There are more hooves clattering across the rocky high country of Yosemite and Sequoia national parks thanks to a multi-agency effort to bolster bighorn sheep populations in the parks.

National park concessionaires, deeply concerned over what they see as three decades of stagnant visitation to the National Park System, want Congress to authorize better marketing of the parks, longer "high" seasons in the parks they believe would generate more revenues for infrastructure improvements, and expanded concessionaire opportunities in the parks.

A much publicized conference, Science for Parks, Parks for Science: The Next Century, opens today at the University of California, Berkeley. Led by the National Park Service and National Geographic Society, conference sponsors propose “to launch a Second Century of stewardship for the parks, 100 years after the historic meetings at UC Berkeley that helped launch the National Park Service.” A specialist on those meetings, Dr. Alfred Runte reports on why the story does not end there.

Across the National Park System, the National Park Service has an estimated half-a-billion-dollars of obligations owed concessionaires who run lodges, restaurants, and even some activities. It's a sum that, while agency officials say it's manageable, has seemingly stifled concessions competition in some parks and diverted tens of millions of dollars from others to reduce debts.