Electronic Supplementary Material 1: Similarity Between the Community at the Monitoring

Electronic Supplementary Material 1: Similarity between the community at the monitoring site and adjacent reefs.

Aim

Determine how similar the monitoring site is relative to adjacent reefs in the region (i.e. Nine-, Seven- and Two-mile Reefs) in terms of species composition (presence/absence) and community structure (percentage cover).

Field sampling

Surveys of the benthic communities on Nine-mile Reef and adjacent Seven- and Two-mile Reefs were conducted during 2000 and 2004 on SCUBA. A series of square photo-quadrats (0.32 m2), acquired with a digital camera, were taken at regular intervals along haphazardly placed transects located at depths of between 12 to 18 m. A total of 1084 photo-quadrats consisting of 322 from Two-mile Reef, 391 from Seven-mile Reef and 371 from Nine-mileReef were captured. Ten grid points were then superimposed onto each of the 1084 photo-quadratsin the laboratory and the benthic cover beneath each point identified to the highest possible taxonomic resolution. The results from the grid-point analyses were then converted to percentage cover.

Data analysis

The average percentage cover per taxon was calculated for each reef (Two-, Seven- and Nine-mile Reefs), for Seven- and Nine-mile Reefs together, and for all three reefs combined. The average percentage cover per taxon from the monitoring site was calculated by averaging across all 22 yr of data. Bray–Curtis similarity values based on the percentage cover data were then calculated between the monitoring site and the other adjacent reefs using untransformed and presence/absence data in two separate analyses.

Results

Bray–Curtis similarity values based on presence/absence data between the monitoring site and the other adjacent reefs ranged from 77 to 87 (Table A). Bray–Curtis similarity values between the monitoring site and the other reefs using untransformed percentage cover data rangedfrom 61 to 83 (Table B).

Table ABray–Curtis similarity values (0–100) between the monitoring site and adjacent reefs in the region based on presence/absence data

Reef / Monitoring site / Nine-mile Reef / Seven-mile Reef / Two-mile Reef / Mean of Nine- and Seven- mile Reefs
Nine-mile Reef / 87
Seven-mile Reef / 77 / 84
Two-mile Reef / 81 / 82 / 84
Mean of Nine- and Seven-mile Reefs / 83 / 96 / 90 / 81
Mean of Nine-, Seven- and Two-mile Reefs / 85 / 94 / 88 / 83 / 99

Table BBray–Curtis similarity values (0–100) between the monitoring site and adjacent reefs in the region based on untransformed percentage cover data

Reef / Monitoring site / Nine-mile Reef / Seven-mile Reef / Two-mile Reef / Mean of Nine- and Seven- mile Reefs
Nine-mile Reef / 73
Seven-mile Reef / 83 / 83
Two-mile Reef / 61 / 77 / 75
Mean of Nine- and Seven-mile Reefs / 71 / 92 / 92 / 78
Mean of Nine-, Seven- and Two-mile Reefs / 69 / 88 / 87 / 86 / 92

Conclusion

Based on the above analyses, the long-term monitoring site is sufficiently similar to adjacent reef communities to be considered typical of reef communities in the region in terms of both the species composition and community structure on these reefs.