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Florida Lake Management Society Annual Conference, Naples, Florida, June 4 – 7, 2007

changes the potential nutritional availability of the OM entering the system. changes affect secondary consumers?

But do those

While there was no relationship between total macroinvertebrate abundance or biomass and TIA, individual functional feeding guilds were affected. Canonical correlation analysis

indicated that collector/gatherer and

OM.

Collector/gatherer,

predator,

predator filterer,

densities were positively related to labile forms and scraper densities were positively related

of to

inorganic seston while collector/gatherer density was negatively related Therefore, the original prediction of increased macroinvertebrate biomass However, the data do indicate that increasing TIA and concomitant increases

to organic seston. was not supported. in the proportion of

labile TOC differentially increase the amount of seston was not affected by increase in the collector-feeding guild. trophic efficiency, which was suggested

collector and predator feeding guilds. Since the total TIA, increased seston quality may explain the relative Similarly, increased seston quality appeared to increase by the relative increase in the predator-feeding guild.

Two other features were important determinants of macroinvertebrate community structure. Riparian structure determined the in-stream condition. First, open canopy streams were dominated by Hydrilla verticillata. Dominance of H. verticillata completely changed the

resource base from terrestrial pattern from relatively steady

detritus to aquatic macrophytes. It to extreme hypoxia/supersaturation

also changes oscillations.

the diel DO The second

determinant patterns. In

was stream hydrology. Undeveloped contrast, urbanized streams displayed

low-order streams displayed ephemeral flow perennial flow patterns; although, this can be

strongly influenced by due to these changes peaked at intermediate Walsh et al. 2005).

stormwater controls in the watershed (Thiele et al. in review). Largely in stream flow, macroinvertebrate biomass and density increased and levels of TIA, unlike many other urban systems (Paul and Meyer 2001,

References

Chadwick, M.A., Dobberfuhl, D.R., Benke, A.C., Huryn, A.D., Suberkropp, K. and Thiele, J.E. (2006) “Urbanization Affects Stream Ecosystem Function by Altering Hydrology, Chemistry, and Biotic Richness.” Ecological Applications 16: 1796-1807. Meyer, J.L., Paul M.J. and Taulbee W.K.. 2005. Stream ecosystem function in urbanizing landscapes. Journal of the North American Benthological Society 24: 602-612. Paul, M.J. and Meyer J.L.. 2001. Streams in the urban landscape. Annual Review of Ecology and Systematics 32: 333-365. Thiele, J.E., Chadwick M.A., Huryn A.D., Benke A.C. and Dobberfuhl D.R. Urbanization in small coastal plain catchments influences stream macroinvertebrates by altering hydrologic regimes. Freshwater Biology, in review. Wallace J.B., Eggert S.L. & Meyer J.L. 1997. Multiple trophic levels of a forested stream linked to terrestrial litter inputs. Science 277:102-104. Walsh, C.J., Roy A.H., Feminella J.W., Cottingham P.D., Groffman P.M. and Morgan II R.P.. 2005. The urban stream syndrome: current knowledge and the search for a cure. Journal of the North American Benthological Society 24: 706-723. ________________________________________________________________________ NOTES

Session 9 – Page 3

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