Should bison be reintroduced to as many areas of the Great Plains as possible, perhaps replacing cattle? Denver Zoo keeper and researcher Bryon Shipley is working with other researchers and volunteers seeking answers to how bison affect biodiversity of the Southern Great Plains in Colorado.
In particular, Bryon is studying the effect bison may have on reptiles and amphibians.
Because bison and grasslands evolved together, the researchers suspect that bison impact grassland ecology more naturally than cattle, and this study aims to provide evidence. “Traditionally,” says Bryon, “bison tend to spread out and continue to move. They govern the time they spend in any one location.” Natural behavior, according to Bryon, causes them to keep moving.
“If a rancher doesn’t want to manage cattle by shifting them periodically to allow land to grow back,” says Bryon, “overgrazing tends to occur.”
Under the direction of Conservation Biology Director Rich Reading, the project is run by the Conservation and Biology Department of the Denver Zoo. The object is to compare the results of the study to what is already known about cattle and to reintroduce bison to as many areas of the Great Plains as possible.
“We want to look at the whole biodiversity picture of the Great Plains,” says Bryon, “including small mammals, birds, reptiles, and vegetation.” This has never before been done in southeastern Colorado.
In its pilot year, the study is expected to take at least three years to obtain sufficient data. Animals are captured and identified, then marked and released, allowing them to be recognized upon re-capture. “That way we can estimate population densities and evaluate ‘species richness’ – looking at how many species there are.”
Reptiles and Amphibians
The effect bison have on reptiles and amphibians may be negative, neutral, or positive. Bryon would like to think that the presence of bison would have at least a neutral effect, if not a direct or indirect positive effect, on the reptile and amphibian populations.
“We want to reintroduce bison as much as possible,” says Bryon, “because that’s one key to maintaining diversity in the Great Plains. You want them to do what they’ve always done in their evolutionary history.”
Shifting Cattle to Different Pasture:
For one rancher’s story of converting to bison, read Buffalo for the Broken Heart by Dan O’Brien.