Wetland Loss in Louisiana

Walker, H. Jesse; Coleman, James M.; Roberts, Harry H.; Tye, Robert S.

doi:10.1080/04353676.1987.11880207

Cited by 40 publications

(18 citation statements)

References 10 publications

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“…Studies of coastal sedimentary sequences (notably Redfield, 1972; McCaffrey and Thompson, 1980;Funnel1 and Pearson, 1989) have reaffirmed the ability of such systems to accrete vertically and prograde laterally under the moderate rates of eustatic sea-level rise (1-10mm a-I) that are characteristic of mid-to late-Holocene time. However, whilst it is recognized that salt marshes are clearly transitional features in the context of the large-scale sea-level and shoreline position changes occurring over longer time-scales ( > lo4 years), concern is now being articulated over the apparent mismatch, in many areas, between present rates of sediment accumulation and local rates of relative sea-level rise Baumann et al, 1984;Stevenson et al, 1986;Walker et al, 1987;Bricker-Urso et al, 1989). In parts of North America and Europe, present and future accretionary deficits translate into major areal losses of ecologically, commercially and recreationally important coastal wetland (Gagliano et al, 1981;Boorman et al, 1989; Burd, 1989).…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation of vertical marsh growth and adjustment to accelerated sea‐level rise, North Norfolk, U.K.

French

1993

Earth Surf Processes Landf

226

153

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In parts of North America and Europe, present and future sedimentary deficits translate into major areal losses of coastal salt marsh. Physically based simulations of medium-to long-term adjustment to accelerated sea-level rise are few, partly due to the difficulty in extrapolating imperfectly understood sedimentation parameters. This paper outlines the implementation and application of a simple one-dimensional mass balance model designed to simulate the vertical adjustment of predominantly minerogenic marsh surfaces to various combinations of sediment supply, tidal levels and regional subsidence. Two aspects of marsh growth are examined, with reference to sites on the macro-tidal north Norfolk coast, U.K.: (i) historical marsh growth under a scenario of effective (long-term) eustatic stability but slow regional subsidence; and (ii) marsh response to various non-linear eustatic rise scenarios for the next century. In contrast to more organogenic North American marshes, sedimentation rates in Norfolk are strongly time-dependent. Where the overall sediment budget is so closely linked to marsh age and relative elevation, some form of numerical simulation offers a preferred means of predicting the impact of accelerated sea-level rise. Simulations performed here show that only the most dramatic eustatic scenarios result in ecological 'drowning' and reversion to tidal flat within the conventional 2100 prediction interval. Currently favoured scenarios give rise to accretionary deficits which are clearly sustainable in the short-term, albeit at the expense of increased inundation frequency and consequent changes in the distribution of marsh flora and fauna.

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Section: Introductionmentioning

confidence: 99%

Numerical simulation of vertical marsh growth and adjustment to accelerated sea‐level rise, North Norfolk, U.K.

French

1993

Earth Surf Processes Landf

226

153

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“…Fixed-crest weirs were historically constructed the landward area is impounded; Herke (1971) in Louisiana coastal marsh channels to reduce referred to these areas as semi-impounded, fluctuations in water levels and salinities and to Louisiana coastal marshes are eroding at an thereby enhance production of submerged aquatic alarming rate as a result of land subsidence, rising vegetation for wildlife (Chabreck 1968). Weirs are sea level, and human activities (Salinas et al 1986; solid barriers with horizontal crests that are usu- Walker et al 1987). Numerous weirs have been ally set at least 15 cm below average marsh ground installed to reduce saltwater intrusion and thereby level.…”

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confidence: 99%

Effects of a Fixed-Crest Weir on Brown Shrimp Penaeus aztecus Growth, Mortality, and Emigration in a Louisiana Coastal Marsh

