[Coral-List] what does this new analysis tell us???
Douglas Fenner
douglasfennertassi at gmail.com
Thu Feb 3 04:47:33 UTC 2022
I want to start out by thanking Lauretta and everyone involved in this
for all the time and effort that went into this. This is fantastic. I see
that the graphs on average world coral cover and algae cover are based on
the latest report from GCRMN (Global Coral Reef Monitoring Network) which
it has a link to. They did the work in the Herculean task of putting
together the vast number of sources of data into regional reports and into
the world report. We owe them a debt of gratitude. To my knowledge, this
is the very first time that anyone has produced from hard data, a graph of
the trends of coral cover for the whole world as well as regions in the
world. This is indeed FANTASTIC in my view.
To find the graph in the report, first click on the link Lauretta gave
for "Global Coral Reef Profile." Go down just a little bit to the "Table
of Contents" on the right, and click on "coral reef condition." Some pink
bars will jump up. Move down just a little and find "Live hard coral
cover" on the left, and "live algae cover" on the right. Scroll down just
a bit to the graphs for these two things. Pink on the left for the coral,
and green on the right for algae.
Here is where I have to compliment Lauretta and the team there.
Notice the axis on the left, down at the bottom is 0% cover. This is the
way it should be graphed, because it allows the reader to see the relative
magnitude of the changes. The original graph in the GCRMN Status report I
found truncated that axis, the axis only goes down to 25%. That magnifies
the variation in the graph. If you want to see the GCRMN report, just
click the black disc with the exclamation point to the right of the title,
and that opens an explanation, scroll down to the end and there is the link
to the GCRMN report, and click on it and it will open up in a separate
window. You have many sub-reports to choose from and browse through.
Easiest to see the graph is to click on the executive report. The graph is
on page 17.
Now a question, what is the biggest, most general thing the graph
shows?? I think that's best seen in the graph that is in the Resource
Watch report Lauretta pointed to. What I see is stability!!! What???
Aren't most of the world's coral reefs badly degraded or even dead???
Shouldn't it show drastic decline??? Not according to this graph based on
something like 12,000 data sets from all over the world. HUH??? Oh, there
is some decline, indeed. But look at the size of the decline. Down from
about 33.5% to 30% in the first decline, and 28% in the second. Does that
fit with the impression we get from various published papers and the
media?? How many media reports have said that half the coral on the Great
Barrier Reef are dead??? I don't remember the exact terminology they
used. If they said "have died," well that's true. Look at the AIMS
monitoring data, the most recent version of it. I'll give the link below.
Yes, half of the corals died, but amazingly, and contrary to all
expectations I would suggest, coral cover completely recovered!!! (isn't
that the definition of "resilient"?) I've pointed this out before, not a
single person posted a response on coral-list and not a single person sent
me an email about it. Not one. Huh???
OK, now with a straight face, tell me that the world's coral reefs
are dead or dying. Tell me that half the corals on the Great Barrier Reef
are dead. They aren't any more!
Please, tell me is this good news or bad??? Surely it is good news
for coral reefs. So why aren't people celebrating??? Why aren't there
"the corals aren't all dead" parties going on all over the world? Where is
the confetti, the balloons, the silly hats and the noise makers?? Don't we
want the reefs to survive? Surely it isn't because no one cares,
scientists have been crying in their masks looking at dead reefs.
Don't get me wrong, there is no evidence that all that mountain of
reports and evidence of individual reefs being mostly dead and the
Caribbean having had a huge decline in corals are wrong. None whatsoever.
I trust every one of them. The El Nino in the Indian Ocean killed about
half the coral there over the whole ocean. Some reefs like Chagos had
about 90% of their corals killed. There are published pictures showing
it. It is beyond discussion, it was real. But notice, some of those reefs
recovered. When I got to go to Chagos in 2014 I think it was, there was
lots of coral. If I didn't know the history, I would not have suspected
that 90% of the corals had been killed. And of course the more recent
bleaching years have done it again in Chagos. My fingers are crossed that
the corals recover again. Maybe they will, maybe they won't. Scary!
Anyone can ask, "how many times can they recover?" As these events happen
more often as the world warms, when will they happen so often the corals
can't recover? That time is coming whether we like it or not, and will be
here sooner than any of us want. We're sitting on the railroad tracks as
the train approaches going full blast.
