The original paradigm of rangeland management was based on the widespread observation that degradation of the range resource was largely due to excessive numbers of livestock. In this paradigm the solution was to reduce stocking rates while allowing season-long continuous grazing to continue. Subsequently, another paradigm was developed following the experience of pioneer rancher conservationists and scientists, who had achieved significant range improvement using growing season deferment to allow recovery periods (Smith 1895; Sampson 1913; Scott 1953; Matthews 1954; Merrill 1954; Hormay 1956; Hormay and Evanko 1958; Hormay and Talbot 1961; Hormay 1970; Müller et al. 2006; Booysen and Tainton 1978; Tainton et al. 1999). A number of earlier researchers confirmed the success of using growing season deferment, often in conjunction with rotational grazing (Rogler, 1951; Merrill, 1954; Reardon and Merrill, 1976; Smith and Owensby, 1978; Daines 1980; Danckwerts et al. 1993; Taylor et al. 1993; Kirkman and Moore 1995).
A third, more radical paradigm was developed in the early 1970s based on earlier writings (Voisin 1959; Acocks 1966) which inspired people such as Savory and colleagues (Savory 1978, 1983; Savory and Parsons 1980; Savory and Butterfield 1999) and Gerrish and colleagues (Gerrish 2004) to explore the merits of multi-paddock, high-density rotational grazing in rangeland ecosystems using grazing periods that were unconventionally short and stocking rates that were considered irresponsibly high. Since then, many ranchers have substantially increased stocking rates while simultaneously improving range vegetation composition using these methods (Goodloe 1969; Tainton et al. 1977; Cumming 1989; McCosker 1994; Earl and Jones 1996; Stinner et al. 1997; Norton 1998, 2003; Sayre 2000; Berton 2001; Gordon 2002). Many in the rangeland science discipline have totally rejected this alternative paradigm, even in the face of much anecdotal evidence (Holechek et al. 1999, 2000; Galt et al. 2000; Briske et al. 2008).
1 Stan Bevers, Extension Economist, Texas AgriLife Extension, P.O. Box 1658, Vernon, Texas 76385.
It is most difficult in science, as in other fields, to shake off accepted views (Dubin 1978). Many scientists feel threatened professionally when an innovative and nontraditional way of thinking is introduced. That is especially true if: (1) a new way of thinking involves a major shift in the scientific paradigm; (2) acceptance of the new theory implies that currently used practices are inadequate or inappropriate; or (3) the new theory threatens the assumptions of the established paradigm. Obsolescence of knowledge threatens the professional integrity of proponents of that knowledge, or the assumptions of the new paradigm appear so contradictory to the assumptions of the accepted paradigm that it is rejected outright. An example from the medical profession is the systematic and long-term intransigence of the established medical profession to prevent legal acceptance of the chiropractic profession, which is now widely accepted and operates with full legal authority (Lisa 1986).
Traditionally, disciplines operate on the tenets of a single major paradigm (Kuhn 1970), which produces valuable but incomplete understanding. All paradigms are a narrow view of the multifaceted nature of most fields of study (Burrell and Morgan 1979; Frost 1980; Provenza 2000). Different paradigms are grounded in fundamentally different assumptions and produce markedly different ways of approaching and building a theoretical base for any discipline (Gioia and Pitre 1990). Considering and comparing more than one paradigm can generate more complete knowledge than is possible with any single paradigm. A broader approach that accounts for differing paradigmatic assumptions yields a more comprehensive understanding of the processes of nature, and their constantly changing manifestations.
It is important to remember when assessing any hypothesis that a single refutation is sufficient to illustrate that the hypothesis being tested should probably be revised to accommodate what has been learned by such a refutation (Kuhn 1970). The numerous instances from research studies outlined in this document and evidence from scores of ranchers around the world provide solid reasons to modify the hypothesis expressed by Briske et al. (2008) that there is no reason to favor multi-paddock rotational grazing over continuous grazing and conservative stocking. Because hypotheses cannot be proved, only rejected, the role of science is to test alternative hypotheses or paradigms and specifically try to refute them. Consequently, we need to expand our methods of enquiry to include ranch-based research and simulation models to develop and test theories, and constantly check conclusions for any inconsistencies between them and evidence from other sources.
