Why did the US government elect to define small preserves of uninhabited wilderness in the 1860 and 1870?

In the 1860s and 1870s, the US government sought to define small preserves of uninhabited wilderness primarily to protect the nation's natural landscapes and resources amidst rapid westward expansion and industrialization. This movement was influenced by the growing conservation ethic and the desire to preserve the unique beauty of areas like Yellowstone, which became the first national park in 1872. The government aimed to promote tourism, foster national pride, and safeguard these spaces from exploitation and development, acknowledging their ecological and cultural significance.