[Coral-List] Is the recent GCRMN Report Unintentionally Misleading? (Re: New Paper: Resilient corals in the Phoenix Islands)

Austin Bowden-Kerby abowdenkerby at gmail.com
Sat Oct 9 00:21:21 UTC 2021

Bula Doug and David and others on Coral List,

Sorry this is posted so late.  I have changed the heading, as this has
broadened to one of global interest, while following the same thread- my
contention that the reports of rosy resilience may be somewhat misleading,
or at best represent a temporary condition that we may soon lose.  We have
a dying patient, but the doctors are focused on how the kidneys are still
functioning, and that the patient is still conscious, rather than the fact
that the arteries are 90% clogged and how the future looks to be quite
grim.  Thanks very much Doug for those many insights and literature
sources. This particular comment resonated: "If you lose 90% of the cover,
how many rare species were just pushed to regional extinction?  If 99%
loss, how many?  Regional extinctions are a step towards global

I just read through the most recent GCRMN "6th status of Corals of the
World Report: 2020 report.  http://gcrmn.net/2020-report/    The report
verifies our concerns- that just about everyone seems to be missing the
local species extinctions and coral community phase shifts that are now
happening in the face of mass coral die-offs- including GCRMN.  How could a
collapse of coral reef biodiversity and ecosystems occur and not be picked
up by the GCRMN data?  This realization has me stunned.  The problem stems
from GCRMN using "coral cover" to indicate the health of coral reefs, with
no mention of coral genera at all.  Without any species or genus data
presented, the change in coral communities and the local extinction of
coral species is being completely missed by those who might intervene to do
something about it!

Using % coral cover as a proxy for coral reef health is like using %
vegetation cover to judge forest ecosystem health, only being able to
distinguish grass (macroalgae) from trees (corals), but without
distinguishing between coniferous vs broadleaf trees or shrubs.  In this
analogy, large massive Porites or Orbicella or Diploastrea colonies might
be likened to the redwood trees, while branching Porites would be akin to
smaller conifers, and Acropora corals might be akin to the broadleaf
vegetation- trees, bushes and shrubs, more diverse in form and also more
palatable and providing many more species with food and habitat- bees,
hummingbirds, fruit and nut eating birds and mammal species, a diversity
which conifer forests can not support.  Percent vegetation or % tree cover
as a forest health measure totally misses the fact that North American
forests have had major mass extinctions of broadleaf species due mostly to
introduced diseases: chestnut, elm, ash, beech, oaks, etc, and that
there has been a major shift from broadleaf to conifer vegetation. Forest
restoration efforts- you would think, would focus on restoring the
natural balance of the original species, but alas, conifers are the primary
focus of reforestation.

While the GCRMN report shows a 14% decline in coral cover globally over the
past decade, which is useful data and a cause for real concern, could this
represent for some reefs an increase in relative or actual cover of Porites
and a severe reduction in Acropora cover?  Without species or genera
specific data in the GCRMN database we can't tell, so it is of limited
value.  Where is the fine scale data, and what does it indicate?

Various coral reef reports (like the one from Tarawa), show that some coral
communities exposed to repeated heat stress are flipping into alternate,
yet coral dominated states.  For many reefs, what I see with my own eyes is
a trend from Acropora dominated reefs to Pocillopora dominated- after the
first heat wave, and then to Montipora and Porites dominated after the
second wave, and finally to Porites dominated or mostly dead rock on the
third and fourth waves. These alternate coral species compositions are
less biodiverse and also provide less habitat for other species- very few
planktonivorous fish for example, and what does that do to the reef food
webs?  The replacement community is also composed of slower growing coral
species, so calcification rates will logically be lower, and the rounded
and tightly packed branched *Porites rus *corals will likely also provide
poorer wave attenuation properties.  Reefs are changing, and we need more
fine-scale data on this process, if we are to intervene to halt or lessen
this cascade of impacts.

My fear is that the Chagos and Kiribati coral species extinctions indicate
an emergent trend that will in the coming decades spread to most if not all
coral reef systems, as severe and more frequent mass bleaching events
emerge. This is not alarmist- these systems are widely expected to collapse
within the next 30 years or so, so why are so many scientists in (what
looks to be) denial, and not dealing with what is already happening on the
forefront of the collapse?

The paradigm that functioning MPAs and clean pristine waters are able to
save coral reefs from warming seas has been shattered, yet I think few have
accepted that reality.  The restoration community continues to talk of
upscaling when the smoke and glow of the approaching firestorm is on the
horizon.  Few in the scientific community seem to realize how far along the
process of collapse and change in the face of climate change really is for
some equatorial coral reefs, and how could they- if there are only a few
published reports, and if these reports focus on any ray of hope or bright
spot that can be found, rather than the horrifically bleak bigger picture
of what has been lost.  I have had to change my own mental models after
witnessing this disaster.  I had thought we had a decade or two more, but
we don't.

