rugosity index for habitat complexity
wallison at dhivehinet.net.mv
Thu May 28 08:23:45 EDT 1998
Hello Caroly and others,
The chain method is beguiling but consider that two very different habitat scales may
produce the same index value. A section of reef with complex, small-scale topographic
variation (e.g., a section of Synarea rus) might produce the same "rugosity" value as a
section with a simpler pattern but larger scale variation (e.g., a few large Porites
colonies sitting on hardground).
Another approach involves measuring the vertical distance from a horizontal line to
substratum at intervals along the line - tie a weight to a tape measure. A sensitive
depth gauge might do the trick too depending on your precision needs. This approach
doesn't necessarily pick up complexity but might if you played with the intervals used.
You might find the following useful:
McCormick, M. (1994). Comparison of field methods for measuring surface topography and
their associations with a tropical reef fish assemblage. MEPS 112: 87-96.
What you use will depend on your info needs and the time and effort you can or will
Good luck, its not a simple question.
William (Bill) R. Allison
Coral Reef Research and Management
ph 960 32 9667 (direct)
fx 960 32 6884 (voice, fax)
e-mail: wallison at dhivehinet.net.mv
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