A Species Report on Buffalo

Buffalo buffalo Buffalo buffalo buffalo buffalo Buffalo buffalo. The North American buffalo was the keystone species of the grassland ecosystem. It dominated the prairie landscape for over ten thousand years, only to be culled from nearly 30 million head to less than a thousand in under a hundred years (Lott 2002, 73). Due to a sweeping public awareness campaign, spearheaded by Theodore Roosevelt, the species rebounded from fewer than 25 wild bison to its current population of over 140,000 head in various public and private herds (Berger 1994, 28). Today, Bison bison bison (henceforth referred to as buffalo or bison) faces a new set of challenges. No longer in demographic peril, management plans now must cope with maintaining genetic diversity and managing population sizes on small, isolated reserves (Wyoming 1996, i).

At eight and a half feet long and six feet tall, the buffalo is a commanding presence on its native grassland, where it dwarfs all species around it but the pronghorn and the elk. Cows generally weigh nearly 1,200 pounds, whereas bulls weigh in at more than a ton (Roe 1970, 57). Their supreme bulk is made all the more impressive by the buffalo's diet. An avowed herbivore, a buffalo will graze, on average, 20 pounds of grass per day (Wyoming 1996, 129). Subsisting mainly on forbs, these ruminators prefer the medium-height grasses of the mixed-grass prairie located between the Rocky Mountains and the Mississippi river and running from present-day Saskatoon to northern Texas (Lott 2002, 71). They breed once every year in August or September and birth in May (Berger 1994, 135).

Though estimates rise to nearly 60 million, revised numbers suggest that at the species' peak around 1500 AD, close to 30 million buffalo roamed in portions of nearly 40 of the 48 contiguous states (Lott 2002, 71). Shortly after that date, however, their population began declining due to the introduction of the horse to the Americas. The horse not only competed with the buffalo for roughage, but also changed the dynamic of the hunt into one far more damaging to the species (171). The gun and the plow, wielded by white settlers, made the greatest contributions to the 'Great Slaughter.' With the 1849 gold rushes and homestead acts of the 1860s, settlers began developing the grasslands for agricultural purposes and replacing the native bluestem and bunchgrass with wheat, corn, and cotton. Known as the "great plow-up," commercial agriculture destroyed close to 75% of the buffalo's natural habitat, dividing it into two herds, northern and southern (91). The transcontinental railroad, finished in 1869, split the two herds permanently and lowered the transport costs of buffalo hides, making large-scale hunting economically feasible. Between 1870 and 1900, wholesale slaughter reduced the species' numbers from 14 million to under 1,000 (167).

Preservation efforts began on the small scale in the 1880s. William Hornaday, a prominent biologist, led an expedition to gather live buffalo for zoos in 1886. From 1889 to 1891, a number of these bison were kept on the National Mall in Washington DC. The herd on the Mall raised public awareness for the animal and the National Bison Society was founded in 1905. President Theodore Roosevelt sat as the ceremonial chair. Growing public support increased the numbers of national herds from two in 1905 to eight in 1913 (Wyoming 1996, 28). Eventually, over 50 public reserves were set up, each containing an average of 300 head, with the largest herds at parks Yellowstone National and Custer State (Berger 40).

Though each herd was administered by its own autonomous body, early management generally followed the same simplistic general plan. All the herds started with a small number of bison, usually under twenty, placed on reserve land. The animals would be permitted to roam, graze, and reproduce with little intervention. Though fairly uncommon, some early efforts were made to preserve genetic diversity by shipping in new lines of bison (Berger 1994, 41). As there were no natural predators due to the culling of coyote and hunting restrictions, populations quickly rose beyond the carrying capacity of the land, about 26 acres per buffalo (Lott 2002, 73). The population boom produced several undesirable effects on the land, from the loss of native grasses and compacting of the soil to the roaming of buffalo beyond the borders of their reserve land (Berger 1994, 267).

These management strategies led to important problems by the 1950s, and each preserve had their own methods of dealing with them. Management of population in the Jackson Herd of Wyoming was minimal, and as a result bison would venture into neighboring Grand Teton National Park during the winter and invade feed lots set up there for elk (Wyoming 1996, 6). Hunting was permitted from the Yellowstone Herd if the bison wandered out of the park. This strategy worked well initially, but in the winter of 1988, a mass migration led to the shooting of more than 550 bison, amounting to a nearly 50% decrease in herd size (Berger 1994, 33).

