[Coral-List] Coral reefs in the Gilbert Islands of Kiribati after more than a decade of multiple stressors

Sara Cannon secanno at gmail.com
Mon Sep 20 18:57:49 UTC 2021


Hi all,

I am a Ph.D. candidate at the University of British Columbia (advised by
Simon Donner), studying coral reef resilience and interactions between
local and global stressors facing coral reefs in the central Pacific.

Simon and I have a new paper out with our Kiribati Ministry of Fisheries
and Marine Resource Development (MFMRD) collaborators in PLoS One that I
wanted to share with the list, and that I also think speaks directly to the
discussion below. We investigated the trajectory of coral reefs in Tarawa
and Abaiang Atolls in the Gilbert Islands from 2012 - 2018, after more than
a decade of multiple stressors: https://doi.org/10.1371/journal.pone.0255304

Here is a short press release summarizing some of our findings and their
implications for management: https://news.ubc.ca/2021/08/
<https://news.ubc.ca/2021/08/11/sticky-questions-raised-by-study-on-coral-reefs/>
11/sticky-questions-raised-by-
<https://news.ubc.ca/2021/08/11/sticky-questions-raised-by-study-on-coral-reefs/>
study-on-coral-reefs/
<https://news.ubc.ca/2021/08/11/sticky-questions-raised-by-study-on-coral-reefs/>

Simon has worked closely with the MFMRD since before 2010. The government
is leading programs to monitor local coral reefs and is also well aware of
(and often directly involved in) the work international researchers are
doing within its borders, as well as the implications of this research. As
you've mentioned, reefs in the Gilberts are unique because they experience
more frequent heat stress than reefs in other parts of the Pacific due to
their location near the equator. These reefs may provide a preview of what
coral reefs elsewhere will look like in the future as the climate continues
to warm and heat stress becomes more frequent.

Simon and I were scheduled to meet our co-authors in Kiribati in 2020 to
repeat our data collection and conduct fish surveys, but unfortunately,
were unable to because of COVID. The MFMRD told us that there was no major
bleaching observed in the Gilberts after our study period ended in 2018. We
also found no evidence of bleaching in 2014 - 2016, when there was a
bleaching-level heat stress event in the Gilberts.

Reefs in Tarawa, the capital of Kiribati and home to about 65,000 people,
were more resistant to the 2004-2005 and 2009-2010 heat stress events than
those in neighbouring Abaiang (population ~5,500) where the reefs
experienced less local pressure. Reefs in Tarawa have high coral cover but
are dominated by a single weedy coral species, *P. rus, *which is resistant
to both heat stress and local disturbance*. *By comparison, reefs in
Abaiang pre-bleaching were home to more sensitive taxa, and bleaching in
2010-2011 followed by a Crown-of-Thorns outbreak in 2013-2014 drove a shift
on these reefs to turf algae-dominance. Despite their lower coral cover,
coral communities in Abaiang were comparatively more diverse than those in
Tarawa in 2018, and we found some signs that they may be in the process of
recovering.

The shift to *P. rus*-dominated reefs in Tarawa will likely come with
trade-offs for local people, although we are not sure exactly how these
will manifest. We hope to address some of these questions in future studies.

I hope this provides useful context (for this discussion and others)!

Best,
Sara

Sara Cannon, M.Sc. (*she/her/hers*
<https://equity.ubc.ca/resources/gender-diversity/pronouns/>)
PhD Candidate, University of British Columbia
Department of Geography, and the
Institute for Oceans and Fisheries
saracannon.ca
@secanno



*I live and work on the traditional, ancestral, and unceded territory of
the xʷməθkʷəy̓əm <https://www.musqueam.bc.ca/> (Musqueam), sḵwx̱wú7mesh
<https://www.squamish.net/> (Squamish), and sel̓
<https://twnation.ca/>íl̓witulh <https://twnation.ca/> (Tsleil Waututh)
nations. Learn more about territorial acknowledgements and find out whose
land you are on here <https://native-land.ca/territory-acknowledgement/>.*
A reading list on Decolonizing Conservation:
bit.ly/decolonizing-conservation


On Mon, Sep 20, 2021 at 6:17 AM Austin Bowden-Kerby via Coral-List <
coral-list at coral.aoml.noaa.gov> wrote:

> Dear Michael,
>
> Thanks for your detailed and thoughtful reply.  Sorry if my letter was
> unkind, your paper is indeed excellent and very useful information.  I
> absolutely agree with your conclusions in the text and at the end about the
> need to conserve and protect these more adapted coral populations.
>
> I also was contacted by Nathan Cook regarding not yet published survey work
> (with Adam Smith and others), that shows some good Acropora populations
> surviving in the Kanton lagoon, but with very little Acropora surviving on
> the reef front where the corals had not developed thermal tolerance due
> to the cooler conditions.  While the continuing presence of Acropora is
> reassuring, I consider that this is not only due to bleaching resistance,
> it is also due to the less severe intensity of the event when compared to
> the islands closer to the equator like Jarvis and Kiritimati Atoll.  If
> that hot water pool had hit Kanton directly, most of these corals would
> also be dead.
>
> The reason I posted my concern was that I had just read one of the several
> news stories which have been posted on social media, using your studies and
> others to present an overly optimistic outlook, which I consider to be out
> of touch with the wider reality.  The news reports on this work fail to
> mention that the Phoenix islands were not as severely impacted by this
> particular heat wave, which severely impacted Jarvis and close to 100% of
> its corals were lost (0.3% cover, Brainard et al. 2018), as well as
> Kiritimati Atoll, which lost 95% of its corals overall and virtually all of
> its Acropora and Pocillopora corals (Bowden-Kerby, 2021). These press
> reports often fail to mention that the bleaching is coming with increased
> frequency and force, and that since the 2014-15-16 event, the Gilbert chain
> experienced  two additional severe bleaching events in 2018-2019, and
> 2019-2020, and that no systematic assessment of the reefs has been done.
>
> My biggest concern is that the Government of Kiribati, perhaps in part due
> to the reporting the media has picked up from your report and others,  has
> remained unaware of the seriousness of the situation.  Imagine what the
> response would be if the reefs Hawaii or Fiji were killed off in a severe
> mass bleaching event?  There are no eyes on Kiribati, as it has been five
> years with no response.  None of the major international conservation NGOs
> work in Kiribati.  But even simply following the NOAA remote sensing data
> should establish that Kiribati's coral reefs are the most impacted from
> bleaching temperatures of any coral reefs on earth, and that a disaster of
> huge magnitude has hit beneath the water, but no one seems to have noticed-
> and so there is absolutely no response!   What lessons might be learned
> that are now being lost?   Kiribati is the leading edge of the predicted
> planetary demise of coral reefs, and therefore the situation warrants a
> proper and more intensive monitoring and assessment program.  For now, the
> Phoenix Islands might be the only part of Kiribati that was at least
> partially spared, but what will the coming years bring?
>
> Again, while the evidence of thermal adaptation on Kanton is a valid reason
> for some hope, it is clear from the data that the main body of the hot pool
> never reached Kanton and nearby atolls.  Jarvis and Kiritimati were
> immersed in the dark heart of the oceanic hot blob of 2015-16, and very few
> corals of any species survived.  The coral populations of Palmyra to the
> North were also on the fringe of the hot blob, and your paper reporting
> corals surviving intact there has also been reported in the media as a
> cause for hope.  Perhaps it is these moderately stressed coral
> populations, where corals can best adapt and become more bleaching
> resistant?  But the big question is whether these more adapted coral
> populations will in the future be able to survive the intensity of heat
> that the region is capable of generating?  There is reason to doubt that
> they will, because the most resistant of the corals are located in the warm
> shallows and within the warm lagoons, and it is these same lagoons and
> shallows which have the potential to get so hot as to exceed all
> possibilities for coral survival.
>
> The Kiritimati mass die-off of corals has impacted me deeply, and caused me
> to reexamine everything I was doing with coral restoration, and to change
> my coral restoration approach.  I kicked myself, and realized: if only we
> had come a few years earlier and collected samples of the bleaching
> resistant corals from the lagoon, and moved them into a nursery near the
> much cooler pass, or transplanted them onto the reef front directly, they
> would certainly have survived.   Now I live with the realization that time