On the other hand, these most impacted coral reefs offer a learning
opportunity and a window into the future for climate change impacts on
coral reefs.  I have visited the future on Kiritimati Atoll, and it
transformed my whole perspective.  I now consider what lessons might be
learned that might help save corals elsewhere, and what might we do to
prevent local coral species extinctions?  Other scientists propose that we
abandon these most impacted coral reefs and focus on less impacted coral
reefs- hopefully more resilient reefs, however that approach admits defeat
on the front lines, and is in essence a retreat in what must increasingly
become a coordinated war on the impacts of climate change.

We have operating what amounts to an endangered Acropora restoration
program on Kiritimati Atoll, where we have established a nursery and have
reestablished spawning in some species.  We continue to devote time to
searching for the eight missing species, with only five of an original
thirteen species of Acropora so far found on the Atoll after several years
of looking.  What we are doing now in Fiji is to actively prepare coral
reefs for the coming onslaught, from lessons that we learned from

We are calling the process  "Active Coral Reef Adaptation" or ACRA, and it
is NOT coral reef restoration.  We are using six strategies to help coral
reefs adapt to increasing temperatures.  The foundation of the program
works mostly with Acropora corals, as they are the first to go, recognizing
that the most bleaching resistant individuals of these corals are not any
more secure over the long haul than their cooler adapted siblings simply
due to their location.  Even though these corals can survive unbleached to
35-38C, the hot reef habitats where we find these corals will inevitably
exceed this temperature in the coming years, resulting in their death.  So
a foundation of the adaptation work is coral rescue and local translocation
from hot nearshore conditions to cooler reefs offshore.  Once the corals
are well established in offshore gene bank nurseries, we then implement
other strategies to help facilitate the sharing of algal symbionts and to
restore sexual reproduction to encourage cross breeding.  We are in the
process of writing this up for publication, but some self funded graduates
students would help in future work, as more questions have been generated
than answered!

I share all of this here and now, because coral reefs are under severe
attack, and the prospects are grim, yet I do not see any comprehensive
battle plans or strategies, or even a consensus that we are at war- or that
there is anything that can be done, other than the obvious action of
solving the root causes of climate change.  But there will be nothing left
of the corals if that is all we do, if we don't wage a war to save corals
from going locally extinct- along with their amazing adaptive traits- our
best hope is to preserve this diversity.  We also need to preserve the cool
adapted diversity, but it can't be done without longer distance

PLEASE lets try to reduce the positive spin on reporting and on journal
titles, and I have had enough of the high tech quick-fix solutions (funded
at least in part by the fossil fuel industry), especially when all that we
have accomplished we have had to crowd-fund for on Global Giving- link

Kind regards to all,


Austin Bowden-Kerby, PhD
Corals for Conservation
P.O. Box 4649 Samabula, Fiji Islands
TEDx talk https://www.youtube.com/watch?v=7PRLJ8zDm0U

Teitei Livelihoods Centre
Km 20 Sigatoka Valley Road, Fiji Islands
(679) 938-6437

