These particular magical animals are at The Nature Conservancy’s Broken Kettle Grasslands in northwest Iowa. Photo: Chris Helzer/TNC
By Chris Helzer, prairie ecologist
Among some prairie enthusiasts, there seems to be a perception that plains bison are magical creatures that live in complete harmony with the prairie.
They eat grasses but not wildflowers, they float just above the ground to avoid stepping on plants or compacting the soil, and they create tidy little wallows that fill with rainwater for tadpoles and wading birds.
Cattle, on the other hand, are evil creatures that seek and destroy wildflowers, removing them from prairies forever. They also stomp all over prairies, trampling plants and birds to death and causing cascades of soil erosion and water pollution.
Let me be clear: I’m a big fan of bison. I feel very fortunate to spend time at The Nature Conservancy’s Niobrara Valley Preserve and other big prairies where I can observe and photograph bison up close.
Bison are distinctive, attractive animals that evoke a sense of history and grandeur… but they are also big stompy animals that go wherever they want, poop all over the place, rub on trees, trample plants (and animals), and can cause erosion issues. None of that is good or bad; it just is.
I’m a fan of cattle too.
They have big beautiful eyes, individual personalities, and can be more playful than their typically stoic faces might hint at. I enjoy spending time around cattle at our Platte River Prairies and in my own family prairie.
In both places, they are a major part of our prairie management strategy, which is aimed at creating and maintaining diverse plant communities and high quality wildlife habitat. (And yes, cattle are also big stompy animals that go wherever they want, poop all over, rub on trees, trample plants and animals, and cause erosion issues.)
TREES AND PONDS
These cattle almost look ashamed of their tendency to hang around in water. In this case, however, we were actually encouraging it as a way to help us control invasive cattails. We pulled the cattle out the next season and this little spot was a great shorebird area, with mud flats with scattered sedges and rushes. Photo: Chris Helzer/TNC
While both bison and cattle can be engaging creatures, there are a few real differences between the way bison and cattle utilize and impact prairies. However, those differences are less stark than you might think.
Based on the best available research and expert knowledge, the biggest distinction between bison and cattle behavior in prairies essentially boils down to this: cattle hang around water and trees more than bison do.
That general pattern is reported in many studies comparing the two, but was most reliably demonstrated in a recent study at The Nature Conservancy’s Tallgrass Prairie Preserve in Oklahoma, where GPS collars tracked animal locations through time.
That study looked at bison and cattle at similar stocking rates and under the same management regime (patch-burn grazing) – though the bison were grazing year-round in a 23,000 acre pasture while cattle were only present for 7 months/year in pastures of around 1000-2000 acres.
The GPS collars showed that cattle were attracted to ponds and trees while bison tended to avoid areas near water and showed no attraction to trees.
Importantly, the same study also showed strong similarities between bison and cattle behavior, namely that both were strongly attracted to the most recently burned areas of pastures and tended to avoid steep slopes.
The conclusion that cattle are attracted to water and shade fits with one of the big objections to cattle grazing by some prairie enthusiasts – that cattle tend to “wreck” areas near ponds and tree groves by repeatedly stomping around and defecating in those places.
While that can be true, those impacts are highest under high stocking rates, and can be avoided by fencing out ponds and trees or greatly reduced by providing long rest periods between grazing bouts.
Those impacts are also less severe in larger pastures, especially when multiple water and shade options are available and cattle are encouraged (or forced) to use each area intermittently. The attraction of cattle to wet and shaded areas can be a real challenge, but it’s not an insurmountable one.
This photo shows the kind of selective grazing cattle can do in a patch-burn grazing system with a moderate stocking rate. Ungrazed forbs in this photo include purple prairie clover, Illinois bundleflower and stiff sunflower – among many others. We like the impacts of this kind of grazing on both plant diversity and insect/wildlife habitat. Photo: Chris Helzer/TNC
The other beef prairie enthusiasts have with cattle (sorry) has to do with their diet. The perception of many is that bison subsist solely on grass, leaving wildflowers untouched, while cattle eat a high percentage of forbs (broad-leaved plants), often leading to the decline of those species over time.
