In leppott/BCGcalc: Biological Condition Gradient, calculator

knitr::opts_chunk$set(echo = FALSE
                      , results = 'asis'
                      , warning = FALSE
                      , message = FALSE)

Purpose

The Macroinvertebrate Thermal Tolerance Index (MTTI) (Hubler et al.) was developed for freshwater wadeable streams in Oregon and Washington. The MTTI calculator generates Maximum Weekly Maximum Temperature (MWMT) values for each macroinvertebrate sample based on the relative abundances and MWMT weighted average optima values of the taxa in the sample (Stamp et al., in progress). MWMT is the metric that Oregon and Washington use for their numeric water temperature standard to protect salmonid habitat and is available from the NorWeST modeled stream temperature database..

The MTTI builds on earlier work by ODEQ (Huff et al. 2006) in which ODEQ developed a thermal tolerance index, but with many fewer samples (328 sites vs. 3658 sites). The MTTI value is not a direct measure of temperature. Rather it is a measure of the response of the macroinvertebrate assemblage to temperature, and can help detect deviation from natural thermal regimes. It may also provide important insights on resiliency. For example, if cold stenotherm taxa are persisting at a site with a NorWeST MWMT value greater than 16°C, investigating what factors make that site suitable for those taxa could inform tactics for restoring or protecting cold water refugia in other streams. Factors likely include habitat quality and complexity, groundwater, refugia, food quality and availability, and level of watershed disturbance.

For more information, contact Shannon Hubler (ODEQ) (Shannon.L.HUBLER@deq.oregon.gov).

Input File

There are three required fields:

SampleID
- Unique sample identifier. Includes any replicate/duplicate information.
TaxaID
- Unique taxa name
Count of individuals

If you named the required fields differently in your input file, it’s ok. Click on the drop-down menus. The list of fields in your input file will appear. Select the correct column headings.

All columns in the input file are carried over into the output file.

IMPORTANT

After uploading the input file, users can skip the File Builder step and go right to the MTTI calculator. Unlike the BCG calculators, users do not have to specify INDEX_NAME or INDEX_CLASS and the taxa translation and attribute addition steps are built into the MTTI R code.