A special issue of the journal Rangelands, October 2013
Sponsored by the Colorado Section Society for Range Management
Edited by Matt Barnes and Ann Hild
|A herd of grass-fed cattle from Blue Range Ranch, herded by George Whitten in a strategic grazing plan on the Baca National Wildlife Refuge, below the Sangre de Cristo Mountains in the San Luis Valley, Colorado, USA. Photo by Matt Barnes.|
Grazing ecosystems are what scientists call complex systems: the whole is greater than the sum of the parts because of the relationships between the parts. The relationships form the web of life, so intricate that their individual and collective behaviors exhibit patterns that are beyond complicated: self-organization with emergent properties, unpredictability, and nonlinear dynamics. This panarchy of nested adaptive cycles between order and chaos is what land managers call “the real world.”
Considerable debate has existed in both the rangeland profession and the ranching community, regarding the efficacy of planned grazing management to achieve plant community, livestock production, and profitability goals. Various forms of rotational deferment, rest, and grazing have been promoted and applied for these purposes. Rotational grazing (a single herd moved through multiple paddocks) in particular has been applied in many variations (e.g., rational, high-intensity/low-frequency, short duration, time control, management-intensive, or cell grazing)—sometimes on a rigid calendar basis, sometimes adapted to actual on-site processes such as plant growth—with apparently inconsistent results. Most grazing studies have found little or no advantage to rotational grazing “systems” over continuous grazing with regard to plant or animal production, particularly in more arid environments, especially when pastures were small and lacking diversity, and grazing treatments were applied rigidly for the sake of scientific rigor. That conclusion has been made many times in the scientific literature including Rangelands. However, there is also substantial evidence in the scientific literature,  documented case studies, and practical experience of ranchers indicating that strategic grazing management that incorporates relatively short grazing periods with adequate recovery afterward can—if well-planned and adaptively managed— have profound and positive effects on the landscape, animal production, and ranch economics.
Both sides of this apparent discrepancy are right, in different ways. In the science of complexity, the types of questions asked and the interpretation of results often differ depending on whether the observer’s orientation is primarily reductionist (emphasizing parts) or holistic (emphasizing systems). Classical range science still stands, but practical experience and the context of complexity expand our frame of reference.
This sponsored issue is intended to move the discussion beyond the old debate, as suggested by the October 2009 sponsored issue on rotational grazing on rangelands, using the framework of complex systems. The pertinent question is not “is rotational grazing better?” but “How can grazing management be informed by ecological processes, and what principles should be applied strategically to adapt to complexity and change?” The objectives are to outline the emerging principles and guidelines by synthesizing the scientific and technical literature on grazing management, and to provide corroborating first-person case studies of strategic management on commercial ranches—so as to show how specific tactics have evolved and are adapted to changing conditions on a landscape scale—and to present the above in a format that lends itself readily to creative application by land managers.
This sponsored issue of Rangelands originated following the Colorado Section SRM’s Strategy Vs. System: Grazing for Desired Outcomes symposium in 2008, Fort Collins, Colorado, organized by Tim Steffens. The articles here are based on presentations at the Strategic Grazing for Complex Adaptive Systems symposium in 2012, at Colorado State University in Fort Collins, intended to synthesize the emerging ideas and resolve some of the lingering questions of the former symposium. A survey of the 139 attendees at the 2012 symposium, with a 52% response rate (N = 71) found that most respondents felt that the symposium had “resolved the old debate” (63%) and had “moved the discussion beyond the old debate” (90%). Most said that they would apply the information on their ranches or in the grazing operations of ranches with which they worked (89%), and an overwhelming majority said that the presentations should be published, either online/open-access or in Rangelands (97%).
