What is the effect of Agriculture on natural ecosystems?
What’s the most ecologically destructive human activity?
The answer is that arable cropland agriculture is the most ecologically destructive human activity. The three most destructive crops on earth are rice, cotton and soybeans. These are closely followed by the other grain and pulse crops (corn, wheat, rye, barley, peas, beans, etc.). These crops are grown primarily as monocultures, an aberration that is never found in a natural ecosystem. In addition, the vast majority of plants used for producing human or livestock feed are annuals or fall-seeded biennials. These plants are 'early succession' plants that are much less efficient at producing biomass and soil carbon than perennial species. Unfortunately for the vegetarian/vegan movement, there are very few perennial plant species that produce human digestible nutrients, making carbon neutral/negative vegetarian/vegan diets very difficult. Properly managed livestock production offers far greater potential for carbon storage than this and regenerative cropland production, when it is achieved, becomes more effective at storing carbon when livestock are integrated into the system.
It is worth noting that many studies show livestock production to be the most ecologically destructive activity. If one adds up the effect of arable cropping to grow feed, downstream pollution from confined feeding operations (CFOs), direct emission from the animals and the energy costs of processing and transport to point of sale, then this is correct. However, this is also a 'straw man' argument as the most destructive single component of this process is arable agriculture for animal feed. If meat is replaced by vegetable based proteins, fats and carbohydrates, the arable component of the equation increases. In addition, the downstream pollution and direct emissions are not directly attributable to the livestock but the management. In a natural ecosystem, biology negates these issues, turning these animal by-products into soil biomass.
A natural grassland ecosystem (70% of the world’s terrestrial surface) consists primarily of mob grazing herbivores, under predator pressure, living on perennial grasses, legumes, sedges, forbes and shrubs growing in an active topsoil with a community of bacteria, archaea, fungi and others. A typical grassland plant ecosystem contains huge diversity ranging from a few dozen species of plants to 170+, all living in a symbiotic relationship with each other, the animals, and the soil ecosystem below. The soil ecosystem is even more diverse, with several billion microorganisms in every cup (250ml) of healthy soil.
The destructiveness of a crop species is determined by the level of invasiveness of the methods used to grow it.
Simply put, tillage, synthetic fertilizer, pesticides, fungicides and herbicides damage or destroy the soil biology of a healthy plant ecosystem. Monoculture crops do not provide sufficient diversity for soil ecology, further damaging the ecosystem. Without a healthy soil ecosystem and a natural plant polyculture growing in it, we have a highly erosive system that leaches nutrients out of the topsoil. This is a totally unsustainable agricultural model.
Don’t berate Grandpa too hard about modern agricultural practices!
We have to be careful not to hammer previous generations too badly. They didn’t have the ability to discover that there were 2+ billion microbes in every cup of healthy soil. They couldn’t have known that the Arbuscular Mycorrhizal Fungi hyphae were able to transport nutrients to individual plants from an area up to 2000 acres (1000 hectares) in size with multiple plant species connected to the same fungal structure. They weren’t aware that AMF existed so how could they know that these fungi can penetrate the vascular structure of 80% of vascular plants, forming arbuscules through which the plant and fungi exchange nutrients in a symbiotic exchange. Nor did previous generations know that their plows tore AMF up and destroyed it.
When they went out to till the weeds that grew in the fields, it was without the knowledge that the tillage destroyed the fungi, resulting in bacterially dominated soil, which encourage broadleaf weed propagation. They didn’t know that broadleaf weeds were nature’s ‘band aid’ and were supposed to grow rapidly to shade exposed soil until perennial grasses, legumes and sedges could recover and recolonize the bare ground. They fought nature’s natural ‘band aids’ unaware that the weeds were trying to repair the damage they were causing.
So, we’ve inherited an unsustainable agricultural model that was the best practice as we understood it in 1940. We’ve added synthetic fertilizer, herbicides, fungicides and pesticides since, plus lots of horsepower and steel, but it really was the best we had until relatively recently.
It was only in the 1950s, with Andre Voisin’s research into grass productivity, followed by Alan Savory and a number of no-till, polyculture and soil health pioneers of the 1970s, 1980s and 1990s that we’ve come to understand soil and plant ecosystem health well enough to develop a ‘regenerative’ agricultural model.
