The SDNM is roughly divided in half by Interstate 8 running east and west. On the north side there are two wilderness areas. The North Maricopa and South Maricopa Wilderness Areas. These areas mostly encompass the North Maricopa and South Maricopa Mountains. On the south side of Interstate 8 is the Table Top Mountain Wilderness and the Sand Tank Mountains.
Roads and Interstates
Unfortunately Interstate 8, though it provides us with access to some beautiful land it is perhaps the most serious threat to large mammals in the SDNM. Moving to find food and water is an important adaptation for desert mammals such as mule deer and bighorn sheep. They need to respond to changes in their environment such as water availability from rainfall and palatable forage in order to survive. They did not evolve with obstructions such as Interstate 8 to hinder their movements. Not only do they have to contend with motorists speeding cross country but there are at leasts two fences they need to cross to get to the other side of the highway. Some animals successfully cross the Interstate, others get run over and others stay on one side and search for food and water. Sometimes the search is futile and they run out of reserves and time before they find suitable relief.
Interstate 8 passes over several arroyos, many of which are quite wide such as Vekol Wash. The bridge provides passage for some animals, but some are too fearful to pass under a bridge. Some that do are easily preyed upon by adaptable predators who simply wait and ambush their prey by taking advantage of the situation.
As Arizona continues to grow there will be new threats posed by new road construction. For example there are plans to build a highway from Interstate 8 north to Interstate 10 forming a barrier between the two Maricopa Wilderness areas and the Sierra Estrella Wilderness Area to the east. If not planned and built with wildlife in mind an important wildlife corridor will be lost.
Today within the the SDNM you can see evidence of the cattle industry in the form of fences, water tanks (charcos), cattle guards, wind mills and the remains of ranch houses. The area south of Interstate 8 has been recently closed to grazing, but the north side is still open to a small number of permitees. The Sand Tank Mountains have been closed to grazing since World War II.
Most desert ecologists agree that the Sonoran Desert is unsuitable for livestock operations. The plant resources found within the Sonoran Desert are limited and better suited for native wildlife. Intense grazing by cattle retards natural plant regeneration and negatively impacts soil conditions leading to erosion and sometimes soil compaction. Invasive plant species, threatening native biodiversity, have been introduced into the Sonoran Desert through livestock feed.
Off Road Vehicle Use
Careless off road vehicle activity has damaged portions of the SDNM. Redundant roads and “two track” roads are numerous and most need to be permanently closed and restored. Fragile archaeological sites, some thousands of years old, are threatened by these roads.
Today portions of the Juan Bautista De Anza National Historic Trail that runs through the SDNM are closed because of reckless OHV use.
Pot hunting, wildlife poaching and fuel wood collections threaten the important resources for which the SDNM was founded. There are not enough law enforcement personnel available to enforce the laws meant to protect the natural and cultural resources found on most of our public land. It is up to all of us to do what we can do to educate the public and to report illegal activities occurring on our land.