Survey Method

The survey protocol is globally standardised and designed by Seagrass-Watch. Onsite field training occurs during every Watergum survey event, however before coming out with us for the first time we request that you complete this course and read over the introduction of the seagrass-watch manual found here: http://www.seagrasswatch.org/manuals.html

Seagrass-Watch has several monitoring strategies depending on the type and location of seagrass meadows. The most commonly used method is described below:

At each site, three parallel 50 m transects (each 25 m apart) are established, but generally only the middle transect is permanently marked. The location of sites is determined by GPS. The seagrass habitats along each transect are sampled by visual observation. At each transect, eleven quadrats are sampled (1 quadrat every 5 m), every sampling event. At least 27% of quadrats sampled are photographed to ensure standardisation/calibration of observers and to provide a permanent record.

Within the 50m by 50m site, lay out and peg down the three 50 transects parallel to each other, 25m apart and perpendicular to shore (see site layout). Within each of the quadrats placed for sampling, complete the following steps:

• Step 1. Take a Photograph of the quadrat

Photographs are taken three times at the 5m, 25, and 45m mark along each transect, or at quadrats of particular interest (if you have a digital camera, you can photograph every quadrat if you wish).

First place the photo quadrat labeller beside the quadrat with the correct code on it.

Take the photograph from an angle as vertical as possible, which includes the entire quadrat frame, quadrat label and tape measure. Try to avoid having any shadows or patches of reflection off any water in the field of view. Tick the photo taken box on the datasheet for that quadrat. Please note: Camera should be set at the highest quality.

• Step 2. Describe sediment composition

To assess the sediment, dig your fingers into the top centimeter of the substrate and feel the texture.

Describe the sediment, by noting the grain size in order of dominance (e.g., Sand, Fine sand, Fine sand/Mud).

• Step 3. Describe other features and ID/count of macrofauna

Note and count any other features which may be of interest (eg. number of shellfish, sea cucumbers, sea urchins, evidence of turtle feeding), within the comments column.

Count or estimate as best you can. Please do not use > or < symbols.

If more than 50% of the quadrat is covered by water, measure and record the water depth in cm.

• Step 4. Estimate seagrass percent cover

Looking down on the quadrat from above, estimate the total percentage of the seabed (substrate) within the quadrat covered by seagrass. – use the percent cover photo standards as a guide.

When estimating cover, estimate the footprint/shadow provided by the seagrass shoots. Always use the percent cover photo standards as your guide. Estimate cover as accurate as possible!

• Step 5. Estimate seagrass species composition

Identify the species of seagrass within the quadrat and determine the percent contribution of each species to the cover.

Use seagrass species identification keys provided.

Use more than 1 feature to identify the species

Total composition must equal 100%

• Step 6. Measure canopy height

Measure canopy height of the dominant strap leaved species ignoring the tallest 20% of leaves.

Measure from the sediment to the leaf tip of at least 3 mature leaf blades (strap leaved species).

Write the 3 measures on the datasheet.

• Step 7. Estimate algae percent cover

Estimate % cover of algae in the quadrat.

Algae are not attached to seagrass but may cover or overlie the seagrass blades.

Macroalgae percentage cover is independent of seagrass cover, for example, you can have 100% seagrass and 100% algae.

Use “Algal percentage cover photo guide”.

• Step 8. Estimate epiphyte percent cover

Epiphytes are algae attached to seagrass blades and often give the blade a furry appearance.

First estimate how much of the blade surface is covered, and then how many of the blades in the quadrat are covered (e.g., if 20% of the blades are each 50% covered by epiphytes, then quadrat epiphyte cover is 10%).

Use the epiphyte matrix to help you in the field. (DOWNLOAD: Epiphyte_matrix.pdf)

• Step 10. Move to next quadart

Repeat steps 1 to 8 for the remaining 32 quadrats