Culling is a wildlife management practice involving the lethal reduction of a species. It has historically been used as a means to control ungulate (hoofed animal) populations in Colorado and throughout the United States. As recently as 2009, it has been used in combination with other population control mechanisms, such as hazing elk herds and treating cow elk with contraceptives, to control populations of elk in Rocky Mountain National Park (RMNP). In particular, culling has elicited controversy and continues to color debates about the appropriate management of national parks throughout the United States.
Definition and Use
The National Park Service defines culling as a conservation tool used “to reduce [ungulate] populations that have exceeded the carrying capacity of their habitat.” Unlike hunting, which is recreational and involves fair chase, culling is “done under very controlled circumstances in order to minimize impacts on park operations, visitors, private inholdings and neighbors.”
Elk have historically experienced sharp population declines and spikes in response to hunting and conservation policies. Overpopulation of elk can harm other species and sometimes disrupt an entire ecosystem. During periods of peak numbers, culling is aimed at removing fertile females to reduce the reproductive capacity of a herd of elk; it seeks to replace the function of one ecological component, predation, with another.
Culling is distinct from reparative restoration, wherein resource managers attempt to repair or reintroduce native components of an ecosystem. In Yellowstone National Park reparative restoration meant the reintroduction of wolves. In Rocky Mountain National Park, replacement restoration has meant replacing predators with skilled, qualified stewards who lethally cull elk herds. Both reparative and replacement restoration have been used to control ungulate populations with varying degrees of success. They have also provoked controversy.
Elk Decline and Recovery
Economic and urban development in late nineteenth-century Colorado brought the decline of the region’s most iconic mammal: the North American elk (Cervus elaphus). A constant stream of explorers, entrepreneurs, and migrants spread out from Denver along the Front Range of the Rocky Mountains, which put constant pressure on already dwindling elk populations. By 1900 unregulated hunting and habitat loss resulted in the elimination of elk throughout much of Colorado, including what became Rocky Mountain National Park. Logging, mining, and other extractive industries destroyed prime elk habitat, even as settlers continued to rely on wild game such as elk to supplement their diets.
Rocky Mountain National Park boosters understood that elk would be a primary park attraction—an essential component of the wilderness experience. In 1913–14, in anticipation of the park’s creation, the Estes Valley Improvement Association and the US Forest Service reintroduced forty-nine elk from Yellowstone National Park. By 1915 the herd had become well established, with numbers stabilizing around thirty head of elk. After reintroducing elk as a primary cultural and natural feature of RMNP’s scenic allure, park stewards fashioned policies to ensure the species’ propagation.
The extirpation of gray wolves and cougars, the primary predators of elk, accompanied the rapid settlement of the American West. In their efforts to ensure elk propagation, RMNP managers sustained the frontier settlers’ decades-long campaign against predators and outlawed elk hunting within the park in 1929.
The policy of predator eradication continued for decades. Park personnel eliminated wolves, cougars, and bears. Monthly superintendents’ reports illustrated the emphasis on maintaining healthy elk herds. Superintendent L. Claude Way’s September 1919 report typified the campaign: “More mountain lions have been reported this year than ever before. I am making arrangements to get lion dogs and am starting an intensive campaign against predatory animals this winter.” While it effectively boosted the local elk population, the removal of predators had cascading effects on RMNP’s ecosystems and eventually inspired resource managers to develop alternatives to manage ungulate populations.
Culling for Preservation
Elk populations exploded as predation declined. Elk herds became sedentary and concentrated in places such as Moraine Park, which served as a prime wintering ground. The elk herds intensively grazed meadows, willows, and aspen stands to the detriment of other species, such as beavers and birds, that relied on these plant communities for forage, cover from predators, and rearing of young. Park stewards carried out two culling campaigns, one in 1944 and another that followed from 1949–53, which eliminated 340 elk in an attempt to minimize damage to these plant communities.
In total, between 1944 and 1953 park personnel eliminated 1,045 elk within the park. Culling stopped abruptly in 1962, when resource stewards estimated elk herds had leveled off to a sustainable number. Soon, however, elk populations climbed once again. Intensive grazing ensued, accompanied by severe damage to vegetation in critical winter habitats. By 2009, according to some biologists, elk density in Rocky Mountain National Park reached 285 per square mile in some places, among “the highest recorded for a free-ranging herd in the Rockies.”
