GCE-LTER Project News

Data set titled 'Wrack classification data based on UAV imagery from Dean Creek on Sapelo Island, GA' was added to the GCE data catalog.  You can view the data set here:  GIS-GCET-2308

Abstract:  We used a DJI Matrice 210 UAV with a MicaSense Altum to collect a total of 20 images from January 2020 - December 2021 in a the Dean Creek marsh on Sapelo Island, GA. Wrack was classified using a principal component analysis. Wrack patches under 1 m2 were excluded from analyses. Wrack classifications were converted to polygon and point data where each point represents a 5 cm x 5 cm pixel. Those files were then used to analyze wrack characteristics, their relation to environmental drivers, and landscape based patterns. For both polygon and point data, we used the National Elevation Dataset (https://gdg.sc.egov.usda.gov/Catalog/ProductDescription/NED.html) to determine the elevation of each wrack patch. Creeks and shorelines were digitized and used to determine each wrack patches' distance to water. We calculated the frequency of wrack deposition at each point by adding together the number of images where that pixel was classified as wrack over the course of the study. Polygon data were related to tide height from a NOAA tidal station data product (Ft. Pulaski, Station 8670870; https://tidesandcurrents.noaa.gov) and wind speed and wind direction from the Marsh Landing weather station (downloaded data for the SAPMLMET met station from: https://cdmo.baruch.sc.edu/) to evaluate the relationship of wrack to environmental drivers.

Citation: Lynn, Tyler. 2023. Wrack classification data based on UAV imagery from Dean Creek on Sapelo Island, GA. Georgia Coastal Ecosystems LTER Project, University of Georgia, Long Term Ecological Research Network.  http://dx.doi.org/10.6073/pasta/964d3375e5bbc81847fa72093bb087ef

Data set titled 'Pred-Ex: Long Term Salt Marsh Predator Exclusion Experiment Conducted at Sapelo Island, GA' was added to the GCE data catalog.  You can view the data set here:  MSH-GCED-2308

Abstract:  In southeastern USA salt marshes, short-term and small-scale experiments indicate that a trophic cascade benefits the foundation plant Spartina alterniflora: marine predators (nekton) positively affect plant biomass by consuming snail and crab herbivores. To test how nekton affect marsh processes when the entire animal community is present, and to test how prior results scale up over time, we conducted a 3-year predator exclusion experiment in a Georgia salt marsh using replicated 19.6 m2 plots. We measured the response of changing density for all marsh invertebrates, conducted snail and crab tethering trials, quantified change in marsh grass biomass, and measured tea bag decomposition rate across all plots.

Citation: Hensel, Marc Simon. 2023. Pred-Ex: Long Term Salt Marsh Predator Exclusion Experiment Conducted at Sapelo Island, GA. Georgia Coastal Ecosystems LTER Project, University of Georgia, Long Term Ecological Research Network. http://dx.doi.org/10.6073/pasta/a2c9c9b9541c511c3e4bfab5e8e4d639

The Historical Palmer Drought Indices data sets on the GCE Data Portal have been updated through June 2023. These data sets include monthly calculations of the Palmer Drought Severity Index, Palmer Hydrological Drought Index, Palmer Modified Drought Index and Palmer Z-index for Georgia Region 9 (coastal counties and Sapelo Island) from January 1895 though June 2023.

More information about these indices as well as links to the original NOAA maps and data pages as well as processed data sets covering the entire USA are available from the GCE Data Portal here.