Biological control of invasive aquatic and wetland plants by arthropods: a meta-analysis of data from the last three decades

Results from the last three decades of aquatic and wetland plant biological control by arthropods were combined using meta-analytical techniques to provide an objective, quantitative understanding of control efficacy that cannot be provided by available narrative reviews. Analyses were performed to determine if differences exist in how well diverse biocontrol agents perform, and if experimental design can impact study results. Across all analyses, biocontrol of the included plants was generally successful. Though little heterogeneity in efficacy was seen between the individual biocontrol agents used, all experimental design analyses showed significant differences between respective study types. Thus, study design can significantly impact the results of biocontrol studies. From these results, we suggest that field studies with controls be performed using subsamples of an area (quadrats, transects, etc.), with biomass or density being the plant variable measured. More long-term (two or more years) and non-target effect studies could also be performed in the future.