Thats sometimes the problem, life can be too adaptable and drown out many other species through competition or predation. The rate species spread from place to place is a factor and humans have certainly impacted that.

The purpose of life is to post dank memes on the internet

Dragonflys, bats and many other animals rely on that as a food source, then other animals rely on the animals eating mosquitoes. Mosquitoes also spread disease which can act as a natural population control for some species. Everything is interconnected in ecosystems. The animals present, the temperature and chemistry of the water, the depth and nutrition of the soil, the plants that grow there. A minor change can ripple throughout the ecosystem and cause major consequences long term. Some of those changes occur naturally, but for the most part humans change ecosystems faster than they can naturally react.