OK, there are lots more things to discuss and figure out. For one,
is 35% cover "high" cover??? Not in my book. The Eddy et al paper
reported that scientists who saw reefs before the decline began estimated
from memory coral cover of 58 or 59%. That is a LOT higher than 35%. I
notice that there is no hint of decline early on in this graph. So that's
a puzzle. Some people have even thought that originally coral reefs had
near 100% coral cover. 35% is a LONG ways from that.
Coral monitoring data is NOT perfect. BUT, in the absence of any
other hard data on coral cover in the past, isn't this the "best available
scientific evidence?" The "best available scientific evidence" is often
quoted as the best standard for management. Why?? Wouldn't "perfect"
evidence be better?? Sure, everybody knows that. But we NEVER have that.
If we wait for perfect evidence to manage anything, we will never manage
anything, and we'll lose the resource. That's why it was adopted for
fisheries management (though all too often probably not followed). Science
is progress, rarely if ever perfection or final proof. Always subject to
improvement in the future.
So I will state that I think this graph is now the "best available
scientific evidence" on the trends and status of coral reefs around the
world. Anybody can take a shot at showing me wrong. Might be good if
people did.
For one thing, the methods used to get to such graphs are not very
transparent to us average nobodys (I'm talking about myself!) who are not
experts in statistics and methods for doing this sort of thing. I'll point
out one major problem I've never seen addressed. And that is that coral
reefs are famously "patchy." Stated differently, they have high spatial
variation over a wide range of scales. If you want to detect change, you
need to hold other variables constant, particularly ones that are powerful
and could produce large artifacts. Spatial differences are one such
variable for monitoring. If someone takes data on coral cover at one
location one year and a different location at a later time, and claims that
the corals have gone down or up, does the data support that conclusion???
Well, strictly speaking, NO. Except during powerful disturbances, coral
change over time tends to be gradual, growth is gradual and slow. Spatial
difference can be huge. One spot has near 100% coral, another is nearly
all sand, and on and on. Now for these big studies, they have to combine
data from many different locations, and it is a good assumption that the
different locations have different coral cover at the same time. By
"locations" I mean everything from transect sites to islands or reefs to
archipelagoes. It is common, even typical, for monitoring programs to
start, run for a while, then stop, maybe restart. Combine lots of records
from different places, when there are differences between locations, and
there are gaps of missing data from particular sites in some years, and for
reefs or islands or even archipelagos, all at different times. How do
people doing these things balance those things out to minimize the
artifacts due to spatial location and get only signal from changes in
time??? Ideally, every location would have data for the entire time
period. We KNOW that is NOT true, there is very little early data and
mountains of late data. What if the locations for early and late are
different?? They HAVE to be different. OK, I'm NOT saying that the
analyses have no way to pull the temporal signal out and throw away the
spatial signal. I just don't know how they do it, or even whether they do
it at all. Often methods sections are very densely written and someone who
isn't an expert on the exact thing the paper is about could never replicate
the paper. All too often.
So OK, I confess to raising a lot more issues than I can address, but
maybe someone can do that for us.
The bigger picture, however, is that there is a clear conflict
between what this data shows, and what we have been saying. There is no
conflict between what has been reported before, destruction of coral has
surely occurred everywhere it has been reported. BUT, BUT, no one has seen
all the world's reefs. Our monitoring sites are not chosen in a random
fashion across archipelagoes, islands, or reefs, even if they are within
reefs. It is too late to change that for data from the past. But at least
shouldn't we acknowledge it? Our monitored reefs may be unrepresentative
of the world's reefs. Maybe. The first report of a huge decline that I
know of was Terry Hughes' report of the decline in Jamaica after Hurricane
Allen and the die off of Diadema. As subsequent analyses were done, the
decline in other Caribbean reefs was not so bad. Then analysis of the
Pacific reported less decline than the Caribbean (so Jamaica decline was
real, but not completely representative). The Indian O certainly got hit
hard by the 1998 El Nino mass bleaching, but some recovered. Now this
analysis reports an amazingly small amount of coral decline when you look
at the world as a whole. That implies that there are a lot of reefs that
have not declined.
Shouldn't we be celebrating? I have to admit, that I'm very
suspicious that people are disappointed that it doesn't show the death of
the world's coral reefs. But notice, this has nothing to do with the
predictions of the upcoming decimation of coral reefs, nor the many reports
of many individual reefs having experienced mass mortalities. All those
are real. There are just a lot of reefs that haven't yet had bad declines.
