Wetland mitigation banking in the Chicago area: an assessment of ecological outcomes and compliance with performance standards

Tillman, Stephen C

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https://hdl.handle.net/2142/109459 Copy

Description

Title

Wetland mitigation banking in the Chicago area: an assessment of ecological outcomes and compliance with performance standards

Author(s)

Tillman, Stephen C

Issue Date

2020-12-11

Director of Research (if dissertation) or Advisor (if thesis)

Matthews, Jeffrey W

Department of Study

Natural Res & Env Sci

Discipline

Natural Res & Env Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Date of Ingest

2021-03-05T21:38:27Z

Keyword(s)

• Wetland mitigation
• Wetland restoration

Abstract

The U.S. Army Corps of Engineers, under Section 404 of the Clean Water Act of 1972, requires that development projects causing negative impacts to wetlands must provide compensation for wetland losses through the wetland mitigation process. The Army Corps prefers that compensation is provided through the purchase of credits from wetland mitigation banks, which are large wetland restoration projects constructed by third-party bank sponsors for the purpose of providing wetland mitigation credits that may be sold for a profit. To evaluate how effectively wetland mitigation banks have achieved the goal of “no net loss” of wetland resources, I have conducted assessments of the regulatory and ecological outcomes of banks in relation to natural wetlands in the Chicago region, which possesses one of the country’s most well-developed banking markets. In Chapter 1, I conducted a review of wetland mitigation policy documents and independent research examining banks to provide a definition and thorough description of the practice of wetland mitigation banking. In Chapter 2, I used data from wetland mitigation banks in the Chicago District of the Army Corps to determine how successful banks were at meeting mandatory ecological performance standards, by which the Army Corps evaluates banks at the end of a required monitoring period. In Chapter 3, I used vegetation data that I collected in 2017 from banks that had previously completed their required management and monitoring periods in order to compare the wetlands in banks to natural wetlands in Illinois that were previously sampled by the Illinois Natural History Survey. I made this comparison between banks and natural wetlands using several vegetation-based metrics and using non-metric multidimensional scaling to compare plant species composition. In Chapter 4, I developed a novel simulation modeling approach to determine how effectively banks replace the specific plant species that are lost from the natural wetlands for which banks may be used as compensation. In Chapter 5, I provided a summary of my primary conclusions from this work. These include the findings that banks typically struggled to meet performance standards limiting dominance by non-native species, while they often met standards related to native species richness and dominance, that the plant communities in banks showed greater ecological quality than those in low-quality, degraded natural wetlands but failed to reach equivalence with high-quality reference wetlands, and that banks typically replaced only about 45% of the native plant species found in impacted natural wetlands which may purchase credits from banks. This work provides new information about the ecological legacy of wetland mitigation banking, which may be used to inform and improve mitigation policy and wetland mitigation bank construction and management.

Graduation Semester

2020-12

Type of Resource

Thesis

Permalink

http://hdl.handle.net/2142/109459

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Copyright 2020 Stephen Tillman

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