Federal officials are boosting efforts at national parks in southern Arizona to prevent what they say is a path of destruction left by illegal immigrants crossing from Mexico.

The U.S. Bureau of Land Management has recruited more than a dozen rangers from other states as it increases patrols of the Sonoran Desert National Monument, about 80 miles south of Phoenix, and the Ironwood Forest National Monument, north of Tucson.

Both sites typically draw drug smugglers and border-crossers because of their remote locations and possible hiding places.

The Arizona Republic first reported on the BLM's plans.

Last October, the agency began seven two-week operations, or what are called "surges," with the most recent one wrapping up earlier this month. Dennis Godfrey, a BLM spokesman, said smugglers and illegal immigrants' presence climbs because of the milder weather.

The rangers are armed and have helped arrest more than 1,200 illegal immigrants. Besides keeping watch, the rangers also lead cleanup efforts.

Since October, the surges have dug up 60 stolen or abandoned vehicles, 60 bikes and at least 24 tons of trash, the BLM said. The illegal trekking has also led to miles of illegal roads, destroying fragile vegetation. Godfrey said rangers have been working on restoring trails and off-road destruction.

A strategy that seems to be making a difference, according to Godfrey, is the establishment of vehicle barriers throughout the Sonoran Desert National Monument. Made from old railroad steel, these barriers block smugglers from driving into wilderness areas.

"Is it the ideal situation for a national monument? No, it is not but when we see results of trash going down and illegal roads way down and illegal trails way down ... that's a trade-off we're willing to take at this time," Godfrey said. Continued...