Dissertation/Thesis Abstract

Evaluating the Success of Prairie Restorations in Southwest Illinois in Providing Suitable Habitat for Prairie Birds
by Alexander, Aaron M., M.S., Southern Illinois University at Edwardsville, 2017, 72; 10274915
Abstract (Summary)

Tallgrass prairie is one of the most endangered ecosystem types in North America, as over 99% of historic tallgrass prairie has been lost, even though it is one of the younger ecosystem types. The main factors behind the dramatic loss of tallgrass prairie include conversion to agriculture or development and a suppression of the natural fire regime in these grassland areas. Any natural prairies left are often too small and isolated to serve as viable habitat for grassland-dependent species, making the efforts at restoring these areas critical. Prairie restoration is crucial to grassland-dependent species because it increases the area of suitable habitat. Once a prairie restoration has taken place, it must be managed and evaluated to keep succession at bay and to help ensure that all restoration objectives have been met. Illinois has less than 1% of natural tallgrass prairie remaining, causing the grassland bird communities of the state to experience severe population declines within their ranges. Grassland bird species are important pollinators and dispersers of plants, and are under significant decline, which make them important priorities for conservation efforts. Birds in general are good ecological indicators of restoration success as they can be seen and heard easily, they have specific habitat requirements, and they are often the first animals to reach a restoration effort. Illinois has seen several prairie restoration attempts take place within the last 40 years, but very few studies have been conducted to assess the relative success or failure of these restoration efforts. The objectives of this study are to (1) examine temporal trends in the avian community composition, richness, and diversity among prairie restorations at The Nature Institute, (2) to test whether these trends are heading in the direction of the old growth reference prairie, and (3) to investigate which habitat attributes are the best predictors of the presence and abundance of prairie bird species. I hypothesize that (1) the restorations are on track to attain the bird community composition and diversity of an old growth prairie; (2) changes in vegetation structure over time during restoration provide suitable habitat for particular species of prairie birds. Five 20 m radius sampling plots were established in each of the study sites and utilized for both avian and vegetation sampling. Avian sampling took part in two periods, one spanning the entire avian breeding season from late May into early August, and the other corresponded with avian migration and lasted from September into late October. Plots were divided into regular distance intervals (0-5 m, 6-10 m, 11-15 m, 16-20 m) and all birds within as well as those flying over and outside of the plot were recorded. Vegetation characteristics (e.g., litter depth, forb coverage, and vegetation height) were measured along a 40 m transect within each study plot. Species richness, Antilog Shannon’s and Simpson’s diversity indices, and density (birds per hectare) for each plot was calculated. Non-metric multidimensional scaling ordination was utilized to visualize patterns within the avian community data and to assess whether or not the restorations were on track to achieve the avian community structure of the old-growth reference prairie. Diversity indices were highest in the youngest restorations before dropping off at the oldest restoration and the reference prairie. Indicator species analysis showed that the northern cardinal, willow flycatcher, indigo bunting, and the ruby-throated hummingbird were indicative of restored prairies less than seven years old, whereas species like the chipping sparrow, common yellowthroat, and the red-winged blackbird signaled older prairie restorations (15-29 years). Field sparrows were found to be indicator species of the old-growth reference prairie used in this study. Non-metric multidimensional scaling showed that each study prairie was different from one another based on their avian communities and that the restorations are not on track to achieve the avian community structure found in the reference prairie. The results of this research will provide valuable information to prairie managers across the region. Results from this study show that small isolated prairie restorations, although good for community outreach and public education on the topic, will not meet objectives related to stopping prairie bird declines in a region. Large and well-connected prairie restorations are ideal for grassland-dependent species when planning out future restoration efforts.

Indexing (document details)
Advisor: Minchin, Peter R.
Commitee: Esselman, Elizabeth J., Essner, Richard L.
School: Southern Illinois University at Edwardsville
Department: Biological Sciences
School Location: United States -- Illinois
Source: MAI 56/05M(E), Masters Abstracts International
Source Type: DISSERTATION
Subjects: Plant biology, Ecology
Keywords: Prairie, Restoration, Tallgrass
Publication Number: 10274915
ISBN: 9780355056150
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