Joseph E. Flotemersch

Linking Ecosystem Services, Rehabilitation, and River Hydrogeomorphology

Assignment of values for natural ecological benefits and anthropocentric ecosystem services in riverine landscapes has been problematic because a firm scientific basis linking these to the rivers physical structure has been absent. We highlight some inherent problems in this process and suggest possible solutions on the basis of the hydrogeomorphic classification of rivers. We suggest this link can be useful in fair asset trading (mitigation and offsets), selection of sites for rehabilitation, cost-benefit decisions on incremental steps in restoring ecological functions, and general protection of rivers.

Historical Monitoring of Biomarkers of PAH Exposure of Brown Bullhead in the Remediated Black River and the Cuyahoga River, Ohio

Abstract Biomarkers of exposure to chemical contamination, benzo[a]pyrene (BAP)- and naphthalene (NAPH)-type metabolites, were measured in brown bullhead from a heavily polycyclic aromatic hydrocarbons (PAHs) contaminated section of the Black River, Ohio, during and immediately after remedial sediment dredging in 1990–1991, and in follow-up revisits in 1993 and 1998. Biomarker levels of bullhead from the historically polluted Cuyahoga River and the protected Old Woman Creek National Estuarine Sanctuary in Ohio were also measured over the same time periods. PAH-bile metabolite concentrations of bullheads from the Black River were still elevated in the year following dredging, but were significantly lower in the later resampling years. Metabolite concentrations of Cuyahoga River bullhead decreased significantly between 1991 and 1993, possibly in response to the shutdown of coking operations on the river. Fish from Old Woman Creek showed some variation in metabolite concentrations among periods, but were consistently lower than the other two rivers at each time. Measurement of bile metabolites proved an effective tool for estimating changes in exposure over time and among sampling sites. Trends in biomarkers indicated lowered exposures in the Black and Cuyahoga Rivers. These findings are likely a result of remediation activities in the Black River and source reduction and incidental sediment displacement in the Cuyahoga River.

Automated riverine landscape characterization: GIS-based tools for watershed-scale research, assessment, and management

River systems consist of hydrogeomorphic patches (HPs) that emerge at multiple spatiotemporal scales. Functional process zones (FPZs) are HPs that exist at the river valley scale and are important strata for framing whole-watershed research questions and management plans. Hierarchical classification procedures aid in HP identification by grouping sections of river based on their hydrogeomorphic character; however, collecting data required for such procedures with field-based methods is often impractical. We developed a set of GIS-based tools that facilitate rapid, low cost riverine landscape characterization and FPZ classification. Our tools, termed RESonate, consist of a custom toolbox designed for ESRI ArcGIS®. RESonate automatically extracts 13 hydrogeomorphic variables from readily available geospatial datasets and datasets derived from modeling procedures. An advanced 2D flood model, FLDPLN, designed for MATLAB® is used to determine valley morphology by systematically flooding river networks. When used in conjunction with other modeling procedures, RESonate and FLDPLN can assess the character of large river networks quickly and at very low costs. Here we describe tool and model functions in addition to their benefits, limitations, and applications.

Critical Role for hierarchical geospatial analyses in the design of fluvial research, assessment, and management

River science and management can be conducted at a range of spatiotemporal scales from reach to basin levels as long as the project goals and questions are matched correctly with the study design’s spatiotemporal scales and dependent variables. These project goals should also incorporate information on the hydrogeomorphically patchy nature of riverine macrosystems which is only partially predictable in type and location from a river’s headwaters to its terminus. This patchiness significantly affects a river’s habitat template, and thus community structure, ecosystem function, and responses to perturbations. Our manuscript is designed for use by senior administrators at government agencies through entry-level river scientists. It analyzes common challenges in project design and recommends solutions based partially on hierarchical analyses that combine geographic information systems and multivariate statistical analysis to enable self-emergence of a stream’s patchy structure. These approaches are useful at all spatial levels and can vary from primary reliance on geospatial techniques at the valley level to a greater dependence on field-based measurements and expert opinion at the reach level. Comparative uses of functional process zones (FPZs = valley-scale hydrogeomorphic patches), ecoregions, hydrologic unit codes, and reaches in project designs are discussed along with other comparative approaches for stream classification and analysis of species distributions (e.g., GAP analysis). Use of hierarchical classification of patch structure for sample stratification, reference site selection, ecosystem services, rehabilitation, and mitigation are briefly explored.