To do so, we must focus not only on comparisons of grazing systems, but on the relationships between biophysical processes and management. While it is certainly possible to understand the processes of nature, and much is known about soils, plants and herbivores, the variation inherent in the manifestation of processes in time and space precludes direct comparisons of grazing systems per se in experimental analyses. All the physical and biological variables in the various processes are in constant flux, as influenced by history, necessity and chance, and therefore their manifestations become unique in time and space (Provenza 2000). Managers must work with physical and biological processes to manage landscapes. Optimally, this involves knowledge of processes combined with flexibility to respond to ever-changing environments, and that can't be studied with classical grazing studies. Flexibility in the face of unending change is what plants, herbivores and people are about, and that involves ongoing interactions among genes, environments and chance (Lewontin 2000).
A large body of evidence from controlled experimentation before the mid-1980s has shown effects of defoliation by grazing animals on plants and the benefits of adequate recovery following defoliation. The benefits of multi-paddock rotational grazing on commercial livestock enterprises have been evident for many years in many countries. However, despite these observations and the benefit to species composition found in numerous studies of planned grazing deferment, most recent rangelands grazing studies suggest that rotational grazing improves neither vegetation nor animal production relative to continuous grazing. Detailed comparisons of research methods and practical experience of successful practitioners of multi-paddock grazing management have identified a number of areas that explain why such different perceptions have arisen. The uneven distribution of livestock in continuously grazed large paddocks leads to localised pasture degradation, which has not been accommodated in the design of most research studies comparing continuous grazing to rotational grazing. This oversight also assumes spatial homogeneity of forage availability and utilization, which is refuted by a large body of observations at larger scales.
This failure to take into account plant and animal processes at appropriate temporal and spatial scales has resulted in incorrect interpretations for rangeland management. Research at a small scale diminishes the degree of selective use and impact that animals have over the landscape. This has resulted in many researchers interpreting the herbivore as an amorphous, diffuse defoliator, that plucks forage in random fashion or like a harvesting machine blanketing the pasture, and even when defoliating selectively does so in a spatially uniform way as implied by Briske et al. (2008). In fact the herbivore is an animal with a point-sampling defoliation apparatus, that moves in forward motion and normally walks long distances, that responds to visual and tactile cues and reacts to its surroundings in various ways, that engages in activities other than defoliation, that is a social creature influenced by history, necessity and chance, that has biological limits to bite size and energy expenditure, and that develops patterns of behavior in response to its environment and companions. Grazing ungulates have an entirely different impact on the landscape than that implied by Briske et al. (2008), as is well documented by work at the landscape scale we have outlined earlier in this chapter. This points to an entirely different and more meaningful way of designing and interpreting grazing trials.
Another reason for mixed results is that researchers have often applied treatments that did not adequately consider physiological effects, complementary relationships among soils, plants, animal behavior, preferences and selectivity, and ecological processes like water and mineral cycles. As a result, they often do not address nor provide valid answers to practical questions such as: how good is this management option; where is it successful; and what does it take to make it work as well as possible? Consequently, interpretation of grazing trials by some researchers has incorrectly concluded that planned grazing benefits neither vegetation nor animal production relative to continuous grazing. As we have indicated in this document, unless experiments have been conducted in a manner that aims at achieving the best plant and animal responses, the results will probably be misleading in defining the potential of an experimental treatment. Similarly, when reviewing the literature to draw general conclusions (Holechek et al. 1999, 2000, 2004; Briske et al. 2008), each experiment needs to be examined to see how it was conducted and if the objective was such that the study results could be extrapolated to practical ranch situations. If it was not conducted in a manner that current understanding would define as the potential of the treatment, then the interpretation of the experiment will be spurious and misleading. In addition, if such reviews use only references that support a particular viewpoint and do not relate to what a manager needs to know, understanding of the subject will be clouded and not enhanced. Thus it is essential to address and test alternative hypotheses with equal vigor using comparable management goals.
In contrast to the conclusions of many researchers, numerous commercial livestock enterprises in many countries have used a basic knowledge of plant and animal physiology and ecology within an adaptive, goal-oriented management approach to implement successful planned grazing management programs. When evaluated as a body, comparisons of research methods and results and practical experiences of successful planned grazing practitioners identify a number of areas that explain why such different perceptions have arisen. When evaluated using a paradigm encompassing basic ecological and biological principles, these results provide insights that allow the formulation of guidelines for implementing planned grazing management programs that can more effectively meet vegetation, production and financial goals in variable environments relative to continuous grazing and conservative stocking.
