ECOLOGY OF THE SEASHORE lecture resources Bringing ecology to life ECOLOGY OF THE SEASHORE A complete seashore sampling and quantification course on CD-ROM. PowerPoint presentations showing the species you are likely to find and the techniques you need. LECTURE 7 METHODS FOR STUDYING THE ECOLOGY OF THE SEASHORE Part 1: SETTING THE TRANSECT & DESCRIBING THE SHORE PROFILE Photography, text & design by Dr James Merryweather

2 ROCKY SHORES SEASHORE TRANSECTS

TRANSECT TRANSECT TRANSECT 3 TRANSECT TRANSECT TRANSECT Select a site for your transect and lay out a tape measure at right angles to the water’s edge

Mark the top of the transect 4 TRANSECT Mark the top of the transect

TRANSECT Fix a marker at the water’s edge so that you may 5 X X TRANSECT Fix a marker at the water’s edge so that you may return to the site if tides times are unfavourable

TRANSECT If the tide is going out, you can start at 6 X TRANSECT If the tide is going out, you can start at the top of the shore and follow it down

TRANSECT 1 2 If the tide is on its way in, then work up the shore 7 1 X 2 TRANSECT If the tide is on its way in, then work up the shore from low water and do the rest later, from the marker

SHORE PROFILE TRANSECT 8 Surveyor 1 Surveyor 2 Surveyor 3 SHORE PROFILE TRANSECT To describe the profile of the shore, a team of three can gather measurements along the tape at regular intervals

9 PROCEDURE TRANSECT Measuring changes in elevation with ‘levelling poles’ and the horizon - method by Dr Chris Rees of York

TRANSECT LEVELLING POLES Fixed height T-pole Adjustable T-pole 10 Fixed height T-pole Adjustable T-pole (calibrated ) Tape measure TRANSECT LEVELLING POLES

Fixed height T-pole, simply made from two pieces of wood or cane 11 . 1.2 m TRANSECT Fixed height T-pole, simply made from two pieces of wood or cane

TRANSECT 0.2 m 1 m A well-used home-made adjustable T-pole 12 T-piece Removed and clipped to tube when not in use Locking screw 0.2 m Plastic tubing 1 m Zero is here When set at zero, the adjustable T-pole is the same height as the fixed height T-pole (1.2 m) and positive or negative changes in height can be measured as the slider moves, respectively, out or in. TRANSECT A well-used home-made adjustable T-pole with its calibrated slider partly extended

TRANSECT Movable slider of adjustable T-pole 13 Locking screw Zero & starting position is here Positive height difference (cm) Negative height difference (cm) TRANSECT Movable slider of adjustable T-pole calibrated with stick-on centimetre tape

14 Surveyor 1 Step 1 Step 1 NOTE: Surveyors 1 & 2 will be fully occupied, so it is up to surveyor 3 to ensure that both poles are vertical all the time. Surveyor 2 TRANSECT Surveyor 1 loosens the locking screw so that the calibrated slider may move freely as the adjustable T-pole is raised or lowered

Surveyor 2 sights across the T-piece of the fixed height pole . . . 15 Step 2 Step 2 NOTE: reduce error by holding the fixed pole T-piece at 90° from position shown, thus: TRANSECT Surveyor 2 sights across the T-piece of the fixed height pole . . .

TRANSECT Step 3 Step 3 . . . towards the T-piece of the adjustable 16 Step 3 Step 3 TRANSECT . . . towards the T-piece of the adjustable pole operated by surveyor 1 . . .

TRANSECT Step 4 Step 4 . . . and instructs surveyor 1 to raise 17 Step 4 Step 4 TRANSECT . . . and instructs surveyor 1 to raise or lower the adjustable pole . . .

TRANSECT Step 5 Step 5 . . . until the two T-pieces are aligned 18 Step 5 Step 5 TRANSECT . . . until the two T-pieces are aligned with each other and with the horizon

Surveyor 1 locks the calibrated slider by tightening the screw . . . 19 Step 6 Step 6 TRANSECT Surveyor 1 locks the calibrated slider by tightening the screw . . .

TRANSECT Step 7 Step 7 . . . and reads the height difference 20 Step 7 Step 7 TRANSECT . . . and reads the height difference from the scale for surveyor 3 to record

FIXED POLE è ADJUSTABLE POLE è HORIZON 21 horizon Pole should be vertical! TRANSECT FIXED POLE è ADJUSTABLE POLE è HORIZON

TRANSECT Surveyor 3 records the difference in 22 TRANSECT Surveyor 3 records the difference in vertical height from the zero point

TRANSECT If the pole is extended beyond zero, the 23 Locking screw Zero is here Positive height difference (cm) Negative height difference (cm) TRANSECT If the pole is extended beyond zero, the reading is positive, if pushed in it is negative

TRANSECT The process is repeated at predetermined 24 TRANSECT The process is repeated at predetermined intervals (e.g. 2 m) down the entire transect

If shore topography is EVEN and the slope gentle and regular . . . 25 TRANSECT If shore topography is EVEN and the slope gentle and regular . . .

. . . profile measurements will accumulate incrementally . . . 26 TRANSECT . . . profile measurements will accumulate incrementally . . .

. . . and the distance between stations can be greater than 2 m 27 10 m TRANSECT . . . and the distance between stations can be greater than 2 m

TRANSECT If shore topography is UNEVEN and the 28 TRANSECT If shore topography is UNEVEN and the slope steep, the profile can be very variable . . .

. . . and negative measurements will sometimes be recorded 29 -ve TRANSECT . . . and negative measurements will sometimes be recorded

TRANSECT Stations will need to be close together to 30 TRANSECT Stations will need to be close together to produce a meaningful profile of the shore

MEASUREMENTS and CALCULATIONS 31 MEASUREMENTS and CALCULATIONS horizon TRANSECT Measurements for a right-angled triangle are produced and unknowns calculated using the Pythagoras theorem

TRANSECT s The hypotenuse ‘s’ is the predetermined 32 horizon s TRANSECT The hypotenuse ‘s’ is the predetermined distance along the tape (in this case 2 m)

TRANSECT s h The height difference between the two points 33 horizon s reading (h) taken here h TRANSECT The height difference between the two points ‘h’ is measured with the adjustable T-pole

The height difference is read from the zero point 34 Height difference +7 cm zero TRANSECT The height difference is read from the zero point

‘s’ was predetermined, ‘h’ was measured and ‘d’ is calculated 35 horizon s h d TRANSECT d = Ö(s2 - h2) ‘s’ was predetermined, ‘h’ was measured and ‘d’ is calculated

TRANSECT Steep shores require a modification. The height 36 TRANSECT Steep shores require a modification. The height of the adjustable T-pole ‘h’ is fixed at e.g. 0.2 m

TRANSECT s The measured parameter is, therefore, the distance ‘s’ 37 s TRANSECT The measured parameter is, therefore, the distance ‘s’ along the tape between T-poles aligned with the horizon

‘h’ was predetermined, ‘s’ was measured and ‘d’ is calculated 38 s h d TRANSECT d = Ö(s2 - h2) ‘h’ was predetermined, ‘s’ was measured and ‘d’ is calculated

Sum of measured values h Sum of calculated values d 39 s h d Sum of measured values h Sum of calculated values d TRANSECT Plot data for the shore profile

40 X