The three problems of homozygocity, population management, and brucellosis that beset the conservation herds from their inception are still issues today, but new management tactics approach bison from a more holistic perspective afforded by advances in conservation biology. To address the difficulties arising from "increasing yet confined populations in predator-free environs," herd administrators are considering several new tactics. At least 12 national herds now employ limited culling techniques, though their administration varies from herd to herd (Berger 1994, 30). The Custer herd in South Dakota is one of the "most heavily manipulated populations" and relies on the culling of genetically undesirable animals, the removal of cows older than ten years, guided hunts of older bulls, and an annual auction that brings in more than $200,000 per year for the continued management of the herd (36). As an additional strategy, two to five head from the Jackson Herd are presented to local Native Americans for ceremonial hunts and use for traditional crafts (Wyoming 1996, iv).

While it is relatively easy to control populations, dealing with homozygocity is much more difficult. The introduction of new lines into the Yellowstone and Badlands herds has met with poor results. In South Dakota, the new line is being lost to introgression, as its males are more timid than the dominant preexisting line (Berger 1994, 220). Similar results are being recorded at Yellowstone. Bulls imported from Colorado "were so intimidated by the [preexisting bulls] that not one of them ever bred" (Lott 2002, 95).

The third concern, brucellosis, is a bacterial disease carried by buffalo but not suffered by them. Infected cattle have a higher incidence of spontaneous abortion, but buffalo are seemingly unaffected carriers. While there are no documented cases of transmission between cattle and bison, the Department of Agriculture maintains eradication programs in every state (Berger 1994, 33). Current management strategies in Wyoming's Jackson Herd include separation of cattle and bison, vaccination of all cattle and buffalo, and further study of the disease and its transmission (Wyoming 1996, ii).

Unfortunately, as long as buffalo are confined to small, isolated reserves located near cattle ranches, these three problems will continue. The management strategies outlined are far from permanent and require constant human intervention. Of late, overtures have been made to Midwestern state governments and the Federal government to create a National Bison Commons, a "Great Plains Park" where the buffalo would roam free of human intervention (Lott 2002, 203).

Today, 46 million cattle currently graze on the Great Plains. Ill-suited to the environment, their management is dependent on constant human intervention and more than $35 million per year in government subsidies. They overgraze, compact the soil, and destroy riparian zones. Buffalo, on the other hand, cost half as much to raise and can be sold for twice the price of any cow (Palmer 1999, 122). The establishment of a National Bison Commons would alleviate the strain that cattle put on the plains, helping to return native species and establish a natural balance that would require little human intervention (Lott 2002, 203). Semi-annual hunts and tourism would provide not only for the administration of the park, but also for thousands of families in the form of "tasty meat, with far less fat and cholesterol and more protein than beef" (Palmer 1999, 122).

Not only is the idea of a National Bison Commons possible, it's quickly becoming politically possible. Decreasing human populations in the plains states are driving down land prices, and soil depletion and exotics are driving many Midwestern farmers and ranchers to sell (Berger 1994, 39). Canada has already set aside nearly 200 square miles for its own Grasslands National Park (Lott 2002, 204). A similar park in the US would ameliorate all three of the current species concerns while restoring thousands of acres of grassland currently given over to cattle and other exotics. Thirty million bison once roamed the Great Plains, and with a little policy, they can be returned. As economic conditions worsen across the plains states, the prospect of a bison commons becomes more viable.

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Sources Cited

Berger, Joel and Carol Cunningham. 1994. Bison: Mating and Conservation in Small Populations. Columbia University Press: New York. 330 pp.

Lott, Dale F. 2002. American Bison: A Natural Analysis. UC Press: Berkeley. 229 pp.

Palmer, Tim. 1999. The Heart of America. Island Press: Washington, DC. 337 pp.

Roe, Frank Gilbert. 1970. The North American Buffalo. U. Toronto Press: Toronto. 1008 pp.

Wyoming State. Sept.1996. Grand Teton National Park National Elk Refuge. Jackson Bison Herd: Long Term Management Plan and Environmental Assessment. Wyoming: State of Wyoming. 123 pp.