It doesn’t produce the volume of grains or other plant-based products that industrialised agriculture does, but it produces a more diverse choice of healthier, nutrient dense products. Provided humans change their diet back to a more natural omnivorous diet, regenerative agriculture has the potential to support 3 times as many people per acre than cropland agriculture because regenerative methods can produce significantly more nutrition per acre. Polyface Farms in Virginia, the Brown Ranch in North Dakota and White Oak Pastures in Georgia are three very well documented examples, but there are a growing number of regenerative farms across North America, Africa, Australia and New Zealand. Even in Europe, the homeland of invasive tillage agriculture, regenerative agriculture is growing quickly.
Importantly, as regenerative ag builds topsoil and diverse plant ecosystems, there’s no ‘end date’ beyond which all our topsoil is depleted, and human and animal life slowly starves into extinction.
There are other benefits too. Regenerative farms support wildlife alongside livestock and, in the case of conservation agriculture, wildlife become the livestock. Additionally, while only a small percentage of the world’s terrestrial surface is suitable for modern arable cropland agriculture, 40+% of the world’s terrestrial surface can support regenerative rangeland agricultural activity.
Are there too many animals on the planet?
Prior to the beginning of the Quaternary, the Pleistocene Ice Age we currently live in, it is estimated that the total mass of all terrestrial land mammals was between 2 and 2.5 times the current total mass of all animals and humans on earth. Yet this was the period in which most of the world’s rich grasslands and topsoil developed. So, the idea that there are too many animals on earth cannot be logically inferred.
Are animals bad for the environment?
It has been a long-held belief that too many grazing animals are destructive to natural ecosystems because of the long-held belief that ‘overgrazing’ was a function of animal numbers. It’s this belief that led to the Rhodesian Park Service shooting 40,000 elephants in the early 1960s, only to find the ecosystem continued to deteriorate.
The research of Andre Voisin, a French biologist and farmer (author of ‘Grass Productivity’) and subsequent research in Africa by Alan Savory and his contemporaries, revealed that ‘overgrazing’ was not a function of animal numbers, but a function of a plant ecosystem’s time exposure to grazing by herbivores. In fact, when subjected to a very short ‘exposure’ to grazing livestock, followed by a long ‘rest’, grassland ecosystems (40-70% of the world’s terrestrial surface) recover rapidly and become healthy and vibrant as a result of the stimulation of a short exposure to herbivores. When this ‘impact – rest’ becomes a cycle, it becomes a carbon, oxygen and nitrogen ‘pump’ that builds topsoil more rapidly than in any other ecosystem. Nature’s symbiosis in action!
When grazing herbivores act defensively in the presence of predators, they maintain tight herds (mob grazing at 25,000-60,000 lbs per acre) and move continuously, giving plant ecosystems a short period of disruption as they pass, followed by a long period of rest and recovery. Alan Savory’s key addition to Andre Voisin’s work was the discovery that the more brittle the climate (drier and/or more seasonal humidity), the more critical the impact of mob grazing herbivores is to the long-term health of the ecosystem and the more critical careful management practices become.
The reality is that the animals and the ecosystem have a symbiotic relationship and it is how animals act, not how many of them there are, that determines whether their ecological impact is positive or negative. Alan Savory’s book ‘Holistic Management; a common-sense revolution to restore our environment’ covers this issue in detail and explains how careful management can ensure livestock are returned to their natural role as natures grassland ‘pruners and gardeners’.
In the Great Plains of North America, the plant ecosystem consists of multiple species in a diverse polyculture. Most regions have more than 100 species of grasses, legumes, forbes, sedges and shrubs, but some have over 170. Each of these plants provides a different influence on the surrounding plant and soil ecosystems. Of these 100+ species of plants, up to 30 require animal impact (grazing and/or trampling) to facilitate the plant’s reproduction. Take away the animals and these species of plants die out and are lost.
It’s this crucial interdependence between plants, soil and herbivores that makes mob grazing herbivores, (bison in North America, wildebeest in Africa and the ancient cattle of Europe) ‘keystone’ species. Without them the ecosystem loses diversity and, in some cases, experiences a ‘trophic cascade’ in which a large proportion of the ecosystem fails and the process of desertification begins.
