Environmental Indicators of Habitat Quality in a Migratory Freshwater Fish Fauna

/ In general, diadromous (and particularly amphidromous and catadromous) freshwater fishes decline in frequency of occurrence, change age/size structure, and probably also decline in abundance with increasing elevation and distance upstream from the sea. In freshwater fish faunas with a high proportion of migratory species, as in New Zealand, these changes in occurrence and abundance result in a breakdown of the relationship between fish abundance and habitat quality, making application of the index of biotic integrity (IBI) as a measure of habitat quality problematical since the index depends on the relationship between population metrics and habitat quality. An alternative approach applicable to assessing temporal changes in habitat quality and that uses a large database on fish distributions, involves analysis of the distribution of species across their natural distributions. In this paper we generate curves of occurrence of species across ranges of altitude and distance inland and show, through comparisons of data subsets, that the curves are consistent estimators of species' occurrence and therefore useful as indicators of habitat quality.     

Assessing Biotic Integrity of Streams: Effects of Scale in Measuring the Influence of Land Use/Cover and Habitat Structure on Fish and Macroinvertebrates

/ Fish and macroinvertebrate assemblage composition, instream habitat features and surrounding land use were assessed in an agriculturally developed watershed to relate overall biotic condition to patterns of land use and channel structure. Six 100-m reaches were sampled on each of three first-order warm-water tributaries of the River Raisin in southeastern Michigan. Comparisons among sites and tributaries showed considerable variability in fish assemblages measured with the index of biotic integrity, macroinvertebrate assemblages characterized with several diversity indexes, and both quantitative and qualitative measurements of instream habitat structure. Land use immediate to the tributaries predicted biotic condition better than regional land use, but was less important than local habitat variables in explaining the variability observed in fish and macroinvertebrate assemblages. Fish and macroinvertebrates appeared to respond differently to landscape configuration and habitat variables as well. Fish showed a stronger relationship to flow variability and immediate land use, while macroinvertebrates correlated most strongly with dominant substrate. Although significant, the relationships between instream habitat variables and immediate land use explained only a modest amount of the variability observed. A prior study of this watershed ascribed greater predictive power to land use. In comparison to our study design, this study covered a larger area, providing greater contrast among subcatchments. Differences in outcomes suggests that the scale of investigation influences the strength of predictive variables. Thus, we concluded that the importance of local habitat conditions is best revealed by comparisons at the within-subcatchment scale. KEY WORDS: Stream; Biomonitoring; Land use; Scale; Habitat; Fish; Macroinvertebrates     

Assessing Influences of Hydrology,Physicochemistry, and Habitat on Stream Fish Assemblages Across a Changing Landscape1

Abstract: We evaluated the impact of land cover on fish assemblages by examining relationships between stream hydrology, physicochemistry, and instream habitat and their association with fish responses in streams draining 18 watersheds of the Lower Piedmont of western Georgia. Several important relationships between land use and physicochemical, hydrological, and habitat parameters were observed, particularly higher frequency of spate flows, water temperatures, and lower dissolved oxygen (DO) with percentage impervious surface (IS) cover, higher habitat quality with percentage forest cover, and elevated suspended solid concentrations with percentage pasture cover. Fish assemblages were largely explained by physicochemical and hydrological rather than habitat variables. Specifically, fish species diversity, richness, and biotic integrity were lower in streams that received high frequency of spate flows. Also, overall fish assemblage structure as determined by nonmetric multidimensional scaling was best described by total dissolved solids (TDS) and DO, with high TDS and low DO streams containing sunfish‐based assemblages and low TDS and high DO streams containing minnow‐based assemblages. Our results suggest that altered hydrological and physicochemical conditions, induced largely by IS, may be a strong determinant of fish assemblage structure in these lowland streams and allow for a more mechanistic understanding of how land use ultimately affects these systems.     

Impacts to Water Quality and Fish Habitat Associated with Maintaining Natural Channels for Flood Control

A field investigation conducted on Boulder Creek in Boulder, Colorado evaluated impacts of flood control maintenance activities on flood conveyance, water quality, and fish habitat. Thirty-nine transects were monitored at one control site and two maintenance sites over a period of eight months. Each site was visited on more than 50 occasions in order to characterize pre- and post-maintenance conditions, and to monitor maintenance activities. Measurements along the transects included substrate composition, flow depth, velocity, and elevation. Reach-average values were assigned to variables such as in-stream vegetation, streambank stability, and woody vegetation before and after maintenance. Water temperature, dissolved oxygen, pH, specific conductance, and turbidity were sampled, and habitat suitability indices were developed pre- and post-maintenance for seven indicator fish species. Water quality impacts during maintenance consisted of high turbidity levels (> 400 NTU), which returned to background levels (0.1–15 NTU) overnight, as well as changes in mean temperature and pH. Alteration of physical channel characteristics as a result of maintenance had limited effects on habitat quality for four of seven fish species, but caused improvements in habitat quality for three fish species. The main implications of this study for floodplain management are that: (1) Flood control maintenance practices can be in direct conflict with water quality and fish habitat objectives, and should be carefully designed and implemented by an interdisciplinary team. (2) Physical habitat for some fish species can be improved as well as reduced by maintenance activities. Habitat suitability curves may be useful tools for evaluating limiting factors of the habitat and for identifying opportunities for habitat improvements as part of maintenance.     

