Figure 1.
Sampling methods for estimating benthic cover of canopy-forming corals.
(A) A typical colony of Acropora hyacinthus on reefs at Lizard Island. (B), A schematic figure demonstrating intercepts (vertical lines; blue = coral, green `other benthos) on a planar transect, coral cover = 60%. (C), A schematic figure demonstrating benthic transects, here the dotted vertical lines indicate measurements made beneath the canopy; here coral cover = 20%. (D), A schematic figure demonstrating the chain transects, where lines indicate that measurements were made at set distances along a line that conforms to the outline of the coral; here coral cover = 68%.
Figure 2.
Benthic cover of algae and corals using three transect methods on an Acropora-dominated reef.
(A) The estimated cover of corals on an Acropora dominated reef using the three different transect types; canopy forming taxa in white and benthic cover species in dark grey. (B) The estimated cover of algae on the same transects; black bars represent cover of epilithic algal matrix (EAM) and light grey, crustose coralline algae (CCA). A, B, C and X, Y, Z denote statistically different groupings (Repeated Measures ANOVA with Tukey Kramer post-hoc test, α = 0.05).
Figure 3.
Conceptual model demonstrating the effect of canopy removal on an Acropora-dominated reef.
Note the apparent increase in both algae (EAM) and massive corals simply as a result of the loss of the canopy. Start points are based on data collected using planar transects. Canopy-forming cover is reduced by 10% each generation. End points are based on data collected using benthic transects (with no remaining canopy).