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A. Lee Foote

Publications and source records attributed to A. Lee Foote.

10 recordsLinked to original sources
USGS2009

Processes of wetland loss in India

Wetlands in India supply crucial human and animal needs such as drinking water, protein production, fodder, water purification, wildlife habitat, and flood storage. Increased appreciation of uses and threats is essential to protect wetlands where justified. Three quarters of India's population is rural, it places great demands on India's wetlands and losses continue to occur. This paper is based on extensive discussions with natural resource managers, government employees, farmers, academicians, and resource users at dozens of sites in India, as well as an extensive literature search. Twelve important kinds of wetland loss are identified and mechanisms believed to be causing them discussed: (1) agricultural conversion, (2) direct deforestation, (3) hydrologie alteration, (4) inundation, (5) defoliation, (6) altered upper watersheds, (7) accumulative water demands, (8) water quality degradation, (9) wetland consolidation, (10) global climate change, (11) ground-water depletion, (12) exotic species and biodiversity. Wetland understanding, management, and Public awareness in India must continue growing if wetland resources are to remain functional.

Environmental Conservation↗
USGS2005

Effects of managed impoundments and herbivory on wetland plant production and stand structure

Managed impoundments, a form of structural marsh management, have been used to enhance plant production in the rapidly-eroding marshes of coastal Louisiana, USA, yet few studies have quantified their effects by measuring plant production before and after impoundment construction. We tested the effects of structural marsh management on the annual aboveground production and plant stand structure (stem density and stem height) of Spartina patens and Schoenoplectus americanus by collecting measurements before and after the construction of two shallow impoundments. We manipulated the water level in each impoundment by adjusting a single flap-gated culvert fitted with a variable crest weir. Because nutria herbivory also seemed to have a strong influence on plant production in these marshes, we tested the effects of nutria herbivory on the annual aboveground production and plant stand structure of both plant species by collecting data from fenced (ungrazed) and unfenced (grazed) plots located in both managed and unmanaged areas. There were no significant differences in Spartina annual production, stem density, and stem height between managed and unmanaged areas, and Schoenoplectus annual production, stem density, and stem height were greater in unmanaged marsh, indicating that the management method used in this study was not effective in promoting plant production in the rapidly-eroding, brackish, deltaic marshes of coastal Louisiana. Nutria herbivory dramatically reduced the annual aboveground production, stem density, and stem, height of Schoenoplectus , a preferred forage species, and thus altered the structure of the mixed species stand. Herbivory had no significant effect on the annual aboveground production and stem density of Spartina . In the absence of herbivory, the stem height of Spartina increased significantly and coincided with significant increases in the stem density and height of Schoenoplectus . The changes in plant stand structure caused by nutria herbivory may facilitate marsh erosion and ultimately contribute to wetland loss.

Louisiana↗
USGS1997

Effect of hydrologic management on marsh surface sediment deposition in coastal Louisiana

High rates of coastal land loss in Louisiana have prompted efforts to maintain or restore coastal wetland habitats, and structural management of marsh hydrology is one of a number of approaches that has been adopted. The aim of this study was to determine the effect of hydrologic management measures on marsh-surface sediment deposition in the Mississippi deltaic plain. Four impoundments, ranging in size from 50 ha to 177 ha and similarly sized control sites were included in the study. At each site, marsh-surface sediment traps were collected approximately biweekly for 3.5 yr to measure changes in sediment deposition. There was no significant difference in sediment deposition between any of the impoundment and control sites during the premanagement period. The results show no significant difference in marsh-surface sediment deposition between management year 1992–1993 and management year 1994–1995, but management year 1993–1994 had significantly lower sediment deposition than either the first or the last year of the study. Management year 1992–1993 showed the highest sediment deposition when it was assessed across all basins, areas, and sites, and this high rate of deposition is accounted for by the impact of Hurricane Andrew. For all management years there were significant differences between impoundment and control sites, with control sites showing higher rates of marsh surface sediment deposition than impoundments. No clear pattern was identified concerning the influence of various types of hydrologic management on rates of sediment deposition. This reduction in sediment deposition indicated that the areas under management in this study are receiving insufficient inorganic sediment deposition to keep pace with sea-level rise.

Louisiana↗
USGS1995

Wind shear stress measurements in a coastal marsh during Hurricane Andrew

Hurricane Andrew produced changes to the Louisiana wetlands not normally observed after lesser, more common storms. For example, the <25 m/s wind speeds generated by cold fronts and winter storms, and any accompanying storm surge, do not cause substantial, wide-spread alteration of marsh vegetation. During Hurricane Andrew, however, the wind, the wind-driven storm surge, or both produced severe, wide-spread wetland alteration, especially in areas that primarily consisted of densely vegetated floating mats. In a few hours, vegetated brackish marsh was severely torn and large areas were converted to open water, a process that takes decades when driven by geologic subsidence, human intervention, and lesser storms. During the passage of Hurricane Andrew, wind measurements were taken inside an impoundment within a brackish part of Louisiana's coastal wetlands system. At its closest point, the site lay 50 km to the right of the north-trending storm track, placing it in or near the zone of maximum wind (the eye wall). As the hurricane approached, the wind blew from the north; after it passed, the wind direction swung around to the southeast. Several hours after the eye passed, the southeasterly wind drove a 1.5-m storm surge through the area, causing the collapse of the meteorology tower. Wind shear stress calculations, based on data from two vertically stacked sensors, showed a direct correlation between wind shear stress and wind speed. The greatest increase in wind shear stress occurred when wind speed exceeded 20 m/s. Overall, wind shear stress increased more than three orders of magnitude — from approximately 0.01 N/m² at a wind speed of 6 m/s through 1 N/m² at 20 m/s to 18 N/m² at the maximum sustained speed of 43 m/s. Drag-coefficient calculations show that the open-ocean CD formulations, such as the popular WAMDI model, cannot be employed for wetland use because it overestimates CD for velocities less than approximately 20 m/s and underestimates it for higher velocities.

Louisiana↗
USGS1995

Disturbance and recovery of the Louisiana coastal marsh landscape from the impacts of Hurricane Andrew

The impact of Hurricane Andrew on the Louisiana coastal landscape and the initial recovery of wetland plant communities was determined from extensive surveys of a large geographic region of coastal marsh near Atchafalaya Bay and intensive studies of an oligohaline marsh on Otter Bayou. Wind and water movements associated with the hurricane resulted in the formation of compressed marsh, thick sediment deposits, wrack deposition, areas of salt burning, and scour. No sites were entirely without some impact. Sediments were deposited over large areas of coastal marsh. Marsh sites near Atchafalaya Bay had the thickest post-storm accumulations documented, up to 16 cm on average, while inland marsh sites accumulated lesser amounts of sediments. The nature of the sediment deposited on the marsh surface varied with location relative to the path of the storm and sources of sediment. Lateral compression resulted in surface relief 5-10 times greater than normal surface relief. Plant cover quickly recovered in all hurricane impact types except for scour areas and areas of thick wrack accumulation. Shifts in species dominance occurred in laterally compressed areas and are related to increased elevations. These findings suggest that hurricanes result in a variety of impacts in coastal Louisiana marshes and that the heterogeneity of the coastal landscape contributes to the magnitude and distribution of these impacts.

Louisiana↗
USGS1993

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 m 2 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 low relative to most other studies in coastal areas. These data contribute to our understanding of the dynamics of organic matter in degrading coastal wetlands.

Louisiana↗