On Tue, Sep 28, 2021 at 9:01 PM Douglas Fenner <douglasfennertassi at gmail.com>

> I much appreciate the perspective Austin is giving us.
>     I am reminded that several decades ago, someone, I have a feeling it
> might have been Terry Done, pointed out that any reef that had widespread
> mortality including of the giant colonies like massive Porites, can recover
> coral cover and superficially appear recovered, yet the death of
> multi-century old giant corals means that the reef will not recover its
> species composition within even many generations of humans (during which a
> lot of what we consider normal modern society may become unrecognizable).
> I have been frequently reminded by others that coral cover is only a first,
> quick and dirty measure, of what the benthic community is like.  There is
> much, much more and it is important.  Austin is exactly right, the Acropora
> are some of the best species for providing habitat for a wide variety of
> fauna, fish, inverts, etc, which disappear immediately upon the death of
> its host in most cases (because they died).
>       I think Austin has a very important point here.  Acropora is by far
> the largest genus of corals, with an amazing diversity of colony shapes,
> and it has often been pointed out that many of the world's reefs were/are
> dominated by the genus, in both living cover and diversity.  Yes, they are
> often (but not always?) weedy, fast growing species, also they are among
> some of the most affected by disturbances like bleaching, disease,
> hurricanes, crown-of-thorns, etc.  So you can lose loads of them fast, but
> they may be able to grow back fast.
>        If we think that billions of colonies in a species makes that
> species immune to extinction, as a recent paper argued, I beg to differ.
> Check out the "passenger pigeon" in North America.  Estimated to have had a
> population in the billions.  Humans with guns exterminated that species.
>        That paper was based on sampling, as is almost all science.  But as
> far as I could tell, there was no mention of the obvious fact that the
> sampling was (unintentionally and unavoidably) highly biased.  The sampling
> was done by transects.  A massive and admirable study.  BUT, they found in
> their big sampling effort, about half of all the coral species known in the
> Indo-Pacific, perhaps a tad less.  Was it a random sample of all the coral
> species in the Indo-Pacific???  No way.  Such sampling favors the more
> common and widespread species.  It will miss endemic species.  It will miss
> all species that live only at depths that are different from where the
> transects are.  The species missed will be highly enriched in species that
> are rarer than those reported, which will be highly enriched in the most
> abundant species.  So it presents a highly distorted view of the
> Indo-Pacific coral diversity, and all the talk about billions of colonies
> applies to the abundant species in their samples, but does NOT apply to the
> rare species.  Ever heard the phrase that in highly diverse ecosystems most
> species are rare???
>       So why be concerned about rare species??  They're expendable,
> right??  Sure, if you don't care about the diversity of organisms that we
> humans are abusing, and you don't care about whether they survive and
> whether the diversity survives.
>       Which brings me back to the problem of losing species.  The kind of
> thing that's been going on in the equatorial parts of of Kiribati and may
> well be a window into the future of world coral reefs, strikes not at half
> a dozen species of giant Porites corals (fantastic as they are), but at the
> heart of diverse coral reefs, the most diverse coral genus, Acropora, which
> I would argue we don't even know adequately yet.
>       I like to point out that coral reefs probably would recover fine if
> we humans stopped abusing them.  But I hasten to add that recovery is
> possible ONLY if the component species of the reefs have not gone extinct.
> The reason extinction is important is that it is permanent.  That's what
> spurs concerns and efforts.  For more perspective on the dangers of
> extinction for rare species, particularly sessile species like corals that
> can't go out finding their rare conspecifics to mate with, I recommend
> reading up on Allee Effects, there is an abundant literature.  Once some
> species get below a certain number of individuals, their populations may
> enter positive feedback cycles that cause the population to crash and
> extinction to occur.  For coral reef organisms, I recommend Birkeland et al
> (2013).  These effects are strongest for species that are the rarest;
> species that are not rare have mechanisms that provide population
> stability, though the pigeon example shows that there is no absolute
> protection for any species, no matter how abundant.
>       The thin edge of the wedge is already here, several coral species
> have gone regionally extinct in recent years, and one, (Ctenella chagius)
> is very close to the precipice of global extinction (Sheppard et al, 2020
> and references therein).  No, it is not a huge crisis yet, but if these
> equatorial reefs are losing almost all their Acropora, and this is a
> harbinger of what is coming for the world reefs, the alarm bells are
> ringing.  From far off it may seem.  But how much diversity was lost on the
> northern and southern Great Barrier Reef when there was huge mortality that
> drove live cover to low levels, and yes live cover recovered if we are not
> to dismiss the monitoring results of the Australian Institute of Marine
> Science monitoring program??  Check the graphs for coral cover of each of
> the 3 sections over time, they are really quite astounding:
> https://www.aims.gov.au/reef-monitoring/gbr-condition-summary-2020-2021
>   If you lose 90% of the cover, how many rare species were just pushed to
> regional extinction?  If 99% loss, how many?  Regional extinctions are a
