Soil Organic Carbon Content of Compensatory Wetland Mitigation Projects in Auburn, Washington
Presentation Abstract
Wetlands provide many essential ecosystem services, such as water quality improvement, flood prevention, and critical species habitat. 5.5% of land cover in the U.S. is categorized as wetland, yet wetlands are estimated to account for 20-71% of earth’s terrestrial carbon storage (Dahl, 2011, Reddy & DeLaune, 2008). Natural wetlands are often permitted to be developed, and replacement wetlands are subsequently either constructed or restored in their place to fulfill federal regulation. Laws dictate that no net loss of ecosystem function may result due to permitting activity, therefore it is obligatory to engineer wetlands functionally equivalent to those lost. However, despite this requirement there is still a significant loss to wetland ecosystems in both function and areal extent (Turner, Redmond, & Zedler, 2001). This study compares 2 ecosystem functions of constructed and restored wetland mitigation sites in Auburn, Washington: (1) soil organic carbon storage and (2) species richness, and investigates if physical parameters such as size, age, or adjacent land use affect these functions. There was no correlation between size, age, and adjacent land use and these functions. No significant difference was found between the mean species richness of constructed and restored wetlands. It was observed that constructed wetlands store half the % soil organic matter (SOM) (7.8 ±4.0) as restored wetlands (15.312.1) (χ2(1)=9.4, p=0.002) These values are drastically lower than % SOM in similar natural wetlands in the area (45.5 ±34.2) (Horner, Cooke, Reinelt, Ludwa, & Chin, 2001). Soil bulk density was a much better predictor (R2=0.584) of % SOM than soil texture (R2=0.020). The wetlands that were excavated using heavy equipment and layered with top soil had the lowest % SOM values, indicating that this activity is compacting soil and limiting the soil development of these mitigation sites and capacity to store soil organic carbon.
Session Title
General protection, remediation and restoration topics
Conference Track
Protection, Remediation, & Restoration
Conference Name
Salish Sea Ecosystem Conference (2016 : Vancouver, B.C.)
Document Type
Event
Location
2016SSEC
Type of Presentation
Poster
Genre/Form
presentations (communicative events)
Contributing Repository
Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.
Subjects – Topical (LCSH)
Wetland biodiversity--Washington (State)--Auburn; Soils--Carbon content--Washington (State)--Auburn; Ecosystem health--Washington (State)--Auburn
Geographic Coverage
Auburn (Wash.); Salish Sea (B.C. and Wash.)
Rights
This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.
Type
Text
Language
English
Format
application/pdf
Soil Organic Carbon Content of Compensatory Wetland Mitigation Projects in Auburn, Washington
2016SSEC
Wetlands provide many essential ecosystem services, such as water quality improvement, flood prevention, and critical species habitat. 5.5% of land cover in the U.S. is categorized as wetland, yet wetlands are estimated to account for 20-71% of earth’s terrestrial carbon storage (Dahl, 2011, Reddy & DeLaune, 2008). Natural wetlands are often permitted to be developed, and replacement wetlands are subsequently either constructed or restored in their place to fulfill federal regulation. Laws dictate that no net loss of ecosystem function may result due to permitting activity, therefore it is obligatory to engineer wetlands functionally equivalent to those lost. However, despite this requirement there is still a significant loss to wetland ecosystems in both function and areal extent (Turner, Redmond, & Zedler, 2001). This study compares 2 ecosystem functions of constructed and restored wetland mitigation sites in Auburn, Washington: (1) soil organic carbon storage and (2) species richness, and investigates if physical parameters such as size, age, or adjacent land use affect these functions. There was no correlation between size, age, and adjacent land use and these functions. No significant difference was found between the mean species richness of constructed and restored wetlands. It was observed that constructed wetlands store half the % soil organic matter (SOM) (7.8 ±4.0) as restored wetlands (15.312.1) (χ2(1)=9.4, p=0.002) These values are drastically lower than % SOM in similar natural wetlands in the area (45.5 ±34.2) (Horner, Cooke, Reinelt, Ludwa, & Chin, 2001). Soil bulk density was a much better predictor (R2=0.584) of % SOM than soil texture (R2=0.020). The wetlands that were excavated using heavy equipment and layered with top soil had the lowest % SOM values, indicating that this activity is compacting soil and limiting the soil development of these mitigation sites and capacity to store soil organic carbon.