Mapping watershed integrity for the conterminous United States

Watershed integrity is the capacity of a watershed to support and maintain the full range of ecological processes and functions essential to sustainability. Using information from EPAs StreamCat dataset, we calculated and mapped an Index of Watershed Integrity (IWI) for 2.6 million watersheds in the conterminous US with first-order approximations of relationships between stressors and six watershed functions: hydrologic regulation, regulation of water chemistry, sediment regulation, hydrologic connectivity, temperature regulation, and habitat provision. Results show high integrity in the western US, intermediate integrity in the southern and eastern US, and the lowest integrity in the temperate plains and lower Mississippi Valley. Correlation between the six functional components was high (r = 0.85-0.98). A related Index of Catchment Integrity (ICI) was developed using local drainages of individual stream segments (i.e., excluding upstream information). We evaluated the ability of the IWI and ICI to predict six continuous site-level indicators with regression analyses - three biological indicators and principal components derived from water quality, habitat, and combined water quality and habitat variables - using data from EPAs National Rivers and Streams Assessment. Relationships were highly significant, but the IWI only accounted for 1-12% of the variation in the four biological and habitat variables. The IWI accounted for over 25% of the variation in the water quality and combined principal components nationally, and 32-39% in the Northern and Southern Appalachians. We also used multinomial logistic regression to compare the IWI with the categorical forms of the three biological indicators. Results were consistent: we found positive associations but modest results. We compared how the IWI and ICI predicted the water quality PC relative to agricultural and urban land use. The IWI or ICI are the best predictors of the water quality PC for the CONUS and six of the nine ecoregions, but they only perform marginally better than agriculture in most instances. However, results suggest that agriculture would not be appropriate in all parts of the country, and the index is meant to be responsive to all stressors. The IWI in its present form (available through the StreamCat website; https://www.epa.gov/national-aquatic-resource-surveys/streamcat) could be useful for management efforts at multiple scales, especially when combined with information on site condition. The IWI could be improved by incorporating empirical or literature-derived relationships between functional components and stressors. However, limitations concerning the absence of data for certain stressors should be considered.

Eight river principles for navigating the science–policy interface

Scientists and policymakers often work together to develop policy about the sustainable use of river ecosystems. River science plays an important role in developing river policy but how can key aspects of river science be conveyed as a heuristic to navigate the interface between river science and river policy? This paper introduces eight principles that encapsulate the key properties of rivers to consider during the development of river policy: (1) rivers are social–ecological systems; (2) river ecosystems provide valuable ecosystem services; (3) tools should support policy development; (4) knowledge of river ecosystems will always be incomplete; (5) social–ecological systems require interdisciplinary perspectives; (6) science is one of many inputs to be considered; (7) heterogeneity and variability are characteristic of river ecosystems; and (8) scale awareness is essential in river ecosystems. Whereas policy challenges are associated with each principle, consideration of principles in the context of the issue at hand may increase the robustness of river policy and enhance the sustainability of river ecosystems. The eight principles are evaluated in relation to the Water Act 2007 and the draft Murray–Darling Basin Plan to demonstrate how the principles can enhance policy development in the area of water allocation.

Evaluation of an alternate method for sampling benthic macroinvertebrates in low-gradient streams sampled as part of the National Rivers and Streams Assessment

Benthic macroinvertebrates are sampled in streams and rivers as one of the assessment elements of the US Environmental Protection Agency’s National Rivers and Streams Assessment. In a 2006 report, the recommendation was made that different yet comparable methods be evaluated for different types of streams (e.g., low gradient vs. high gradient). Consequently, a research element was added to the 2008–2009 National Rivers and Streams Assessment to conduct a side-by-side comparison of the standard macroinvertebrate sampling method with an alternate method specifically designed for low-gradient wadeable streams and rivers that focused more on stream edge habitat. Samples were collected using each method at 525 sites in five of nine aggregate ecoregions located in the conterminous USA. Methods were compared using the benthic macroinvertebrate multimetric index developed for the 2006 Wadeable Streams Assessment. Statistical analysis did not reveal any trends that would suggest the overall assessment of low-gradient streams on a regional or national scale would change if the alternate method was used rather than the standard sampling method, regardless of the gradient cutoff used to define low-gradient streams. Based on these results, the National Rivers and Streams Survey should continue to use the standard field method for sampling all streams.

