Considering frogs and toads very much like mosquitos and mosquito larvae as a food source, what most likely happened in Kathy Durrum's situtaion is that by introducing mosquito dunks and killing the larvae they removed the food source for the frogs which caused a large number of them to starve to death. Removing the dunks allowed the mosquito population to proliferate which then also allowed the predators of mosquitos, frogs and toads, to also proliferate. Any time you remove or reduce the amount of an animal from an environment that is a small ecosystem you're doing damage to that entire system, not just the one specific animal in it.

Mosquito dunks.

Get mosquito dunks. They look like little donuts that float for a short time on the water surface and kill the mosquito larvae biologically with a bacteria.

Just a thought. You say it is a wildlife pond. Don't forget bats will love to swoop over your pond to eat the mosquitos once they emerge. And when diving beetles and dragonfly larvae etc arrive in your pond, they, being carnivores, will need something to eat. The wider the range of plant and live food, the greater the range of creatures your pond will potentially support. So think of the mozzie larvae not as a pest but as a resource or "bait" for pond creatures.