Any comments on the protocol should be directed to the GCRC (gcrc@uga.edu). Groups interested in participating in this standardized monitoring effort should contact Joe Richardson (richards@savstate.edu).
Protocol updated September 2003.
Download
and print standardized
data sheet (PDF)
You'll
need one copy for each quadrat (18).
Overview:
This protocol provides a standardized method for monitoring physical, chemical,
and biological characteristics of marshes. We recommend that sites be established
in both marsh die-off and control areas, and that they be monitored quarterly
(March, June, September, and December).
Setup:
Individual sites may require adjustment of the protocol.
Ladders (flat on the marsh surface with a plank across them) are recommended for accessing some areas.
At each sampling site, set up 3 transects 10 m apart (ideally) in a dieback area and an unaffected area. Transects should; 1) run the length of the area, 2) be 2 m wide, and 3) run perpendicular from a creek bank to the marsh interior. Make sure not to walk within the transect area to minimize impact to the marsh. Mark the location of 3 permanent quadrats (0.5 m x 0.5 m) evenly spaced along the length of each transect with a PVC pole. Prior to installation, the PVC should be calibrated as follows: a zero point should be marked with a Sharpie or labeling tape, and then the pole should be marked at 5 cm intervals +/-25 cm above and below the zero point. When the pole is placed in the marsh, the zero point should sit at the marsh surface so changes in marsh surface height can be measured over time.
If a clear transition zone is evident (strong demarkation between live marsh and dieback area), use permanent flags to mark the transition (the border between mud and plants) as a way to document changes in the extent of the dieback area.
Take a photograph (if possible) of each quadrat, the transects, and any usual features. If a GPS unit is available, record the location of each transect.
There should be a total of 9 quadrats in the 'healthy' marsh area and 9 in the dieback area (3 quadrats/transect x 3 transects) for a total of 18 quadrats per site.
Sampling frequency:
Sampling should be carried out quarterly (March, June, September, December)
at low tide (begin approximately 2 hrs before low tide). Be sure to record the
time of sampling.
Before starting vegetation counts, prepare holes (see below) for collecting porewater.
Vegetation:
Marsh vegetation should be monitored within each 0.5 m x 0.5 m quadrat set up
along the transect. In addition, the location of major vegetation boundaries
along the transect (dead marsh - live marsh, Spartina - Juncus, etc.) should
be recorded.
Stem counts:
Plant stems should be counted in each quadrat. Only stems that are rooted inside the quadrat should be counted. Separate counts should be made for each species present. Three categories of stems should be used: live stems >15 cm (tall shoots), live stems <15 cm (short shoots), and dead stems.
Plant height:
The height of the five tallest plants in each quadrat should be measured to estimate vegetation height. Where more than one species is present, plant heights should be recorded for each species.
Leaf color:
Observations of leaf color should be recorded.
Epifauna:
Note live and dead fauna. All counts are done in the same quadrats used for
the vegetation survey.
If snails and crab
holes are too numerous to count in a the 0.5 x 0.5 m quadrat, use a designated
(southeast, or lower-right) corner of the permanent quadrat, and count in 0.25
m x 0.25 m areas. Be sure to specify quadrat size on the data sheet.
Snails:
Species should be identified and separate counts made for each species. Snails should be counted only if they are on the ground or on plant stems rooted inside the quadrat (snails on overhanging stems should not be counted). For periwinkles, the number greater or less than 10 mm in size (measured from the aperture to the apex of the shell) are recorded separately.
Crabs:
Crab densities should be measured by counting the number of crab holes > 5 mm (= approximately the diameter of a pencil).
Mussels:
Counts are made in 0.5 m x 0.5 m quadrats. Note whether dead mussels are present.
General:
Note the presence or absence of a clear transition zone, and the distance
for each quadrat from this area. If possible, sketch the site and label the
quadrats.
Other
observations:
How does the soil look, feel, smell? Is sulfide obviously present? Is there
erosion? Unusual drainage patterns?
Physicochemical
Characteristics:
If possible, get a temperature reading (useful if corrections are needed
for salinity or pH) on the soil (we will try to obtain some probe-type soil
thermometers).
Set this up before vegetation counts.
Porewater collection and analysis
Use a broomstick-sized rod (or PVC) to core a 15 to 20-cm deep hole adjacent to each quadrat to allow it to fill with porewater. Sample the water in this hole (~15 cm below marsh surface) for measurements of salinity (with a refractometer), pH (use a meter, not test strips or dye kit), and Eh (if possible).