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Environmental contaminants in redheads wintering in coastal Louisiana and Texas Environmental contaminants in redheads wintering in coastal Louisiana and Texas

Whole body and liver analyses indicated that wintering redheads (Aythya americana; n = 70) in coastal Louisiana (one site) and Texas (two sites) were relatively free of contamination with common trace elements, organochlorines, and hydrocarbons. Most trace elements, including As, Cr, Hg, Mg, Mn, Ni, Pb, Se, Sr, and Zn, were within background concentrations in livers; levels of B, Cd, Cu...
Authors
T.C. Michot, T. W. Custer, A.J. Nault, C. A. Mitchell

Production and decomposition of Spartina patens in a degrading coastal marsh Production and decomposition of Spartina patens in a degrading coastal marsh

Production and decomposition rates were calculated for Spartina patens in a mesohaline coastal marsh in Louisiana. Production was estimated to be 800 g m2 yr-1 during 1991 and 1,696 g m-1 yr-1 during 1992. The relative decomposition rate of S. patens stems was -0.001152 g g-1 d-1 which may be restated as a half life of 395 days. Both production and decomposition rates for this area are...
Authors
Lori A. Johnson, Kathleen A. Reynolds, A. Lee Foote

Diet differences in Redheads from nearshore and offshore zones in Louisiana Diet differences in Redheads from nearshore and offshore zones in Louisiana

Habitat management decisions for diving ducks in winter are limited by the lack of information concerning their use of nearshore and offshore zones. Therefore, we compared diets of redheads (Aythya americana) collected from nearshore (n = 206) and offshore (n = 72) zones during winters at the Chandeleur Islands, Louisiana, 1987-89. A greater (P 0.05) proportion of redheads from nearshore...
Authors
Thomas C. Michot, A.J. Nault

Nesting habitat of Belding’s Savannah sparrows in coastal salt marshes Nesting habitat of Belding’s Savannah sparrows in coastal salt marshes

Although the Belding’s Savannah sparrow (Passerculus sandwichensis beldingl) is listed as endangered in California, little is known about the factors that affect its abundance and distribution. Numbers of breeding pairs, nesting territory sizes, and vegetation characteristics were measured at fourteen study plots in two southern California coastal wetlands, Tijuana Estuary and Los...
Authors
Abby Powell

Spectral reflectance and canopy structure characteristics of gulf coast wetland vegetation types Spectral reflectance and canopy structure characteristics of gulf coast wetland vegetation types

Field measurements of canopy structure and species composition are related to spectral reflectance measurements taken with a radiometer over a number of marsh sites. Marsh vegetation types are discussed in terms of their characteristic canopy structure and phenology; the influence of these characteristics on spectral reflectance will be examined. Vegetation types that are discussed...
Authors
R. Spell, Elijah W. Ramsey III

Ecological Benefits of the Conservation Reserve Program Ecological Benefits of the Conservation Reserve Program

No abstract available.
Authors
Christopher P. Dunn, F. Stearns, Glenn R. Guntenspergen, David M. Sharpe

Marsh submergence vs. marsh accretion: Interpreting accretion deficit data in coastal Louisiana Marsh submergence vs. marsh accretion: Interpreting accretion deficit data in coastal Louisiana

The apparent imbalance between relative sea-level rise and vertical marsh accretion is frequently cited as a major factor in the problem of wetland loss in Louisiana. Rates of relative sea-level rise are high in Louisiana due to high rates of subsidence. Although marsh accretion rates are also high, they are usually insufficient to maintain the relative elevation of the marsh surface...
Authors
Denise J. Reed, Donald R. Cahoon

The examination of a competition matrix for transitivity and intransitive loops The examination of a competition matrix for transitivity and intransitive loops

Recent examinations of competition matrices for transitivity (species A > species B > species C) have used techniques that can be subject to certain biases. First, recent theoretical and empirical analyses have shown that traditional measures of competitive performance are biased in favor of the larger species. It is argued that this size bias has the potential to bias analyses of...
Authors
James B. Grace, Glenn R. Guntenspergen, Janet R. Keough
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