[Coral-List] Coral Reef Degradation

Steve Mussman sealab at earthlink.net
Tue Jul 26 16:43:15 EDT 2016

Dear John,

How would I express your findings in layman's terms if I wanted to advise and inform an audience composed of dive industry professionals?  Would I be consistent with your findings if I said . . . "it is certainly beneficial to address local stressors, but we should not lose sight of the fact that even the world's most "pristine" reefs like those found in remote areas of the Pacific and well-managed, no take MPAs in the Caribbean will eventually succumb to the impacts of a warming world if we don't take aggressive and timely steps to address climate change"?  Is that going too far?  What's the prognosis for the world's best coral reefs if we just continue to do business as usual?

Steve Mussman
Sea Lab Diving 


-----Original Message-----
>From: "Bruno, John" <jbruno at unc.edu>
>Sent: Jul 25, 2016 10:42 PM
>To: "coral-list at coral.aoml.noaa.gov" <coral-list at coral.aoml.noaa.gov>
>Subject: Re: [Coral-List] Coral Reef Degradation
>Dear Dennis,
>“Perhaps the message here is that no reefs are outside the influence of humans?”
>I agree.
>Also, we have used this database (actually, the extended form using all years) to test whether MPAs can effectively mitigate coral loss. Our results suggest they can, but only after decades of effective implementation (Selig & Bruno, 2010) and not in response to warming (Selig et al., 2012). Local management did not generally decrease the negative effect of warm anomalies on coral cover. We also found that the negative effect of thermal stress was strongly dependent on pre-disturbance coral cover (higher cover reefs were much more susceptible when holding the magnitude of thermal stress constant). This result has been observed in numerous local and regional studies (e.g., Graham et al., 2008) and also in meta-analyses of resistance to other types of disturbances (e.g., Zhang et al., 2014). This finding is one reason why the combined effects of warming and local stressors could be antagonistic, rather than synergistic as widely assumed. I.e., other disturbances could make a reef less susceptible to warming by reducing coral cover and/or the cover of disturbance-sensitive species (Côté & Darling, 2010).
>Note, the results of our study (http://www.nature.com/articles/srep29778) do not indicate local impacts do not matter/do not effect coral cover – clearly they sometimes do. Instead the results suggest that local impacts are either swamped by warming or that local and global stressors are antagonistic, rather than synergistic. The results also do not suggest we shouldn’t manage locally! IMO there are numerous obvious benefits of restoring coral reef fish communities and reducing coastal pollution, even if those actions don’t measurably benefit corals in a warming world. In other words, I believe local management is necessary but insufficient to conserve / restore coral communities.
>John Bruno
>Professor, Dept of Biology
>UNC Chapel Hill
>Côté IM., Darling ES. 2010. Rethinking Ecosystem Resilience in the Face of Climate Change. PLoS Biology 8:e1000438. DOI: 10.1371/journal.pbio.1000438.
>Graham NAJ., McClanahan TR., MacNeil MA., Wilson SK., Polunin NVC., Jennings S., Chabanet P., Clark S., Spalding MD., Letourneur Y., Bigot L., Galzin R., Ohman MC., Garpe KC., Edwards AJ., Sheppard CRC. 2008. Climate Warming, Marine Protected Areas and the Ocean-Scale Integrity of Coral Reef Ecosystems. PLoS ONE 3:e3039.
>Selig ER., Bruno JF. 2010. A global analysis of the effectiveness of marine protected areas in preventing coral loss. PLoS One 5:e9278.
>Selig ER., Casey KS., Bruno JF. 2012. Temperature-driven coral decline: the role of marine protected areas. Global Change Biology 18:1561–1570. DOI: 10.1111/j.1365-2486.2012.02658.x.
>Zhang SY., Speare KE., Long ZT., McKeever KA., Gyoerkoe M., Ramus AP., Mohorn Z., Akins KL., Hambridge SM., Graham NAJ., Nash KL., Selig ER., Bruno JF. 2014. Is coral richness related to community resistance to and recovery from disturbance? PeerJ 2:e308. DOI: 10.7717/peerj.308.
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