WH AT
H E A LT H Y R E E F ?
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IS A
The Healthy Reefs for Healthy People Initiative uses
the term "health" as an easily understood bridging
Healthy Reefs for Healthy People is a collaborative
concept that connects natural systems and humans20.
international initiative that generates user-
But just what is a healthy reef? How can we, as
friendly tools to measure the health of the
managers, divers, researchers, fishers and other reef
Mesoamerican Reef Ecosystem, and delivers
stewards, recognize a healthy reef?
scientifically credible reports to improve
ecosystem management and sustain social well-
Over the past year we posed that question to various
being.
audiences. People told us that signs of a healthy
reef would be: "the presence of indicator species,"
Our working definition of reef health is based
"maintaining key processes like herbivory," "having
on a consideration of both ecological and social
higher fishing catches/landings," or even "just looking
well-being:
like it did in years past."
A reef is healthy if it maintains its structure
Clearly, there is no simple definition of reef health. Still,
and function and allows for the fulfillment of
most people, from scientists to stakeholders, agree
reasonable human needs.
that Mesoamerican Reef conditions have deteriorated
(- adapted from N.O. Nielsen, University of Guelph)
over the past 25 years. Corals -- the structural
engineers of a healthy reef -- have dramatically
declined, food webs and key natural processes have
been disrupted, and populations of many important
commercial species and focal species have been
We need standardized techniques to assess and
decimated. These signs are obvious ones of poor reef
describe the physical structure of the reef itself, as
health.
well as the ecological structure of reef inhabitants.
We need practical methods to monitor reef function
Many reefs give us mixed signals. Some reefs, for
through time--including the weeks, months and
example, have a relatively high abundance of predatory
years following disruptive events (e.g., hurricanes or
fish (indicating good health) but a low density of
bleaching episodes). We also need measures of well-
coral recruits or coral cover (indicating poor health).
being among the human communities that rely on the
Nevertheless, the overall trend worldwide and on our
reef for their food and livelihoods.
own Mesoamerican Reef is one of continuing general
decline. It is generally easier to recognize an unhealthy
This guide therefore profiles, one-by-one, a
reef than to define what constitutes a healthy one.
comprehensive collection of 58 such indicators to
assess the ever-evolving state of affairs on the reef in
It is important to remember that a reef is always part of
terms of ecosystem structure and function, the driving
a larger ecosystem--a dynamic community of people,
forces effecting change on the reef, and societal well-
plants, animals and microorganisms, all interacting
being and governance.
with each other and with the environment in which
they live. Any definition of reef health must therefore
The indicators themselves are merely the fundamental
be aligned with the comprehensive principles of
ingredients for building our new measurable definition
ecosystem health, recognizing that people are an
of reef ecosystem health. The variety of possible
integral part of the system too21,22,23.
combinations of indicators and indices is limited only
by our own creativity and understanding. The art of this
One of the most important aims of the Healthy Reefs
science will be in the development of reliable indices
for Healthy People Initiative is to compile a suite of
and models drawing from a set of key indicators and a
practical, quantitative measures of reef health that
broad collaboration of the minds.
can help transform a general definition into something
more tangible, more amenable to measurement, and
better equipped to offer answers to our fundamental
question of "How can we efficiently track the health of
our vast ecosystem -- as well as our rapidly changing
human communities?"
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