General:
This data set is part of an on-going LTER project at the Plum Island Ecosystem (PIE) site. The sampling location is in a Spartina alterniflora-dominated marsh at Law's Point between the Rowley River and West Creek in Rowley MA. A boardwalk was built to access 12 permanent sampling plots (1m2 each). There are 4 treatments within the boardwalk structure (3 replilcates each). The 4 treatments are Control, N-fertilized, P-fertilized, and N+P-fertilized. Only the untreated, control plots are addressed in this data set.
Sampling Description:
The biomass estimation method is non-destructive. Two permanent subplots were established in each of 3 control plots in the marsh. Each subplot is 10cmx10cm. The subplots are labeled 1&2, with subplot 1 being the more northerly and/or westerly subplot. In May and June, plants in the subplots are tagged with bird ID bands. Approximately monthly from May to October, heights of the tagged plants and associated culms are measured to the nearest cm. Plant heights are read into a digital recorder. Descriptions of the locations of the plants within the quadrat are also recorded (e.g. northwest corner or northwest of tag #xxxx). Plant measurements are always taken with the observer on the same side of the quadrat for ease in tracking individual plants throughout the growing season.
The plant census at began in June 1999. In May 2006 the Control census plots were relocated due to potential contamination from fertilized plots. The census subplots kept the same id#’s from when they were within the boardwalk for continuity within the ACCESS database.
Data processing:
Plant data are entered first into an EXCEL spreadsheet, and eventually transferred to an ACCESS data base. Outputs from ACCESS are processed with two FORTRAN programs. The FORTRAN programs use algorithms to convert the ACCESS data outputs to plant weight, density, births, deaths and growth (Morris and Haskin, 1990). Fortran outputs are entered into SAS programs to calculate means.
References:
(Morris and Haskin, 1990. Ecology 71(6):2209-2217)
(SAS System for Windows; release 8.02; SAS Institute, Inc; Cary, NC)
Elevation:
LTE-MP-LPA, ~ 1.1 meters NAVD88
