[Coral-List] Evidence that ocean warming has caused most Caribbean coral loss

[Bruno, John]

Dear Dennis,

I respectfully disagree. For ecologists, determining the relative role of different factors in driving patterns is largely the point of our field.  It has nothing to do with feeling "our subdiscipline is the most important”.  Good ecology means testing multiple hypotheses that explain an observation, retesting those hypothesis over and over, etc. Its not about ego - this is fundamentally what "trying to understand the nature of the system" IS.

Identifying the causal drivers of population declines is fundamental to species conservation. This concept goes way back to Graeme Caughley, and forms the basis of the “declining population paradigm” in conservation science. It isn’t necessarily “all tied together”. Every plausible factor that could possibly influence a pattern doesn’t necessarily have a measurable role. Most species are weak interactors and lots of processes aren’t all that common or important. In the case of coral decline, there are literally dozens of possible explanations and since conservation dollars are finite and we can’t tackle every problem, its critical to identify the main causes. Doing so is not a “waste of bandwidth”. Moreover, it’s common (on the coral-list) to assume the interaction of two important stressors is synergistic; that’s often true at the individual-level, but at the community level they are just as likely to be antagonistic, i.e., they dampen each others effects. Figuring stuff like this out is important to effectively managing reefs.

(As an aside, my view is that there is certainly evidence of local impacts, like pollution. The challenge is to figure where that’s the case (we do VERY little monitoring of water quality on reefs) and also how to address it (its a tough problem). Just screaming that all the loss is due to pollution and that nutrient pollution is widespread in the ocean is not supported by the science. We should follow the lead of local management in places like the Florida Keys, Bermuda, etc where they’ve (largely) tackled nutrients, anchor damage, fishing, etc.)

Sincerely,

John



On May 3, 2017, at 2:55 PM, Dennis Hubbard <Dennis.Hubbard at oberlin.edu<mailto:Dennis.Hubbard at oberlin.edu>> wrote:

Hi Elizabeth:

None of this helps answer the question going around of what is the "primary" driver of reef decline. If anyone hasn't read it, I highly recommend Jeremy Jackson's "Reefs Before Columbus" article in Coral Reefs awhile back.... it is sobering, as is John Pandolfi's follow-up discussions of how early anthropogenic impacts might have kicked in.

So, for me, as a reef scientist, it really doesn't make a great deal of sense to argue over what is worse just so we can feel "our subdiscipline is the most important". It's all tied in together and, while we take up bandwidth with this, we could be spending that time trying to understand the nature of the system better.

As a reef GEO-scientist, when I think back to the "good old days, I'm thinking early Holocene.

Best,

Dennis