rugosity index for habitat complexity
Bob Steneck
Steneck at maine.maine.edu
Wed May 27 16:50:27 UTC 1998
Dear Caroly and other coral reefers,
On measure of habitat complexity is the "spatial index" (Rogers et al
1983). It involves stretching a floating (poly) line over the reef
marked at 1 m intervals. Then under each interval you determine the
linear dimension of all components you can reach. The chain link of a
known size is the easiest way to do this. You count the number of links
of all components under each meter length and you get a summed value of
meters of reef per linear meter. This Spatial Index (SI) is thus
expressed as m/m.
My work in Jamaica and St. Croix (Steneck 1994) had 4 and 2.75 m/m at
3 and 10 m respectively in 1978 (the value dropped to 1.5 and 1.25 in
1982 after Hurricane Allen). St. Croix had around 2 and 1.5 m/m for 3
and 10 m respectively in 1988. Obviously a featureless pavement will
have a value of 1 m/m.
Refs:
Rogers, C. S., Gilnack, M., Fits, H. C. 1983. Monitoring of coral reefs
with linear transects: a study of storm damage. J. Exp. Mar. Biol. Ecol.
66: 285 - 300.
Steneck, R. S. 1994. Is herbivore loss more damaging to reefs than
hurricanes? Case studies from two Caribbean reef systems (1978 - 1988).
pp 220 - 226. In: Ginsburg RN (ed) Proc Colloquium on Global Aspects of
Coral Reefs: Health, Hazards, and History, 1993. Rosensteil School of
Marine and Atmospheric Science, University of Miami, Miami, Florida.
Cheers,
Bob Steneck
----------------------------
Robert S. Steneck
Professor, School of Marine Sciences
University of Maine
Darling Marine Center
Walpole, ME 04573
207 - 563 - 3146
e-mail: Steneck at Maine.Maine.EDU
The School of Marine Sciences Web site:
http://www.ume.maine.edu/~marine/marine.html
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