Post-bleaching shifts in coral-associated species richness
Randomized observed species richness (Figure 3) and Chao 1 estimated species richness (Figure 4) of associated species varied significantly across certain time points and/or between live and dead corals. In July 2008, which was 6-13 months post-bleaching and within the 2007-2008 La NiƱa period, live and dead corals supported similar observed (20-21 species) and Chao 1 estimated (40-41 species) total species richness (Figures 3A, 4A). However, observed total species richness on dead corals increased to 25 species in January 2009 relative to July 2008 (including seven fishes and 19 macroinvertebrate species), and then it declined thereafter until February 2010 (Figure 3A). By contrast, observed total species richness (and observed fish richness) on live corals was initially higher in July 2008 (and higher than on dead corals in July 2008) and comprising 20 species (including 9 fishes and 11 macroinvertebrate species), decreased in January 2009, and remained stable through February 2010 (Figure 3A-B).
Across all sampling dates, Chao 1 mean estimated total richness was 16-41 and 16-61 total species (Figure 4A), 4-10 and 5-16 fish species (Figure 4B), and 10-21 and 8-73 invertebrate species (Figure 4C) associated with live and dead corals, respectively. Similar to observed species richness, between July 2008 and January 2009, Chao 1 estimated total and invertebrate species richness on dead corals underwent a nearly 50% increase, from 41 to 61 total species richness and from 25 to 73 invertebrate richness, then declined significantly to 25 total and 20 invertebrate species richness in July 2009, and ultimately to 16 total and 8 invertebrate species richness in February 2010 (Figure 4A&C). By contrast, Chao 1 estimated total and invertebrate species richness on live corals did not significantly differ across most time points, and fluctuated from 41 to 24 to 35 total species and 21 to 21 to 18 invertebrate species from July 2008 to July 2009, but it significantly declined to 16 total and 10 invertebrate species richness in February 2010 (Figure 4A&C). By contrast, Chao 1 estimated fish richness declined over time on dead corals (from 16 to 7 to 5 to 9 species) and live corals (from 10 to 4 to 7 to 5 species), and in July 2008 it was significantly higher than in any other time periods (Figure 4B).