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Year Published: 2004

Connecting ground water influxes with fish species diversity in an urbanized watershed

Valley Creek watershed is a small stream system that feeds the Schuylkill River near Philadelphia, Pennsylvania. The watershed is highly urbanized, including over 17 percent impervious surface cover (ISC) by area. Imperviousness in a watershed has been linked to fish community structure and integrity. Generally, above 10 to 12 percent ISC there is...

Steffy, L.Y.; McGinty, A.L.; Welty, C.; Kilham, S.S.

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Year Published: 2004

Differential consumption of eastern red cedar (Juniperus virginiana) by avian and mammalian guilds: Implications for tree invasion

Increased abundance and distribution of eastern redcedar (Juniperns virginiannus), a native species in the Great Plains, has been associated with changes in ecosystem functioning and landscape cover. Knowledge of the main consumers and dispersal agents of eastern red cedar cones is essential to understanding the invasive spread of the species. We...

Horncastle, V.J.; Hellgren, E.C.; Mayer, P.M.; Engle, David M.; Leslie, D.M.

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Year Published: 2004

Elevation and stream-size thresholds affect distributions of native and exotic warmwater fishes in Wyoming

This study was conducted to assess the influence of elevation and stream width on the occurrence of 28 native and six exotic fish species using data collected (1954-2003) from 1,114 stream reaches in Wyoming. Medians and ranges of elevation and stream width were used to assess how elevation and stream width influenced the occurrence of individual...

Quist, M.C.; Hubert, W.A.; Rahel, F.J.

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Year Published: 2004

Factors affecting swimming performance of fasted rainbow trout with implications of exhaustive exercise on overwinter mortality

We evaluated the effects of body size, water temperature, and sustained swimming activity on swimming performance and the effects of exhaustive exercise on mortality of fasted juvenile rainbow trout. Fasting caused swimming performance to decline more rapidly for small fish than large fish, and warmer water temperatures and sustained swimming...

Simpkins, D.G.; Hubert, W.A.; Del Rio, C.M.; Rule, D.C.

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Year Published: 2004

Gene flow and genetic characterization of Northern Goshawks breeding in Utah

Adult movement and natal dispersal data demonstrate that Northern Goshawks (Accipiter gentilis) are able to travel over long distances, suggesting a large functional population. However, these data are unable to determine whether these movements contribute to gene flow among adjacent breeding areas. We used eight microsatellite DNA loci and...

Sonsthagen, Sarah A.; Talbot, Sandra L.; White, C.M.

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Year Published: 2004

Habitat restoration across large areas: Assessing wildlife responses in the Clearwater basin, Idaho

Over the past century, fire suppression and prevention have altered disturbance regimes across the Pacific Northwest, resulting in a significant divergence of historical and current conditions in forested habitats. To address this continuing trend in habitat changes and begin restoring historical patterns of disturbance, the Clearwater Basin Elk...

Scanvara, L.K.; Servheen, G.; Melquist, W.; Davis, D.; Scott, J. M.

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Year Published: 2004

Hydrologic aspects of marsh ponds during winter on the Gulf Coast Chenier Plain, USA: Effects of structural marsh management

The hydrology of marsh ponds influences aquatic invertebrate and waterbird communities. Hydrologic variables in marsh ponds of the Gulf Coast Chenier Plain are potentially affected by structural marsh management (SMM: levees, water control structures and impoundments) that has been implemented since the 1950s. Assuming that SMM restricts tidal...

Bolduc, F.; Afton, A. D.

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Year Published: 2004

Redistribution and growth of the Caspian Tern population in the Pacific Coast region of North America, 1981-2000

We examined nesting distribution and demography of the Pacific Coast population of Caspian Terns (Sterna caspia) using breeding records and band recoveries spanning two decades since the first population assessment. Since 1980, population size has more than doubled to about 12 900 pairs, yet the proportion of the population nesting at inland (18...

Suryan, R.M.; Craig, D.P.; Roby, D.D.; Chelgren, N.D.; Collis, K.; Shuford, W.D.; Lyons, Donald E.

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Year Published: 2004

Relationships between wintering waterbirds and invertebrates, sediments and hydrology of coastal marsh ponds

We studied relationships among sediment variables (carbon content, C:N, hardness, oxygen penetration, silt-clay fraction), hydrologic variables (dissolved oxygen, salinity, temperature, transparency, water depth), sizes and biomass of common invertebrate classes, and densities of 15 common waterbird species in ponds of impounded freshwater,...

Bolduc, F.; Afton, A. D.

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Year Published: 2004

Seasonal variation in American black bear Ursus americanus activity patterns: Quantification via remote photography

Activity pattern plasticity may serve as an evolutionary adaptation to optimize fitness in an inconstant environment, however, quantifying patterns and demonstrating variation can be problematic. For American black bears Ursus americanus, wariness and habitat inaccessibility further complicate quantification. Radio telemetry has been the primary...

Bridges, A.S.; Vaughan, M.R.; Klenzendorf, S.

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Year Published: 2004

Structural complexity and land-surface energy exchange along a gradient from arctic tundra to boreal forest

Question: Current climate changes in the Alaskan Arctic, which are characterized by increases in temperature and length of growing season, could alter vegetation structure, especially through increases in shrub cover or the movement of treeline. These changes in vegetation structure have consequences for the climate system. What is the...

Thompson, C.; Beringer, J.; Chapin, F. S.; McGuire, A.D.

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Year Published: 2004

Swimming endurance of bull trout, lake trout, arctic char, and rainbow trout following challenge with Renibacterium salmoninarum

We tested the swimming endurance of juvenile bull trout Salvelinus confluentus, lake trout S. namaycush, Arctic char S. alpinus, and rainbow trout Oncorhynchus mykiss at 9°C and 15°C to determine whether sublethal infection from a moderate challenge of Renibacterium salmoninarum administered months before testing affected the length of time fish...

Jones, D.T.; Moffitt, C.M.