Friday, November 15, 2013
Allan Savory: Myth And Reality
By George Wuerthner
Allan Savory is an advocate for the livestock management system known as, Holistic Management (HM). He is a former member of the Rhodesian Parliament (now Zimbabwe) and has made his living as a consultant with the Savory Institute. He is best known for his recent appearance as a TED speaker where he made a number of controversial statements that he has been advocating for decades, as well as some new claims. His most recent assertion is the idea that more livestock grazing may be the solution to global warming.
In short, Savory’s basic theme is a variation on what has been called “short duration grazing” or “mob grazing”. Under such scenarios livestock, typically cattle are tightly herded through a confined pasture (small pastures) or rangeland so that the animals cannot be selective in their choice of food. Then the livestock are moved rapidly on to the next grazing area, and the previously grazed area is rested from livestock for an extended period of time, so the plants can recover and regrow. Savory’s advocacy for monitoring and careful attention to livestock plant utilization is consistent with well-established range management principles.
However, many of his observations about animal behavior, plant ecology, evolutionary history and carbon storage are well outside the accepted scientific consensus. And these ideas can lead to damaged ecosystems and in the case of his ideas about livestock and global warming may actually be counterproductive—leading to greater GHG emissions if implemented according to his ideas.
As with everything in science, there are few absolutes. There is great variation in land productivity, climate, and the experience of ranchers and farmers who are managing livestock that can affect outcomes. One may experience or hear about examples where Savory’s prescriptions appear to be valid, but as stated below they are usually isolated exceptions. Exceptions do not invalidate the rule.
The few scientific experiments that Savory supporters cite as vindication of his methods (out of hundreds that refute his assertions), often fail to actually test his theories. Several of the studies cited on HM web site had utilization levels (degree of vegetation removed) well below the level that Savory actually recommends.
The following are among Savory’s most debatable ideas that a majority of scientists and observers believe are contrary to standard rational understanding and observation.
MYTH: Livestock grazing can reduce Green House Gases and reduce global warming.
REALITY: One of Savory most recent claims is that grazing will stimulate the translocation of carbon from the atmosphere to the roots of plants, thus increasing domestic livestock numbers and grazing, Savory asserts, will significantly reduce global GHGs. While it is true that significant amounts of carbon are stored in the soils of rangelands, the ability to capture and transfer additional atmospheric carbon to grassland soils is very limited. Most arid grasslands have low productivity, thus low ability to store new sources of carbon.
Furthermore, a full GHG accounting would demonstrate that domestic livestock are among the largest source of global GHG. Methane emissions from domestic livestock, particularly cattle, are considered one of the largest sources of global GHG. Livestock also emit nitrous oxide that is even more potent as a greenhouse gas. Together these emissions are considered by the United Nations Food and Agricultural Organization to be responsible for up to 18% of global GHG.
Even worse much of the livestock pasture around the world has been created and continues to be created by the destruction of forests which results in the release of even more carbon into the atmosphere. The replacement of forests with grass pasture thus increases overall carbon emissions. According to a recent review by World Watch Institute utilizing this full accounting system livestock production may be responsible for as much as 50% of all global GHG. Thus a reduction of domestic livestock numbers would go much further towards reduction of global atmospheric carbon than any small amount of carbon which might be sequestrated as a result of growth from grasses related to livestock grazing.
MYTH: Holistic Management is superior to other grazing management strategies.
Reality: Due to particular unique aspects of a livestock operation, HM methods may produce better results than other livestock management methods for that specific operation. However, in side by side comparisons with other grazing methods, if EQUAL attention to forage utilization and timing is followed HM methods have not been shown to be superior. And in many other situations HM has resulted in poorer condition livestock and damage to the land resources.
The qualifier is that equal attention to forage utilization and timing is important because much of the success reported for HM has to do with a significant change in livestock producer effort as well as capital investment in more range developments like watering troughs and fencing that, along with intensive monitoring, resulted in better animal distribution. These results are often compared to past lack luster management whereby livestock were left to forage with little supervision. This frequently resulted in overgrazing in some areas, while other parts of the pasture, ranch or farm were barely utilized.
However, it is important to note, efficient cropping of forage by HM methods is not necessarily an improvement for wildlife and plants, soils, water quality, and other values since intensive grazing has many negative effects on these ecosystem values. For many species the lightly grazed areas on the ranch or farm were/are places where wildlife find/found refugia and suitable habitat. Many beneficial insects, pollinators, and larger wildlife such as reptiles, amphibians, birds, and mammals benefit from the lightly grazed areas and can be critical for ecosystem functioning.
MYTH: Savory’s intensive grazing management strategies have led to greater livestock production and economic gains for ranchers and are a panacea for declining ranch/farm bottom line.
REALITY: Many ranchers cannot or are not able to adopt Savory’s intensive grazing management. First, the intensive management required by HM methods to be successful often requires significant investment in fencing, water development and other infrastructure. It also requires diligent attention to livestock grazing effects and movement. This kind of diligence and attention is often difficult for ranchers and farmers to implement due to economic and/or human constraints. Other limitations to the success of HM techniques are climate and terrain. HM works best in flat terrain where livestock impacts can more equally be distributed and where adequate moisture exists for plant regrowth.
MYTH: Most rangelands suffer from “overrest” not overgrazing.
REALTY: Overgrazing is the cumulative effect of multiple cropping of plants that leads to a decline in plant energy reserves, reduction in root mass, seed production/reproductive effort, and is often accompanied by soil erosion and overall changes in plant composition on a site. In the absence of livestock grazing, plants recover energy reserves, seed and reproductive effort typically improves and soil erosion is reduced. There are no documented examples of “overrest”.
