Water is by far the most critical element of this ecosystem. The word riparian refers to a region where plants and animals are able to thrive due to the availability of water, either near or at the soil surface. San Pedro's perennial flow is an uncommon occurrence in the Southwest today. Due to the abundance of food and water, this National Conservation Area (NCA) supports over 350 species of birds, over 80 species of mammals, and more than 40 species of amphibians and reptiles. Bird watching is one of the most popular activities at San Pedro; about half of the number of known bird species in North America frequent this region.
Threats to the NCA
The increasing population of the surrounding area makes managing the NCA's water supply a huge challenge. Groundwater depletion puts all the unique plant and animal species of San Pedro at risk. Extensive livestock grazing and ranching in the region further diminishes the valuable water supply. Increasing off-road vehicle use threatens the sustainability and integrity of the land.
History of the NCA
Between 9000 and 6000 BCE the Clovis Culture were the first known human occupants in the San Pedro River Valley. Their stone tools and weapons can still be found at both the Lehner Mammoth Kill Site and Murray Springs Clovis Site.
Francisco Vasquez de Coronado, a general in the Spanish Army, led an expedition through San Pedro Valley in 1540 in search of the Seven Cities of Gold. In 1821, the newly independent Mexicans moved into the upper San Pedro Valley and took over the large Spanish cattle ranches that had been created earlier. In the 1850s, American settlers from the east moved into the region and reestablished cattle ranching and farming. Silver was discovered in the area in 1877, and the valley boomed until the mines flooded about 10 years later.
Noting the ecological and historical significance of this region Congress designated it as a NCA on November 18, 1988.