[Coral-List] two questions for coral listers
John Bruno
jbruno at unc.edu
Thu Nov 8 14:40:41 EST 2007
First, is anyone aware of an example (preferably published) where
macroalgae have alleviated some stress or otherwise benefitted corals
in terms of growth, survival, etc? I have heard people talk about
observing that shading by macroalgae can reduce bleaching and
bleaching-related mortality, but don't recall seeing any studies on
this and have not been able to dig any up using various search engines.
Second, is anyone aware of an example in which after herbivore
populations were replenished (either naturally or via management)
macroalgal cover/biomass remained "high"? This question really gets
at whether "phase shifts" to macroalgal dominance are "permanent
states" or simply responses to the removal of top down control.
Every example I can think of clearly indicates that once herbivores
return (e.g., Diadema to the north coast of Jamaica ala Edmunds and
Carpenter 2001, Carpenter and Edmunds 2006) macroalge immediately
return to formerly very low cover and abundance (which also suggests
that top down rather than bottom up forces were the primary cause of
the change in macroalgal cover in the first place).
Thanks for any examples, ideas or advise you might have.
JB
John Bruno, Ph.D.
Associate Professor
Department of Marine Science
The University of North Carolina at Chapel Hill
Chapel Hill, NC 27599-330
jbruno at unc.edu
www.brunolab.net
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