We selected 9 transects from a set of 40 marsh surveys conducted in 2000 and 2001 to use as a baseline for monitoring changes in species composition and marsh elevation across a broad spatial scale in the Plum Island Estuary. In the early surveys, latitude, longitude and elevation, as well as salt and brackish marsh vegetation composition were documented using cover classes on individual plots. Results from those surveys have been compiled here.
Forty transects within the PIE LTER were surveyed for vegetation cover, species composition, and marsh elevation in fall 2000 and summer 2001. A subset of 9 of these transects was selected for monitoring in 2021 and at to-be-determined intervals beyond that. This data set includes the 9 transects that we are still monitoring. Mapping protocols varied between 2000 and 2001. Of the 9 transects selected, only one, NELS, was initially sampled in 2000. We have interpreted data, methodologies, metadata and fieldnotes from the original files to the best of our ability.
The length and number of sampling points of each transect varied based on the size of the marsh being investigated. Latitude, longitude and elevation of each sampling point was recorded with FastStatic measurements using a Trimble 4800 receiver and TSC-1 controller (from UNAVCO www.unavco.org).
At each sample point, all vegetation within a small circular area surrounding the established point was identified to the species level when possible, and cover classes were assigned to each species present. Spartina alterniflora was divided into two height categories, short and tall. The classification scheme used at the NELS transect in 2000 was slightly different from that used at the remaining transects in 2001. In 2000, letters are used to identify 2 cover classes; in 2001 numbers are used to identify 4 cover classes. In both years, '0' is also used to indicate that a plant species is absent from the plot.
The cover classes were as follows:
Cover Class Description
0 Species not present
D Species is the only species present (NELS transect only)
P Species is present along with other species (NELS transect only)
1 Dominant species
2 Co-dominant species
3 Species is present in approximately equal abundance to other species in the plot
4 Minor species
Plant data and comments related to the sampling point were recorded on data sheets in the field, and transcribed into computer spreadsheets at a later date.
Version 1: March 11, 2022, original upload of data and metadata to comply with importation to DEIMS7 and LTER Data Portal. Used MarcrosExportEML_HTML (working)pie_excel2007.xlsm 28/12 8:18 PM for QA/QC to EML 2.1.0