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| Titel |
Macroinvertebrate community responses to a dewatering disturbance gradient in a restored stream |
| VerfasserIn |
J. D. Muehlbauer, M. W. Doyle, E. S. Bernhardt |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 15, no. 6 ; Nr. 15, no. 6 (2011-06-09), S.1771-1783 |
| Datensatznummer |
250012850
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| Publikation (Nr.) |
 copernicus.org/hess-15-1771-2011.pdf |
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| Zusammenfassung |
| Dewatering disturbances are common in aquatic systems and represent
a relatively untapped field of disturbance ecology, yet studying
dewatering events along gradients in non-dichotomous (i.e. wet/dry)
terms is often difficult. Because many stream restorations can
essentially be perceived as planned hydrologic manipulations, such
systems can make ideal test-cases for understanding processes of
hydrological disturbance. In this study we used an experimental
drawdown in a 440 ha stream/wetland restoration site to assess
aquatic macroinvertebrate community responses to dewatering and
subsequent rewetting. The geomorphic nature of the site and the
design of the restoration allowed dewatering to occur predictably
along a gradient and decoupled the hydrologic response from any
geomorphic (i.e. habitat heterogeneity) effects. In the absence of
such heterogeneous habitat refugia, reach-scale wetted perimeter and
depth conditions exerted a strong control on community structure. The
community exhibited an incremental response to dewatering severity
over the course of this disturbance, which was made manifest not as
a change in community means but as an increase in community
variability, or dispersion, at each site. The dewatering also affected
inter-species abundance and distributional patterns, as dewatering and
rewetting promoted alternate species groups with divergent habitat
tolerances. Finally, our results indicate that rapid rewetting – analogous
to a hurricane breaking a summer drought – may represent
a recovery process rather than an additional disturbance and that such
processes, even in newly restored systems, may be rapid. |
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