Tree Trade-Offs in Stream Restoration: Impacts on Riparian Groundwater Quality.

Autor: Wood KL; Department of Geology, University of Maryland, College Park, MD, USA.; Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA., Kaushal SS; Department of Geology, University of Maryland, College Park, MD, USA.; Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA., Vidon PG; SUNY College of Environmental Science and Forestry, Syracuse, NY, USA., Mayer PM; US Environmental Protection Agency, Office of Research and Development, Center for Public Health and Environmental Assessment, Pacific Ecological Systems Division, Corvallis, OR, USA., Galella JG; Department of Geology, University of Maryland, College Park, MD, USA.; Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA.
Jazyk: angličtina
Zdroj: Urban ecosystems [Urban Ecosyst] 2022 Jun 01; Vol. 25 (3), pp. 773-795.
DOI: 10.1007/s11252-021-01182-8
Abstrakt: Riparian zones are a vital interface between land and stream and are often the focus of stream restoration efforts to reduce nutrient pollution in waterways. Restoration of degraded stream channels often requires the removal of mature trees during major physical alteration of the riparian zone to reshape streambank topography. We assessed the impact of tree removal on riparian groundwater quality over space and time. Twenty-nine wells were installed across 5 sites in watersheds of the Washington D.C. and Baltimore, Maryland, USA metropolitan areas. Study sites encompassed a chronosequence of restoration ages (5, 10 and 20 years) as well as unrestored comparisons. Groundwater wells were installed as transects of 3 perpendicular to the stream channel to estimate nutrient uptake along groundwater flow paths. Groundwater samples collected over a 2-year period (2018-2019) were analyzed for concentrations of dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), total dissolved nitrogen (TDN), and dissolved components of calcium (Ca), potassium (K), magnesium (Mg), sodium (Na), sulfur (S) and other elements. Results showed some interesting patterns such as: (1) elevated concentrations of some nutrients and carbon in riparian groundwater of recently restored (5 year) sites; (2) decreasing linear trends in concentrations of TDN, K and S in groundwater during a 2 year shift from wet to dry conditions; (3) linear relationships between DOC (organic matter) and plant nutrients in groundwater suggesting the importance of plant uptake and biomass as sources and sinks of nutrients; (4) increasing concentrations in groundwater along hydrologic flow paths from uplands to streams in riparian zones where trees were recently cut, and opposite patterns where trees were not cut. Riparian zones appeared to act as sources or sinks of bioreactive elements based on tree removal. Mean TDN, DOC, and S, concentrations decreased by 78.6%, 12.3%, and 19.3% respectively through uncut riparian zones, but increased by 516.9%, 199.7%, and 34.5% respectively through the 5-year cut transects. Ecosystem recovery and an improvement in groundwater quality appeared to be achieved by 10-20 years after restoration. A better understanding of the effects of riparian tree removal on groundwater quality can inform strategies for minimizing unintended effects of stream restoration on groundwater chemistry.
Competing Interests: Competing Interests The authors have no conflicts of interest to declare that are relevant to the content of this article.
Databáze: MEDLINE
Externí odkaz: