[Coral-List] amazing recovery of corals in the Southern Line Islands after bleaching mortality
Douglas Fenner
douglasfennertassi at gmail.com
Sun Nov 6 03:45:42 UTC 2022
I was just alerted to another popular story about the recovery of the
Southern Line Islands that we've been discussing.
https://www.npr.org/2022/11/02/1132950728/coral-reef-resurrected-climate-change-bleaching-protection-nat-geo
This one is by the US organization called "National Public Radio."
They provide text on this web page that covers the story and repeats much
of what was on the other web pages we've seen. But the last part is
something I haven't read about this story yet. It quotes Enric Sala as
saying:
"It's great to show that protection of biodiversity, protection of marine
life can actually provide resilience to global warming," he said.
Maybe this is partly a problem of the definition of "resilience." Some
people have considered there to be two processes, "resistance" and
"resilience." The first being how much damage a distubance causes, and the
second how fast the reef can recover. Some people use the word
"resilience" to refer to both. I tend to thing that confuses things,
because it appears to me that the two have very different processes. I
think there are reports that in remote, protected areas (such as Chagos in
the Indian Ocean as well as the Southern Line Islands), bleaching can kill
corals just as easily as it can in areas heavily impacted by humans. But
this rapid recovery illustrates that highly protected areas can recover
very quickly.
One thing is "only" half of the corals had been killed. Some
places like Jarvis Is in the Line Is right next to the equator lost 90% of
their coral due to high temperature bleaching, as did Chagos in the Indian
O. Wouldn't be surprising if recovering from 90% loss might be slower than
from 50% lost (??)
The other thing is "protection." The southern Line Islands are
protected by vast distances from any humans. I would be surprised if
Kiribati legally protecting it had much of any effect, they can't possibly
put a patrol boat out there to enforce it, it is way too far away (and
that's not the fault of the government of Kiribati, that's just the costs
of putting a boat out that far and logistics of keeping a boat there all
the time, which are prohibitive). But I'm not informed on these issues,
I'm speculating. It does make a difference as to whether this can be
replicated elsewhere. It is not possible to move other reefs into such
isolated locations, but it is possible to try to protect them with
patrols. The operative word being "try." Maybe the great isolation of
these reefs protects them even better than patrols can protect MPAs in most
places. Plus, there are zero people there, and only a tiny island if any.
So near zero runoff of sediment and nutrients, no other local impacts of
humans. Maybe that's an important ingredient? What do people think?
A second thing. On this web page, there is a blue stripe below the
title and authors, which says "5-minute listen." If you click on that,
you'll get a 5 minute sound track from the radio show. He says that the
spillover of fish from protected areas, fishermen catch more fish than
before. I think that is a point that is debated by at least some fisheries
scientists, such as Ray Hilborn. Hilborn says that while there may be more
catch just outside the MPA boundaries than there was in that location
before the MPA, that increase does not compensate for the loss of fisheries
inside the boundaries of the MPA. My impression is that it is easiest to
demonstrate the increase in larger fish inside the MPA, not as easy to
demonstrate that the fish catch outside the MPA has increased, but I don't
know of any demonstration that the increase in catch outside the MPA is
larger than the loss of catch inside the MPA. Does anybody know of an
example of a demonstration of that on a coral reef??
Total catch is something that fishermen and fisheries scientists see
as a goal. Protection, preservation, and recovery of natural ecosystems
are things that conservationists see as goals. MPAs are put in place for
conservation purposes and can serve that purpose well even though they are
not panaceas, but in many places they have to have support of fishermen to
be successful, and that requires the fishermen to see good fish catches.
So for conservation, helping fish catches outside can help conservation
inside an MPA.
Oh, and my understanding is that you are quite right about coralline
algae being more sensitive to acidification than coral. I think that is in
part due to the fact that they secrete high-magnesium calcium carbonate,
which dissolves easier in low pH water.
Cheers, Doug
On Thu, Nov 3, 2022 at 8:03 PM Douglas Fenner <douglasfennertassi at gmail.com>
wrote:
> Austin,
> I think we as scientists have to tell the story, and the whole story,
> about reality. Whether that story is good, bad, or ugly. No sugar
> coating. I post these things so people are aware of them, usually without
> commenting on the article. So I post it whether it seems good or bad. But
> then I hope people will respond, and I particularly appreciate when people
> add to the story and point out aspects that aren't included in the story,
> like what you've done this time. So thank you, we all can learn.
> Perhaps this story is one of a glass half full but also half empty.
> Myself, if I saw a reef that had almost all of its coral killed, to see
> that coral cover had recovered so much, that would be a huge relief.
> That's a lot better than if it remained dead for 40+ years, like in
> Discovery Bay, Jamaica, isn't it?? I agree that it is a phase shift. When
> phase shifts on coral reefs were first reported, they were the phase shifts
> in the Caribbean from coral dominated to macroalgae dominated. Many of us,
> myself included, thought that phase shifts were from coral to macroalgae.
> Turns out that shifts to macroalgae domination are the exception, not the
> rule, as demonstrated in the paper by Bruno et al. (2009). Now, as your
> references document, there is increasing evidence of reefs that have had
> their corals hit hard, which recover much of their coral cover, but with a
> different coral community.
> Personally, if I had a favorite reef and over 90% of its corals were
> killed by a heat wave from climate change or crown of thorns, or a cyclone,
> and its coral cover recovered, I'd be delighted the coral cover returned
> even if it was a different coral community. For some time, people have
> been pointing out that coral cover isn't everything, and they are right,
> you are right. Just because the coral community is different now, does not
> mean that it will remain so forever. There will surely be more mass coral
> mortality events, and maybe next time the coral won't recover and we'll be
> wishing it had, even if it was changed. Or maybe, some of the new coral
> species will be able to withstand even higher temperatures, or not. We may
> be entering uncharted waters.
> I'm not claiming that phase shifts to different coral communities
> are nothing. Clearly, this is important. If we had a choice, we wouldn't
> be choosing to have these phase shifts happen. Interestingly, they aren't
> all changing to the same coral species.
> Using the word "extinction" without qualifying it, could lead to
> some people taking it to mean things for which there isn't hard evidence.
> In this story (which is not a peer-reviewed published scientific paper), it
> is obvious that some species had drastic local population reductions from
> the heat wave bleaching. There are a variety of different types of
> extinction that can be distinguished. Local extinction, commercial
> extinction, functional extinction, and global extinction being some of
> them. None of these reports would imply global extinction of any species.
> These are tiny, isolated islands and most corals have gigantic species
> ranges, at least the way coral species are presently defined and recorded.
> The article doesn't even claim any local extinctions, though they could
> only find one colony of Pocillopora for one island. It is very hard to get
> definitive evidence of extinction, because it is essentially the null
> hypothesis, which can't be proven. And in practical terms, even on a small
> reef, every square inch can't be searched, usually only a tiny fraction of
> the area can be searched. The species we think is extinct could be in the
> area we haven't searched, stranger things have happened. Obviously, the
> drastic reductions in some species reported in this article would be
> functional extinctions.
> Anyhow, the word "extinction" is often not used with qualifiers, and
> without qualifiers often used to indicate global extinction. And I see no
> evidence in this article of any global extinctions. No evidence does not
> mean it didn't occur, it just means no evidence to support the idea. May
> appear in the future, who knows.
> I think you have a good and valid point, that just because coral
> cover returned, doesn't mean that the coral community didn't undergo a
> phase shift, and such coral community phase shifts are now being found to
> be far more common than we knew. And I would agree that community phase
> shifts may be a threat. Not only has the coral community had a phase
> shift, but it sounds like the new community has a lower diversity. It will
> be interesting to see what the reduction in diversity is. It may not be in
> the form of some species that were present no longer being present, it may
> be that it is in the form of formerly common species becoming rare, while
> one or a few become common or even dominant.
> Cheers, Doug
>
> Bruno, J. F., Sweatman, H., Precht, W. F., Selig, E. R., and Schutte, V.
> G. W. 2009.
>
> Assessing evidence of phase shifts from coral to macroalgal
> dominance on coral
>
> reefs. *Ecology* 90, 1478–1484.
>
> On Tue, Nov 1, 2022 at 10:52 AM Austin Bowden-Kerby <
> abowdenkerby at gmail.com> wrote:
>
>> Thanks Doug,
>>
>> Yes, this sounds encouraging- on the surface, and the photos are
>> beautiful! However if you look more deeply, it is a lot less hopeful.
>> What this represents is yet another case of near total phase shift in the
>> coral population, and the local extinction of a whole list of species. The
>> actual reality is this: due mass bleaching, the coral population of the
>> Southern Line Islands has gone from a diverse population dominated by
>> Pocillopora and Acropora, to one dominated by a single species of
>> Montipora.
>>
>> A similar phase shift has happened in Tarawa, in the Gilbert chain, due
>> to bleaching, with the end state being a single species: Porites rus
>> (Cannon et al, 2021). In Kiritimati Atoll, the mass bleaching resulted in
>> the local extinction of many Acropora species and a big reduction in
>> Pocillopora, leaving behind only remnants of massive Porites and massive
>> Pavona, (Bowden-Kerby et al, 2021). In Moorea, the phase shift has gone
>> from Acropora dominated to Pocillopora dominated (Edmunds, 2018; Carlot et
>> al, 2020), related to bleaching and COTS predation. This phase shift has
>> been well documented for the Red sea as well (Riegl et al, 2013), with a
>> shift away from Acropora towards Pocillopora and Porites, attributed to a
>> combination of mass bleaching and COTS predation.
>>
>> These phase shifts transform the habitat characteristics of the reef,
>> away from what the original species. The resulting reefs provide poor
>> habitat for juvenile fish and plankton-feeding fish like Chromis, which
>> require branching coral species. These phase shifts represent weedy and
>> long-lasting coral species, which can dominate the settlement surfaces and
>> prevent larval based recovery of the reef back to its original coral
>> population. Few of these authors seem to understand this, and so they
>> celebrate and use the word "recovery" in their titles. However, these
>> phase shifts represent degraded alternate steady-state conditions.
>> Unfortunately GCRMN will support these authors, as it only looks at coral
>> cover, not genera, and so it will not pick up or highlight these phase
>> shifts and species extinctions either.
>>
>> I have two recommendations related to this information:
>> 1. GCRMN needs to be updated to include coral genera! Seriously- how can
>> GCRMN be missing so much of the plot?
>> 2. The authors of these sorts of "recovery" studies need to present phase
>> shifts with less glee and celebration. A more detached and honest view will
>> present the tragedy that has happened. Yes, the alternative state
>> sometimes is rather glorious and beautiful, appearing to be an improvement
>> over barren rock, but the fact is that these phase shifts represent
>> local extinction events for coral species essential to ecosystem function,
>> fisheries, and coral reef geology. And these phase shifts might also
>> prevent the return to the original populations, cementing in the extinction
>> event.
>>
>> We can not allow increasing coral cover to trick us into thinking that an
>> actual recovery has happened.
>> If we do, we risk being seduced by the enemy and missing the evil plot
>> that climate change is weaving, tricking us into inaction!
>>
>> I think that there is enough evidence to come to the conclusion that
>> coral reefs are dying out as a series of phase shifts. Only this
>> recognition will help us refrain from celebrating the shift, and to stop
>> labeling it recovery.
>> Only by understanding these basic processes occurring on coral reefs
>> under increasing stress, can we then begin saving the reefs.
>>
>> What happens when the next mass bleaching event or perhaps predators or
>> disease kills off much of the Montipora of the Southern Line Islands? Will
>> this unstick the alternative steady state and allow recovery? Not unless
>> there is a source of coral larvae from the original, now missing coral
>> species. How does a high coral cover single-species dominated reef get
>> restored to its original highly diverse state? On Kiritimati, after the
>> mass coral die-off in 2015-16, and while coral cover was still under 5% for
>> the two remaining massive species, we turned our focus to finding the few
>> remnant survivors of formerly dominant Acropora and Pocillopora coral
>> species, and growing them within a recovery nursery. The focus was on
>> restoring sexual process to the corals, by collecting the widely spaced and
>> ecologically extinct survivors, growing them, and getting them back
>> together. While several formerly abundant Acropora coral species could not
>> be found, we have succeeded in restoring reproduction to patches of seven
>> Acropora and two Pocillopora species.
