Appendix A. Descriptions of the sampling design and dates.
1. Sampling design: spatial arrangement of quadrats and transects.
a. Study areas permanently marked for repeated censuses (see Fig.1 in text for locations).
1) Inner Flat: two sites, each a pair of contiguous square meter quadrats, 70 m south of the shore of the island; the sites are 43 m apart, exposed at some low tides.
2) Protected Crest: One site, located on the southwest reef edge, about 420 m SE. of the island; three contiguous square meter quadrats in a line, exposed at some low tides. Three additional quadrats were used for autocorrelation analyses.
3) Exposed Crest: Two sites, located on the north reef edge about 1100 m northeast of the island; site 1 is four contiguous square meter quadrats in a square, site 2 is one square meter quadrat 316 m to the west along the crest. All quadrats exposed at some low tides.
4) Exposed Crest Transects: Two sites: No.1, established in 1976, is located about 50 m west of site 2 of the Exposed Crest study area; it is a belt transect 23 m long, 1.5 m wide. Site no. 2, about 3 m north of site 1 of the Exposed Crest study area, is a belt transect 17 m long, 2 m wide. Both are exposed at some low tides.
5) Exposed Pools: One site, located in a large pool north of the exposed crest, about 30 m north of site 2 of the Exposed Crest study area; two square meter quadrats 5 m apart; depth at low tide 0.5 m.
6) Protected Slope: seven sites (each is a subtidal horizontal line transect, 20 m long), beginning just below extreme low tide level, about 200 m west of the Protected Crest study area. They are parallel to the crest, spaced 10 m apart, measured along the substrate, at 0, 10, 20, 30, 40, 50, 60 m. The depths of the transects below extreme low tide level are, respectively: 1.4, 2.8, 4.2, 5.6, 7, 8.4, 9.8 m. The average slope is 8 degrees.
7) Exposed Slope: five sites (each a subtidal horizontal line transect, 20 m long), beginning just below extreme low tide level, 20 m directly north of the Exposed Pools study area. They are all parallel to the crest, spaced 10 m apart, measured along the substrate, at 0, 10, 20, 30, and 40 m. The depths of the transects below extreme low tide level are, respectively: 2.8, 5.6, 8.4, 11.2, and 14 m; the average slope is 20 degrees. The 0 transect was 40 m long in 1972 only; in 1985, the 0 and 20 m transects were 15 m long.
b. Sites with single censuses.
1) Line transects in each of the study areas with permanently marked quadrats (see "a" in footnote, Table 4).
2) Eighteen belt transects on the inner flat sampled in 1989; each is 0.5 m wide, 30 m long, all located 60 to 120 m south of the shore of the island, the beginning point and azimuth direction of each chosen randomly, but never closer than 30 m apart, the whole set extending over 800 m along the inner flat (see "b" in footnote, Table 4).
3) Two sets of square meter quadrats spaced at randomly chosen distances apart: (1) east of the Exposed Pool permanent quadrats, at the same depth, and (2) on the reef crest, to the east and west of the permanent quadrats of the Protected Crest study area (see "c" in Table 4).
4) Large-scale photographs on the Reef Flat south of the island. These photographs were taken in August 1983 using a floating quadrat of PVC pipes, from each corner of which a PVC pipe rose to form a quadrupod that supported two cameras about 8 m above the water surface. The camera shutters were operated remotely by a radio-controlled switch; the cameras were lowered on a line to change film. The quadrat was 6 × 7 m, within which floated six open-topped boxes, each 1 m × 2.5 m, 20 cm deep, made of clear perspex. These boxes formed a 3 m × 5 m rectangle that acted like a "glass-bottomed boat", so that the corals in the photographs were not obscured by surface reflections. Taken from the 8-m height, each photograph included the bottom with its organisms in the 3 m × 5 m area of the perspex boxes. They were taken at low tide, in water about 0.5 m deep. A mosaic of such photographs was taken by pushing this rig along a 40-m line marked by a measuring tape, each photograph overlapping the previous one by about 0.5 m. We repeated this process along four parallel lines, spaced 4 m apart, resulting in a mosaic of overlapped photographs, 16 m × 40 m in size. A mosaic of overlapping photographic prints was then taken into the field and the corals identified. We could identify all corals larger than about 100 cm2 on these photographs. We took three such mosaics, the first at the Inner Reef Flat, centered 62 m south of the beach rock, a second, centered 36 m further south at the Middle Reef Flat, and a third on the Outer Reef Flat, about 50 m north of the south Protected Reef Crest. The Inner Reef Flat mosaic included the permanent square meter sites.
2. Dates of the censuses at Heron Island.
a. Permanent quadrats at the four shallow study areas; photographs were taken on the following dates (day-month-year). Initals of study areas listed in parentheses after a date signify that photographs of only that area were taken on that date; if all areas were photographed on a date, no initials are listed. Since photographs of a site were often taken on more than one day in the week spent at Heron Island, the day given below is the midpoint of that week. The dates of the photographs were: 10-9-62 (EP), 13-10-62 (EP, EC); 10-12-62 (IF); 1-1-63, 25-3-63, 5-7-63; 2-10-63, 30-10-63; 23-8-65; 9-2-67; 26-8-69; 16-7-70; 5-8-71, 2-10-71, 1-12 71; 5-1-72, 14-4-72, 26-5-72, 12-7-72, 4-9-72; 18-8-74; 24-8-76 (EC, IF, PC); 27-8-77 (EP, PC);16-8-78; 28-7-80; 28-8-81; 8-9-83; 23-11-84 (EP-W, IF, PC); 10-12-85; 24-2-86; 26-8-88; 7-2-89 (EC, IF, PC); 5-9-90; 8-9-91; 26-9-92; 16-9-93, 3-11-94, 7-10-95, 25-10-96, 16-9-97, 5-10-98, 9-9-99, 12-10-2000, 17-10-2001.
b. Subtidal Slopes: 16-7-72 (PS); 5-9-72 (ES); 14-12-85; 9-9-91 (ES); 26-9-92; 7-11-94, 7-10-95, 25-10-96, 16-9-97, 5-10-98, 9-9-99, 12-10-2000, 17-10-2001
c. Exposed Crest Transects: 25-8-76 (no.1); 18-8-78; 27-7-80; 28-8-81; 5-9-83; 12-12-85; 27-8-88; 2-9-90; 6-9-91; 24-9-92, 7-11-94, 7-10-95, 25-10-96, 16-9-97, 5-10-98, 9-9-99, 12-10-2000, 17-10-2001
d. Other transects and quadrats: dates of sampling are given in Table 4 in Connell et al 1997.
3. Effect of sample size (N) on the indices of Species Richness (S) and Diversity (D). (Regressions of S or D on N at each census).
Inner Flat: S = 0.964 +0.235 N , r squared = 0.863, N = 31
Inner Flat: D = 1.02 + 0.116 N , r squared = 0..617, N = 31
Protected Crest: S = 6.55 +0.138 N , r squared = 0.823, N = 26
Protected Crest: D = 3.89 + 0.071 N , r squared = 0..736, N = 26
Exposed Crest: S = 2.16 + 0.224 N , r squared = 0.951, N = 22
Exposed Crest: D = 2.11 + 0.087 N , r squared = 0.756, N = 22
Exposed Pools: S = 6.13 + 0.179 N , r squared = 0.661, N = 22
Exposed Pools: D = 6.25 + 0.033 N , r squared = 0.063, N = 22
Literature Cited
Connell, J. H., T. P. Hughes, and C. C. Wallace. 1997. A 30-year study of coral abundance, recruitment, and disturbance at several scales in space and time. Ecological Monographs 67:461–488.