Many different people have had an affect on the conservation movement. Sometimes that was negative, sometimes positive. People change things in a variety of ways. There is not one certain way that someone can affect the movement. People differ, and therefore their methods for either helping or hurting the movement will differ. For example, one could try to help the movement by bringing matters to the courts to change laws, while someone else could try to reach out to the communities for support.
The first person who really inspired interest in the conservation movement that I will discuss is George Perkins Marsh. He was born in Woodstock, Vermont and was a politician, diplomat, and scientist. He loved nature a great deal. He wrote the book "Man and Nature". With his strong history and geography knowledge, as he traveled to many places, he was able to create a book that was very knowledgeable. His book laid the groundwork for conservation. The book served as a warning to man what could happen if they continue using the land as they are. He did not directly influence or impact any of the main leaders in the conservation movement. His book did impact the movement though, by allowing it to begin. If it was not for him, maybe not as much of the public would be interested in conservation.
George Bird Grinnell, unlike Marsh, looked more scientifically at conservation. He was more interested in managing the forests with all aspects of nature in mind. He was particularly interested in preserving the forests of the Adirondack because the forest grounds allows for water flow since it is moist. This was called the watershed approach. Grinnell worked with Theodore Roosevelt often, and together they were very powerful. Grinnell was often thought to be the power behind Roosevelt. Grinnell gave Roosevelt the knowledge that he would need to protect the conservation movement.
John Muir was another man involved with conservation who was close with Roosevelt. He had a personal friendship with Muir. Muir impacted the movement because he was so different. Not many people understood him and his deep love of nature. That can intrigue more people into the movement. The Hetch Hetchy controversy, even though he did not win, brought a lot of attention to the movement.
Gifford Pinchot also did influence Roosevelt. He was the head of the Division of Forestry of the US department of Agriculture. He had a major impact on Roosevelt and was able to influence him often. Pinchot's beliefs were more utilitarian. He believed in "the greatest good for the greatest number". That means that he believed in using the resources available to man, but not abusively, so that there is plenty for future generations. With Pinchot, however, Roosevelt signed over 16 million acres to be part of the National Forest system. He brought this influence to Roosevelt.
Aldo Leopold was influenced by Pinchot. Their beliefs differed, but they were both passionate about what they did. Leopold believed in the spiritual factors of nature, while Pinchot looked at the resources of nature. Leopold said that man and nature were equal parts of the world. Nature does not need to be conquered. Leopold impacted the movement because he was able to introduce a compromise. He believed in preserving nature for its spiritual factors. He was able to compromise with others who believed that the land needed to be used. They were able to create parts of the land that would be untouched and other parts that would be able to be used by man.
All of these men were able to influence the movement. They inspired interest and even worked on directly changing how the land could be used.

Conservation 9.8 of 10 on the basis of 1962 Review.