President Obama with his wife Michelle, and daughters Malia and Sasha, during a visit to the Grand Canyon in Arizona. (Alex Brandon/AP)

Foreigners from Europe and Asia have long been some of the most loyal visitors to sites including Yellowstone, the Grand Canyon and the Grand Tetons. But European visits are down slightly this year at 392 sites operated by the National Park Service, Ron Tipton, vice president for policy with the National Parks Conservation Association, a private group advocating for the NPS.

Total visits to national parks topped 281.3 million in 2010, a decline of about half a percent from 2009, according to agency stats. Less reliable monthly data compiled by park rangers shows that park visits are off 2 percent year-to-date at all parks and historic sites. (Total numbers and an official visitor tally for 2011 won’t be known until next March, according to Tipton.)

So why the slide?

“Clearly the value of the euro and the status of their economy is affecting things on the margins,” said Tipton, who’s been tracking park developments for three decades. Though the Park Service doesn’t keep exact tallies on the number of foreign visitors, “It’s significant in some parks, especially the Grand Canyon, the Everglades, and Yosemite,” he said.

Steadily rising gas prices — a big factor for travelers who fuel up RVs and campers for longer overnight stays in parks — may also be dragging the numbers down, he said.

The Park Service didn’t respond to requests for comment, but reported last week that summer visits to Yellowstone — the system’s most popular park — topped 3 million for the third straight year despite cold weather in May, the start of the agency’s summer season.

Yellowstone recorded slightly more than 3 million recreational visits between May and September of this year, down from 3.3 million in 2010, or a 6 percent year-to-year slide, the agency said. July was the most popular month at Yellowstone, with 906,935 recreation visits.

NPS tallies “recreational visits” by counting the number of days a visitor spends inside a park. So if a tourist spends three days at a park, those would count as three individual recreational visits. If three people spent three days at a park, that would count as nine visits, according to Tipton.

Another factor potentially dragging down park visits? Tipton said Japanese tourists who frequent western parks in large numbers are likely unable to do so this year because the country’s earthquake and tsunami.

And if you’re wondering, the largest year for visitation at national parks was in 1987, when 287.2 million visitors were recorded. Here’s a look at visits in the last few years, according to NPS data:

2010 - 281.3 million

2009 - 285.5 million

2008 - 274.8 million

2007 - 275.5 million

2006 - 272.6 million

2005 - 273.4 million

2004 - 276.9 million

2003 - 266.1 million

Follow Ed O’Keefe on Twitter: @edatpost

Further reading:

Ken Salazar urges more Latino-themed national parks, sites

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