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Topography, hydrology and Spartina alterniflora growth range for restored salt marsh Elders Point East, Jamaica Bay, New York

Shafiei, Farshad (2012) BION35 20121
Degree Projects in Biology
Abstract
Restored salt marsh; topography, hydrology and vegetation

Coastal salt marshes are shaped through a combination of physical (i.e., sediment accumulation/erosion) and biological (i.e., vegetation) processes. They are characterized by fine sediments and halophytic vegetation. The accretion rate and elevation change has been indicated as one of the most important factors in ecology of the marshes. The inundation regime and growth range of Spartina alterniflora also play major roles in formation of the marsh and sustaining it. Sea-level rise, sediment deficiency, hydrodynamic modifications of the bay and eutrophication have been hypothesized as major contributors to dramatic salt marsh loss in Jamaica Bay, New York. This study has been... (More)
Restored salt marsh; topography, hydrology and vegetation

Coastal salt marshes are shaped through a combination of physical (i.e., sediment accumulation/erosion) and biological (i.e., vegetation) processes. They are characterized by fine sediments and halophytic vegetation. The accretion rate and elevation change has been indicated as one of the most important factors in ecology of the marshes. The inundation regime and growth range of Spartina alterniflora also play major roles in formation of the marsh and sustaining it. Sea-level rise, sediment deficiency, hydrodynamic modifications of the bay and eutrophication have been hypothesized as major contributors to dramatic salt marsh loss in Jamaica Bay, New York. This study has been motivated by the issue of marsh loss and evaluation of Elders Point East restoration project.

Salt marsh plants live within a narrow elevation range that is often less than 2 m. Topographic changes of less than 10 cm have been shown to significantly influence plant community in marshes. The Real Time Kinematic-Global Positioning System (RTK-GPS) was used to survey the island surface to compare with pervious study. The elevation data were used to create a Digital Elevation Model (DEM) for the marsh using ArcGIS 10.0 Geostatistical Analysis tool. The elevation model from this project indicates that using RTK-GPS would be the best method in comparison to Light Detection And Ranging (LiDAR) data for Jamaica Bay marshes. I could achieve the overall accuracy of ±8 cm for Elders Point East, however the accuracy of LiDAR data from previous work produced ±29 cm.

The extent of inundation and the tidal range need to be evaluated to determine the sustainability of the marsh since the vegetation growth range is depended on inundation. In order to evaluate site specific hydrology, I deployed three tidal gauges (Non-Vented Titanium Water Level Loggers) to capture 2 months water level data. The reduction process was implied according to Tidal Datums Handbook from National Oceanic and Atmospheric Administration (NOAA) to compute site specific tidal datums. The comparison of tidal range with recent studies within the bay indicates 3 cm increase in mean tidal range. This indicates that tidal range has been increasing within the bay at the same rate with sea-leave rise (3.9 mm yr-1) since 2007.

At Elders Point East the S. alterniflora upper limit and lower limit of the growth range in relation to Mean High Water (MHW) were 0.45 m and -0.32 m, respectively (Growth range = 0.77 m).

The site specific growth range of S. alterniflora in this study, reported elevation change and accretion rate implies that the Elders Point East will be less vulnerable with respect to sea-level rise in comparison to marshes where the plants are located at lower elevations.

Advisor: Patricia Rafferty
Master´s Degree Project 45 credits, 2012
Department of Biology, Lund University, National Park Service, Gateway, Jamaica Bay (Less)
Please use this url to cite or link to this publication:
author
Shafiei, Farshad
supervisor
organization
course
BION35 20121
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
3799625
date added to LUP
2013-05-23 12:22:41
date last changed
2013-05-23 12:22:41
@misc{3799625,
  abstract     = {Restored salt marsh; topography, hydrology and vegetation

Coastal salt marshes are shaped through a combination of physical (i.e., sediment accumulation/erosion) and biological (i.e., vegetation) processes. They are characterized by fine sediments and halophytic vegetation. The accretion rate and elevation change has been indicated as one of the most important factors in ecology of the marshes. The inundation regime and growth range of Spartina alterniflora also play major roles in formation of the marsh and sustaining it. Sea-level rise, sediment deficiency, hydrodynamic modifications of the bay and eutrophication have been hypothesized as major contributors to dramatic salt marsh loss in Jamaica Bay, New York. This study has been motivated by the issue of marsh loss and evaluation of Elders Point East restoration project. 

Salt marsh plants live within a narrow elevation range that is often less than 2 m. Topographic changes of less than 10 cm have been shown to significantly influence plant community in marshes. The Real Time Kinematic-Global Positioning System (RTK-GPS) was used to survey the island surface to compare with pervious study. The elevation data were used to create a Digital Elevation Model (DEM) for the marsh using ArcGIS 10.0 Geostatistical Analysis tool. The elevation model from this project indicates that using RTK-GPS would be the best method in comparison to Light Detection And Ranging (LiDAR) data for Jamaica Bay marshes. I could achieve the overall accuracy of ±8 cm for Elders Point East, however the accuracy of LiDAR data from previous work produced ±29 cm. 

The extent of inundation and the tidal range need to be evaluated to determine the sustainability of the marsh since the vegetation growth range is depended on inundation. In order to evaluate site specific hydrology, I deployed three tidal gauges (Non-Vented Titanium Water Level Loggers) to capture 2 months water level data. The reduction process was implied according to Tidal Datums Handbook from National Oceanic and Atmospheric Administration (NOAA) to compute site specific tidal datums. The comparison of tidal range with recent studies within the bay indicates 3 cm increase in mean tidal range. This indicates that tidal range has been increasing within the bay at the same rate with sea-leave rise (3.9 mm yr-1) since 2007. 

At Elders Point East the S. alterniflora upper limit and lower limit of the growth range in relation to Mean High Water (MHW) were 0.45 m and -0.32 m, respectively (Growth range = 0.77 m). 

The site specific growth range of S. alterniflora in this study, reported elevation change and accretion rate implies that the Elders Point East will be less vulnerable with respect to sea-level rise in comparison to marshes where the plants are located at lower elevations.

Advisor: Patricia Rafferty
Master´s Degree Project 45 credits, 2012
Department of Biology, Lund University, National Park Service, Gateway, Jamaica Bay},
  author       = {Shafiei, Farshad},
  language     = {eng},
  note         = {Student Paper},
  title        = {Topography, hydrology and Spartina alterniflora growth range for restored salt marsh Elders Point East, Jamaica Bay, New York},
  year         = {2012},
}