Funny enough that’s exactly what happens here in Oregon. Most of the wetlands were drained for farming, or just because we could. Turns out our selfish human geo-engineering had benefits to humans.

Whenever we restore a wetlands, the area goes from “surprisingly low amounts of mosquitoes most of the time” back to “fuck I can’t go outside”

https://www.opb.org/news/article/restored-marsh-breeds-swarm...

There are ways to somewhat mitigate this through more intelligent wetland design methods, but ultimately no way to even mostly resolve the problem without more intensive control methods, which sometimes end up being pesticides.