Managers need to know how to work adaptively within their operations to produce the best results and minimize inherent problems. Successful ranchers modify their management to achieve the best possible outcomes in terms of profitability and enhancing or maintaining ecosystem health. Researchers have much to learn by working with successful ranchers. Examples of this research approach have compared continuous grazing with an intensive grazing system on commercial ranches (Earl and Jones 1996; Jacobo et al. 2006). The ranches were adaptively managed for the best possible outcomes within the constraints of each system. Using this approach, many of the constraints inherent in the way some grazing systems research has been conducted could be avoided. Monitoring ranches that have been successfully operating intensive grazing management for many years, often decades, might also be the only way we can address the pertinent question raised by Burke et al. (1998) on the much neglected subject of time needed to register changes in rangeland ecosystems. Simulation modeling represents an additional and complementary research approach where cost and logistics preclude field experimentation over large spatial and temporal scales (e.g., Hahn et al. 1999; Beukes et al. 2002; Diaz-Solis et al. 2003; Teague and Foy 2004). This approach is well suited to evaluating the managerial and ecological components of grazing systems, both independently and in combination.
Published research and experience from ranchers has indicated that the following management factors are the keys to achieving desired goals: (1) Careful grazing and financial planning to reduce costs, improve work efficiency, enhance profitability, and achieve environmental goals; (2) Providing sufficient growing season deferment to maintain or improve range condition; (3) Grazing grasses and forbs moderately during the growing season for a short period and allowing adequate recovery; (4) Timing grazing to mitigate detrimental effects of defoliation at critical points in the life cycle of preferred species inter- and intra-annually; (5) Where significant regrowth is likely, grazing the area again before the forage has matured too much; (6) Flexible stocking to match forage availability and animal numbers in wet and dry years, or having a buffer grazing area available; (7) Using fire to manage livestock distribution; and (8) Using multiple livestock species. These can be achieved with more control in multi-paddock systems but the same principles can be applied in pauci-paddock systems as practiced by many ranchers in many countries.
The benefits of properly implemented, planned grazing management, as well as the results of poorly implemented programs have been evident for many years on commercial livestock enterprises in many countries, and are also evident from research trials. For those managers who wish to use simple, less management-intensive operations, various pauci-paddock systems can be employed to plan recovery periods during the growing season with or without using planned rotational grazing. The outlined management guidelines will maximize benefits and minimize potentially negative results. More intensive management with appropriate use of multi-paddock systems can increase productivity and improve rangeland health if managed appropriately using the guidelines above. The key to sustainability using these high-intensity systems is high stock density with short grazing periods and moderate utilization, followed by recovery periods to maintain forage nutritional status and productivity. More even animal distribution is automatically achieved by such a system, and the benefit of this to livestock production is already evident from research studies involving small paddocks and to wild and domestic animals on large ranches. In the variable climate associated with all range ecosystems, management needs to be flexible so animal numbers match forage amounts and animals are presented with high quality material in both wet and dry years. As each ranch and rancher is different we have carefully avoided suggesting whether less or more-intensive management is better. We have throughout concentrated on providing information that will aid in improving management for any level of management intensity.
Managing grazing does not necessarily involve more fencing. Fire can be used to spread grazing pressure and minimize the negative effects of overgrazing on more heavily used patches and areas in a grazing unit and enhance vegetation structural heterogeneity and wildlife habitat. Rotational grazing may also be partly implemented through methods other than intensive fencing, including rotating access to water sources (Martin and Ward 1970), strategic supplementation (Bailey and Welling 2007), herding (Bradford 1998; Coughenour 1991; Butler 2000; Bailey 2005; Bailey et al. 2008), and manipulating animal behavior (Provenza 2003a; Launchbaugh and Howery 2005).
Science is a tool to help people understand the processes of nature (Provenza 2000). With regard to grazing management, researchers have used this device primarily to understand interrelationships among physical and biological processes that link soils, plants and herbivores. They have not, as Briske et al. (2008) point out repeatedly, focused on the most important feature of the system, namely the human element of management. Understanding processes is of little value without the flexibility to continually create in the face of uncertainty, and that is what the human element at its best brings to the table in the form of management. Thinking in terms of grazing systems is far less important than understanding processes and determining how to achieve management goals using that knowledge. What matters is feedback from constantly monitoring and continually adjusting the movements of herbivores to ensure the nutrition and health of soils, plants, herbivores and ultimately people. All of that depends upon animals frequently moving across landscapes, whether driven by their needs for nutrients, a herder, rotations through fenced paddocks, fire, or predators (Provenza 2003b; Provenza et al. 2003). People are the glue that links soils, plants and herbivores in grazing systems, and if we really want to understand the innovation and integration essential to the successes of those relationships, we must understand what the best managers do (Provenza 2003a).
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