Rethinking restoration ecology of tallgrass prairie: considering belowground components of tallgrass restoration in southern Ontario
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Date
2019-03-13
Authors
Cray, Heather Ann
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Journal ISSN
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Publisher
University of Waterloo
Abstract
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.
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Keywords
tallgrass prairie, restoration ecology, southern Ontario
LC Keywords
prairie ecology, restoration ecology, grassland ecology, prairie plants, Ontario