Quantifying invertebrate resistance to floods: a global-scale meta-analysis
- Publication date
- Publisher
- 'Wiley'
Abstract
Floods are a key component of the ecology and management of riverine
ecosystems around the globe, but it is not clear whether floods have predictable effects on
organisms that can allow us to generalize across regions and continents. To address this, we
conducted a global-scale meta-analysis to investigate effects of natural and managed floods on
invertebrate resistance, the ability of invertebrates to survive flood events. We considered 994
studies for inclusion in the analysis, and after evaluation based on a priori criteria, narrowed
our analysis to 41 studies spanning six of the seven continents. We used the natural-log-ratio
of invertebrate abundance before and within 10 days after flood events because this measure of
effect size can be directly converted to estimates of percent survival. We conducted categorical
and continuous analyses that examined the contribution of environmental and study design
variables to effect size heterogeneity, and examined differences in effect size among taxonomic
groups. We found that invertebrate abundance was lowered by at least one-half after flood
events. While natural vs. managed floods were similar in their effect, effect size differed among
habitat and substrate types, with pools, sand, and boulders experiencing the strongest effect.
Although sample sizes were not sufficient to examine all taxonomic groups, floods had a
significant, negative effect on densities of Coleoptera, Eumalacostraca, Annelida, Ephemeroptera,
Diptera, Plecoptera, and Trichoptera. Results from this study provide guidance for
river flow regime prescriptions that will be applicable across continents and climate types, as
well as baseline expectations for future empirical studies of freshwater disturbance.Keywords: Quantitative synthesis, Environmental flows, River management, Disturbance ecolog