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Mower E.,Mississippi Cooperative Fish and Wildlife Research Unit | Miranda L.E.,U.S. Geological Survey
Lake and Reservoir Management | Year: 2013

Managing water storage and withdrawals in many reservoirs requires establishing seasonal targets for water levels (i.e., rule curves) that are influenced by regional precipitation and diverse water demands. Rule curves are established as an attempt to balance various water needs such as flood control, irrigation, and environmental benefits such as fish and wildlife management. The processes and challenges associated with amending rule curves to balance multiuse needs are complicated and mostly unfamiliar to non-US Army Corps of Engineers (USACE) natural resource managers and to the public. To inform natural resource managers and the public we describe the policies and process involved in amending rule curves in USACE reservoirs, including 3 frameworks: a general investigation, a continuing authority program, and the water control plan. Our review suggests that water management in reservoirs can be amended, but generally a multitude of constraints and competing demands must be addressed before such a change can be realized. © 2013 Copyright Taylor and Francis Group, LLC.

Miranda L.E.,U.S. Geological Survey | Krogman R.M.,Mississippi Cooperative Fish and Wildlife Research Unit
Fisheries | Year: 2015

It has been conjectured that reservoirs differ in the rate at which they manifest senescence, but no attempt has been made to find an indicator of senescence that performs better than chronological age. We assembled an indicator of functional age by creating a multimetric scale consisting of 10 metrics descriptive of reservoir environments that were expected to change directionally with reservoir senescence. In a sample of 1,022 U.S. reservoirs, chronological age was not correlated with functional age. Functional age was directly related to percentage of cultivated land in the catchment and inversely related to reservoir depth. Moreover, aspects of reservoir fishing quality and fish population characteristics were related to functional age. A multimetric scale to indicate reservoir functional age presents the possibility for management intervention from multiple angles. If a reservoir is functionally aging at an accelerated rate, action may be taken to remedy the conditions contributing most to functional age. Intervention to reduce scores of selected metrics in the scale can potentially reduce the rate of senescence and increase the life expectancy of the reservoir. This leads to the intriguing implication that steps can be taken to reduce functional age and actually make the reservoir grow younger. © 2015, American Fisheries Society.

Krogman R.M.,Mississippi Cooperative Fish and Wildlife Research Unit | Miranda L.E.,U.S. Geological Survey
Lake and Reservoir Management | Year: 2016

Fish habitats in many aging US reservoirs have become degraded and require broad-scale assessment to rate their status and facilitate rehabilitation efforts. To help prioritize habitat projects in reservoirs, we assembled a rating system for large reservoirs in the contiguous United States. Using responses to an online questionnaire about fish habitat impairment in 1299 large US reservoirs, we applied multivariate analyses to identify combinations of habitat impairment descriptors that quantified broad impairment types (i.e., a construct). Resulting constructs reflected point source pollution, nonpoint source pollution, excessive nutrients, algae blooms, siltation, limited nutrients, mudflats and shallowness, limited connectivity to adjacent habitats, limited littoral structure, nuisance species, anomalous water regimes, and large water level fluctuations. Scores were summed across constructs to create a composite number that rated overall reservoir habitat impairment. Construct and composite scores differed among geographic ecoregions of the United States. This rating system could provide a starting point for prioritizing reservoirs for habitat rehabilitation and enhancement projects. © 2016 This article not subject to US copyright law.

Miranda L.E.,U.S. Geological Survey | Krogman R.M.,Mississippi Cooperative Fish and Wildlife Research Unit
River Research and Applications | Year: 2014

The tailwater is the reach of a stream immediately below an impoundment that is hydrologically, physicochemically and biologically altered by the presence and operation of a dam. The overall goal of this study was to gain a nationwide awareness of the issues afflicting tailwater reaches in the United States. Specific objectives included the following: (i) estimate the percentage of reservoirs that support tailwater reaches with environmental conditions suitable for fish assemblages throughout the year, (ii) identify and quantify major sources of environmental stress in those tailwaters that do support fish assemblages and (iii) identify environmental features of tailwater reaches that determine prevalence of key fish taxa. Data were collected through an online survey of fishery managers. Relative to objective 1, 42% of the 1306 reservoirs included in this study had tailwater reaches with sufficient flow to support a fish assemblage throughout the year. The surface area of the reservoir and catchment most strongly delineated reservoirs maintaining tailwater reaches with or without sufficient flow to support a fish assemblage throughout the year. Relative to objective 2, major sources of environmental stress generally reflected flow variables, followed by water quality variables. Relative to objective 3, zoogeography was the primary factor discriminating fish taxa in tailwaters, followed by a wide range of flow and water quality variables. Results for objectives 1-3 varied greatly among nine geographic regions distributed throughout the continental United States. Our results provide a large-scale view of the effects of reservoirs on tailwater reaches and may help guide research and management needs. Published 2013. This article is a U.S. Government work and is in the public domain in the USA. © 2014 John Wiley & Sons, Ltd.

Vilella F.J.,Mississippi Cooperative Fish and Wildlife Research Unit
Open Ornithology Journal | Year: 2014

We investigated the relationship between red-cockaded woodpecker (Picoides borealis) reproductive success and microhabitat characteristics in a southeastern loblolly (Pinus taeda) and shortleaf (P. echinata) pine forest. From 1997 to 1999, we recorded reproductive success parameters of 41 red-cockaded woodpecker groups at the Bienville National Forest, Mississippi. Microhabitat characteristics were measured for each group during the nesting season. Logistic regression identified understory vegetation height and small nesting season home range size as predictors of red-cockaded woodpecker nest attempts. Linear regression models identified several variables as predictors of red-cockaded woodpecker reproductive success including group density, reduced hardwood component, small nesting season home range size, and shorter foraging distances. Red-cockaded woodpecker reproductive success was correlated with habitat and behavioral characteristics that emphasize high quality habitat. By providing high quality foraging habitat during the nesting season, red-cockaded woodpeckers can successfully reproduce within small home ranges. © Wood et al.; Licensee Bentham Open.

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