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Research about Louisiana

Source-linked reports with geographic coverage including Louisiana.

At least 757 records · Page 42Linked to original sources
USGS1992

Hydrological, geomorphological, and chemical effects of Hurricane Andrew on coastal marshes of Louisiana

Hydrological conditions are reported for the hurricane-induced storm surge at marsh sites in Terrebonne and Barataria Basins. There was a 6 hour or greater delay in the arrival of the storm surge at interior marsh sites compared to coastal locations. A water surge of about 1.5 m with a salinity of 10–15‰ was recorded at an intermediate salinity marsh site in Terrebonne Basin where significant geomorphological changes occurred with lateral movement and stacking of marsh vegetation and sediment, erosion, and the conversion of wetlands to open water. A residual salt wedge attributed to the storm surge was detected in sediments at this intermediate marsh site about 55 days after the hurricane. In the pore water, at 30 cm in depth, there were increases in alkalinity, ammonia, phosphate, and manganese, but not iron or sulfide, although there was a significant depletion of sulfur with respect to chloride. The increases in concentration of these species in the pore water suggests that there was an increase in organic matter decomposition. Although increases in sulfide phytotoxicity were not obvious, the residual salinity of pore water may influence wetland loss through longer-term impacts on macrophyte production. Storm-induced sediment deposition, which will help ameliorate wetland loss, was observed at a salt marsh site in Terrebonne Basin.

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USGS1992

Food preferences of spring-migrating blue-winged teal in southwestern Louisiana

We studied effects of pair status, molt intensity, and year on food selection by migrating male blue-winged teal (Anas discors) in southwestern Louisiana during springs 1990 and 1991. Diets consisted primarily of animal foods; but plant material, consisting mostly of seeds, comprised as much as 44%. There was no difference in animal food consumption by paired and unpaired males; however, the proportion of animal material in the male diet was greater in 1990 than in 1991. Animal food consumption was not positively correlated with mean molt intensity. Food preferences of paired and unpaired males were similar in both years. Animal foods, especially benthos and organisms associated with vegetative substrates, were preferred to seeds and freeswimming invertebrates. We recommend that habitat management for spring-migrating blue-winged teal focus on production of invertebrates, especially long-lived forms such as dragonflies, hemipterans (except water boatmen), midges, and other dipterans.

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USGS1991

Control of pest species: Tree shelters help protect seedlings from nutria

Various methods of nutria preventative techniques were tested in attempts to curb the loss of seedlings due to nutria capturing. The results of testing possibly indicate that tree shelters have real potential for use in forest restoration projects on sites with moderate nutria populations. Tree shelters may even prove effective on sites with high nutria populations, as long as alternative food supplies are available.

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USGS1991

Water resources data, Louisiana, water year 1990

Water resources data for the 1990 water year for Louisiana consist of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; and water levels and water quality of ground water. This report contains records for water discharge at 60 gaging stations; stage only for 13 gaging stations and 7 lakes; water quality for 49 surface-water stations (including 12 gaging stations), and 87 wells; and water levels for 212 observation wells. Also included are data for 117 crest-stage and flood-profile partial-record stations. Additional water data were collected at various sites not involved in the systematic data-collection program, and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Louisiana.

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USGS1990

Food habits of wintering canvasbacks in Louisiana

We studied the food habits of canvasbacks ( Aythya valisineria ) at Catahoula Lake (inland) and the Mississippi River Delta (coastal), Louisiana, from November 1987 to February 1988. Plant foods comprised >97 aggregate percent dry mass of the canvasback diet. The proportion of plant material eaten did not vary with sex, age, or month, or differ between study sites or nocturnal and diurnal collections. Tubers of chufa flatsedge ( Cyperus esculentus ) and common arrowhead ( Sagittaria latifolia ) made up 94% of the canvasback diet at Catahoula Lake. Common and grassy arrowhead ( Sagittaria graminea ) tubers and American bulrush ( Scirpus americanus ) rhizomes and seeds formed 94% of the canvasback diet at the Mississippi River Delta. Consumption of specific food taxa did not vary with sex, age, or month at either study site. Canvasbacks at the Mississippi River Delta preferred seeds of American bulrush over all other foods, but American bulrush rhizomes were underrepresented in the diet. Densities of subterranean plant foods at Catahoula Lake and the Mississippi River Delta are apparently higher than at other major canvasback concentration areas and enable canvasbacks wintering in Louisiana to improve their physical condition before spring migration.