Knudsen

Paille

Rogers

et al. 1989

North American Journal of Fisheries Management

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We investigated the effects of water‐control weirs on growth, emigration, and mortality of brown shrimp. Juvenile brown shrimp were captured, marked, and released in two shallowwater marsh ponds. One pond had a weir at its only exit. All surviving marked brown shrimp were recaptured as they emigrated from each pond. Shrimp remained in the weired pond 12–18 d longer after marking than in the unweired pond. Growth of brown shrimp was best described by quadratic functions and was significantly faster in the weired pond than in the unweired one although differences in growth may have been confounded by delayed emigration from the weired pond. Estimated monthly instantaneous mortality of juvenile brown shrimp, from marking to recapture, ranged from 0.550 to 1.582 in the weired pond and 0.877 to 1.270 in the unweired pond and apparently varied between years. Even though brown shrimp remained in the weired pond longer, peaks in emigration from both ponds coincided with new and full moons. Mean total lengths of marked brown shrimp at emigration ranged from 83 to 106 mm for the weired pond and from 66 to 84 mm for the unweired pond. Size of shrimp at emigration and time of emigration varied between years. Although brown shrimp emigrating from the weired pond were larger than those from the unweired pond, probably due to faster growth and delayed emigration, conclusions from concurrent research were that total biomass of brown shrimp emigrating from the unweired pond was more than double the biomass from the weired pond.

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“…5 (Gagliano et al 1981). The general pattern of habitat change over the past 60 yr has been attributed to the interaction among several regional factors (Deegan et al 1984, Walker et al 1987, Wells 1996, Roberts 1997 including: (1) deltaic lobe abandonment, (2) eustatic sea-level rise and subsidence, (3) changes in the introduction of freshwater and sediments from the Mississippi and Atchafalaya Rivers, and (4) human modification of internal hydrology (Day and Templet 1989, Baumann and Turner 1990, Boesch et al 1994, Reed 1995, Day et al 1997, Roberts 1997, Turner 1997. However, these regional factors have been analyzed mostly at small scale (Salinas et al 1986, Dozier et al 1983, Deegan et al 1984, Nyman et al 1993.…”

Section: Introductionmentioning

confidence: 99%

Landscape Modeling of Coastal Habitat Change in the Mississippi Delta

Reyes

White

Martin

et al. 2000

Ecology

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A landscape model was developed to investigate and predict the environmental factors affecting wetland habitat change within the Barataria and Terrebonne basins of coastal Louisiana, USA. The model linked an overland‐flooding hydrodynamic module, using cells of 100 km2 in size and operating at a 1‐h time step, and a spatially articulated ecosystem module, resolving habitat type and change for 1‐km2 cells in daily time steps. Integration across different temporal and spatial scales was accomplished with interpolation routines and averaging algorithms. Forcing functions included dominant regional processes, such as subsidence, sedimentation, and sea‐level rise. Hydrologic functions were calibrated against existing climate and hydrologic time series, while habitat information was compared to maps prepared by the United States Fish and Wildlife Service (USFWS) for 1978 and 1988. Spatial calibration was done by initializing the landscape pattern of the model to a 1978 USFWS habitat map. After a 10‐yr simulation, the results were compared against a 1988 USFWS habitat map. Simulated maps had an accuracy of 85–90 (out of a maximum of 100), based on a multiple resolution fit algorithm. For validation, the model was initialized with a 1956 USFWS habitat map, and the results from a 32‐yr simulation were compared to the 1988 USFWS habitat map. The landscape model produced reasonable regional agreement, despite the fact that small‐scale processes and features were not included. The validation runs produced land‐loss rates that matched historical trends with an accuracy fit above 75. The model simulated 30 years into the future, starting in 1988, testing for long‐term climate variability under diverse scenarios. Results indicated that weather variability impacts land‐loss rates more than replication of extreme weather years. Even when extreme dry and wet years were repeated, the model predicted lower land loss when compared to historical records. This is indicative of the ability of the simulated plant communities to adapt to repetitive climatic forcing functions.

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Wetland Loss in Louisiana

Cited by 40 publications

References 10 publications

Numerical simulation of vertical marsh growth and adjustment to accelerated sea‐level rise, North Norfolk, U.K.

Numerical simulation of vertical marsh growth and adjustment to accelerated sea‐level rise, North Norfolk, U.K.

Effects of a Fixed-Crest Weir on Brown Shrimp Penaeus aztecus Growth, Mortality, and Emigration in a Louisiana Coastal Marsh

Landscape Modeling of Coastal Habitat Change in the Mississippi Delta

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