CADStat: Statistical Tools for Causal Analysis
Predicting environmental conditions from biological observations
Introduction
This module estimates environmental conditions from
observations of benthic macroinvertebrates for a set of sites,
by combining observations of each particular taxon with a
taxon-environment relationship. This calculation has three
steps. First, observations of benthic macroinvertebrates are
matched with standard taxonomic names, with a full taxonomic
hierarchy. Second, operational taxonomic units (OTUs) are
defined for the data set, so that each individual taxon is
counted at a consistent taxonomic level. Third, observations
are matched with existing taxon-environment relationships and
an estimate of environmental conditions computed.
The module is initiated by choosing Analysis Tools -> Predicting env. conditions from biological observations from the menus. A dialog box should appear as follows:
Input files
Active Dataset: This file is a data frame that
contains observations of benthic macroinvertebrate. The file
can be selected from the working directory or loaded using the
Browse option. At least three columns are required
in this data frame: (1) a unique sample identifier (specified
by selecting the appropriate field in Site ID:, (2)
taxon names (specified in Taxon Name, and (3) the
number of individuals of a particular taxon within a
particular sample (Taxon Count).
Coefficient data: Select a coefficient file that
represent taxon-environment relationships from those available
in bio.infer. Two coefficient files are
currently available: temperature and sediment relationships
in the western U.S. (coef.west.wt) and sediment
relationships in the eastern U.S. (coef.east.sed).
Alternatively, a
user generated coefficient file (using the bio.infer script taxon.env) can be loaded.
Output file
Results: Select this option to save the results of
the script in a separate text file.