Performance of National Maps of Watershed Integrity at Watershed Scales

Watershed integrity, the capacity of a watershed to support and maintain ecological processes essential to the sustainability of services provided to society, can be influenced by a range of landscape and in-stream factors. Ecological response data from four intensively monitored case study watersheds exhibiting a range of environmental conditions and landscape characteristics across the United States were used to evaluate the performance of a national level Index of Watershed Integrity (IWI) at regional and local watershed scales. Using Pearson’s correlation coefficient (r), and Spearman’s rank correlation coefficient (rs), response variables displayed highly significant relationships and were significantly correlated with IWI and ICI (Index of Catchment Integrity) values at all watersheds. Nitrogen concentration and flux-related watershed response metrics exhibited significantly strong negative correlations across case study watersheds, with absolute correlations (|r|) ranging from 0.48 to 0.97 for IWI values, and 0.31 to 0.96 for ICI values. Nitrogen-stable isotope ratios measured in chironomids and periphyton from streams and benthic organic matter from lake sediments also demonstrated strong negative correlations with IWI values, with |r| ranging from 0.47 to 0.92, and 0.35 to 0.89 for correlations with ICI values. This evaluation of the performance of national watershed and catchment integrity metrics and their strong relationship with site level responses provides weight-of-evidence support for their use in state, local and regionally focused applications.

Characterization of River Networks: A GIS Approach and Its Applications

Fluvial geomorphology provides the basis for characterizing complex river networks and evaluating biophysical processes within watersheds. Understanding the spatial organization of morphological features, their influencing processes, and resultant geomorphic diversity in stream networks are important for efficient restoration, river health assessment, and improving our knowledge of the resilience of riverine landscapes. River characterization is a means to determine the biophysical character of river networks but many methods are fraught with pitfalls, such as the use of incorrect variables and limited acknowledgment of the hierarchical organization of rivers. In this paper, a top-down geographic information system-based approach for determining the physical typology of river networks is outlined. A suite of multivariate analyses are used to develop a nomenclature for functional process zones (FPZs) - large tracts of the river network with similar hydro-geomorphological character. Applied to the Little Miami River, Ohio, six distinct FPZs emerged, which had a nonuniform distribution along the river network. Some FPZs repeated downstream; others were rare in terms of total length and number of FPZ segments. The physical structure of the Little Miami River network was analyzed using a series of community metrics. Application of this approach for river monitoring, establishing reference conditions, as well as management of threatened and endangered species and asset trading is highlighted.

Benthic macroinvertebrate field sampling effort required to produce a sample adequate for the assessment of rivers and streams of Neuquén Province, Argentina

This multi-year pilot study evaluated a proposed field method for its effectiveness in the collection of a benthic macroinvertebrate sample adequate for use in the condition assessment of streams and rivers in the Neuquén Province, Argentina. A total of 13 sites, distributed across three rivers, were sampled. At each site, benthic macroinvertebrates were collected at 11 transects. Each sample was processed independently in the field and laboratory. Based on a literature review and resource considerations, the collection of 300 organisms (minimum) at each site was determined to be necessary to support a robust condition assessment, and therefore, selected as the criterion for judging the adequacy of the method. This targeted number of organisms was collected at all sites, at a minimum, when collections from all 11 transects were combined. Subsequent bootstrapping analysis of data was used to estimate whether collecting at fewer transects would reach the minimum target number of organisms for all sites. In a subset of sites, the total number of organisms frequently fell below the target when fewer than 11 transects collections were combined.Site conditions where < 300 organisms might be collected are discussed. These preliminary results suggest that the proposed field method results in a sample that is adequate for robust condition assessment of the rivers and streams of interest. When data become available from a broader range of sites, the adequacy of the field method should be reassessed.