Event Title

Testing the Field of Dreams Hypothesis: Applications of Meta-analysis to River Restoration

Presenter Information

Scott Miller

Location

ECC 303/305

Event Website

https://water.usu.edu/

Start Date

4-1-2008 11:45 AM

End Date

4-1-2008 12:00 PM

Description

Recent national reviews of river restoration have called for rigorous, quantitative evaluations of project success. Meta-analysis represents one tool for testing the efficacy of common restoration practices due to its ability to integrate multiple small-scale, poorly replicated studies and to determine what ecological and methodological factors explain variable responses. We used meta-analysis to test whether physical habitat restoration increases macroinvertebrate density and richness. The assumption that macroinvertebrate communities benefit from habitat improvements, sometimes called the ‘field of dreams’ hypothesis, is an underlying tenant of many restoration projects, despite the paucity of quantitative tests. We then compared our results to experimental evaluations of the niche availability hypothesis; the core theory underlying the field of dreams hypothesis. A review of the literature identified 53 studies, of which 28 met our selection criteria. Of those, only 10 had sufficient replication necessary to calculate a variance-weighted effect size. For these 10 studies, adding boulders or large woody debris (LWD) significantly increased richness relative to upstream controls, while density increases approached significance. LWD additions had more significant, positive impacts on macroinvertebrate density and richness than boulder additions. Analysis of all studies, both replicated and unreplicated, corroborated results of the 10 replicated studies. Compared to experimental tests of the niche availability hypothesis, physical habitat restoration resulted in lower density and richness increases; however, only richness responses to boulder additions were significantly lower.

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Apr 1st, 11:45 AM Apr 1st, 12:00 PM

Testing the Field of Dreams Hypothesis: Applications of Meta-analysis to River Restoration

ECC 303/305

Recent national reviews of river restoration have called for rigorous, quantitative evaluations of project success. Meta-analysis represents one tool for testing the efficacy of common restoration practices due to its ability to integrate multiple small-scale, poorly replicated studies and to determine what ecological and methodological factors explain variable responses. We used meta-analysis to test whether physical habitat restoration increases macroinvertebrate density and richness. The assumption that macroinvertebrate communities benefit from habitat improvements, sometimes called the ‘field of dreams’ hypothesis, is an underlying tenant of many restoration projects, despite the paucity of quantitative tests. We then compared our results to experimental evaluations of the niche availability hypothesis; the core theory underlying the field of dreams hypothesis. A review of the literature identified 53 studies, of which 28 met our selection criteria. Of those, only 10 had sufficient replication necessary to calculate a variance-weighted effect size. For these 10 studies, adding boulders or large woody debris (LWD) significantly increased richness relative to upstream controls, while density increases approached significance. LWD additions had more significant, positive impacts on macroinvertebrate density and richness than boulder additions. Analysis of all studies, both replicated and unreplicated, corroborated results of the 10 replicated studies. Compared to experimental tests of the niche availability hypothesis, physical habitat restoration resulted in lower density and richness increases; however, only richness responses to boulder additions were significantly lower.

https://digitalcommons.usu.edu/runoff/2008/AllAbstracts/42