Selecting islands and shoals for conservation based on biological and aesthetic criteria

Consideration of biological quality has long been an important component of rating areas for conservation. Often these same areas are highly valued by people for aesthetic reasons, creating demands for housing and recreation that may conflict with protection plans for these habitats. Most methods of selecting land for conservation purposes use biological factors alone. For some land areas, analysis of aesthetic qualities is also important in describing the scenic value of undisturbed land. A method for prioritizing small islands and shoals based on both biological and visual quality factors is presented here. The study included 169 undeveloped islands and shoals ⩽0.8 ha in the Thousand Islands Region of the St. Lawrence River, New York. Criteria such as critical habitat for uncommon plant and animal species were considered together with visual quality and incorporated into a rating system that ranked the islands and shoals according to their priority for conservation management and protection from development. Biological factors were determined based on previous research and a field survey. Visual quality was determined by visual diagnostic criteria developed from public responses to photographs of a sample of islands. Variables such as elevation, soil depth, and type of plant community can be used to classify islands into different categories of visual quality but are unsuccessful in classifying islands into categories of overall biological quality.     

Assessing Water Quality at Large Geographic Scales: Relations Among Land Use,Water Physicochemistry,Riparian Condition,and Fish Community Structure

Data collected from 172 sites in 20 major river basins between 1993 and 1995 as part of the US Geological Survey's National Water-Quality Assessment Program were analyzed to assess relations among basinwide land use (agriculture, forest, urban, range), water physicochemistry, riparian condition, and fish community structure. A multimetric approach was used to develop regionally referenced indices of fish community and riparian condition. Across large geographic areas, decreased riparian condition was associated with water-quality constituents indicative of nonpoint source inputs—total nitrogen and suspended sediment and basinwide urban land use. Decreased fish community condition was associated with increases in total dissolved solids and rangeland use and decreases in riparian condition and agricultural land use. Fish community condition was relatively high even in areas where agricultural land use was relatively high (>50% of the basin). Although agricultural land use can have deleterious effects on fish communities, the results of this study suggest that other factors also may be important, including practices that regulate the delivery of nutrients, suspended sediments, and total dissolved solids into streams. Across large geographic scales, measures of water physicochemistry may be better indicators of fish community condition than basinwide land use. Whereas numerous studies have indicated that riparian restorations are successful in specific cases, this analysis suggests the universal importance of riparian zones to the maintenance and restoration of diverse fish communities in streams.     

A Web‐Based Decision Support System for Assessing Regional Water‐Quality Conditions and Management Actions1

Booth, Nathaniel L., Eric J. Everman, I‐Lin Kuo, Lori Sprague, and Lorraine Murphy, 2011. A Web‐Based Decision Support System for Assessing Regional Water‐Quality Conditions and Management Actions. Journal of the American Water Resources Association (JAWRA) 47(5):1136‐1150. DOI: 10.1111/j.1752‐1688.2011.00573.x Abstract: The U.S. Geological Survey National Water Quality Assessment Program has completed a number of water‐quality prediction models for nitrogen and phosphorus for the conterminous United States as well as for regional areas of the nation. In addition to estimating water‐quality conditions at unmonitored streams, the calibrated SPAtially Referenced Regressions On Watershed attributes (SPARROW) models can be used to produce estimates of yield, flow‐weighted concentration, or load of constituents in water under various land‐use condition, change, or resource management scenarios. A web‐based decision support infrastructure has been developed to provide access to SPARROW simulation results on stream water‐quality conditions and to offer sophisticated scenario testing capabilities for research and water‐quality planning via a graphical user interface with familiar controls. The SPARROW decision support system (DSS) is delivered through a web browser over an Internet connection, making it widely accessible to the public in a format that allows users to easily display water‐quality conditions and to describe, test, and share modeled scenarios of future conditions. SPARROW models currently supported by the DSS are based on the modified digital versions of the 1:500,000‐scale River Reach File (RF1) and 1:100,000‐scale National Hydrography Dataset (medium‐resolution, NHDPlus) stream networks.