MYTH: In the absence of livestock grazing, plants become moribund and die.
REALITY: There is ample evidence that plants do not require livestock grazing to remain viable. First, there are few places on Earth where plants are not “grazed” or “browsed” by natural herbivores including larger native mammals like bison, wildebeest or guanaco to small animals like ground squirrels and grass hoppers. So plants do not “need” livestock to thrive and on public lands at least we can and should promote native herbivores over exotic domestic livestock.
Secondly, one can easily refuse this statement by visiting any number of natural areas that lack livestock and nevertheless have thriving grassland/rangeland ecosystems. Most National Parks do not permit livestock grazing. And there are literally tens of thousands of small and large grass covered landscapes that for one reason or another naturally exclude livestock like isolated buttes, cliffs, gorges, mesa, plateaus, and even rail and highway right of ways.
MYTH: Hoof action increases water infiltration and helps to plant seeds.
REALITY: Nearly all studies (dozens or hundreds) that have reviewed the effect of hooves on soil infiltration have shown that a thousand pound cow compacts soil, reducing the space between soil particles and thus reducing water penetration and increasing water runoff.
Seeds do not require hoof action to germinate. The plants in rangelands have many different adaptations to ensure adequate recruitment without “hoof action.” Some seeds are attractive to seed eating species like some birds, voles, even ants that carry seeds to their burrows or new locations and help distribute and plant the seeds. Other plants have special adaptations like needle grass which “drills” itself into the ground to ensure successful germination.
MYTH: Biocrusts capping soil surface inhibits plant growth, preventing seeds from penetrating the soil and water from soaking into the ground. Biocrusts need to be broken up by hoof action.
REALITY: Biocrusts are common throughout grassland ecosystems around the world. They are particularly common in arid landscapes where they play a critical role in ecosystem health and function. Biocrusts cover the soil between the spaces in bunchgrass communities (bunchgrasses are common in arid landscapes) keep other plants from germinating and competing for nutrients and water. Biocrusts can decrease the germination of large seeded annual grasses that are degrading grasslands and increasing fire frequency in grasslands and steppe habitats. While inhibiting annual grasses the biocrusts help the perennial grass species thrive.
MYTH: Livestock, particularly cattle, can be managed so as to emulate native species that may no longer graze grasslands.
REALITY: The notion that livestock can replace or emulate the native grazers that may have inhabited a region prior to conversion to domestication. Nearly all plant communities have multiple herbivores that chomp, chew, and graze upon their leaves, stems and even roots. This includes everything from nematodes in the soil that “graze” on roots to grasshoppers, ground squirrels, birds like geese to larger mammals like deer, elk and bison. However, funneling above ground biomass (leaves, stems, etc.) into a single animal like a cow simplifies energy flow in the ecosystem. It can also result in uneven herbivory on plants since the natural collection of animals all graze different plants, different parts of plants at different times and seasons than the single herbivore effects of one or two kinds of domestic animals.
MYTH: Domestic animals like cattle are merely replacing herds of native species like bison that once roamed grasslands.
REALITY: There are substantial evolutionary differences between domestic animals like cattle and native species like bison. Bison naturally move more frequently than cattle. They are better at defending themselves against native predators. They can exist on lower quality forage than cattle.
Furthermore, most of the American West did not have large grazing herds of bison and/or other large mammals. For instance, bison were largely absent or found in very small numbers west of the Continental Divide. Most of the Great Basin of what is now Nevada, western Utah, southern Idaho, southeast Oregon historically did not have large herds of grazing animals, nor did Arizona, much of California, Oregon and Washington.
MYTH: Domestic animals like cattle merely replaced extinct native herbivores that once roamed the western United States.
REALITY: Sometimes Savory advocates will admit that historically large herds of bison, elk and other grazing mammals were absent from much of the West. But they argue that cattle are merely replacing Ice Age herbivores like giant sloth and ancient bison that are now extinct.This ignores the fact that grasslands have not remained static since the last Ice Age. Indeed, in the absence of large herbivores, western grasslands have evolved in response to climate variation, and changing evolutionary pressures. The absence of large grazing mammals permitted plants with a low tolerance for grazing pressure to occupy much of the arid West. These plants invested energy in developing extensive root systems and other mechanisms to survive in arid environments but have few adaptations that permit them to survive grazing by large mammals.
MYTH: Plants need to be grazed and benefit from livestock grazing.
REALITY: Savory mixed up compensation with need and an economic value with a biological one. The grazing of a plant harms the plant, especially if the cropping occurs during the growing season. Plants can compensate for this loss but often do so at a cost to their overall fitness. Grazing the top of a grass means that the bottom or root of the plant will compensate for it but only with a loss of capital and root mass, weakening the plant that now needs rest from grazing.
The loss of photosynthetic material (leaves) by grazing causes a plant to respond by translocation of energy from roots or other parts of the plant to build new leaf material—assuming there is sufficient moisture, nutrients and other critical elements available to recover from the grazing event.
Thus cropping may result in greater overall biomass production as plants seek to compensate for their loss of leaf material. However, the production of more above-ground biomass is often done at the expense of other important plant material including a reduction in root growth, loss of reproductive effort (the plants expends energy on leaf production instead of seed production), and so forth. It is hardly a “benefit.”
To characterize compensation from a harmful event as a need is analogous to suggesting that shooting and poisoning of coyotes is a “benefit” to coyotes because they compensate for these losses by producing additional pups.