It is also worth noting that predators are essential in maintaining this natural symbiosis. It’s the threat of predation that causes the bison/wildebeest etc. to live in dense herds constantly on the move. Without the threat of predators, the herbivores become more sedentary and herds split up into smaller, less dense groups and their impact on the grassland ecosystem falters.
It’s this lack of predator pressure that was causing the ecosystem to fail in the Rhodesian Parks in the 1950s and 1960s. The predators had been removed from the ecosystem, resulting in a trophic cascade and ecosystem failure.
A similar trophic cascade occurred in Yellowstone Park in the US when wolves were hunted out of the region by settlers. For several decades, scientists monitored a steady decline in ecosystem health and biodiversity in Yellowstone, accompanied by increasing erosion along the rivers.
In the early 1990s, timber wolves were reintroduced to Yellowstone and the effect they had was dramatic. Within a few short years, the rivers stabilised and stopped eroding, the aspen groves along the rivers began to recover and both plant and animal biodiversity began to recover. The influence of pack hunting predators on the grazing ruminants of the park changed their behavior back to a natural state, with a beneficial effect on the entire ecosystem.
Soil health is the foundation of ecosystem health.
When properly stimulated by grazing herbivores, a grassland ecosystem becomes the world’s most efficient carbon sink. When you look at a forest, you are looking at decades or even centuries of carbon stored in biomass. In a grassland ecosystem, the grasses absorb carbon from the atmosphere where it is transferred into the soil in the form of soil organic compounds. The process by which this occurs is covered on the page titled ‘Is Livestock destroying the environment?’.
In a healthy soil ecosystem, carbon is sucked out of the air by plants and deposited in soil. Microbiology in the soil process the carbon as food and supply nutrients to the plants. Dead plant material is deposited on the surface and processed by worms, bugs and bacteria into soil organic matter, building topsoil.
It is worth noting that 97.5% of the dry matter mass of grass comes from the atmosphere and only 2.5% comes from the minerals in the subsoil. Contrary to popular conception, plants don’t grow out of soil, soil grows out of plants. Plants take atmospheric compounds, carbon dioxide, nitrogen, etc., add water and micronutrients from soil biology and turn it all into carbon rich topsoil.
But only when the animals are there to help. Without them, particularly in brittle ecological regions, the plant ecosystems degrade, soil is exposed and erodes, and desert replaces lush grasslands. If we till the soil and/or grow monoculture crops, we accelerate this process.
How can you help?
Simple. Learn about regenerative agriculture and what products it produces. Read some good books by Andre Voisin, Alan Savory, Gabe Brown, Joel Salatin and other regenerative pioneers.
Visit a few regenerative farms and ranches. Buy direct from the farmer or from local stores that carry their products. Plant a polyculture in your back yard and keep a few chickens to process your kitchen scraps into eggs and fertilizer.
Vote for politicians who will de-regulate the food industry to allow innovation instead of corporate stagnation. Challenge them to change agricultural land ownership and use legislation. Regenerative agriculture requires years of time and infrastructure investment, making owner/operator family farms more able to adopt regenerative techniques when compared with farms relying on rental contracts that may be cancelled before the results of such effort and investment can be realized. Support small business and tell your friends.
I know of dozens of central Albertan farmers who haven’t made the shift to regenerative agriculture but have gone no-till and are itching to switch to a better system. Your encouragement and support will help them take the first step and start producing you more natural and nutrient dense foods.
Gabe Brown (‘Treating the farm as an Ecosystem’ on YouTube) from Brown Ranch often says ‘who need sleep when you’re having so much fun?’ and Will Harris III (star of ‘One Hundred Thousand Beating Hearts’ on YouTube) says ‘I’d do for free what I now do for a living.’ and Joel Salatin of Polyface Farms (more YouTube vids than you could count) wrote a book entitled, ‘The Sheer Ecstasy of being a Lunatic Farmer’ among many others.
Join the revolution. It tastes good, preserves wildlife habitat and natural ecosystems, keeps you out of the doctor’s office and it’s fun.
Most importantly, it could mean the next generation will inherit an environment in better condition than the one we did. That would be freaking awesome!!
Please take the time to listen to Will Harris of White Oak Pastures explain their regenerative farm story. It's their farm that is the subject of a 2019 Quantis study that shows regenerative livestock production to be carbon negative. 3.5kg of stored carbon, or 12.8kg of CO2, per kg of beef produced.