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Across the Fence by Bill Rinehart Science Director's Remarks |
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The Tallgrass Prairie Preserve is entirely owned and operated by The Nature Conservancy, a non-profit, science-driven conservation organization whose mission is to preserve plants, animals, and natural communities that represent the diversity of life on Earth by protecting the lands and waters they need to survive. It is supported by individual contributions, corporate and foundation grants, and membership dues. The Conservancy presently has over one million members worldwide. One of the objectives of preserve managers is to maintain a relatively consistent stocking rate on the land. To accomplish this, a target forage removal rate of a little under 20% of the amount that grows each year has been established. This is the amount of forage they expect the bison to consume annually. A similar amount of vegetation is typically lost in a year-round grazed unit due to trampling and, in the case of bison, wallowing. Total annual forage removal is therefore targeted at about 40%. Although this is considered a fairly conservative stocking rate, the challenge is in balancing the growth of the herd (animal units) with the forage base that's available. What the range managers are doing on an annual basis is adding more acreage to the bison unit to keep pace with the growth of the herd so a relatively consistent stocking or foraging rate is maintained. The stocking rate on the preserve is fairly light and the prairie could easily handle more animals, but the decision is to err on the conservative side. The next increase in the size of the bison pasture is scheduled to follow this year's roundup. Following last year's roundup, 62 animals were sold, 43 were purchased and 13 traded from outside sources for genetic purposes. The ones purchased were paid for by revenues from sold animals and The Conservancy's Adopt-A-Bison program. The traded animals were acquired from the Konza Prairie Preserve near Manhattan, KS, a little under 9,000 acre preserve located at the northern end of the Flint Hills that The Conservancy owns, but is managed by Kansas State University, and the Conservancy's Cross Ranch Preserve located near Hensler, ND. Preserve bison have never posed a serious problem where they've tried to leave the preserve en masse. More frequently, they have gotten through some of the old internal fences that will eventually be removed, but were still on the preserve. They seem to be at home on the preserve, likely because there is plenty of room for them to roam and because they aren't held in a confined environment. Bison are naturally very susceptible to stress accumulation. Although they may not show it outwardly, they may show it by trying to gore each other. When the herd is worked at roundup in the fall, handlers try to be as quick and efficient as they can, try to keep the noise down, and not whoop and holler like they might with cattle. The less that bison are harassed, the better it is for everybody. The preserve's roundup and corral system is built to emphasize safety for the animals and for the humans who work them. Following their turn through the squeeze tub and chutes, the further the animals can be away from the center of the corral and all that's going on there, the better for the animals. For that reason, smaller holding pens to the north and east are continually being added to the corral system. This keeps the preserve crew of four ranch hands who live and work on the preserve busy building something at all times to keep corral size up with herd growth. A patch burn study will begin this spring under the auspices of OSU in several cattle pastures. A graduate student will be involved. Only one-third of a pasture will be burned per year in the cattle grazing area of the preserve and normal beef stocking rates will be maintained there over a period of three years. The idea is that in the "patch burn" pastures, there will be different habitat opportunities. The graduate student will be looking at plant community responses to that burning regimen and will also study the effect on prairie nesting birds. Preserve staff will be working closely with the cattle lessee to get livestock production information. Typically there are two different schools of researchers on the preserve. There are the agronomists who look at cattle production in terms of weight gains and then there are the wildlife investigators who look at plant and animal life. An effort will be made to combine the results of the two into something that is quantifiable. Although DNA studies have not been conducted on the preserve's bison herd, they have been conducted on some of the larger public herds in South Dakota and Kansas. These herds had experienced very little cross-fertilization and the results showed no significant evidence that those herds needed to be moved around for genetic purposes. Kenneth Adams, who put together his herd in the 1980s from a broad base of different herds, donated the preserve's original herd. This helped assure genetic diversity of the preserve's original herd. The impact of white tail deer on the preserve's ecosystem is not a concern at this time mainly because there is no cropland nearby to attract them. There is no knowledge of coyotes being a predator for bison, which have actually been seen chasing coyotes, probably for fun. Coyotes have also been seen moving through a herd of bison that hardly acknowledged their presence. These examples indicate that coyotes don't threaten bison. According to an OSU study, the most numerous prairie grazers historically were bison. Re-establishing bison back onto the prairie, therefore, comprises the main herbivore component of the prairie ecosystem. The first bison calf from this year's crop was sighted Thursday, March 22, 2001. This year's calf crop is expected to produce around 400 head. |