Macroinvertebrate Taxonomy Requirements

Taxonomy_table_Nov_2005.xls (pared down from database)

Having the correct taxonomy is the first step in formatting your data, and can be the trickiest. Probably >95% of the taxa names will fit right into be database. The other 5% are the tricky ones, where you'll have to associate the Latin name that you were provided with a name that the database and model will understand. To add to the challenges, taxonomic specialists sometimes discover new species or change existing names. If you run into indecipherable problems, we recommend you get the assistance of the taxonomist who processed your samples.

The models are very particular about the spelling, symbols, spaces and format of the taxa names (called Operational Taxa Units or OTUs) for use in the model. For example, the mayfly species Diphetor hageni must be written as Diphetor_hageni for use in the model.

The first thing you need to do is compare a combined taxa list for all your sites to the DEQ names and codes that will eventually be used in the model. We've provided a taxonomy table spreadsheet that should help with this process. For new samples, you may want to provide this table to your taxonomist and ask them to please match the taxa names to those in the first column. If there are discrepancies, they can solve them or discuss them with you.

The DEQ taxa list is more detailed than what is eventually used in the PREDATOR models, however, you still want your taxonomist to identify organisms to the genus/species level because you will then be able to use the data in the stressor models which require more detailed taxonomy.

The PREDATOR models require a consistent level of taxonomy. While building the model, some taxa that were identified to species or genus were aggregated to genus or family to fit with the models' parameters (e.g., all species in one genus were lumped together). Alternatively, some taxa that couldn't be identified to a detailed level were excluded from analyses (e.g.,  immature specimens that were only able to be identified to family were deleted from datasets while the members of that family that could be identified to genus or species remained).  A hypothetical example of this procedure is shown below (Table 1).

Table 1.  A hypothetical example of how consistent taxonomic levels are achieved.  “Lowest level identification” = the lowest taxonomic level achieved by an expert taxonomist.  “Sample abundance” = the number of individuals collected at a site.  “Unique taxa” = a taxonomic level where there are no individuals in a sample at a lower, related taxonomic level.

This exercise resulted in a list of taxa names called operational taxonomic units (OTUs) that may vary in their level of taxonomic resolution, but are unique from one another. Data will come to us at the Lowest Level of Identification. You'll want to retain that level for the database, because the process of aggregation and omission will be performed for you by the database queries.

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