2.3. Five groups of bioindicator candidates
2.3.1. Benthic cover and diversity
Transects were laid parallel to the reef slopes. In Study 1, underwater
video imagery was recorded along two 25 m long transects
at each location. Benthic cover and richness were quantified by
identifying substrata underneath five points on each of 40 frames
per transect (200 points per transect; Abdo et al., 2004). In Study
2, a digital photograph was taken every half meter along two
20 m long transects at each location, and 32 images per transect
were randomly selected for identification of the organisms beneath
5 fixed points on each image (Jonker et al., 2008). Scleractinian corals
(i.e., hard corals) and octocorals (i.e., soft corals and sea fans)
were identified to the highest taxonomic resolution possible, distinguishing
72 operational taxonomic units. However, for the statistical
analyses, many uncommon coral genera were pooled into
families and macroalgae were grouped into red algae (Rhodophyta),
brown algae (Phaeophyta) and green algae (Chlorophyta).