[Coral-List] Best practice for LIT surveys
joshua at nova.edu
Mon Dec 29 09:49:21 EST 2008
The line-intercept method is utilized in the AGRRA protocols and yields good
results. You are correct that movement of the tape limits easy interpretation
of intercepted corals, especially when there is strong surge. You can
minimize movement by putting good tension on the line, but that requires
strong supports (e.g. permanent stakes) on either end. When I employ this
method, I do not wrap the tape around corals or any other object, preferring
to observe the movement of the line over several surge-cycles and "averaging"
the position for data collection. I agree that wrapping the line or
purposefully running it to minimize movement introduces bias and is something
to avoid. Another option is to use 1/16" braided nylon line instead of a
fiberglass tape. The nylon line is not affected as much as the wider tape by
surge, but is still subject to movement. This would also require the use of
an alternate measuring device to determine linear distance of the coral under
the non-marked line.
The LIT is an effective technique, but does have its limitations.
Nova Southeastern University
From: coral-list-bounces at coral.aoml.noaa.gov
[mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of Lindsay Sullivan
Sent: Sunday, December 28, 2008 4:21 PM
To: coral-list at coral.aoml.noaa.gov
Subject: [Coral-List] Best practice for LIT surveys
If anyone has experience of using the line intercept transect (LIT) method to
carry out benthic assemblage surveys I wonder if you could help me.
I have been taught that in high surge conditions the fibreglass tape must be
secured to coral colonies to prevent it moving around, wound around massive
colonies and through the fingers of branching and digitate colonies for
example, however I have concerns that (a) this is damaging to the coral and
(b) the survey is no longer random or even haphazard, but that the results
are selected by the diver as he carefully tucks the tape around coral.
Does anyone have similar opinions or experiences of this method and can offer
possible solutions? Despite the common usage of LITs for coral reef surveys I
have been unable to find detailed instructions of how to ensure the
tape remains secured close the substrate and in a straight line, so wonder if
perhaps this is an accepted weakness of the method?
Any thoughts would be greatly appreciated.
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