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Coral Species Richness a Full Decade After Two Bleaching Events
van Woesik, R., Sakai, K., Ganase, A. and Loya, Y. 2011. Revisiting the winners and the losers a decade after coral bleaching. Marine Ecology Progress Series 434: 67-76.

The authors write that "over the past three decades, thermal stress events have damaged corals globally." However, they say that few studies "have tracked the recovery process or assessed whether winners in the short term are also winners in the long term."

What was done
In a research program designed to address this important subject -- which they conducted on the southeastern reef of Sesoko Island at the Tropical Biosphere Research Center of the University of the Ryukyus, Okinawa, Japan (26°38'N, 127°52'E) -- van Woesik et al. repeatedly evaluated (1997, 1999, 2000, 2001, 2004, 2007, 2010) a coral assemblage that experienced the significant thermal stress events of 1998 and 2001.

What was learned
The four researchers found that "by 2007, species richness had recovered to ~13 species per m2, which was similar to species richness in 1997," and that "hard coral cover increased from 3% in 2001 to 47% in 2010." However, they found that "species composition had undergone change," in that "some species were thermally tolerant and increased in relative abundance through time," some "increased in relative abundance through the thermal stress and remained constant thereafter," and some "were neither winners nor losers through time."

What it means
Van Woesik et al. write that their findings suggest that the ecosystem they studied was "able to absorb the thermal stressors without undergoing change to a less desirable state," citing the similar findings of Holling (1973) and Scheffer and Carpenter (2003)," as well as the fact that "Acropora populations had fully recovered seven years after an extreme thermal-stress event in Palau (Golbuu et al., 2007)," plus the fact that in the Arabian Gulf, "Riegl and Purkis (2009) showed that Acropora assemblages could recover from thermal-stress cycles occurring every fifteen years."

Golbuu, Y., Victor, S., Penland, L., Idip Jr., D., Emaurois, C., Okaji, K., Yukihira, H., Iwase, A. and van Woesik, R. 2007. Palau's coral reefs show differential habitat recovery following the 1998-bleaching event. Coral Reefs 26: 319-332.

Holling, C.S. 1973. Resilience and stability of ecological systems. Annual Review of Ecology and Systematics 4: 1-23.

Riegl, B. and Purkois, S. 2009. Model of coral population response to accelerated bleaching and mass mortality in a changing climate. Ecological Modelling 220: 192-208.

Scheffer, M. and Carpenter, S.R. 2003. Catastrophe regime shifts in ecosystems: linking theory to observation. Trends in Ecology and Evolution 18: 648-656.

Reviewed 21 December 2011