How "healthy" are the national parks?

With the National Park Service approaching its centennial in less than five years, that's not an unreasonable question to ask, though it's also one we should be weighing frequently. While many consider the parks to be preserves safe from impacts, the truth is that society's crush is weighing on them, heavily in some cases.

Human crowds and their associated infrastructure, non-native species, air and water pollution, and even climate change are casting various impacts on the parks.

Little more than a decade ago, in February 2000, Mike Finley, then superintendent of Yellowstone National Park, issued a State of the Park report that was written as a "candid appraisal" of both the park's natural and cultural resources. In it the superintendent and his staff pointed to "some disturbing trends, such as the escalating encroachment of alien plants, animals, and disease organisms, and concern about the future of the park's geothermal systems and bison and pronghorn populations. This report documents the paucity of staff and funding available to manage these complex and often controversial natural resource issues."

Unfortunately, the concern raised in that report hasn't diminished with the years. A new report created to track the "vital signs" of natural, cultural, and historic resources in the park reiterates many of the natural resource concerns raised more than a decade ago.

Whereas the 2000 report cited the growing non-native lake trout population in Yellowstone Lake as a "looming threat" to the native Yellowstone cutthroat trout and many terrestrial species that rely on the cutthroats for nourishment, the Yellowstone National Park: Natural Resource Vital Signs report released Monday notes that, despite the "removal of more than 550,000 lake trout" since 1994, no progress is being made on reducing the lake trout numbers.

"The number of lake trout caught per 100 meters of net in one night (catch per unit of effort) has been rising since 2002, suggesting that the population has been increasing faster than the fish are being removed," says the report, which was prepared by the Yellowstone Center for Resources.

Just as the State of the Park report cited mine-related pollution in Soda Butte Creek near the park's northeastern entrance, the current report notes that "tailings remain in the Soda Butte Creek floodplain, impairing the segment of the creek that extends downstream to the park boundary. Park staff periodically measure arsenic, copper, iron, and selenium in the water and sediment at the boundary."

The new report goes on, stating that visibility is below either "a historical range or scientific opinion as to the level needed to maintain biological viability," ozone levels as well as nitrogen precipitation are also comparatively high, non-native aquatic species such as New Zealand mud snails and whirling disease are established in the park's waters, and non-native mountain goats on the Northern Range could be impacting native bighorn sheep, a concern also raised in the State of the Park report.

"Just because it’s Yellowstone National Park doesn’t mean there aren't resource issues that don’t need to be addressed very significantly," says Patricia Dowd, who runs the National Parks Conservation Association's Yellowstone field office.

The data in the new report, as with that in the 2000 report, are intended to help land managers and biologists both monitor trends and the health of the park and its surrounding Greater Yellowstone Ecosystem, and adopt standards.

The report's authors still have a number of desirable "resource conditions" to establish in areas such as winter air quality at both the West Entrance and Old Faithful, invasive plants and aquatic nuisance species, and winter soundscapes and wildlife diseases, among other areas. But the data they do have in some areas raises concerns -- as did the data presented in 2000 -- over the health of Yellowstone and that of the surrounding national forests and nearby Grand Teton National Park.

For instance, according to the latest report:

* "Data collected at the northeast entrance indicate that the growing season (number of days from May through October with lowest temperature above freezing) has been starting earlier and lengthened from an average of 88 days (1985–1996) to 117 days (2000–2010). It was 130 days in 2009 and 118 days in 2010."

* Nitrogen levels linked to fertilizer use and feedlots outside the park's boundaries are a "significant concern," while ozone levels "may be high enough to cause biomass loss in sensitive species such as aspen."

* "Based on water quality standards for aquatic life, the state of Montana considers a portion of Reese Creek on the park’s northern boundary impaired. Streamflow in 2009 and 2010 remained above the minimum threshold stipulated by adjudicated water rights, but irrigation by adjacent landowners often leaves too little water to sustain healthy invertebrate and fish populations. As a result of mining activity 8 km from the park, tailings remain in the Soda Butte Creek floodplain, impairing the segment of the creek that extends downstream to the park boundary."

* "More than half of the park’s known bald eagle nests have been in the Yellowstone Lake area, where the percentage of nests that produce fledglings has declined from 50% (1984–2000) to 30% (2001–2010). Possible causes include the reduction in cutthroat trout abundance, human disturbance, and climate change."

Another interesting finding in the report is that more people might be visiting Yellowstone on an annual basis than its resources can tolerate. According to the authors, while 3.6 million visited the park in 2010, annual visitation between 2.8 million and 3.3 million would put less stress on Yellowstone's resources.

Visitor activities and associated infrastructure has affected many park resources, including:

* air and water quality, and the natural soundscape;

* wildlife habitat, distribution, and habituation;

* the spread of non-native plants, diseases, and aquatic organisms;

* the functioning of geothermal features

  Ms. Dowd was not surprised by that finding.

“People love Yellowstone. It is a concern. You look at Yellowstone National Park and having over 3.6 million people visit the park every year, you have to look at is Yellowstone being loved to death? I’m not being hysterical about it, I’m being very realistic,” she says. “The demands on the park are changing. I think that’s another reason why having adequate park funding for Yellowstone is essential. How can you have a flat or declining budget when you have more people visiting the park and more impacts on that ecosystem.

“When you have 900,000 people visit in the month of July, that’s more people than live in the state of Montana. It’s urban planning," the NPCA representative adds. "You talk to the folks inside the park, and they are seeing a lot of pressure. People in the gateway communities want people to come to Yellowstone. How you balance that I don’t know.”

An interesting finding in the report, one presumably unrelated to humans, is that geologic activity in Yellowstone is rising.

"The University of Utah’s seismograph stations detected more than 3,200 earthquakes in the park in 2010, the largest count since 1985. From mid-January to mid-February, a swarm of about 2,300 quakes occurred about 10 miles northwest of Old Faithful. The two largest earthquakes, magnitude 3.7 and 3.8, were felt throughout the park and in surrounding communities, but both occurred after 11 PM and had little effect on park visitors. Beginning in 2004, GPS and InSAR measurements indicated that parts of the Yellowstone caldera were rising up to 7 cm per year, while an area near the northern caldera boundary started to subside."

There are a few relative bright spots in the report:

* Grizzly bear populations reached 602 in the Greater Yellowstone Ecosystem in 2010, the largest number since the recovery program began in 1975.

* The percentage of whitebark pine acreage in the park infected by mountain pine beetles in 2010 stood at 7 percent of nearly 282,000 acres, down from 15 percent in 2009.

* Bighorn sheep numbers are approaching 400 individuals, an increase in the overall population since 1995 despite the wolf recovery program.

Going forward, the Yellowstone Center for Resources, along with its research partners, will continue to monitor the park's vital signs, and build on this report with further data not only on natural resources but also on cultural resources.

For the time-being, though, the condition of Yellowstone seems disconcertingly similar to where it was when the 2000 report was published with the following statement from Mr. Finley:

"Is Yellowstone at risk? The answer is yes. Will it remain at risk? Only if the American public ceases to care, if budgetary needs are not met, or if the many county, state, and federal jurisdictions whose decisions affect Yellowstone do not recognize and act upon our collective interest in safeguarding essential resources beyond the park's boundary, resources without which the park itself will be tragically diminished."