The purported result is that bison-grazed prairies maintain high plant diversity, including an abundance of rare plant species, while cattle-grazed prairies become degraded as numerous forb species are grazed out of existence.
While that’s a big overgeneralization, it’s an understandable one because a number of research projects have reached that conclusion.
Unfortunately, those research projects have largely compared bison and cattle under very different circumstances.
Diet comparisons are usually made between bison in a single huge pasture (often under patch-burn grazing management) and cattle in a rotational grazing system – often at a higher stocking rate.
As a result, it’s not clear whether observed differences between bison and cattle diets are due to biological differences or grazing systems.
Imagine if you were given 30 days’ worth of groceries at the beginning of each month. You’d likely eat many of your favorite foods first and then make do with whatever’s left toward the end of the month.
Comparing your diet to that of someone who was allowed to go grocery shopping every day would be completely unfair, wouldn’t it?
Unfortunately, that’s essentially the comparison made by many research projects comparing the diets of cattle and bison.
Cattle in a rotational grazing system can only choose from the available plants in their particular paddock, and don’t get a new set of choices until they are moved into a new paddock.
In contrast, cattle or bison that spend their whole season in a large pasture, especially one in which a portion has been recently burned, can regulate their diet much more freely.
They spend most of their time eating their favorite foods (mostly grasses) in the most recently burned patch, but they can also travel elsewhere if the supply in that patch runs low. In addition, by regrazing their favorite plants over and over, livestock can keep them in a state of high nutritional value for much of the season.
We did some research back in 2001 in which we evaluated the forage choices of cattle in a patch-burn grazing system under a moderate stocking rate (Helzer and Steuter 2005).
Our data showed that those cattle were very selective toward grasses, and ate very few forbs under those conditions. That research, along with observations other scientists and cattle managers at patch-burn grazed sites, has led to an altered perception of the forage selection differences between cattle and bison – namely, that many of the differences are driven more by grazing system than by biology.
Bison at The Nature Conservancy’s Niobrara Valley Preserve in Nebraska. These animals are in a 10,000 acre pasture where they have plenty of room to roam. Photo: Chris Helzer/TNC
Prairie managers have to make difficult decisions about how to create and maintain diverse plant and animal communities at their sites.
One big choice is whether to graze or not to graze a particular prairie. Regardless of whether it is grazed by bison or cattle, a grazed prairie is going to look and act very differently than an ungrazed prairie.
Many plants will be stepped on and eaten. Some portions of the prairie will be more heavily visited than others and will get trampled down. Short-lived opportunistic plants will become more abundant, due to the weakening of dominant grasses through repeated grazing.
Some managers will see those effects as positive, but others will not — depending upon the management needs of a particular prairie. Regardless, deciding whether or not to graze has far greater consequences than the subsequent decision about whether to graze with bison or cattle.
If the decision to graze has been made, it’s important to recognize the appropriate criteria for deciding between bison and cattle. Bison do act somewhat differently than cattle, especially around water and trees.
However, those differences depend heavily on scale. Both cattle and bison create areas of bare soil around drinking water sources, and both create trails as they move from one favorite place to another.
In small pastures, those impacts are multiplied because both bison and cattle are forced to visit the same places repeatedly, which can lead to repeated trampling of plants, soil compaction, and other issues.
The differences between a small bison-grazed pasture and a small cattle-grazed pasture are pretty minimal.
In larger pastures (thousands of acres in size), grazing animals have room to spread out. At that scale, bison-grazed pastures tend to have fewer heavily grazed and trampled areas near trees and standing water than cattle pastures do.
While that can certainly be a perk of using bison, it’s also important to remember that even in large cattle-grazed pastures, the proportion of the overall pasture that receives that kind of heavy impact is very small.
