BCGcalc - Biological Condition Gradient, Calculator
Functions to calculate Biological Condition Gradient (BCG)
using input files with one row per sample with metric values
and site classes as columns. A second file with the BCG Rules
(example included) to define the memberships is also needed.
The three main functions convert metric scores to metric
memberships following fuzzy set BCG Rules
(BCG.Level.Assignment), combine metric memberships to level
memberships according to BCG Rules (BCG.Level.Membership), and
then assign a BCG primary and secondary level based on level
memberships (BCG.Level.Assignment). Originally developed as a
package for use with BCG for Puget Lowland/Willamette Valley
but has been further enhanced for use with multiple communities
(benthic macroinvertebrates, fish, periphyton, or coral) and
different rule sets. Oregon and Washington reference - "Stamp,
J. and J. Gerritsen. 2018. Calibration of the Biological
Condition Gradient (BCG) for Macroinvertebrate Assemblages in
Puget Lowland/Willamette Valley Freshwater Wadeable Streams.
Prepared by Tetra Tech for the US EPA Office of Water, Office
of Science and Technology and US EPA Region 10." BCG process
documentation - "USEPA. 2016. A Practitioner’s Guide to the
Biological Condition Gradient - A Framework to Describe
Incremental Change in Aquatic Ecosystems. EPA 842-R-16-001.
Office of Science and Technology, Washington, DC 20460."
