R.A. Progar and A.R. Moldenke, Oregon State University, moldenka@bcc.orst.edu
Figures 1 & 2. Typical headwater streams in western
Oregon are often associated with large amounts of
coarse woody debris.
Figures 3 & 4. Square-meter emergence trap were used to collect emerging adult aquatic insects from headwater streams.
Figure 7. The pattern of emergence was bimodal, with
strong peaks in the spring and summer seasons.
Figure 5. Total emergence was highest from temporary
streams flowing through clearcuts and lowest in temporary
streams flowing through forests.
Figure 6. Total biomass was higher from either stream type flowing through clearcuts than forests.
Figure 8.The spring peak is characterized by many small
bodied insects, the summer peak by fewer large bodied insects. 
Figure 9. Richness was unimodal in all stream types. It was slightly higher in streams flowing through clearcuts in perennial and temporary stream flows.
Conclusions:
•
•Vast numbers of flying insects emerge from upland headwaters, particularly temporary streams. 
•The high abundances observed in temporary streams likely results from the lack of vertebrate predation by fish and salamanders. 
•
•Whether headwater streams are temporary or perennial, flowing through clearcut or forested upland, the biological significance is the same.  They provide a significant source of potential prey for upland fauna.  The majority of the flighted biomass eventually ends up transferred to terrestrial-riparian and upland-dwelling fauna. 
•
•Headwater streams are a refuge for many stream invertebrates and a reservoir of biodiversity for downstream recolonization.
•
•Birds, bats and even terrestrial predaceous insects share a huge stake in the appropriate management of these overlooked habitat resources.
•Future studies should address trophic interactions with fish, amphibians, birds, bats, mammals, and other invertebrates to assess the importance of the role these streams play in the forest ecosystem.
Headwater streams are linear corridors of abundant food sources that supply far more flying insects as food for terrestrial vertebrates than upland sources.
ARE HEADWATER STREAMS IMPORTANT TO FOREST ECOSYSTEMS?:
ADULT AQUATIC INSECT COMMUNITIES IN TEMPORARY AND
PERENNIAL HEADWATER STREAMS IN WESTERN OREGON
Figures 10 & 11. The community feeding guild composition remains nearly consistent regardless of canopy cover type;
only the percentage of dead-leaf shredders change.