07/31/2013 Env Bd Packet - Laserfiche WebLink

Home Search

• • the Family Biotic Index stream health chart. This is consistent with stream health scores from 2010 (5.1) and 2011 (4.4). In 2012, a larger and more diverse sample was identified, but more families with high tolerance values were present, so the FBI average remained stable. Number of individuals: A large sample offers more confidence for a more reliable data set. SHEP protocol requires a minimum of 100 individual invertebrates to be picked and identified per sample. 210 invertebrates were identified in this sample. This sample size is good. Dominant Family: The dominant family was Gammaridae (scuds). Gammaridae dominated 51.4% of the sample, and has a tolerance value of 4 on a scale of 0 -10 (the lower the tolerance value, the lower their tolerance to pollution). They are closely related to Hyalellidae (note the pollution tolerance difference). The distinction between the two families is the flagellum found on the antennae of Gammaridae. They are important food sources for fish and invertebrate predators. They can be extremely abundant in water bodies without fish and are important in the breakdown of organic matter. (Guide to Aquatic Invertebrates of the Upper Midwest, R.W. Bouchard, Jr). Number of Families: In 2012, 20 families were identified in the sample. This compares to 11 families in 2011 and 16 families in 2010. In general, a more diverse sample suggests a healthier stream environment. EFT: Ephemeroptera - Plecoptera - Tricoptera (Mayfly - Stonefly - Caddisfly) are three Orders of invertebrates with low tolerance to pollution. The more of these families in a sample, the better. More than 10 -12 families is considered good. In 2012, 4 EPT families were identified in the sample and made up 17% of the sample. 4.1.5 Hardwood Creek Overall Data Summary Interpretation of the Hilsenhoff Biotic Index Sampling Sites 2007 2008 2009 2010 2011 2012 Hardwood Creek `Above' 7.2 63 6.6 6.0 5.0 5.0 Hardwood Creek `Below' Na Na Na 5.1 4.4 4.6 Hardwood Creek continues to show improvement, and initial findings indicate that an abundance of habitat and modest organic pollution levels contribute to good overall stream health in this portion of the watershed. The Family Biotic Index score of 5.3 at the Hardwood Creek `Above' site, and the Family Biotic Index score of 4.6 at the Hardwood Creek `Below' site, indicate a stream health score of "Good ".