Ecological Targets for Rehabilitation of the Rouge River (original) (raw)
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Fish as indicators for the assessment of the ecological integrity of large rivers
2000
Fish communities in large rivers are characterized by a high diversity, which reflects the structural diversity and habitat richness of inshore zones and connected floodplains. The connectivity of the different habitat elements in a broad spatio-temporal context, i.e., at various scales from catchment to microhabitat -and their nestednessdefine the fitness of fish species both on the individual level (e.g., growth performances) and population level (i.e., population structure, mortality, etc.). Relevant spatial scales can be the whole river course in the case of some anadromous migrators or the availability of complementary microhabitat elements, e.g., during the early ontogeny of a species. The significance of connectivity at various scales from whole river to local reach have to be evaluated based on the requirements, reaction norms, and ecological flexibility of individual species. Integrity has to be evaluated in several respects:
River Research and Applications, 2006
The Upper Mississippi River is a dynamic floodplain river that has been largely transformed by navigational levees and dams since the 1930s. The pools upstream of each dam are lake-like and only about the upper third of each reach retains a riverine character. In contrast, the Wisconsin River is not managed for commercial navigation and today its lower 149 km represent one of the least-degraded large river reaches in central North America. Riverine reaches in both the Mississippi and Wisconsin rivers have similar macro-habitats including numerous islands, large side channels, and connected backwaters and floodplain lakes. In this study, shoreline electrofishing samples were collected during summer 2002 and 2003 to characterize resident fish assemblages. We compared fish species abundance, biomass, and biotic integrity along main and side channel borders between the Upper Mississippi River and the Lower Wisconsin River. We expected that, in the absence of environmental degradation, fish composition and structure would be similar between the Mississippi and Wisconsin rivers, and between channel types within each river. Nonmetric multidimensional scaling and redundancy analysis revealed that fish species in the Mississippi River, unlike in the Wisconsin River, were characteristic of non-riverine habitats. We consider non-riverine fish assemblages indicative of environmental impairment. The main and side channel sites in the Mississippi River had more variable fish assemblages than the Wisconsin River. Analyses of fish index of biotic integrity scores showed that environmental condition was excellent for both channel types in the Wisconsin River, whereas in the Mississippi River the side channel was rated good and the main channel only fair. We conclude that differences between the two rivers and between channel types of the Mississippi River are consistent with direct and indirect effects of navigation. This study demonstrates the utility of a fish index of biotic integrity, an inexpensive and rapid bioassessment tool, for detecting change in ecological health on one of the world's largest rivers.
Development of a Multimetric Index for Assessing the Biological Condition of the Ohio River
Transactions of the American Fisheries Society, 2003
The use of fish communities to assess environmental quality is common for streams, but a standard methodology for large rivers is as yet largely undeveloped. We developed an index to assess the condition of fish assemblages along 1,580 km of the Ohio River. Representative samples of fish assemblages were collected from 709 Ohio River reaches, including 318 ''leastimpacted'' sites, from 1991 to 2001 by means of standardized nighttime boat-electrofishing techniques. We evaluated 55 candidate metrics based on attributes of fish assemblage structure and function to derive a multimetric index of river health. We examined the spatial (by river kilometer) and temporal variability of these metrics and assessed their responsiveness to anthropogenic disturbances, namely, effluents, turbidity, and highly embedded substrates. The resulting Ohio River Fish Index (ORFIn) comprises 13 metrics selected because they responded predictably to measures of human disturbance or reflected desirable features of the Ohio River. We retained two metrics (the number of intolerant species and the number of sucker species [family Catostomidae]) from Karr's original index of biotic integrity. Six metrics were modified from indices developed for the upper Ohio River (the number of native species; number of great-river species; number of centrarchid species; the number of deformities, eroded fins and barbels, lesions, and tumors; percent individuals as simple lithophils; and percent individuals as tolerant species). We also incorporated three trophic metrics (the percent of individuals as detritivores, invertivores, and piscivores), one metric based on catch per unit effort, and one metric based on the percent of individuals as nonindigenous fish species. The ORFIn declined significantly where anthropogenic effects on substrate and water quality were prevalent and was significantly lower in the first 500 m below point source discharges than at least-impacted sites nearby. Although additional research on the temporal stability of the metrics and index will likely enhance the reliability of the ORFIn, its incorporation into Ohio River assessments still represents an improvement over current physicochemical protocols.
Fish community response to floodplain inundation in a regulated river
Journal of Freshwater Ecology, 2014
Floodplain connectivity has been identified as an important element of river ecosystem function for enhancing biological productivity, yet most of the world's large rivers have been managed to reduce river-floodplain connectivity to protect human interests. Flow events in the Missouri River basin during the summers of 2010 and 2011 offered a unique opportunity to investigate the influence of floodplain connectivity on fish communities. The floods created aquatic habitats not generally available on the main stem and the magnitude and duration of the 2011 event have not occurred since the main-stem dams were closed. Therefore, the objectives were to: (1) document species use on available floodplain habitats and assess age-0 fish presence, (2) compare spatial and temporal distribution of fish species, and (3) evaluate fish community responses at different discharges. Age-0 fish dominated the fish community during the 2010 and 2011 floods, representing 90% and 94% of all fish collected each year. Species composition during the 2011 flood was different above and below the Platte and Missouri rivers confluence (ANOSIM; r ¼ 0.211; p < 0.001) and between individual sites (r ¼ 0.667; p < 0.001) but did not change temporally (r ¼ 0.086; p ¼ 0.244). Comparison of the age-0 fish community response to varying water levels also differed (r ¼ 0.619; p ¼ 0.038) annually. The effects of this flood on the fish community of the Missouri River initially appear to have been beneficial for the native fish community; however, continued research and evaluation will verify the flood's effects.
