Regenerative grazing is often touted as the answer to just about every challenge in our current food system. Billed as a ‘natural’ fix, the concept appeals to environmentally conscious consumers who want to buy their meat from a farm that’s beneficial to the ecosystem.
The marketing tells them what they want to hear — allowing cattle to graze on land restores nutrients in the soil and preserves biodiversity — it can even reverse climate change.
Many of these claims have been fundamentally disproven. But one regenerative grazing notion continues to linger — the idea that cattle ranching is a fundamental part of biodiversity, that grasslands across the world and especially in the U.S. need livestock in order to thrive. The presence of livestock and other domesticated animals trampling across grasslands, the argument goes, enhances biodiversity rather than destroys it.
Despite the big claims, the opposite is true, according to a study published in the spring. Over 1.5 million cattle graze on U.S. public lands to the detriment of biodiversity, wiping out wild plants and woody trees, and crowding out deer and elk from grazing. Even low-density grazing alters ecosystem biodiversity and the quality and quantity of food available for native wildlife. So why does this myth about nature and farmed cattle persist?
It might just be because regenerative ranching would need a lot of land to scale up — at least 2.5 times more land than feedlot cattle to meet the demand for meat consumption in the U.S. alone. To address this, some proponents of regenerative ranching want the grasslands, woodlands, shrublands and conservation lands across North America all to be available to ranchers for their grazing livestock. Some advocates have even argued for opening up federal conservation lands to keep up with the demand for meat, arguing this would provide sustainable beef while ‘restoring’ the structure and function of grasslands across the nation.
Yet these claims rest mostly on historical evidence of the bison herds that once roamed the land. And here’s what these proponents get wrong — cattle are not bison. Their grazing behavior and their impact on the land are entirely different. And what’s more — there’s a widespread fundamental misunderstanding of what biodiversity is and why it’s so important.
Biodiversity Helps Create Resilience
Biodiversity has become a catch-all term used to describe the wide variety of life found on earth, from animals and plants to the genetic material found in fungi and other microbes.
In practical terms, biodiversity provides raw materials for human consumption, sustaining livelihoods for diverse populations from fishermen to farmers across the world.
From an ecological point of view, however, biodiversity plays a much larger role — keeping ecosystems healthy and resilient by enabling the sort of interplay between different species that is critical for the ecosystem, like pollinating plants and even predator-prey relationships.
The right balance of biodiversity helps an ecosystem regulate itself — keeping itself in balance even when exposed to natural disturbances like windstorms and fires, or droughts and insect infestations. Functioning biodiverse ecosystems can even thrive in the face of some natural disturbances, like periodic fires. Many plant species depend on these fires for reproduction and growth.
What’s more — resilient ecosystems protect human communities too. A growing number of scientific studies suggest a connection between decreasing biodiversity rates and an uptick in global disease outbreaks.
Native grasslands, savannas and shrublands are able to survive for centuries when they are part of a biodiverse, resilient ecosystem. These environments rely on plant and animal species that are endemic to the land for their resilience, but when livestock herds are introduced to these lands, cattle grazing habits and behavior alter the growth of native plants, which in turn can affect the population of animals that rely on native plants for survival.
Cattle Herds Destabilize Ecosystems
Livestock grazing can destabilize a resilient ecosystem by altering the type of plants and animals that can grow within the ecosystem, making way for invasive plant or animal species. Invasive species are animals or plants with the ability to grow and reproduce rapidly while wiping out other species of plants and animals. When these grow unchecked, they eventually replace the native plants or animal population — sometimes both.
The growth of invasive species alters the ecosystem, which now struggles to achieve a new balance or an alternative stable state. Ecosystem resilience, therefore, is directly related to its ability to prevent non-native, invasive species from taking over and doing damage to the inherent diversity of the ecosystem.
The key point here is that biodiversity is more than just a wide variety of species in an ecosystem. The specific type of species present and the relative number of each species present are all critical for maintaining ecological resilience. This delicate balance of biodiversity matters. It ensures that the ecosystem as a whole can weather disturbances like droughts and protect less resilient species from damage. And while proponents of regenerative grazing often paint an idyllic, pastoral fantasy of a time when bison roamed freely across the vast grasslands of the U.S., the fact is that livestock cattle and bison have a very different impact on an ecosystem and its biodiversity.
Cattle Graze in Uniquely Damaging Ways
Cows and bison differ in all behaviors — including how they stand, move and graze. Cattle spend almost double the time grazing — 45-49 percent — in comparison to bison — who spend just over a quarter of their time doing so (26-28 percent). And while land needs some amount of disturbance to enable soil turnover, it turns out that the kind of soil disturbance provided by cows trampling over the soil is not the best for preserving biodiversity. And these critical differences in grazing behavior have downstream effects on the ecosystems they inhabit.
Unlike bison and other non-domesticated animals that feed on grasslands and tend to walk with a light gait and in smaller groups, cattle trampling over the soil damages the soil crust and leads to soil compaction, impeding root growth and lowering soil quality. Degrading the biotic soil crust destabilizes the soil, affecting its ability to absorb water and contain organic matter, which in turn leads to reduced soil fertility and limits the types of plants that can grow.
The types of plants bison and cattle prefer to graze on are also remarkably different. Unlike cattle, who prefer to graze steadily on flowering herbs like clover, milkweed and sunflower, free-roaming bison cover a much larger area, grazing on different varieties of grass, such as perennial grasses, but leaving certain areas of the prairie untouched.
On the other hand, as cattle wander across the land, they spread the seeds of grass through their manure, fur and hooves, and that, in turn, can spread invasive species across the land too. Cattle trail over the soil, paving the way for invasive grass species to proliferate.