In addition, there are management options that can be used to minimize the size and severity of those impacts by cattle. Those include fenced exclosures around sensitive areas and tactics that shift the locations where cattle spend most of their time (such as creating new burned patches, turning on/off drinking water facilities, and moving mineral feeders around).
The upshot is that there can be some prairie conservation benefits of using bison.
However, those benefits accrue most strongly in very large pastures, and even at that scale, there are cattle management strategies that can close that gap considerably. On the flip side, bison come with their own set of complications and costs.
I spend most of my time working at our Platte River Prairies, and I’m often asked why we don’t have bison at those sites.
There are several good reasons for that, starting with management flexibility. The cattle that graze our Platte River Prairies belong to our neighbors, and our lease arrangements allow us to dictate how many, where, and for how long cattle graze each year.
Between years, or even within years, we can pretty easily change those plans if we get unexpected weather patterns or just don’t like the way things look.
That kind of adaptive management is much more difficult with bison, especially because if we had bison, we’d have to own the herd and keep them on our prairies year round.
A second reason we use cattle is financial. It takes a much lower investment in infrastructure and personnel to lease cattle than to own bison.
We have to provide a good perimeter fence (usually a four-wire barbed wire fence) to hold cattle in our pasture, and provide water for them to drink. Beyond that, the owner of the cattle trucks them in when we ask for them, and then gathers and trucks them away again when we’re done.
If we owned a bison herd, we would need a much stouter, and more expensive fence, and a very expensive corral system to use for an annual roundup, sorting, and inoculation process.
In addition, we would be responsible for conducting that roundup, doctoring animals when if needed, and for dealing with buying/selling animals to maintain our desired herd size.
All of that takes time and people, and that’s expensive.
At our Niobrara Valley Preserve, the 22,000 acres of bison pasture can hold enough bison that income from selling excess animals covers many of those costs. That wouldn’t pencil out in our much smaller prairies down on the Platte River.
Conservancy employee Doug Kuhre runs the hydraulic-operated gates at a bison sorting corral during an annual roundup at the Niobrara Valley Preserve. Photo: Chris Helzer/TNC
The last reason we run cattle instead of bison is that in our relatively small prairies (200-600 acres), the behavior of bison would not be very different than that of cattle.
We might see less stomping around in standing water and under trees, but we can already manage those impacts by controlling whether/how often cattle have access to those areas.
Most importantly, through our use of patch-burn grazing, electric fence enclosures and exclosures, and our ability to set and change grazing intensity, timing, and frequency, we are getting the prairie management impacts we want by using cattle.
We can get cattle to graze very selectively in order to suppress grasses and give wildflowers a chance to flourish, and to create the kind of patchy habitat structure many wildlife and insect species need to thrive.
In other cases, we can get them to graze much less selectively in order to create a particular habitat structure or other impact. As a result, we are maintaining resilient and diverse prairies – and that is our ultimate goal.
Cattle aren’t so bad when you get to know them… More importantly, they can serve as very effective tools for prairie conservation… even if they don’t look exactly like bison. Photo: Chris Helzer/TNC
Plains bison nearly disappeared completely from the grasslands of North America as European settlement spread across the continent.
The ongoing recovery of bison is an important indicator of prairie conservation success, and I hope that upward trend continues.
At the same time, I worry about the tendency of some to heap accolades upon bison while dismissing cattle as inherently destructive. The differences between them simply don’t warrant that kind of broad categorization.
If grassland conservation is our goal, we should be sure we’re open to using whatever strategies (or animals) can help achieve that. In very large prairies, bison may be the best fit – assuming the logistics and costs of owning bison make sense.
In other situations, however, deciding whether bison or cattle are most appropriate is not a simple matter. It’s a decision that should be based on facts and management objectives — not on aesthetics or mythology.
Note: This story originally appeared on Chris Helzer’s blog, The Prairie Ecologist.
Opinions expressed on Cool Green Science and in any corresponding comments are the personal opinions of the original authors and do not necessarily reflect the views of The Nature Conservancy.