0+ Fish as Indicators for the Ecological Status of Large Rivers
River Systems
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Fishes as Environmental Indicators of Riverine Ecosystem
International Journal for Research in Applied Science & Engineering Technology, 2020
The ecological condition of river is represented by the condition of their biotic communities-the living components of aquatic ecosystems that integrate many forms of human disturbances and modification of river stream and the measurements of this subject was the topic of particular interest. Stressors or the pressures that human being exert on aquatic systems through their use of the surrounding environment are commonly the chemical, physical and biological components of the ecosystem. These have the potential to degrade biotic integrity. Some common chemical stressors are toxic compounds, excess nutrients etc. Most of the physical stressors are created when we modify the physical habitat of a river network-excess sedimentation, bank erosion etc. All these can degrade biotic integrity. Water quality plays vital role in riverine ecosystem health regulation. Environmental indicators have been defined as "physical, chemical, biological or socioeconomic measures that best represent the key elements of a complex ecosystem or environmental issue. An indicator is embedded in a well developed interpretative framework and has meaning beyond the measure it represents. Using indicators, it is possible to evaluate the fundamental condition of the environment without having to capture the full complexity of the system. Indicators are based on the best scientific understanding currently available so that changes in these simple measures can be related to more complex environmental trends.
Brazilian Archives of Biology and Technology, 2005
Freshwater is a basic need for the mankind. Effective biological tools (ecologically based, efficient, rapid and consistently applicable to different ecological regions) are needed to measure the "health" of rivers. Adapting such tools over a broad geographic area requires a detailed understanding of both the patterns of organisms assemblage composition and distribution within and among water bodies under natural conditions, and the nature of the major environmental gradients that cause or explain these patterns. A comprehensive review of the available litterature dealing with the identification of environmental factors structuring riverine fish assemblages under natural conditions permits to identify the most consistent ones.
Fish Communities as Indicators of Environmental Quality in the West River Watershed
The West River bordering New Haven and West Haven, Connecticut, is under evaluation for potential restoration of a former salt marsh. As part of a larger survey of biota associated with this river, the fish fauna was examined in the estuary and adjacent freshwaters. The results provide baseline data for monitoring restoration efforts and indicate the environmental health of the river. The fish communities lacked intolerant species, included significant numbers of individuals of non-native fishes, and showed low abundance and diversity of the native species, all indicating that this stretch of the river represents poor fish habitat with significant ecological disturbances. Some sites contained individuals with excessive parasites, tumors, ulcers, and fin erosion, which suggests physiological stress and potential human health hazards. These problems are localized in the vicinity of combined sewage outflows and/or storm sewer runoff from streets. They are exacerbated by periodic low flow or stagnant waters caused by the tide gates. Salt marsh restoration with tide-gate modification could improve habitat for species with commercial and recreational value and improve movement of diadromous fishes.
Effects of large river restoration on currently used bioindicators and alternative metrics
Freshwater Biology, 2015
1. Data-rich restoration experiments offer opportunities to test the ability of bioassessment tools, such as those currently used to assess the 'ecological status' of waterbodies targeted by the European Water Framework Directive, to detect observed ecological changes. 2. Minimum flow increases in four regulated reaches of the French Rhône River modified the invertebrate and fish communities in a predictable way, as detailed in other articles of this Special Issue. We tested the ability of several fish and macroinvertebrate metrics currently used in bioassessment to detect these changes. In addition, we considered changes in metrics that are expected to respond specifically to flow increase. These metrics were related to the habitat requirements of species, the ecological specialisation of communities and the abundance of macroinvertebrate functional groups (seen as surrogates for ecosystem attributes). 3. For invertebrate communities, bioassessment metrics based on richness had equivocal responses to restoration and the Potamon-Type Index demonstrated no or contradictory responses to restoration. The French biotic index was not sensitive to restoration and instead depicted spatial differences in biological quality. For fish communities, the French fish index was marginally sensitive in the reach with the largest minimum flow increase and some of its metrics were sensitive in other reaches. 4. Contrasting with commonly used bioassessment indices and metrics, several metrics related to habitat requirements appropriately indicated the observed changes in community structure. Large flow changes increased the proportion of fish and macroinvertebrate individuals with preferences for midstream habitats, fast currents, deep waters and/or coarse substrates. However, these changes did not translate into the expected increase in ecological specialisation. In addition, functional metrics indicated that restoration led to higher proportions of grazers and higher availability of suspended food for filtering collectors, suggesting a return to the ecological conditions of a large river. 5. The mixed and potentially contradictory responses of the different metrics confirm the difficulty of establishing benchmarks for ecological indicators in large-regulated rivers and the need to design appropriate bioassessment metrics.