Reefs at Risk

[Ouida Meier]

     After being out of town, then reading the debate about the source 
     and degree of threat to reefs in Florida in one lump, I forwarded 
     the discussion to a student currently away at a field station and 
     sent the following note along with it.


     Dear Paulette,

     ...

     The neat thing about the coral-list discussion I sent you is that 
     the people who wrote in are some of the major players in the 
     region. Reading between the lines, you also begin to get an idea 
     of how nasty some of the interactions can be among scientists 
     there - people in this field, for some reason, tend to take a 
     position and then make it a very personal thing, maybe because 
     one survival strategy is to become increasingly 
     competitive/aggressive/defensive as "territories" become smaller. 
     One would think this problem is big enough to engender 
     cooperation instead.

     You know my own take on the whole situation in Florida: most of 
     the rigorous studies that have taken place over reasonable time 
     periods have shown declines in Florida's reefs (Dustan and Halas 
     1987, Porter and Meier 1992). Our current large-scale monitoring 
     project is also showing declines; since we're still collecting 
     and analyzing data from that study I will mention only those 
     facets that have been completed and publicly released so far. 

     The scary thing is that the data from these 3 studies show 
     several different kinds of reef decline over time: percent cover 
     of reef-building corals is decreasing, percent cover of fire 
     corals (milleporids) and macroalgae is increasing, local species 
     diversity is declining (rare corals becoming more rare), spatial 
     complexity of the habitat is declining as branching corals die 
     out, and incidences of disease are becoming more frequent, more 
     widespread geographically, and more diseases are being found in 
     more species of coral. 

     While in some parts of the world declines in reefs can be clearly 
     attributed to one particular source of impact (e.g., severe 
     overfishing, or sedimentation from coastal development), this is 
     not the case in the Florida Keys. Instead, I would argue that 
     Floridian reefs should be considered severely threatened because 
     they are exposed to multiple environmental impacts. You know from 
     the pollution and toxicology work you're doing now that 
     synergistic effects on organisms from multiple pollutants are 
     frequently greater than the summed effects from each of the 
     individual pollutants. I think the same principal of complexity 
     of interaction applies to communities, ecosystems, and probably 
     to the global system as well.

     I think the best clue we have that multiple sources of 
     environmental impact are at work IS the fact that we have 
     measured multiple kinds of reef decline, without even looking 
     very far beyond the coral components. People get frustrated when 
     they can't trace a specific, measurably changing parameter back 
     up its causal chain to a single measurable cause, but we're 
     dealing with genuine ecosystem networks of interaction here, not 
     threads or chains, with system properties like contribution of 
     indirect effects on top of that, and with multiple sources of 
     environmental impact on top of THAT. 

     This is not to say that identifying the most damaging sources of 
     impact is an intractable problem, but effects propagate 
     differently through network systems than they do along threads. 
     Acknowledging and dealing with complexity is really very 
     different from the linear ways we normally try to understand 
     things and solve problems in science. But at this point in time, 
     making progress with problems in complex systems like coral reefs 
     will require biting that bullet - finding ways to deal with 
     complexity of interaction in a rigorous fashion.

     Ouida

     *****************************
     Dr. Ouida W. Meier
     Department of Biology
     Western Kentucky University
     Bowling Green, KY 42101
     ouida.meier at wku.edu
     *****************************