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Stream Health: biotic integrity variation in Owasco Lake watershed. Susan F. Cushman Hobart and William Smith Colleges 2007 Finger Lakes Research Conference October 6 th , 2007. Background. Owasco Lake was ranked with the worst water quality in Finger Lakes (Halfman, 2005).
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Stream Health: biotic integrity variation in Owasco Lake watershed Susan F. Cushman Hobart and William Smith Colleges 2007 Finger Lakes Research Conference October 6th, 2007
Background • Owasco Lake was ranked with the worst water quality in Finger Lakes (Halfman, 2005). • One of the smaller lakes, but largest watershed area to lake volume ratio. • Research on stream water quality indicated subwatersheds supply varied concentrations of elevated nutrients and pollutants which may impact overall stream health.
Objectives • To assess the biotic health of streams draining Owasco Lake watershed • To examine relationships between water quality and biotic community
Sampling Methods • Kicknet sample • Disturbed sediment upstream of D-net for 5 mins moving across channel diagonally in riffle habitat
Laboratory Subsampling • Samples preserved in 70% ethanol were rinsed in U.S. standard # 30 sieve • Invertebrates were subsampled and sorted by order until 100 individuals were counted • Insects were identified to family • Data was analyzed using Percent Model Affinity (PMA) developed by Bode et al. (2002).
Richness EPT Family Richness
Percent Model Affinity • Watershed composition: • Hemlock • -57% Ag • 42% Forest • 1% Urban • Veness • -85% Ag • -0% Forest • -1% Urban • -14% Wetlands Slightly impacted
Water quality and PMA Adj-r2 = 0.35
Both IBI’s indicate degradation along the southern end of the Inlet Benthic community in Hemlock is very healthy, compared to streams at northern end (Veness, Sucker, Dutch Hollow) Elevated stream nutrient concentrations appear in streams with high biotic integrity Conclusions
Conclusions cont’d • Biotic impacts are evident along the Inlet, and are consistent with biological assessment by Bode et al. (2006). • County line displays low IBI values, however the community seems to improve downstream before entering Owasco Lake. • Future research on algal standing crop may indicate relationship between nutrients and benthic macroinvertebrate community.
Acknowledgements • John Halfman and Jim Ryan (HWS) • Robert Bode and Gary Neuderfer (NYSDEC) • Funding: Senator Michael Nozzolio