[Coral-List] Let's not forget the bigger ecosystem

Fri Feb 17 12:06:27 EST 2017

Hi Tim:

In my case, you're preaching to the choir. A few of us recently put
together an edited volume (Coral Reefs at the Crossroads) as a first
attempt to get folks who think at different scales and from different
perspectives to approach a couple of fundamental reef-related topic for
different disciplinary standpoints - this would be a logical candidate for
the next one.

While I'm not the person to attempt a systems level look at trophic
cascades, we are trying to look at the collective impact of the complex
bioerosion web on reef building in modern reefs and, by extension, at least
back over the past 10,000 year. I have been trying to pull together as much
systematic and anecdotal information on Caribbean bioeroders, predators,
histories, etc. so we can at least understand the directionality (and at
least qualitative changes) in bioerosion over the past 4 or 5 decades. This
is different from what you are advocating, but the exercise has made me
appreciate how shallow our understanding is at the systems level and how
hard it is to go to the deep end of the pool.

Best,

Dennis

On Fri, Feb 17, 2017 at 10:22 AM, Tim McClanahan <tmcclanahan at wcs.org>
wrote:

> Thanks Dennis
>
> That trophic cascade idea has been around for some time but without much
> formalized scientific investigation. From my reading of the Caribbean
> literature, I also am not really sure if one could trace it in a formalized
> scientific sense. It is discussed informally among Caribbean reef
> scientists and there a smatterings of the idea in various papers but I have
> not seen a full conceptualization and testing of it with field data. Why
> has this important idea not been more formalized, tested, experimentally
> manipulated, modeled, and retested..? This is what we are supposed to do as
> scientists.
>
> It is likely that Diadema numbers recorded in many reefs before their die
> off was a result of the loss of the Queen triggerfish, so why are so many
> reef scientists searching to return Diadema to a baseline as opposed to a
> baseline for various predators and fish herbivores?  Why has so little work
> been done to estimate what baseline numbers are for Queen triggerfish and
> parrotfish as compared to the larger number of studies of Diadema?  I
> imagine this results from research expediency rather than the importance of
> the information.
>
> K-le wrote me and told me " It is difficult to incorporate things in your
> study if they are not there...".  Ok, but there are scattered protected
> areas and closures that could get some attention to determining these
> levels if we examined fish abundance and biomass on a larger scale. Some
> preliminary work on this was done by our group with the little data we
> could organize. I believe this was just a start, however, as it does not
> specifically and thoroughly address baselines of key species or functional
> groups specific to the Caribbean.
>
> http://www.nature.com/nature/journal/v520/n7547/abs/nature14358.html
>
> We tried to do some trophic cascade work in the little time that I have
> had for field work in the Caribbean but then largely studied Echinometra
> and the jolthead porgy, because that is what was left in the Belize reefs
> that I studied.  Nonetheless, it did suggest this cascading effect but
> indicated one in tatters due to the lack of some key players, namely the
> queen triggerfish and Diadema.
>
> http://scientific-papers.s3.amazonaws.com/McClanahan_1999.pdf
>
> A quick search on google scholar for long spined urchin and D. antillarum
> produces >20000 references with a maximum citation of 640.  A search of
> queen triggerfish and Balistes vetula gets around 1400 references with a
> maximum citation of 60. Very few of the Balistes papers are about
> ecological roles, focusing more on basic biology.
>
> I have to think we spend too much effort on expediency and scientific
> impact and not on what actual ails and could potentially heal our beloved
> ecosystem.
>
>
> TRM
>
> PS.   If you find this sort of mismatch of incentives and needs
> interesting, read the paper below.
>
> ttps://www.researchgate.net/profile/Tim_Mcclanahan/
> publication/230680731_Human_and_coral_reef_use_
> interactions_From_impacts_to_solutions/links/0c96052fc34ba1d2ff000000.pdf
>
> On Wed, Feb 15, 2017 at 3:29 PM, Dennis Hubbard <
> dennis.hubbard at oberlin.edu> wrote:
>
>> Tim:
>>
>> Excellent points. My recollection for the Caribbean 'model" was that, as
>> the parrotfish were eaten off the reefs, *Diadema* was picking up the
>> slack, but the Queen Triggerfish was keeping them in check. While not a
>> favored food fish, once other options were removed, the QT declined
>> rapidly, allowing the *Diadema* to go wild. Again only a recollection,
>> but some had even postulated that this was a boom-and-bust scenario for