> is ticking away for the remaining hot pocket reefs and thermally adapted
> coral populations everywhere- including those in Kanton lagoon, are in
> grave danger of dying out in the coming years.  This is why we now focus
> most of our restoration efforts on moving coral samples from the hottest
> parts of the lagoons and nearshore reefs into cooler waters at the passes
> and eventually to the reef front, so that some of the most heat adapted
> corals stand a good chance of surviving the next massive heat wave.  After
> all these are for the most part the exact same species. The corals you have
> recorded for Kanton and the other Phoenix Islands are precious resources
> for the future.  If a program to sample multiple genotypes of these
> bleaching resistant corals and to transplant them to where the water will
> never reach the 35-40C conditions possible at some future date for the
> lagoons, they will not only survive, but they may not even bleach at all.
> The corals can then also spread their resilience.  But how long do we
> have?  When can we begin?
>
> Lastly, is my perspective on Acropora is as an old timer, living in
> Micronesia as a pre-teenage and teenage boy in the 1960s, and visiting many
> islands and atolls in the 1970s and 80s, my recollection is that the reef
> front and lagoon populations of just about all atoll reefs are Acropora
> dominated- at least they were back then. Tuvalu and Tokelau, the nearest
> coral reefs, both remain Acropora dominated.  So to me it seems that Kanton
> and the Phoenix islands must be atypical- already on their trajectory to
> alternate steady states?  I suspect that a geological core would show
> Acropora dominance up until relatively recent times.  Did a phase shift
> happen when no one was watching?  On geological timescales, I don't see
> much prospect for non-Acropora reefs keeping up with rising seas and/or
> natural subsistence, but of course any coral at all is better than none.
>
> Thanks for listening,
>
> Austin
>
> Austin Bowden-Kerby, PhD
> Corals for Conservation
> P.O. Box 4649 Samabula, Fiji Islands
> https://www.corals4conservation.org
> TEDx talk https://www.youtube.com/watch?v=7PRLJ8zDm0U
>
> 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
>
> https://www.globalgiving.org/projects/happy-chickens-for-food-security-and-environment-1/
>
>
>
>
>
> On Thu, Sep 16, 2021 at 7:07 PM Michael Fox via Coral-List <
> coral-list at coral.aoml.noaa.gov> wrote:
>
> > Dear Austin,
> >
> >
> > Thanks for sharing your perspective. However, mid-ocean atoll systems are
> > not all dominated by *Acropora* in their natural state as you are
> > suggesting. Indeed, the assumption that they "should be" inevitably leads
> > to incorrect interpretations of ecosystem trajectory.
> >
> >
> > A history of benthic monitoring in the Phoenix Islands extending to the
> > late 1960s indicates *Acropora* was not the most dominant coral in at
> least
> > the last 60 years. Further, while we don't contest that bleaching has
> > reduced *Acropora* abundance in the area, these declines are not as
> > pervasive as you imply. At specific sites where we know *Acropora* to
> have
> > been locally dominant, it is recovering, rather than disappearing.
> Notably,
> > as of 2018 Kanton's lagoon reefs are composed primarily of table and
> > staghorn *Acropora*, which have recovered from almost complete mortality
> in
> > 2002.
> >
> >
> > Kiribati is comprised of 33 islands across three unique archipelagos that
> > span nearly 3.5 million square kilometers of ocean. We think it is wrong
> to
> > assume that observations from Kiritimati over a narrow window of time can
> > be generalized to the rest of the reefs in Kiribati, some of which have
> > withstood and recovered from recurrent heatwaves over centuries.
> >
> >
> > The impact of the 2015-16 heatwave on reefs across the Pacific basin
> cannot
> > be overstated and is a warning of what we're facing today and in the
> > future. However, as the global coral reef community works to forestall
> > coral reef extinction, it is important to engage in thoughtful discussion
> > based on facts and accurate natural history. If some sites on coral reefs
> > are managing to keep pace with climate change, like those on Kanton
> Island
> > in PIPA, lets pay attention, identify the mechanisms by which this
> > resilience is conferred, and keep open minds. We have a lot still to
> learn.
> >
> >
> > All the best,
> >
> > Mike
> > _______________________________________________
> > Coral-List mailing list
> > Coral-List at coral.aoml.noaa.gov
> > https://coral.aoml.noaa.gov/mailman/listinfo/coral-list
> >
> _______________________________________________
> Coral-List mailing list
> Coral-List at coral.aoml.noaa.gov
> https://coral.aoml.noaa.gov/mailman/listinfo/coral-list
>


More information about the Coral-List mailing list