and three levels of aquatic life use support: (1) no impairment or only minor impairment (full 

 support); (2) moderate impairment (partial support); and (3) severe impairment (nonsupport). 

 These impairment levels correspond to excellent, good, fair, and poor biological integrity, 

 respectively. In cold, high-gradient mountain streams, natural stressors will often mimic the 

 effects of man-caused impairment on some metric values. 



Quality Assurance 



Several steps were taken to assure that the study results are accurate and reproducible. 

 Upon receipt of the samples, station and sample attribute data were recorded in the Montana 

 Diatom Database and the samples were assigned a unique number, e.g., 2664-01. The first part 

 of this number (2664) designates the sampling site (Jackson Creek near mouth) and the second 

 part (01) designates the number of periphyton samples that that have been collected at this site 

 for which data have been entered into the Montana Diatom Database. 



Sample observations and analyses of soft (non-diatom) algae were recorded in a lab 

 notebook along with information on the sample label. A portion of the raw sample was used to 

 make duplicate diatom slides. The slides used for the diatom proportional counts will be 

 deposited in the Montana Diatom Collection at the University of Montana Herbarium in 

 Missoula. The duplicate slides will be retained by Hannaea in Helena. Diatom proportional 

 counts have been entered into the Montana Diatom Database. 



Results and Discussion 



Results are presented in Tables 3, 4 and 5, which are located near the end of this report 

 following the references section. Copies of aquatic plant field sheets are included in Appendix 

 A. Appendix B contains a diatom report for each sample. Each diatom report includes an 

 alphabetical list of diatom species in that sample and their percent abundances, and values for 65 

 different diatom metrics and ecological attributes. 



