Monitoring Invertebrates during Mosquito Abatement in Bandon Marsh

From 2009-2011 the US Fish and Wildlife Service worked to restore the Ni-les’tun unit of the Bandon Marsh National Wildlife Refuge into a functioning tidal wetland for use by native fish. An unintended consequence to this action was the creation of ponded-water areas that were colonized by the summer salt marsh mosquito, Aedes dorsalis. The purpose of our study was to monitor the effect of Bti treatment on non-target organisms in the ponded-water habitats and to see what invertebrates were available as potential prey for fish that use the marsh. Samples were collected from the ponded-water of the upper and lower portions of the marsh, as well as from the streams running through the marsh. Each sample was split into a biomass and ID portion for each site for analysis.  Two-way Anova analyses were run on the data collected and showed that site type and sample period had the greatest impact on what we saw in the pools and streams. We were also able to show that Bti had no statistically significant effect on non-target organisms.