From this:

...migrants and drug smugglers (marijuana, mainly) are attracted to parts of Arizona for a specific reason. On these federal lands, environmental regulations prevent the Border Patrol from doing its job. That's what the mainstream media won't report... [On the video below], (Rep. Rob Bishop) makes this simple point. The U.S. side of the 1,950-mile border with Mexico is about 60 percent private land and 40 percent federal. "Almost all" of the migrants and drug smugglers come across federal lands, protected by stringent "wilderness" designations or endangered species rules. The federals are submissive before the environmental regs that interfere with border enforcement. The Border Patrol, a division of Homeland Security, has to complete lengthy environmental reports and get permission from the Departments of Agriculture and Interior before it can do anything. This can take several months.

The author contrasts the situation in Arizona with that in Texas where most land is private, which makes some sense. And, he says that Rep. Raul Grijalva - someone on the opposite side from Bishop - "seems to be primarily interested in representing Mexican interests", something I've found to be true. (Unfortunately, the author tries to weave this into a larger libertarian-oriented framework against redistributionism and environmentalism and the like. Giving this issue a partisan sheen isn't generally advised.)

The 37-minute Bishop video from June referred to above is at http://peekURL.com/vq864qf
For the 2-minute version, see http://peekURL.com/vvkj6l2
And, Bishop challenges Department of the Interior secretary Ken Salazar on http://peekURL.com/vum86ga
The reader is encouraged to go to one of Salazar's public appearances and ask him when he'll be doing the items on the last video, or ask him to explain exactly why he won't be doing them.
Bishop is also the sponsor of HR 5016: "To prohibit the Secretaries of the Interior and Agriculture from taking action on public lands which impede border security on such lands, and for other purposes.".