Aquatic Entomologist-Critical Trends and Assessment Project
I sample wadeable streams across Illinois to assess their biological integrity. These sites are randomly chosen so that across the state, average stream health is measured. Three orders of sensitive aquatic insects are used as indicators for this purpose. These are the mayflies (Ephemeroptera), stoneflies (Plecoptera), and caddisflies (Trichoptera). The total species richness of these three insect orders per unit effort is referred to as the EPT index. Generally speaking, the higher the index number, the better the stream health.
The EPT taxa were chosen because of the Survey's historic commitment to their study. Frison's (1935) work on stoneflies cut the mold for regional surveys of aquatic insects. Harris and Webb (1995) updated the nomenclature and added species in their revisitation of Illinois stoneflies. Ross (1944) followed closely with the "Caddis Flies, or Trichoptera, of Illinois." Until very recently, it was the only species-level treatment of a large, regional caddis fauna in North America. Moulton and Stewart's (1996) treatment of the caddis fauna of the Interior Highlands (Ozarks and Oachita Mts. and surrounding areas) is the only treatment of similar scope. Burks (1953) work on the Illinois mayfly fauna is still the only regional, species-level treatment in the Midwest. Much of the Midwest fauna were named by Frison, Ross, and Burks, and their types and the specimens from their state and regional surveys are maintained in the INHS collection.
An effort is currently underway to database the specimen-level information accompanying these specimen. In fact, all the Plecoptera have been databased--over 18,400 records (about 100,000 specimens). Currently, we have computerized nearly 13,000 mayfly records and over 24,000 caddisfly records. These databases enhance our efforts to assess stream biotic integrity in Illinois, document local species extirpations and increases in range, and increase the efficiency of specimen lending activities at the Survey. The stonefly database is currently available on the web, you may find it at the following URL:www.inhs.uiuc.edu/cbd/EPT/index.html.
NUMBER OF SPECIES OF EPT KNOWN TO OCCUR IN ILLINOIS
MAYFLIES
STONEFLIES
CADDISFLIES
107
Burks 1953
Randolph and McCafferty 1998
Mayfly Central