This environmental history has a rich legal history as well.
For one thing, the law in this case has had clear and substantial effects on the material environment and on its interactions with society, as the exploding horse population and federal efforts to cope with it have led to a three-way conflict between ranchers, horse advocates, and the government. It is hard to imagine understanding this environmental history without understanding the legal aspects of the story.
There is also much insight into American environmental politics and culture to gained from the history of the law itself. Take this sentence from the statute's preamble:
Congress finds and declares that wild free-roaming horses and burros are living symbols of the historic and pioneer spirit of the West; that they contribute to the diversity of life forms within the Nation and enrich the lives of the American people; and that these horses and burros are fast disappearing from the American scene.It's all here: the Wild West, biodiversity (with a place for feral exotics), ecocentricism and anthropocentricism, environmental declension.
The law's origins are colorful, too, stemming from a letter-writing campaign by children, orchestrated by the Weekly Reader. An attack on the constitutionality of the statute by the state of New Mexico led to the 1976 US Supreme Court decision of Kleppe v New Mexico, which recognized broad federal powers of environmental regulation in and around federal lands. A lot of environmental and legal history could be learned from exploring the legal history of the western range, including not only the Wild Free-Roaming Horses and Burros Act but the Taylor Grazing Act of 1934, the nineteenth-century federal land disposal acts, and more.