Geoscience Reference
In-Depth Information
Fig. 4.1 Map of southern New England, USA, showing the extent of watersheds
4.2.2 Sensitive Taxa
This study developed models on both number of EPT individuals (abundance)
and number of EPT taxa (genera). Total EPT abundance (NEPT) was defined as
each individual within the Ephemeroptera order (mayflies), Plecoptera order
(stoneflies), or Trichoptera order (caddisflies). The number of EPT taxa was simply
a tally of the number of different genera represented by NEPT, which can also be
considered as EPT taxa diversity or taxa richness.
These data were obtained from the U.S. Geological Survey's National Water
Quality Assessment (NAWQA) program, which has collected chemical, biological,
and physical water quality data from watersheds across the country since 1991.
At the time of this study, data from over 7,000 surface sites could be found within
the NAWQA archives, including biological data for over 2,500 stream reach
segments. A search of the online NAWQA Data Warehouse (
http://water.usgs.
gov/nawqa/data
) was restricted to the southern New England states of Connecticut,
Rhode Island, and Massachusetts. The tabular results from the search included
sample station ID and geographic coordinates, as well as the Order and Genus
attributes necessary for calculating number of EPT individuals (abundance) and