>> *Diadema* - except for that pesky microbe that appears to have come
>> through the Panama Canal. Certainly this is not at the large scale you are
>> advocating. However, it was a start. The fact that folks went from the
>> fish/urchin vs algae relationship to a paradigm in which fish/urchins and
>> coral abundances were intimately tied together illustrates how little we
>> probably do understand all of this. Fortunately, as a geologist, I only
>> have to think about how much they scrape, bore and grind from the reef
>> edifice and don't have to understand the subtext behind the main play.
>>
>> Dennis
>>
>> On Wed, Feb 15, 2017 at 1:29 PM, Tim McClanahan <tmcclanahan at wcs.org>
>> wrote:
>>
>>> Listers
>>>
>>> I often find the sea urchin - parrotfish - nutrient focus of many coral
>>> reefs studies to lack the bigger ecosystem-environment picture. We each
>>> measure and bring in our own interests and interpretations based on our
>>> disciplinary foci.  One of my main foci has been top-down controls and
>>> the
>>> larger food web interactions within environmental contexts.  Sea urchins
>>> and parrotfish exist in a larger food web and so it is always challenging
>>> to conclude about their ability to control the ecosystem without looking
>>> at
>>> their position in the larger food web-environment.
>>>
>>> I think the work in the Caribbean suffers from this limited foci problem
>>> too often. I rarely hear Caribbean coral reef scientists on this list who
>>> study and quote any work on the predators who control parrotfish and sea
>>> urchins apart from humans. Certainly these functional groups are part of
>>> the larger food web, so they must have their own influences and not be
>>> isolated or controlling independently of impacts on their own
>>> populations.
>>> Is this ecosystem-view just too complicated and difficult to study and
>>> understand? Regardless, I hope reef scientists might make a better effort
>>> to study the larger system when possible.
>>>
>>> In case readers are interested, the paper published open access in the
>>> link
>>> below looked at many possible controls on calcifiers in the Indian Ocean
>>> and concluded the extreme temperatures and the red-lined triggerfish were
>>> probably having strong and equal effects on the calcifying community.
>>> There were no effects of Diadema or parrotfish but a role of Echinometra
>>> via it's interactions with it's main predator - Balistapus undulatus.
>>>
>>> http://www.int-res.com/abstracts/meps/v560/p87-103/
>>>
>>> Can these regional difference be explained away as another region or
>>> system?  Or could work in other systems lack this larger ecosystem
>>> perspective and therefore coming to parochial conclusions? We won't know
>>> until the larger ecosystems are studied in all regions and compared. I
>>> think much critical work needs to be done..
>>>
>>> TRM
>>>
>>> --
>>> -----------------------------------
>>> Tim McClanahan, PhD
>>> Senior Conservation Zoologist
>>> Wildlife Conservation Society
>>> Coral Reef Conservation
>>> Kibaki Flats no.12
>>> Bamburi, Kenyatta Beach
>>> P.O. Box 99470
>>> Mombasa, Kenya
>>> Postal Code: 80107
>>>
>>> Cell Phone: Kenya +254 (0) 792 765 720 and 725 546 822
>>> Skype - trmcclanahan
>>> US Land lines - 530 581-7460
>>> US Cell Phone - 415 260 3415
>>>
>>> Research papers, methods, and talks
>>>
>>> https://www.researchgate.net/profile/Tim_Mcclanahan
>>> ___________________________________
>>> _______________________________________________
>>> Coral-List mailing list
>>> Coral-List at coral.aoml.noaa.gov
>>> http://coral.aoml.noaa.gov/mailman/listinfo/coral-list
>>>
>>
>>
>>
>> --
>> Dennis Hubbard
>> Chair, Dept of Geology-Oberlin College Oberlin OH 44074
>> (440) 775-8346
>>
>> * "When you get on the wrong train.... every stop is the wrong stop"*
>>  Benjamin Stein: "*Ludes, A Ballad of the Drug and the Dream*"
>>
>>
>> Click here
>> <https://www.mailcontrol.com/sr/hOTlCIETEHXGX2PQPOmvUrWC5kUscXsEm6qi3gNx17joPtcSRW9y8J6yLQGjj6MDljICWf!taeIFoPzuIXnePg==>
>> to report this email as spam.
>>
>
>
>
> --
> -----------------------------------
> Tim McClanahan, PhD
> Senior Conservation Zoologist
> Wildlife Conservation Society
> Coral Reef Conservation
> Kibaki Flats no.12
> Bamburi, Kenyatta Beach
> P.O. Box 99470
> Mombasa, Kenya
> Postal Code: 80107
>
> Cell Phone: Kenya +254 (0) 792 765 720 and 725 546 822
> Skype - trmcclanahan
> US Land lines - 530 581-7460 <(530)%20581-7460>
> US Cell Phone - 415 260 3415 <(415)%20260-3415>
>
> Research papers, methods, and talks
>
> https://www.researchgate.net/profile/Tim_Mcclanahan
> ___________________________________
>

-- 
Dennis Hubbard
Chair, Dept of Geology-Oberlin College Oberlin OH 44074
(440) 775-8346

* "When you get on the wrong train.... every stop is the wrong stop"*
 Benjamin Stein: "*Ludes, A Ballad of the Drug and the Dream*"