[Coral-List] FW: Remnancy vs Resilence

[Precht, Bill]

To All on the Coral-List:

During the last few weeks we have read a host of different opinions
about what to do about Florida's reefs and also what to do about reefs
in general.  

Recent scientific papers and newspaper articles have admonished the U.S.
Government for not doing enough to protect the valuable reef resources
of the Florida reef tract.   While we are all in agreement that
Florida's coral reefs are threatened, I argue that understanding the
main causes of their decline (and their recovery) are of paramount
importance in devising science-based management and restoration
strategies for these systems.  The generally accepted model of coral
reef decline is that the shift from a more desirable, coral-dominated
state to a less desirable, macroalgae-dominated state was primarily a
consequence of long-term overfishing and/or coastal eutrophication,
making them more susceptible to other recent disturbances.  This model,
mostly based on weak inference and perpetuated in the literature by a
series of affirmative ad hoc revisions, has retarded ecological
discovery and confounded the direction of ecosystem management. 

For Florida's coral reefs the implied lack of management is based on the
hypothesis that the main causes of reef degradation are historical in
nature and the woes that beset this system are entirely local,
man-induced, and reversible.  While it is easy to take this view,
evidence linking overfishing and coastal eutrophication to coral reef
degradation in Florida remains elusive (specifically the decline of
corals and concommitant increases in macroalgae). Unfortunately,
politicians, NGO's, managers and the public are receptive to such
arguments because runoff from agricultural lands in the Everglades,
sewage treatment (or lack thereof) in the Florida Keys, or
overharvesting of finfish and shellfish are things that make intuitive
sense and also have strong emotional appeal. 

In the case of Florida, the catastrophic decline in coral cover
(particularly for acroporid corals) started in the late 1970s and was
empirically observed to be driven proximally by hypothermic temperature
stress and disease outbreaks, especially white-band disease. More
recently, long-lived mounding corals such as the Montastraea annularis
species complex have also been killed by ENSO-enhanced coral bleaching
and a host of other coral diseases (1983 - present). Paleoecological and
ecological data indicate that this coral mortality is largely decoupled
from changing levels of herbivory or water quality, and that reef
dynamics on a regional level are at best weakly linked to present and
past levels of nutrients or fishing pressure.  

Improving water quality and conserving stocks of reef fish should be and
clearly are high priorities of management, but the positive, localized
impact on corals will be minimal in the face of regional- to
global-scale stressors such as disease epizootics and increasing
sea-surface temperature related to global warming. Management steps are
already in progress in the Florida Keys to clean up nearshore waters as
well as system-wide water quality and habitat restoration efforts under
the Comprehensive Everglades Restoration Plan.  When completed,
engineering solutions to improve the quality of nearshore waters will
only benefit the offshore reefs.  Unfortunately, no form of
locally-based stewardship, scientific management or scientific policy
including total protection could have prevented or changed the overall
trajectory of coral loss or ameliorated the major disturbances
responsible for reef decline in Florida.  In fact, what we have seen in
Florida has been mirrored throughout much of the Caribbean.  It has
become clear, that regional and global-scale stressors now far outweigh
all local issues, however, this should not be taken to mean that local
issues are not real or unimportant.  

So what to do?  Without coming to grips with the big-picture,
global-scale, politically challenging stuff - reefs will be managed to
death at the local-scale.  Or should I say, reefs will die in front of
the very managers and scientists dedicated to protecting them.  Is this
a grim view of the future or a snapshot of the last few decades?  In
either case, we need to start thinking and actly globally if reefs as we
know them (or knew them) are to have a fighting chance.

Bill Precht
Miami, FL