You are here:
USA-scale patterns in wetland water quality as determined from the 2011 National Wetland Condition Assessment
Citation:
Trebitz, A., J. Nestlerode, AND A. Herlihy. USA-scale patterns in wetland water quality as determined from the 2011 National Wetland Condition Assessment. ENVIRONMENTAL MONITORING AND ASSESSMENT. Springer, New York, NY, 191(262):24 p., (2019). https://doi.org/10.1007/s10661-019-7321-7
Impact/Purpose:
The focus of this manuscript is to assess the utility of water quality data in assessing the Nation’s wetlands. Whether water quality sampling should be part of the 2011 National Wetland Condition Assessment was a matter of some debate in initial planning discussions. Arguments in favor included that water quality data had proven utility in NARS assessments for other waterbody types and would provide a valuable baseline for a variety of research and management related questions. Arguments against included that water quality data would not be universally obtainable, and might be too variable and site-specific to yield insight. Water quality samples were in fact unobtainable from a substantial percentage of the NWCA sites, but concerns about excessive variability and lack of broad patterns were unfounded. Our analyses demonstrate that water quality exhibits the same general patterns and responds to the same landscape drivers in wetlands as in other waterbody types across the US, and that classifiers capable of organizing the patterns in variability can be found. Water quality data have proven utility in ecological assessments of wetlands over broad geographic scales and should be a core part of future NWCA surveys.
Description:
Water quality data are a central to ecological condition assessments of lakes, streams, and coastal waters but are less often obtained in wetlands. The 2011 National Wetland Condition Assessment, which spanned natural wetlands across the conterminous USA, provided an unprecedented opportunity to examine water quality patterns across broad wetland types and geographic scales. Our analyses focused on conductivity, total nitrogen and phosphorus (TN, TP), and algal chlorophyll a (CHLA), which were temporally more stable than NH4 and NOx. Conductivity, CHLA, TN, and TP varied by 3 to 4 orders of magnitude and were inter-correlated. Nutrient ratios became increasingly N-limited with increasing levels of TP but not TN. A substantial percentage of sites lacked standing water within the randomly selected assessment area. Compared to woody-type wetlands, herbaceous wetlands more frequently yielded a water sample and had higher nutrients and CHLA but lower TN:TP ratios. Compared to national data for other waterbody types, wetlands had higher TN and TP but not planktonic CHLA. Regional water quality differences were consistent between inland wetlands and lakes and streams, and between coastal wetlands and the marine nearshore. Wetlands were influenced by landuse/landcover at broad spatial scales, with correlations of TN, TP, and CHLA to percent agriculture or natural land stronger for whole watersheds than smaller buffer areas. COND was related to landuse/landcover in inland wetlands but reflected seawater influence in coastal wetlands. Water quality across wetlands exhibits the same general patterns and responds to the same landscape drivers as across other water resource types, even if wetland water quality data are less readily obtained
URLs/Downloads:
DOI: USA-scale patterns in wetland water quality as determined from the 2011 National Wetland Condition Assessment