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;i Table 2. Review of Key Findings of Urban Stream Studies Examining the Relationship of Urbanization on Stream Quality Ref Yr Location Organism Key Finding • 4 91 Seattle Fish habitat, Channel stability and fish habitat Channel stability quality declined rapidly after 10% Imp. 11 94 Maryland brown abundance and recruitment of brown trout trout declines sharply at 10-15% I 1 82 Atlanta Aquatic Insects negative relationship between number of insect species and urbanization in 21 streams 14 87 Northern Aquatic Insects urban streams had sharply lower Virginia diversity of aquatic insects, when human population density exceeded . 4 persons/acre.(estimated 15 -25% Imp cover) 16 90 New York Fish Spawning resident and anadromous fish eggs and larvae declined sharply in 16 tributary • ' streams that were more than 10% 1. 24. 94 Delaware Aquatic Insects insect diversity at 19 stream sites dropped sharply at 8 to 15% I • 24. 94 Delaware habitat quality strong relationship between insect diversity and habitat quality; majority of 53 urban streams had poor habitat 22. 92 Maryland Fish fish diversity declined sharply with increasing I, loss in diversity began at 10-12% I. ,� 22. 92 Maryland Aquatic Insects insect diversity metrics in 24 i subwatersheds shifted from good to poor beyond 15% L 2. 94 Maryland Fish/insects fish, insect and habitat scores were all . ranked as poor in 5 subwatersheds that . were greater than 30% imperviousness. •- • 15 79 Maryland Aquatic Insects mac roinvertebrate and fish diversity and Thh declines rapidly after 10% I. 17. 93 Seattle Fish marked shift from less tolerant coho • salmon to more tolerant cutthroat trout populations noted at 10-15% I at 9 sites 26 88 Ontario Aquatic Insects Strong negative relationship between biotic integrity and increasing urban land use/riparian condition at 209 measured stream sites. Degradation begins at about 10% 1 . 19 86 Seattle Aquatic Insects mac oinvertebrate community shifted to chironomid, oligochaetes and amphipod species tolerant of unstable conditions _ 27 83 Seattle Salmon marked reduction in coho salmon populations noted at 10-15% l at 9 sites • 28 93 Seattle Wetland plant Mean annual water fluctuation was • spec1e3 inversely correlated to plant and Amphibians. amphibian density in urban wetlands. Sharp declines noted beyond IO% 1 12 86 New Aquatic Insects Drop in insect taxa from 13 to 4 noted Jersey in urban streams 29 91 Ohio Aquatic Insects, l00% of 40 urban sites sampled had . Fish fair to very poor index of biotic (!BI) integrity (181) scores.