Research in RMNP indicated that without predators, the elk population had become larger, more concentrated, and less migratory. Elk ravaged aspen and willows, reducing them to stubble. According to the authors who developed the Elk and Vegetation Management Plan (EVMP), an environmental impact statement aimed at addressing elk-related environmental decline in the park, high elk populations and densities “altered aspen and montane riparian willow plant communities in the park, primarily in the core winter range,” which reduced “the biodiversity of plants and animals in those communities.” Reduced migration contributed to degradation of local elk habitat. Resource stewards also determined that this behavior resulted in a “reduction in overall wildness of the population,” a primary reason visitors came to RMNP.
Even though it is widely perceived that Yellowstone National Park had successfully reintroduced wolves in the 1990s, RMNP adopted culling as the preferred alternative to control its elk herds. Culling, the plan’s authors said, constituted an “efficient and humane way to reduce herds of animals that are habituated to the presence of humans.”
In 2009 Rocky Mountain National Park finalized the EVMP, which resulted from seven years of intensive research, followed by four years of interagency collaboration to determine how to best implement the plan. Following the procedures outlined in the National Environmental Policy Act (1969), the general public as well as the towns of Estes Park and Grand Lake, Larimer and Grand Counties, and other municipalities commented on the five alternatives outlined in the plan: 1) No active management of elk; 2) Rapid lethal reduction combined with redistribution methods; 3) gradual lethal reduction combined with redistribution and the use of exclosures; 4) gradual lethal reduction through the use of fertility control drugs; and 5) the lethal reduction of the elk combined with the intensive management of reintroduced gray wolves.
Public comment on the EVMP ranged from those who applauded the NPS for appropriately managing the elk to frustration from those who felt that the NPS had failed to leave the park unimpaired for future generations. Although the EVMP adopted culling as the preferred alternative, RMNP has continued to use exclosures as well as contraceptives to protect willow and aspen stands and to maintain the elk herd at an optimal size (approximately 600-800 animals on the winter range). Every five years RMNP assesses the success of the EVMP's various strategies. Adaptive management provides resource stewards the flexibility to fine-tune what alternatives, or combination thereof, it uses to achieve the desired elk population. Since the EVMP's adoption in 2009, a total of fifty-two elk have been culled to bring the herd within the optimal population range.
Restoring a Wild Colorado
Culling its iconic elk herds is not an image coveted by the National Park Service. The 1964 Wilderness Act defines wilderness “as an area where the earth and its community of life are untrammeled by man” that is to be protected to “preserve its natural conditions.” The EVMP contradicts this natural regulation language in its call for park stewards to intervene in elk management in order to restore biodiversity in RMNP.
That wild elk, iconic symbols of unspoiled nature, have destroyed the park’s biodiversity has called into question the possibility of preserving communities of life where natural forces dominate. The spike in elk population has complicated Americans’ often static view of wilderness and challenged the notion that snapshots or vignettes of primitive America can be preserved within dynamic ecosystems. Most important, the increased elk population has illustrated the problems inherent in simply allowing previously managed landscapes to return to a natural state. Although RMNP has strived to allow natural processes to reign within the park, habitat loss and the removal of predators continue to complicate elk management, both with and without human intervention.
Current opponents of culling point to the success of wolf reintroduction (reparative restoration) in Yellowstone. However, pragmatic park stewards maintain that RMNP is one-ninth the size of Yellowstone, is an hour away from Denver, and is situated within a matrix of private and public lands with different management objectives. They argue it would be difficult if not impossible to keep the predators from harassing livestock and communities outside the park’s boundaries.
Meanwhile, advocates of culling highlight its success in checking elk populations to the benefit of greater biodiversity in RMNP. Culling expeditiously addressed the ecological decline within RMNP, and it sidestepped the hot button issue of wolf reintroduction. Since the adoption of the EVMP, willow and aspen stands have begun to rebound without the assistance of wolves. However, multiple wolf sightings in Colorado over the past twelve years have given rise to the argument that wolves may make their own comeback in the state, and managed reintroduction would allow for greater control of the wolf population. But the Colorado Parks and Wildlife Commission does not agree; the commission voted in January 2016 not to allow the reintroduction of wolves into the state.