Washington, DC — The National Park Service should withdraw a report concluding that a herd of hybridized bison marooned on the North Rim are wildlife “native” to Grand Canyon National Park, according to a formal administrative complaint filed today by Public Employees for Environmental Responsibility (PEER). That 2015 report reversed the prior NPS position and lacks any scientific basis, the complaint charges, but would operate to prevent complete removal of the herd from the park.
PEER is challenging a Park Service document entitled “Grand Canyon National Park Bison Technical Assistance Report,” commonly called the “Plumb Report” after its lead author. This 2015 report overrode the previous NPS scientific stance that the hybridized herd introduced by a rancher in 1906 are not “native” to the park. This Plumb Report also narrowed the options available to NPS – as the agency may not extirpate native animals from national parks. As a result, NPS is now embracing a plan pushed by the Arizona Game & Fish Commission to conduct hunts to “cull” the herd back to more manageable levels.
Citing requirements of the Information Quality Act, PEER is demanding retraction of the Plumb Report because its conclusion that this herd is native to the Grand Canyon is cut out of academic whole cloth –
- There is no scientific evidence that the historic range of bison ever extended down to Arizona. Even the sources cited by the Plumb Report make no such finding;
- The report ignores the Park Service’s own standards for what constitutes exotic wildlife that is supposed to be removed if the introduced species is harming park resources; and
- It bases much of its analysis on an unsupported analogy between the cattalo of Grand Canyon and the behavior of the iconic wild horses that swim at Virginia’s Assateague Island.
“These cattalo are no more native to the Grand Canyon than pythons are native to the Everglades,” stated PEER Executive Director Jeff Ruch. “The Park Service has improperly engaged in a results-driven review designed to support what the Arizona Game & Fish Commission wants.”
This orphaned herd now has as many as 800 members. These 2,000 pound animals congregate in a small, very fragile part of the park’s North Rim where they have apparently learned they will not be hunted. This stagnant herd is harming rare plants, fouling lakes and ponds and carving erosive trails into the North Rim.
In 2014, Grand Canyon was developing an evaluation of alternatives which included removing the cattalo herd from the park altogether. The Plumb Report killed that plan and now the park is posting a quick assessment of the culling option favored by the state.
Under the Information Quality Act, the Park Service has 60 days to defend the report or it must be withdrawn and its conclusions barred from use in decision making.
“To counter the uncontested fact that these cattalo were introduced by humans, this report creates a fiction that Grand Canyon is within of the historic range of the plains bison even though there is no archeological, biological or cultural support for that notion,” Ruch added. “If bison had spent any time longer than a spring break at the Grand Canyon there would be some evidence of it.”
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