I think this new graph is the "best available scientific evidence"
now, until we get better. I think we need to change our tune, and
celebrate a little (even though this does NOT mean that we humans saved the
reefs, rather simply that we haven't killed them all YET.) We are blessed
with more coral in the world than we thought we had. That's GOOD NEWS!
(no denying it won't last, though!!)
In summary, I'd like to paraphrase Mark Twain. When a newspaper reported
he had died, he said "My death has been greatly exaggerated." Clever guy.
Of course later he did pass away.
So I'll paraphrase him: "The deaths of the world's coral reefs has been
greatly exaggerated." Anybody care to argue otherwise?? (I actually would
welcome that, I think it needs to be discussed and NOT IGNORED.)
Personally, I think we need to make our statements, especially to the
press, so that they fit with the actual "best available scientific
evidence" the best we can. If we cry "wolf" too many times and there is no
wolf, and then when there really is a wolf, nobody may come to help, and
the reefs will be in even worse trouble. No??
Cheers, Doug
Eddy, T. D., Cheung, W. L., and Bruno, J. F. 2018. Historical baselines of
coral cover on tropical reefs as estimated by expert opinion. PeerJ 6:
e4308
The AIMS most recent monitoring report:
https://www.aims.gov.au/reef-monitoring/gbr-condition-summary-2020-2021
Scroll way down for the graphs for the northern, central, and southern
Great Barrier Reef. See the huge declines and the amazing recovery.
On Fri, Jan 28, 2022 at 10:40 AM Lauretta Burke via Coral-List <
coral-list at coral.aoml.noaa.gov> wrote:
> The World Resources Institute
> <
> https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.wri.org%2F&data=04%7C01%7CLauretta.Burke%40wri.org%7C8ddf465f154a47ab0dae08d9e299a1d3%7C476bac1f36b24ad98699cda6bad1f862%7C0%7C0%7C637789971762899865%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=y6jbaqL74YGSqFtABvZ8%2BTXHvL4viuHMvOqcUzU15nA%3D&reserved=0
> >
> and partners have developed a *Global Coral Reef Profile*
> <
> https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fresourcewatch.org%2Fdashboards%2Fcoral-reefs&data=04%7C01%7CLauretta.Burke%40wri.org%7C8ddf465f154a47ab0dae08d9e299a1d3%7C476bac1f36b24ad98699cda6bad1f862%7C0%7C0%7C637789971762899865%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=cqV65BjexngQp%2FQfpbPfGUfTqEdzS3rSifOaSidngGo%3D&reserved=0
> >
> and ten regional dashboards
> <
> https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fresourcewatch.org%2Fdashboards%2Fcoral-reef-dashboards&data=04%7C01%7CLauretta.Burke%40wri.org%7C8ddf465f154a47ab0dae08d9e299a1d3%7C476bac1f36b24ad98699cda6bad1f862%7C0%7C0%7C637789971762899865%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=q8M2cAkxUkhTqPK51p4ph6NvLoM1Ur3h3Me%2BAIBlUZA%3D&reserved=0
> >
> which provide an overview of the world’s coral reefs including
> consolidated, map-based information and indicators on the value of coral
> reefs, the threats they are facing, the factors which promote coral
> resilience, progress on protecting reefs, and what actions are needed to
> save them.
>
> The dashboards integrate information from the Global Coral Reef Monitoring
> Network, NOAA Coral Reef Watch, Mapping Ocean Wealth, UNEP, Global Mangrove
> Watch, Protect Planet / World Database on Protected Areas, MPAtlas, 50
> Reefs, and data on local threats to coral reefs, including water quality.
> The maps and indicators provide links to all the original data sources and
> data providers.
>
> See https://resourcewatch.org/dashboards/coral-reef-dashboards
> <
> https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fresourcewatch.org%2Fdashboards%2Fcoral-reef-dashboards&data=04%7C01%7CLauretta.Burke%40wri.org%7C8ddf465f154a47ab0dae08d9e299a1d3%7C476bac1f36b24ad98699cda6bad1f862%7C0%7C0%7C637789971762899865%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000&sdata=q8M2cAkxUkhTqPK51p4ph6NvLoM1Ur3h3Me%2BAIBlUZA%3D&reserved=0
> >
> for access to all.
>
> Please send me any comments.
>
> Best,
>
> Lauretta Burke (lauretta at wri.org)
> _______________________________________________
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