The difference between environmentalists and environmental agencies is that environmentalists are not paid and normally have a stronger feeling towards the environment. The way it works is when the environmentalists discover problems with the environment, they complain to the environmental agencies.
The Sierra Club and the Audubon Society are both major environmentalist groups. They have been active with the Everglades. They both want to see the Everglades restored as closely as possible to its condition BEFORE humans moved to the areas within the Everglades and drained it to make their homes livable.
Both of these Environmentalist groups are taking a large part in trying to help save the Everglades and its inhabitants from extinction. They have been striving towards something such as the Restudy for years and now its here. They have different views on the environmental impact in the 20th Century, but both agree the 21st Century will be the year to regain the Everglades from the edge of extinction.