplands. The success of tallgrass prairie restoration has been mixed and many knowledge gaps
exist, especially pertaining to soil biota. With the goal of addressing key knowledge gaps identified
by restoration practitioners, this thesis investigates the invasive earthworm populations of restored
and remnant tallgrass prairie sites across southern Ontario, establishes the dietary preferences of the
largest and most widespread invasive earthworm Lumbricus terrestris with respect to seeds
commonly used in tallgrass prairie restoration, and examines below-ground (soil bacterial
community) as well as traditional above-ground (vegetation community) measures of restoration
success for different methods of tallgrass prairie restoration. The core significant original
contributions of this dissertation are 1) invasive earthworms are present and abundant in all remnant
and restored tallgrass prairies in southern Ontario; 2) the largest and most widespread invasive
earthworm, Lumbricus terrestris, can play an important role in seed granivory in tallgrass prairie
habitats, and these effects are uneven across the target and weed species investigated; and 3) above and below-ground measures of restoration success can tell different stories, and conventional
restoration methods do not maintain microbial communities similar to high quality remnant prairie in
the short term, whereas sod mat transplants do. Recommendations for practice include considering
interactions with invasive earthworms in restoration and ecosystem management plans, considering
alternative measures and methods of tallgrass prairie restoration, and broadening the definition of
restoration success to encompass the retention and restoration of below-ground ecosystem
components. By deliberately engaging the end-users of this research in question development and
producing and communicating context-specific results and recommendations that can guide future
management decisions, this dissertation is in line with the core tenants of translational ecology, which
is suggested as a way forward for the discipline of restoration ecology.