[Coral-List] Let's not forget the bigger ecosystem
tmcclanahan at wcs.org
Wed Feb 15 13:29:56 EST 2017
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.
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..
Tim McClanahan, PhD
Senior Conservation Zoologist
Wildlife Conservation Society
Coral Reef Conservation
Kibaki Flats no.12
Bamburi, Kenyatta Beach
P.O. Box 99470
Postal Code: 80107
Cell Phone: Kenya +254 (0) 792 765 720 and 725 546 822
Skype - trmcclanahan
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