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Marked Plots



NSF grant – DEB10-50694. 60 months, 1/1/2011 to 12/31/2020. LTREB: Ecosystem response to climate change: role of ecological subsidies and species interactions.  Oregon State University

The purpose of photographing the same areas in the mid to lower intertidal mussel beds is to quantify annual fluctuations in abundance of sessile organisms, and thus document the “boom and bust” annual cycle of Mytilus trossulus.

Sites: Fogarty CreekBoiler BayYachats BeachStrawberry HillCape BlancoRocky Point

Replicates per Site: 5, consisting of one 4m x 4m plot.


4 meter long bungee with pipe fittings zip-tied to it, 0.25 m2 photo-quadrat, camera with waterproof case, blue 15 cm ruler

Setup in Field:

Five 4 m2 marked plots were placed in low zone in areas where entire four meter plot was relatively flat.  Plots are numbered from north to south with one being northmost and 5 being southmost.  The marked plots were put in similar areas in low intertidal as Pre-Emption plots and have ½ lag screws marking corners with large white zip-ties on lags.


In field stretch bungee around marked plot placing pipe fittings on the corner lag screws.  Take one photo of entire marked plot.  Then take sixteen photos of the marked plot using the 0.25 m2 photo-quadrat.  This is best done if you keep track of the vantage point you took the entire marked plot picture.  Then start from the upper left corner of the marked plot and flip the 0.25 m2 quadrat around the marked plot in a sinusoid pattern, taking the subsequent photos (numbered in the diagram below).  Doing this, the sixteenth/last photo should be taken in the lower left corner of the marked plot.  TAKE CARE to make sure each photograph is in focus.

Plots are photographed once a year in the summer. 

In the lab, photographs should be relabeled (ex. 1_5 or 2_entireplot; with the marked plot number first and the photograph of the marked plot second) and put photographs into a new folder with the corresponding to the site and date in the LTREB folder under the Marked Plot project. Naming convention should have the site, date, project, and replicate number in the name of the file.  Example for Boiler Bay on April 8, 2014, replicate one picture five: BBYX00_20140408-MarkedPlots-1_5.jpg