Flood effects on aquatic invertebrate taxa: A meta-analysis

Floods are a major component of the flow variability of lotic systems and act as distinct disturbance events on a variety of riverine biota.  While a number of case studies examine the effects of flood events on aquatic invertebrates, the degree to which floods affect different groups of aquatic taxa has not been quantitatively investigated across studies.  Here we present the results of a meta-analysis investigating the effects of floods on aquatic invertebrate taxa.  A literature search revealed at least 26 studies compatible with our inclusion requirements, primarily that pre and post invertebrate data is reported for distinct flood events with recorded magnitude.  We examined density of invertebrate taxa pre and post flood events (per defined spatial units) as the response variable.  In the short term (10 days or less since flood), floods have significant negative effects on all invertebrates (Hedge’s d 95% CI does not overlap zero).  We are currently investigating post-flood recovery effects and effects of flood magnitude on a variety of taxa through continuous fixed effects models.  Quantitative syntheses of effects of different aspects of the flow regime on aquatic taxa will allow broader understanding of important components of the natural flow regime for different taxa.