(This exercise is based on Bruno, J. P. and E. R. Selig. 2007. Regional decline of Coral Cover in the Indo-Pacific: Timing, Extent, and Subregional Comparisons. PLoS ONE 8: e711.)
(Note: The reference above links directly to the article on the journal’s website. In order to access the full text of the article, you may need to be on your institution’s network [or logged in remotely], so that you can use your institution’s access privileges.)
As was discussed in the chapter, coral reefs are important marine communities, containing as many as a million species, with extraordinarily high taxonomic and morphological diversity. Moreover, some of the species of fish that rely on coral reefs for habitat are economically important.
Human activity has resulted in climate change and associated warming of oceans. The warmer ocean temperatures contributes to bleaching of corals, due to loss of photosynthetic pigments, leading to their eventual disappearance from reefs across the oceans. How fast is this occurring? Are corals being lost at different rates in different regions of the world? These are among the questions John Bruno and Elizabeth Selig of the University of North Carolina explored in their recent paper.
To determine how quickly corals are being lost, Bruno and Selig first quantified the current area covered by live coral reefs in regions in the southwestern Pacific Ocean (called the Indo-Pacific region).
Figure 1 The locations of the different subregions within the Indo-Pacific region the authors examined.
Question 1
In which country is the Great Barrier Reef located?
Question 2
Which subregion lies directly east of Southwestern Pacific?
Figure 2 The mean percentage coral cover of ten different subregions in the Indo-Pacific as measured in 2002–2003. Standard errors are denoted by bars, and the numbers listed are the numbers of reefs surveyed.
Question 3
What was the range in percent mean coral cover across the regions? Which subregions had the lowest values? Which subregions had the highest values?
Figure 3 The distributions of coral cover across the entire region for 1980–1983 (top) and for 2003 (bottom).
Question 4
Next, Bruno and Selig went to the scientific literature to ascertain what fraction of reefs had coral cover in the early 1980s (Figure 3). Describe the patterns that you see. To what degree had coral reef cover changed over the two decades?
Figure 4 The distributions of coral cover for the Philippines, Mainland Asia, and the Great Barrier Reef.
Question 5
What patterns do you see in Figure 4?
Question 6
The Great Barrier Reef has been described as one of the best-managed and most pristine coral reefs in the world. Based on the results from this study, what conclusions can you draw about threats to the Great Barrier Reef and to coral reefs globally?
