D3205: The impact of salinity pollution on mosquito oviposition in urban environments

Salinity pollution is a growing threat to freshwater ecosystems. Coupled with the effects of climate change and anthropogenic alterations of the hydrologic cycle, it is expected to only increase in severity and extent over time. The run-off from road de-icing salt is a major source of salinity pollution in temperate urban areas. Salt pollution can eliminate salt-intolerant species, changing competitive interactions and predator effects in salt-tolerant species. Mosquitos (Diptera: Culicidae) generally display high salinity tolerance; salinized stormwater and natural ponds found in areas with high road densities could be advantageous oviposition habitats due to a reduction in salt-intolerant competitors and predators. My project identifies how salt-polluted water affects mosquito oviposition choice, and how post-colonization dynamics (i.e., changes to predator/competitor abundance) affect urban mosquito abundance through a mesocosm field experiment. We had three treatments (high, low, and no salt), and we took samples of the invertebrate community in each mesocosm. We found that the high salinity treatment had the most mosquito larvae throughout the season, while the low and no salt treatments had fewer mosquito larvae and a higher abundance and species diversity of other invertebrates. My research ultimately demonstrates how road salt influences the abundance of disease vector mosquitoes across cities and suburban landscapes.