[Coral-List] Accuracy of Point Count in Monitoring Ecosystem Change
Phil Dustan
dustanp at cofc.edu
Wed Feb 1 09:19:53 EST 2012
Dear Listers,
I'd like to draw your attention to a new online publication that
evaluates the robustness of a commonly used method to estimate benthic
cover: point counting which is particularly used in large-scale,
long-term coral reef monitoring projects such as the Florida Keys Coral
Reef Evaluation and Monitoring Project. In short it explores the error
limits of point counting in a world of degrading coral reefs:
Getting to the Point: Accuracy of Point Count in Monitoring Ecosystem
Change by Eric Pante and Phillip Dustan
Journal of Marine Biology, Volume 2012 (2012), Article ID 802875,
doi:10.1155/2012/802875
While some authors have addressed questions on the statistical
sensitivity of point counting under specific conditions, the general
robustness of the method has never been tested to the best of our
knowledge. In this communication, we report results from computer
simulations based on real data from the Bahamas that strongly suggest
that the number of points needed to robustly estimate benthic cover
depends on overall cover and benthic heterogeneity, and therefore, the
point-counting effort (number of points being identified) must be
tailored to fit particular conditions. Our results indicate that the
sampling density must be _increased_ as reefs degrade in order to
maintain the same level of accuracy and precision. Thus it is important
that investigators periodically re-evaluate point-counting parameters
when benthic cover is expected to vary over the course of the monitoring
project to insure valid data.
We hope that the results of this communication will motivate the
community to better justify their sampling design when using point
counting.
The paper may be accessed directly at:
http://www.hindawi.com/journals/jmb/2012/802875/
Sincerely,
Phil
--
Phillip Dustan Ph.D.
Department of Biology
College of Charleston
Charleston SC 29424
(843) 953-8086 voice
(843) 953-5453 (Fax)
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