Understanding Coastal Ecosystems Room 201D
Jan 25, 2023 10:50 AM - 11:50 AM(America/Chicago)
20230125T1050 20230125T1150 America/Chicago Understanding Coastal Ecosystems Room 201D 2023 Bays and Bayous Symposium mbnep@mobilebaynep.com
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Monitoring Wetland Vegetation in Response to Climate Changes with NDVI
10:50 AM - 11:05 AM (America/Chicago) 2023/01/25 16:50:00 UTC - 2023/01/25 17:05:00 UTC
Coastal wetlands are important for the function and balance of natural ecosystems. Factors related to climate change, sea level rise, natural and man-made hazards, and hydrologic modifications (including channelization, surface water diversions, dredging, etc.) impact the viability of coastal wetlands. Regular monitoring of wetland environments is possible through the utilization of geospatial technologies and satellite imagery providing a method of improved assessment and management. This study provides an assessment of the wetlands associated with the Weeks Bay National Estuarine Reserve located in southeast Alabama. The assessment was performed from the analysis of Normalized Difference Vegetation Index (NDVI) data derived from the Landsat 8 satellite. NDVI values were analyzed at both seasonal and annual time frames from 2013 to 2021. This analysis helps to identify changes in the overall health, biomass, and greenness of the selected wetland environments. The initial results showed a decrease in wetland NDVI values over the eight-year period. The current analysis is comparing wetland NDVI values with climate related variables for an improved understanding of the wetland dynamics in this region. Climate data for precipitation amounts, duration, and intensity are being used to evaluate the impact of precipitation days (days with and without rain) for annual and seasonal trends in change.
Presenters
SS
Sadia Alam Shammi
Mississippi State University, Geosystems Research Institute
JC
John Cartwright
Mississippi State Univeristy
Using Unoccupied Aircraft Systems to Monitor Restored Wetland Vegetation Communities
11:20 AM - 11:35 AM (America/Chicago) 2023/01/25 17:20:00 UTC - 2023/01/25 17:35:00 UTC
Acquiring detailed information on wetland plant communities is critical for monitoring wetland ecosystem restoration and management. Field data collection is often costly and time-consuming. Remote sensing with unoccupied aircraft systems (UAS) provides high-resolution aerial images with the potential for vegetation mapping. This high-resolution imagery comes with its own challenges, including large data storage needs, technical knowledge needed for processing, increased spectral variability within vegetation patches, and expensive post-processing software. These challenges are exacerbated with sites larger than 20 ha. We discuss an alternative method to monitoring wetland vegetation community composition at several restoration sites throughout Alabama and Florida using randomly generated points to sample a percentage of the total site area. Flight plans were preprogrammed with the UAS capturing an aerial image at a fixed altitude at each previously determined point. All flora present in the middle 1 m2 square were identified in post-processing, and on-ground vegetation density counts were conducted in a random subset of points for ground-truthing. These early efforts in applying UAS technology show great promise as a cost-effective option for wetland vegetation monitoring.
Presenters Alex Rodriguez
Dauphin Island Sea Lab
Co-Authors
ML
Megan Laufer
Dauphin Island Sea Lab
RB
Ronald Baker
University Of South Alabama, Dauphin Island Sea Lab
Not All Marsh Edge is Equally Valuable Fish Habitat: Variation in Fish Community Structure Across Mississippi Sound, Alabama
11:35 AM - 11:50 AM (America/Chicago) 2023/01/25 17:35:00 UTC - 2023/01/25 17:50:00 UTC
The seaward fringes of salt marshes are widely recognized as essential habitat for a diversity of ecologically and economically important species. However, spatial variation in the value of marsh-edge habitat remains largely unexplored. To explore variation in the value of marsh edge as nekton (fish and mobile crustaceans) habitat, we quantified nekton density with a drop sampler in marsh edge (outer ~1 m of flooded salt marsh grass) and adjacent open water (~10 m offshore from marsh edge) habitats. We collected 60 drop samples each in summer and fall of 2022 at 10 sites spanning Mississippi Sound, AL, in contexts ranging from open coastal shorelines, through sheltered bays, to tidal marsh creeks, and along upstream-downstream gradients in riverine environments. Sites also varied in fetch, the extent of adjacent SAV, elevation profiles, and flooding patterns. As expected, nekton densities were far higher in the flooded marsh edge than in adjacent unvegetated open water habitats. Further analysis will identify key drivers of variation in the value of marsh edge, and quantify the relative importance of marsh edge and adjacent SAV for various species. These findings will refine designations of Essential Fish Habitat, help guide the design of marsh creation and restoration projects that seek to maximize fishery habitat benefits, and help predict the responses of fisheries species to future changes in habitat extent and configuration.
Presenters
RB
Ronald Baker
University Of South Alabama, Dauphin Island Sea Lab
Co-Authors
RG
Rebecca Gilpin
Mississippi State University, Northern Gulf Institute
Alex Rodriguez
Dauphin Island Sea Lab
JC
Just Cebrian
Northern Gulf Institute
TO
Tia Offner
Mississippi State University
Mississippi State University, Geosystems Research Institute
Dauphin Island Sea Lab
University of South Alabama, Dauphin Island Sea Lab
No moderator for this session!
Mississippi-Alabama Sea Grant Consortium
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