> step towards global extinctions.  Do we KNOW for a fact that there are no
> species endemic to that region that were driven to global extinction???  I
> don't think we do.  Zoe Richards (2018) wrote a paper asking if we knew
> whether there were any "silent" (unrecorded) extinctions on the Great
> Barrier Reef.  If I remember, the answer was we don't know, there are too
> many species and we don't monitor but a tiny tiny fraction of the
> diversity.  Unfortunately it seems like we aren't really trying very hard
> even to sample.  Among other things, we need to monitor the abundance and
> trends of individual coral species, like we do fish.
>      So, I don't recommend complacency in this issue, and I thank Austin
> for his perspective.
>       But of course, we need to attack the primary cause of all this.  For
> that I recommend an article that points out that NONE of the leading
> economic power countries on the planet are in line with the Paris
> Agreement.
> https://edition.cnn.com/2021/09/15/world/climate-pledges-insufficient-cat-intl/index.html
>      Cheers, Doug
> Birkeland, C., M. W. Miller, G. A. Piniak, C. M. Eakin, M. Weijerman, P.
> McElhany, M. Dunlap,
>        and R. E. Brainard. Safety in numbers? Abundance may not safeguard
> corals from increasing carbon dioxide. BioScience 63: 967-974.
> Sheppard, C., A. Sheppard, and D. Fenner. 2020. Coral mass mortalities in
> the Chagos Archipelago over 40 years: Regional species and assemblage
> extinctions and indications of positive feedbacks. Marine Pollution
> Bulletin 154: 111075
> Richards, Z. T., Day, J. C. 2018.  Biodiversity of the Great Barrier Reef-
> how adequately is it protected?  PeerJ   https://peerj.com/articles/4747/
> On Thu, Sep 16, 2021 at 2:43 PM Austin Bowden-Kerby via Coral-List <
> coral-list at coral.aoml.noaa.gov> wrote:
>> Thanks for that David,
>> I agree with you, as far as on geological timescales.  But for Kiribati,
>> on
>> the leading edge of the global coral reef collapse, unfortunately the
>> oceanic reefs are doing as bad or worse than the lagoons. The ocean facing
>> reefs are adapted to cooler waters so they kick the bucket as badly as the
>> lagoonal corals when mass bleaching temperatures arrive and where they can
>> linger for over half the year.  For the Gilbert chain, bleaching
>> temperatures dominated for 30 months out of 60 since 2014, until La Nina
>> conditions finally arrived last year, giving them a one or two year break.
>> The thermal stress is superimposed on both ocean and lagoon habitats, and
>> corals tend to adapt to near the upper thresholds for their symbionts.  So
>> all corals, of both lagoon and ocean reefs, are equally stressed and in
>> danger of being wiped out.  I conjecture that the most resilient
>> coral populations will be found at the transition between lagoon and
>> oceanic conditions- the reef passes.  If this hypothesis is correct, then
>> those reef pass areas are where our conservation efforts might best be
>> focused.
>> The lessons of Kiribati have taught us a lesson for Fiji and Tuvalu and
>> Samoa, where it is still not too late.  Our strategy in recent years is to
>> locate and move corals of the same species as those on the ocean facing
>> reefs- from the warm lagoons, nearshore reef flats, and hot pockets, out
>> to
>> the cooler outer lagoon and pass areas where we establish them in gene
>> bank
>> nurseries. The goal is to create patches of these resistant corals on the
>> ocean reefs themselves, where they stand a much better chance into the
>> future, and where they can then begin to spread their resilience.
>> Mother Earth has a fever, but she has a strategy of Her own to protect the
>> coral reefs- sea level rise.  Imagine the positive impact that adding one
>> or two meters of water will have on the shallow coral reefs globally.
>> Vastly more area for corals to grow, increased upward scope for growth,
>> and
>> a cooling of the lagoons and shallows. Of course the coastal areas and
>> human populations may not fare so well.  But seriously, we
>> deserve every millimeter!
>> Regards to all,
>> Austin
>> .
>> Austin Bowden-Kerby, PhD
>> Corals for Conservation
>> P.O. Box 4649 Samabula, Fiji Islands
>> https://www.corals4conservation.org
>> https://www.globalgiving.org/projects/emergency-response-to-massive-coral-bleaching/
>> <
>> https://www.globalgiving.org/projects/emergency-response-to-massive-coral-bleaching/
>> >
>> Teitei Livelihoods Centre
>> Km 20 Sigatoka Valley Road, Fiji Islands
>> (679) 938-6437
>> http:/www.
>> <
>> http://permacultureglobal.com/projects/1759-sustainable-environmental-livelihoods-farm-Fiji
>> >
>> teiteifiji.org
>> http://permacultureglobal.com/projects/1759-sustainable-environmental-livelihoods-farm-Fiji
>> https://www.facebook.com/teiteifarmstay
>> https://www.globalgiving.org/projects/happy-chickens-for-food-security-and-environment-1/
>> On Thu, Sep 16, 2021 at 6:29 AM David Blakeway via Coral-List <
>> coral-list at coral.aoml.noaa.gov> wrote:
>> > In assessing these reefs I think it's worth considering where they're
>> at in
>> > terms of their natural life cycle. Kiribati, for example, looks pretty
>> > terminal to me. You could imagine that 1000 years ago it might have
>> > resembled Tabueran (3.86, -159.32) and 1000 years from now it might look
>> > like Washington Island (4.68, -160.38). That process (losing all lagoon
>> > corals) is completely natural. And probably wouldn't be a gradual
>> > incremental process (on our timescale); more likely the lagoon coral
>> > community would undergo massive fluctuations in the terminal stage,
>> while
>> > heading toward long-term senescence. I agree that preserving Kiribati
>> > corals is critical insurance. My point is just that--for reefs in
>> > general--we shouldn't expect good stable coral cover and diversity in
>> > late-stage reefs approaching sea level.
>> > _______________________________________________
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