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Publications

Publications from USGS science centers throughout the Southeast Region.

Filter Total Items: 10362

Diffuse-flow conceptualization and simulation of the Edwards aquifer, San Antonio region, Texas Diffuse-flow conceptualization and simulation of the Edwards aquifer, San Antonio region, Texas

A numerical ground-water-flow model (hereinafter, the conduit-flow Edwards aquifer model) of the karstic Edwards aquifer in south-central Texas was developed for a previous study on the basis of a conceptualization emphasizing conduit development and conduit flow, and included simulating conduits as one-cell-wide, continuously connected features. Uncertainties regarding the degree to...
Authors
R. J. Lindgren

Phylogeography, phylogeny and hybridization in trichechid sirenians: Implications for manatee conservation Phylogeography, phylogeny and hybridization in trichechid sirenians: Implications for manatee conservation

The three living species of manatees, West Indian (Trichechus manatus), Amazonian (Trichechus inunguis) and West African (Trichechus senegalensis), are distributed across the shallow tropical and subtropical waters of America and the western coast of Africa. We have sequenced the mitochondrial DNA control region in 330 Trichechus to compare their phylogeographic patterns. In T. manatus...
Authors
J. A. Vianna, Robert K. Bonde, S. Caballero, J. P. Giraldo, R. P. Lima, A. Clark, M. Marmontel, B. Morales-Vela, M. J. De Souza, L. Parr, M. A. Rodriguez-Lopez, A. A. Mignucci-Giannoni, J. A. Powell, F. R. Santos

Regional and local species richness in an insular environment: Serpentine plants in California Regional and local species richness in an insular environment: Serpentine plants in California

We asked how the richness of the specialized (endemic) flora of serpentine rock outcrops in California varies at both the regional and local scales. Our study had two goals: first, to test whether endemic richness is affected by spatial habitat structure (e.g., regional serpentine area, local serpentine outcrop area, regional and local measures of outcrop isolation), and second, to...
Authors
S. Harrison, H.D. Safford, J.B. Grace, J.H. Viers, K.F. Davies

Dietary exposure of mink (Mustela vison) to fish from the Housatonic River, Berkshire County, Massachusetts, USA: Effects on reproduction, kit growth, and survival Dietary exposure of mink (Mustela vison) to fish from the Housatonic River, Berkshire County, Massachusetts, USA: Effects on reproduction, kit growth, and survival

We evaluated the effects of feeding farm-raised mink (Mustela vison) diets containing polychlorinated biphenyl (PCB)-contaminated fish from the Housatonic River (HR; Berkshire County, MA, USA) on adult reproductive performance and kit growth and survival. Diets contained 0.22-3.54% HR fish, providing 0.34-3.7 ??g total PCBs (TPCB)/g feed wet wt (3.5-68.5 pg toxic equivalence [TEQ]/g)...
Authors
S.J. Bursian, C. Sharma, R.J. Aulerich, B. Yamini, R.R. Mitchell, C.E. Orazio, D.R.J. Moore, S. Svirsky, D. E. Tillitt

Genetic structure of natural and restored shoalgrass Halodule wrightii populations in the NW Gulf of Mexico Genetic structure of natural and restored shoalgrass Halodule wrightii populations in the NW Gulf of Mexico

The decline of seagrass communities worldwide has sparked an urgent need for effective restoration strategies, which require a working knowledge of population genetic structure. Halodule wrighti is a common seagrass of the Caribbean region that is being restored to areas of the Gulf of Mexico, yet little is known of its population genetics. This study provides an assessment of individual...
Authors
S.E. Travis, P. Sheridan

Response of Tridens flavus (L.) A. S. Hitchc. to soil nutrients and disturbance in an early successional old field Response of Tridens flavus (L.) A. S. Hitchc. to soil nutrients and disturbance in an early successional old field

Soil nutrients and disturbance are two of the main abiotic factors that influence plant dominance (canopy cover), density, and fecundity in early successional old field plant communities. The manner in which the dominant species in old field successional systems respond to the interaction of nutrients and disturbance is poorly known. We examined the dominance, density of flowering...
Authors
Y. A. K. Honu, D.J. Gibson, B.A. Middleton

Water-clover ferns, Marsilea, in the Southeastern United States Water-clover ferns, Marsilea, in the Southeastern United States

A surge in the collection of exotic Marsilea, M. mutica, M. minuta and M. hirsuta in the southeastern United States has prompted the need for updated identification aids. This study provides an annotated key to all water-clover ferns occurring in the region. It describes and illustrates recently documented exotic species and a previously misidentified western introduction. It details the
Authors
Colette C. Jacono, David M. Johnson

Assessment of reproductive effects in largemouth bass (Micropterus salmoides) exposed to bleached/unbleached kraft mill effluents Assessment of reproductive effects in largemouth bass (Micropterus salmoides) exposed to bleached/unbleached kraft mill effluents

This study evaluated the potential effects of different concentrations of bleached/unbleached kraft mill effluent (B/UKME) on several reproductive endpoints in adult largemouth bass (Micropterus salmoides). The kraft mill studied produces a 50/50 mix of bleached/unbleached market pulp with an estimated release of 36 million gal of effluent/day. Bleaching sequences were C90d10EopHDp and...
Authors
M. S. Sepulveda, D. S. Ruessler, N. D. Denslow, S. E. Holm, T. R. Schoeb, T. S. Gross

A structural equation model analysis of postfire plant diversity in California shrublands A structural equation model analysis of postfire plant diversity in California shrublands

This study investigates patterns of plant diversity following wildfires in fire‐prone shrublands of California, seeks to understand those patterns in terms of both local and landscape factors, and considers the implications for fire management. Ninety study sites were established following extensive wildfires in 1993, and 1000‐m2 plots were used to sample a variety of parameters. Data on...
Authors
J.B. Grace, Jon E. Keeley

Influence of propagule flotation longevity and light availability on establishment of introduced mangrove species in Hawai'i Influence of propagule flotation longevity and light availability on establishment of introduced mangrove species in Hawai'i

Although no mangrove species are native to the Hawaiian Archipelago, both Rbizopbora mangle and Bruguiera sexangula were introduced and have become naturalized. Rbizopbora mangle has spread to almost every major Hawaiian island, but B. sexangula has established only on O'ahu, where it was intentionally introduced. To examine the possibility that differences in propagule characteristics...
Authors
J. A. Allen, K. W. Krauss
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