Development of Soil Properties and Nitrogen Cycling in Created Wetlands
Mitigation wetlands are expected to compensate for the loss of structure and function of natural wetlands within 5–10 years of creation; however, the age-based trajectory of development in wetlands is unclear. This study investigates the development of coupled structural (soil properties) and functional (nitrogen cycling) attributes of created non-tidal freshwater wetlands of varying ages and natural reference wetlands to determine if created wetlands attain the water quality ecosystem service of nitrogen (N) cycling over time. Soil condition component and its constituents, gravimetric soil moisture, total organic carbon, and total N, generally increased and bulk density decreased with age of the created wetland. Nitrogen flux rates demonstrated age-related patterns, with younger created wetlands having lower rates of ammonification, nitrification, nitrogen mineralization, and denitrification potential than older created wetlands and natural reference wetlands. Results show a clear age-related trajectory in coupled soil condition and N cycle development, which is essential for water quality improvement. These findings can be used to enhance N processing in created wetlands and inform the regulatory evaluation of mitigation wetlands by identifying structural indicators of N processing performance.
KeywordsAge-trajectory Denitrification potential Freshwater created wetlands Nitrogen cycling Nitrogen mineralization Organic carbon
- Bruland GL, Richardson CJ (2005) Spatial variability of soil properties in created, restored, and paired natural wetlands. Soil Science Society of America Journal 69:273–284Google Scholar
- Erwin KL (1991) An evaluation of wetland mitigation in the South Florida water management district, vol 1. South Florida Water Management District. Final Report, West Palm Beach (FL)Google Scholar
- Gee GW, Bauder JW (1986) Particle-size analysis. In: Klute AE (ed) Methods of Soil Analysis, Part 1. Physical and Mineralogical Methods. American Society of Agronomy, Madison, WI, pp 383–411Google Scholar
- Groffman PM, Holland EA, Myrold DD, Robertson GP, Zou X (1999) Denitrification. In: Robertson GP, Coleman DC, Bledsoe CS, Sollins P (eds) Standard soil methods for long-term ecological research. Oxford University Press, New YorkGoogle Scholar
- Hunt CB (1967) Physiography of the United States. W. H. Freeman and Co, San Francisco, CA, USAGoogle Scholar
- Kentula ME, Brooks RP, Gwin SE, Holland CC, Sherman AD, Sifneos JC (1992) An approach to improving decision making in wetland restoration and creation. Corvallis, ORGoogle Scholar
- National Research Council (2001) Compensating for wetland losses under the Clean Water Act. National Academy Press, Washington, D.C., USAGoogle Scholar
- Nelson DW, Sommers LE (1996) Total carbon, organic carbon, and organic matter. In: Sparks DL (ed) Methods of soil analysis. Part 3. Methods. Soil Science Society of America, Madison, pp 1001–1006Google Scholar
- Noe GB (2011) Measurement of net nitrogen and phosphorus mineralization in wetland soils using a modification of the resin-core technique. Soil Science Society of America Journal 75:760–770Google Scholar
- Paul EA, Clark FE (1996) Soil microbiology and biochemistry, 2nd edn. Academic, San Diego, CaliforniaGoogle Scholar
- SPSS for Windows (2006) Version 15. SPSS, Inc, ChicagoGoogle Scholar
- U.S. Army Corps of Engineers (2010) Wetlands compensatory mitigation fact sheet (accessed December 2010, available at http://www.epa.gov/owow/wetlands/pdf/CMitigation.pdf).
- Vitousek PM, Aber RW, Howarth GE, Likens GE, Matson PA, Schidler SW, Tilman DG (1997) Human alteration of the global nitrogen cycle: Sources and consequences. Ecological Applications 7:737–750Google Scholar
- Weatherbase Website (2011) Thirty-year climate data for Washington D.C. area (accessed February 2011, available at http://www.weatherbase.com/weather/weatherall).
- Wolf KL, Ahn C, Noe GB (in press) Microtopography enhances nitrogen cycling and removal in created mitigation wetlands. Ecol EngGoogle Scholar
- Wolf KL, Noe GB, Ahn C (unpublished data) The effects of hydrologic connectivity on nitrogen fluxes in created and natural wetlands of the Virginia PiedmontGoogle Scholar