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USGS1990

Influence of ingested lead on body mass of wintering canvasbacks

We determined the prevalence of lead shotgun pellets in gizzards of canvasbacks ( Aythya valisineria ) collected at Catahoula Lake and the Mississippi River Delta, Louisiana, during winter 1987-88 to assess the influence of ingested lead shot on canvasback body mass. The prevalence of ingested lead shot was significantly higher at Catahoula Lake (27%) than at the Mississippi River Delta (4%). Canvasbacks collected at Catahoula Lake showed significant differences in prevalence of ingested lead shot by age and month. We attributed age-related and seasonal variations to differences in foraging effort and exposure time. Body mass of canvasbacks at Catahoula Lake, after accounting for age, monthly variation, and body size, was significantly reduced (120 g or 10%) in birds that had lead shot in their gizzards.

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USGS1990

Water resources data, Louisiana, water year 1989

Water resources data for the 1989 water year for Louisiana consist of records of stage, discharge, and water quality of streams; stage, contents, and water quality of lakes and reservoirs; and water levels and water quality of ground water. This report contains records for water discharge at 60 gaging stations; stage only for 14 gaging stations and 7 lakes; water quality for 35 surface-water stations (including 12 gaging stations), and 84 wells; and water levels for 232 observation wells. Also included are data for 104 crest-stage and flood-profile partial-record stations. Additional water data were collected at various sites not involved in the systematic data-collection program, and are published as miscellaneous measurements. These data represent that part of the National Water Data System operated by the U.S. Geological Survey and cooperating State and Federal agencies in Louisiana.

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USGS1990

Diurnal time-activity budgets of wintering canvasbacks in Louisiana

We determined diurnal time-activity budgets of Canvasbacks ( Aythya valisineria ) at Catahoula Lake and at the Mississippi River Delta, Louisiana, from December 1987 to March 1988. Canvasback feeding, resting, locomotory, and comfort activities varied by month and location with a month-location interaction. Moreover, the percentage of time spent feeding varied by sex with a month-sex interaction. Study site differences in the time- activity budgets of wintering Canvasbacks may be related to characteristics of their foods, foraging mode, disturbance level, and physical features of habitats at the two study sites. Canvasbacks wintering in Louisiana generally spent less time feeding and more time resting during the day than they did in Mississippi or coastal South Carolina. Levels of agonistic behavior were lower than those observed in South Carolina. We found no evidence of male dominance of female Canvasbacks in Louisiana.

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USGS1989

Accretion and canal impacts in a rapidly subsiding wetland II: Feldspar marker horizon technique

Recent (6–12 month) marsh sediment accretion and accumulation rates were measured with feldspar marker horizons in the vicinity of natural waterways and man-made canals with spoil banks in the rapidly subsiding environment of coastal Louisiana. Annual accretion rates in a Spartina alterniflora salt marsh in the Mississippi deltaic plain averaged 6 mm in marsh adjacent to canals compared to 10 mm in marsh adjacent to natural waterways. The rates, however, were not statistically significantly different. The average rate of sediment accretion in the same salt marsh region for a transect perpendicular to a canal (13 mm yr −1 ) was significantly greater than the rate measured for a transect perpendicular to a natural waterway (7 mm yr −1 ). Measurements of soil bulk density and organic matter content from the two transects were also different. This spatial variability in accretion rates is probably related to (1) spoil bank influences on local hydrology; and (2) a locally high rate of sediment input from lateral erosion associated with pond enlargement. In a brackish Spartina patens marsh on Louisiana’s Chenier plain, vertical accretion rates were the same along natural and canal waterways (3–4 mm yr −1 ) in a hydrologically restricted marsh region. However, the accretion rates for both waterways were significantly lower than the rates along a nonhydrologically restricted natural waterway nearby (11 mm yr −1 ). The vertical accretion of matter displayed semi-annual differences in the brackish marsh environment.

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USGS1989

Rising water levels and the future of southeastern Louisiana swamp forests

An important factor contributing to the deterioration of wetland forests in Louisiana is increasing water levels resulting from eustatic sea-level rise and subsidence. Analyses of long-term water level records from the Barataria and Verret watersheds in southeastern Louisiana indicate an apparent sea level rise of about 1-m per century, mainly the result of subsidence. Permanent study plots were established in cypress-tupelo stands in these two watersheds. The tree, water level, and subsidence data collected in these plots were entered into the U.S. Fish and Wildlife Service’s FORFLO bottomland hardwood succession model to determine the long-term effects of rising water levels on forest structure. Analyses were made of 50–100 years for a cypress-tupelo swamp site in each basin and a bottomland hardwood ridge in the Verret watershed. As flooding increased, less flood tolerant species were replaced by cypress-tupelo within 50 years. As flooding continued, the sites start to become nonforested. From the test analyses, the FORFLO model seems to be an excellent tool for predicting long-term changes in the swamp habitat of south Louisiana.

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