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Lost in Space: Minimum Confidence Intervals for Idealized PHABSIM Studies
Author(s) -
Williams John G.
Publication year - 1996
Publication title -
transactions of the american fisheries society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.696
H-Index - 86
eISSN - 1548-8659
pISSN - 0002-8487
DOI - 10.1577/1548-8659(1996)125<0458:lismci>2.3.co;2
Subject(s) - transect , chinook wind , confidence interval , sampling (signal processing) , environmental science , statistics , oncorhynchus , habitat , hydrology (agriculture) , mathematics , econometrics , fishery , ecology , geology , computer science , fish <actinopterygii> , oceanography , geotechnical engineering , filter (signal processing) , biology , computer vision
The physical habitat simulation model (PHABSIM) produces curves showing the relation between flow and habitat that are often used as evidence for decisions on the management of water resources. The curves show values of “weighted usable area” (WUA) over discharge. Minimum confidence intervals for the curves can be developed with the bootstrap method if transects are randomly located within sampling units. This is illustrated with bootstrap simulations that develop minimum confidence intervals for several model rivers, defined in terms of sampling procedures and values of WUA for juvenile chinook salmon Oncorhynchus tshawytscha at 15 transects on the Feather River, California. The simulations show that the chance location of transects in PHABSIM studies can introduce such great uncertainty into the resulting curves of WUA over discharge that the curves can be meaningless. Therefore, it is crucial that confidence intervals be developed for curves of WUA over discharge before PHABSIM results are presented to decision makers.