The historic removal of gray wolves from the U.S. West facilitated the rise of mid-ranking predators across the region, wreaking havoc on historical ecosystem dynamics, a new study has found.
Yet just how much havoc — both to their immediate prey and much farther down the line — remains unclear due to a dearth of data, according to the study, published Wednesday in BioScience.
The disappearance of wolves particularly led to a spike in elk populations, which then damaged plant communities through overgrazing, per the study. Also of note was an upswing in medium-sized carnivores like coyotes that threaten smaller animals.
“Various national parks in the western United States, which are considered the crown jewels of American wilderness, lack their apex predators, resulting in them being shadows of their supposed ecological integrity,” the authors stated.
Exacerbating that problem, they contended, is the fact that “restoration decisions made without consideration of past conditions may themselves continue to alter ecosystems in novel ways.”
To support that assertion, the researchers delved into 96 studies conducted in 11 national parks where gray wolves had been eliminated, from 1955 to 2021. They found that only 39 of those studies explored the historical presence of wolves and other large carnivores.
By failing to account for that loss, about 59 percent of these studies may have neglected basic shifts to ecosystems across the U.S. West, according to the researchers.
“By the 1930s, wolves were largely absent from the American West, including its national parks,” lead author William Ripple, a scientist at Oregon State University and the Conservation Biology Institute, said in a statement.
Ripple marveled at the finding that most of the published ecological research from the area took place after the wolf extirpation. This dearth of knowledge, he explained, could have led to faulty understandings “of plant community succession, animal community dynamics and ecosystem functions.”
Moving forward, the researchers advocated for increased integration of historical context when conducting ecological studies — with hopes of informing future conservation-related decisions in national parks and elsewhere.
“Studying altered ecosystems without recognizing how or why the system has changed over time since the absence of a large predator could have serious implications for wildlife management, biodiversity conservation, and ecosystem restoration,” Ripple added.