Bison roam away from water sources for longer times as well, leading to less pollution of streams, lakes and other water bodies in grassland. Cattle tend to stay closer to water sources and often trample stream banks, which can lead to soil erosion and increased soil particulate matter present in stream water. This in turn leads to less vegetation and less shelter for organisms that live in waterways. The increased presence of soil in streams can alter the aquatic ecosystem and has been known to kill fish eggs through oxygen deprivation. Cattle also pollute bodies of water with their urine and manure, damaging aquatic life throughout.
Meanwhile, bison form crater-like wallows in the soil, creating different soil dynamics that can collect rainwater and harden. The abandoned wallows are colonized by distinctive, heterogeneous plants and are important habitats for many animals.
A recent study looked at data collected over 29 years to research land impacts from bison compared to cattle grazing — finding the land grazed by bison increased the growth of native plant species by 86 percent. The resulting biodiversity made the ecosystems resilient to the most extreme drought experienced in over forty years. But within that same period of time, livestock grazing increased the growth of plants by just 30 percent.
This is just one study, but it’s part of a growing body of evidence that shows grasslands, savannas and shrublands already get the necessary amount of soil disturbance from native grazers such as bison and deer. While a limited number of cattle on the grasslands may be able to mimic the effect of native animals under controlled circumstances, replacing the gentle to intermediate grazing that native animals offer with cattle would not be beneficial to the land. Adding grazing livestock damages the biodiversity and resilience of ecosystems rather than enhancing it.
When large human-led livestock herds are moved into grasslands, the number of small native animals that feed on grass and shrubs are quickly outcompeted for food and resources, and that leads to a decline in their numbers. As the number of small animals declines, there is decreased food for predatory animals like coyotes, foxes and lynxes, which in turn leads to a decline in their numbers too. All of this shows large numbers of grazing cattle are not a boon for biodiversity — but are in fact a total bust.
Wild Grazers Treated Like Livestock Pests
In some parts of the U.S., ranchers and government organizations are going so far as to allow the killing of animals that are native to the land because they deem these creatures “livestock pests.” When livestock owned by ranches — that also happen to enjoy heavily subsidized cattle grazing and dairy leases — are allowed to share the land with native ruminants, the native ruminants and other wildlife end up suffering. The ongoing situation of the tule elk at the Point Reyes National Park is a case in point.
Tule elk were a critical part of the Point Reyes peninsula ecosystem for about 10,000 years before they went extinct in the 1800s. Their reintroduction to the Point Reyes National Seashore in the 1970s was once a conservation success story.
Today however, the tule elk now jostle for food and resources with the cattle who are part of mega-ranching operations that lease the public lands adjoining the park. The National Park Service has prioritized the needs of beef and dairy ranchers who consider the elk a nuisance and a threat to their livestock. Ranchers have built tall fences to keep the elk away from food and water sources, and elk attempting to jump the fences often get maimed and die. Many other elk starve and dehydrate to death, further reducing their numbers.
Unlike cattle, who tend to forage intensively within smaller areas, elk walk long distances and forage over a larger area. Cattle ranching in this area has done little to help the biodiversity of vegetation and water bodies in the park but has instead stripped the land of its nutrients and caused erosion, causing an epidemic of invasive weeds at the Point Reyes Seashore. The native shrubs and grass that belong to the area such as perennial bunchgrass, purple needlegrass and the California oatgrass have all been replaced by invasive plants such as European annual grasses and thistles. The Point Reyes water sources have become among the most contaminated bodies of water in the U.S. because of the livestock feces and urine, which has in turn damaged the biodiversity and resilience of those aquatic ecosystems.
The fenced land where elk graze, on the other hand, has maintained a strong presence of native perennial vegetation. Unlike the invasive annual grasses that have taken over the lands grazed by livestock, the native plants are part of a resilient ecosystem there, one which uses the moisture from the fog belt to stay green year-round.
The changes in biodiversity extend to the animal and bird populations as well. Dairy operations near Point Reyes practice silage mowing — ranchers cut pastures of green foliage crops and preserve them as livestock fodder — which displaces and kills small mammals, ground-nesting birds and their chicks, which become food for ravens. Studies have then shown an uptick in ravens measured after silage mowing at Point Reyes, whose populations negatively impact the small mammals and nesting birds.
Curbing Livestock Grazing Boosts Biodiversity
Point Reyes is just one example. A recent meta-analysis of 109 independent studies looked at the effects of high-intensity livestock grazing on every continent except Antarctica. With few exceptions, curbing livestock grazing was shown to increase diversity across herbivores, pollinators and predators.
Stopping livestock grazing entirely caused an increase not only in the number of plants but with time, there was also an increase in the different types of plants that were seen on the land. In some cases, however, even decades after the livestock had been removed from the lands, the original diversity of the species of animals and plants within the ecosystems was never recovered. The original biodiversity was lost forever, with the best hope for the future to maintain the alternate stable state before it degrades even further.
Biodiversity loss at this scale has a devastating impact. The findings of a United Nations-backed study released in May 2019 confirm that we are now facing the extinction of over one million species within the coming decades, ushering in the sixth great extinction. The number of animals living on Earth has been reduced by 60 percent since the 1970s, with individual populations of species in the billions lost all over the planet.
Opening up the grasslands for livestock might serve as a temporary means of meeting our insatiable demand for meat, but such a move will only lead to further biodiversity loss and all of its devastating consequences, from which we may never recover.
Devatha Nair, Ph.D. is a science writer who uses her doctoral training to research and write about global food systems and their impact on human and non-human animals. Her writings have covered topics that range from the use of antibiotics and pesticides in farms to the role played by language in enabling bias against non-human animals. As a biomaterials scientist, she is also the author of multiple peer-reviewed journal articles and book chapters. She has a Ph.D. in mechanical engineering from the University of Colorado.