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Filter Total Items: 3377

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 arelow relative
Authors
Lori A. Johnson, Kathleen A. Reynolds, A. Lee Foote

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 had foo
Authors
Thomas C. Michot, A.J. Nault

Wetland systems and their response to management

No abstract available.
Authors
Glenn R. Guntenspergen, J.R. Keough, J. Allen

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 Peñasquitos Lago
Authors
Abby Powell

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 include Panicum
Authors
R. Spell, Elijah W. Ramsey III

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

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. This situati
Authors
Denise J. Reed, Donald R. Cahoon

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 transitivity. Se
Authors
James B. Grace, Glenn R. Guntenspergen, Janet R. Keough

Survival of female canvasbacks wintering in coastal Louisiana

Annual survival probabilities of female canvasbacks (Aythya valisineria) are lower than those of males, but sources and timing of mortality are poorly understood. To further elucidate causes of reduced annual survival in female canvasbacks, we estimated survival rates for radio-tagged females in coastal Louisiana during winters 1988-91. Survival estimates for winters 1988-91 were 0.946 ± 0.072 (es
Authors
William L. Hohman, Ronald D. Pritchert, Joseph Moore, D.O. Schaeffer