>>
>> A 22 minute presentation on our 'Reefs of Hope' strategies is here
>> https://youtu.be/arkeSGXfKMk And to the list: we welcome self-funded
>> research partners and graduate students in our sites.
>>
>> Vinaka, and kind regards to all,
>>
>> Austin
>>
>> Cannon SE, Aram E, Beiateuea T, Kiareti A, Peter M, Donner SD (2021)
>> Coral reefs in the Gilbert Islands of Kiribati: Resistance, resilience, and
>> recovery after more than a decade of multiple stressors. PLoS ONE 16(8):
>> e0255304. https://doi. org/10.1371/journal.pone.0255304
>>
>> Edmunds, P.J. Implications of high rates of sexual recruitment in
>> driving rapid reef recovery in Mo’orea, French Polynesia. 2018. Nature:
>> Scientific Reports. 8:16615 doi:10.1038/s41598-018-34686-z
>>
>>
>> Carlot J., Rove`re A., Casella E., Harris D., Grellet-Mun C., Chancerelle
>> Y., Dormy E., Hedouin L., Parravicini V. 2020. Community composition
>> predicts photogrammetry-based structural complexity on coral reefs. Coral
>> Reefs. doi: 10.1007/s00338-020-01916-8
>>
>>
>> Riegl B., Berumen M., Bruckner A. 2013. Coral population trajectories,
>> increased disturbance and management intervention: a sensitivity analysis.
>> Ecology and Evolution 3(4): 1050–1064
>>
>> doi: 10.1002/ece3.519
>>
>>
>> Bowden-Kerby, A., Romero, L., and Kirata T. 2021. Chapter 17: Line
>> Islands Case Study. In: Active Coral Restoration: Techniques for a
>> changing planet, David Vaughn, Editor. 610pp.
>>
>>
>>
>> Austin Bowden-Kerby, PhD
>> Corals for Conservation
>> P.O. Box 4649 Samabula, Fiji Islands
>>
>>
>> https://www.globalgiving.org/projects/emergency-response-to-massive-coral-bleaching/
>> <https://www.globalgiving.org/projects/emergency-response-to-massive-coral-bleaching/>
>>
>>
>>
>>
>>
>>
>>
>>
>> On Wed, Nov 2, 2022 at 6:01 AM Douglas Fenner via Coral-List <
>> coral-list at coral.aoml.noaa.gov> wrote:
>>
>>> Once devastated, these Pacific reefs have seen an amazing rebirth
>>>
>>>
>>> https://www.nationalgeographic.com/magazine/article/once-devastated-these-pacific-reefs-have-seen-an-amazing-rebirth-feature
>>>
>>> Cheers, Doug
>>>
>>> --
>>> Douglas Fenner
>>> Lynker Technologies, LLC, Contractor
>>> NOAA Fisheries Service
>>> Pacific Islands Regional Office
>>> Honolulu
>>> and:
>>> Coral Reef Consulting
>>> PO Box 997390
>>> Pago Pago, American Samoa 96799-6298 USA
>>>
>>> Switching to renewable energy could save trillions-up to $12 TRILLION by
>>> 2050.
>>> https://www.bbc.com/news/science-environment-62892013
>>>
>>> 1 in 6 deaths worldwide can be attributed to pollution, new review shows
>>>
>>> https://www.msn.com/en-us/health/medical/1-in-6-deaths-worldwide-can-be-attributed-to-pollution-new-review-shows/ar-AAXozQh
>>>
>>> UN: World on fast track to disaster, but we can avert it
>>> https://www.youtube.com/watch?v=9xBVD8r0aHQ
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>>
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