Meta-analysis of the impacts of water management on aquatic communities

Abstract

Systematic meta-analyses were conducted on the ecological impacts of water management, including effects of (i) dewatering on macroinvertebrates, (ii) a hypolimnetic release on downstream aquatic fish and macro invertebrate communities, and (iii) flow modification on fluvial and habitat generalists. Our meta-analysis indicates, in general, that (i) macroinvertebrate abundance is lower in zones or areas that have been dewatered as a result of water fluctuations or low flows (overall effect size, –1.64; 95% confidence intervals (CIs), –2.51, –0.77), (ii) hypolimnetic draws are associated with reduced abundance of aquatic (fish and macroinvertebrates) communities (overall effect size, –0.84; 95% CIs, –1.38, –0.33) and macroinvertebrates (overall effect size, –0.73; 95% CIs, –1.24, –0.22) downstream of a dam, and (iii) altered flows are associated with reduced abundance of fluvial specialists (–0.42; 95% CIs, –0.81, –0.02) but not habitat generalists (overall effect size, –0.14; 95% CIs, –0.61, 0.32). Publication bias is evident in several of the meta-analyses; however, multiple experiments from a single study may be contributing to this bias. Fail-safe Ns suggest that many (>100) studies showing positive or no effects of water management on the selected endpoints would be required to qualitatively change the results of the meta-analysis, which in turn suggests that the conclusions are reasonably robust.

Missouri River Scaphirhynchus albus (pallid sturgeon) effects analysis—Integrative report 2016

“…2) (DeLonay, Chojnacki, Jacobson, Albers, and others, 2016). Empirical evidence suggests that dam-induced thermal alteration has substantial implications for stream productivity and the growth of organisms (Haxton and Findlay, 2008). Increasing water temperature in some aquatic systems has been positively correlated with rates of primary productivity (Winemiller, 2004) and secondary production of aquatic invertebrates (Plante and Downing, 1989).…”

Changes in the fish community of the upper Tiber River after construction of a hydro-dam

“…Some studies have showed that dam-induced thermal alterations have significant implications for stream productivity and the reproduction, growth, distribution and assemblage of organisms (Haxton and Findlay, 2008). Generally the biodiversity downstream of a dam is lower than in natural environments because of a reduced temporal heterogeneity in flow and temperature regime (Ward and Stanford, 1983;Jakob et al, 2003).…”

Application of systematic review methodology to food and feed safety assessments to support decision making

“…Interpreting results and drawing conclusions 8 There are some common types of bias that can occur in many different study designs. In health care research these are often classified as selection, performance, detection, attrition and reporting biases.…”