Summary of the Sponsored Issue
Collectively, grazing studies and on-the-ground experience provide evidence for widely applicable guidelines for ecological process-based management to achieve ecological and economic goals by manipulating grazing intensity, distribution across time and space, the diversity of plants available to grazing animals, and animals’ selection thereof. Effective management of these grazing parameters depends primarily on four sets of variables: (1) stocking rate, both for a grazing period and for the grazing season or year; (2) timing, frequency, and duration of grazing and recovery periods; (3) spatial distribution of grazing; and (4) diversity of plants available and selection of those plants by grazing animals. While many of these guidelines can be found in the popular literature, they have not previously been reconciled with the existing science in a cohesive way.
This issue is also partly inspired by the format of the book Resilience Thinking. The leading article synthesizes the scientific literature on complexity, transformation, and creativity, as a context for the issue. Following the introductory article are a series of four pairs of articles, based on the four continua mentioned above: one a presentation of a management principle and general guidelines, including the most relevant underlying evidence from the scientific and technical literature; and the other a documented case study to explain how that particular principle (often in conjunction with others) was applied for successful, process-based and goal-oriented grazing management in the complex context of a commercial ranch.
Complex Creative Systems
Background: science and management. In the lead article, Provenza et al. relate grazing management to complexity principles, ecological processes, and endless transformation. They also illuminate the relationship between science and management.
Organisms and landscapes are ever in the process of creating relationships in which all things incessantly arise, transform, and vanish. In such environments, organisms don't survive by merely adapting to where they live. Instead, they actively participate in creating conditions to thrive. Creative engagement means nurturing ever-changing relationships as landscapes transform. By engaging in ways that cultivate and affirm creativity, we can influence change, though our actions inevitably cause some outcomes no one anticipates. Our ability to create as systems ever transform is enhanced when scientists and managers rekindle our relationships with one another and with the landscapes we inhabit.
Optimum Stocking Rate
The applied science. Frasier and Steffens present a model for determining the economic optimum stocking rate, showing that it is dependent on the ratio of variable costs to the value of production, independent of fixed (overhead) costs. They indicate that variable costs and capacity are related to grazing management methods in time and space.
Land, equipment, permanent labor, management, and conservation efforts are examples of overhead, or fixed costs. Money to meet these obligations comes from total gross margin (total value of production - total variable costs). Optimal economic stocking rate will be within the range where average animal performance is maximized and where total animal production per unit land area is maximized. As long as there is variable cost associated with stocking animals, optimal stocking rate will be lower than that at which production/unit area is maximized. Overhead costs, while having an effect on total profit, do not influence optimal stocking rate.
The art of management. Ortega et al. present a case study of the complexity of the optimum stocking rate determination, as well as the importance of monitoring the variation in the optimum stocking rate, and using that monitoring to make timely management decisions with maximum flexibility to accomplish specific objectives. A decade of data from a ranch in south Texas support principles of grazing management, including stocking rate adjustments, monitoring protocols, and grazing management decisions during a drought, and in wet years.
The concepts of managing a flexible stocking rate and monitoring range and animal responses are not new; as a matter of fact, academicians and extension agents have been publishing information and making recommendation for decades. However, in most cases practitioners have a hard time applying these recommendations. For practitioners, it is difficult to manage ranches using the correct stocking rate for rangelands with variable rainfall patterns, it is a moving target, it is dynamic in time and space, and it is affected by different climatic factors that we cannot control.
Grazing Distribution in Time
The applied science. Steffens et al. describe the most important aspects of grazing management in the dimension of time, emphasizing grazing planning based on the dynamic ecological process of plant recovery.
Periodic adequate periods free from defoliation must be provided to prevent the degradation that occurs due to non-random severe defoliation of preferred plants that can create focal points for degradation. In order to fully recover, a plant must regrow a full complement of leaves to replenish photosynthetic capacity. Grazing and nongrazing periods must coincide with those necessary for desired plants for positive plant community changes to occur. Non-grazing periods do not provide recovery when growth does not occur, so in semi-arid environments they must often approach or exceed a full growing season to accomplish that physiological target.
The art of management. Grissom and Steffens present a case study from the plains of eastern Colorado showing the different ecological and economic results of inadequate and adequate recovery periods, and planning grazing based on the seasonal variation in the relative palatability of cool and warm season plants.
Rancho Largo Cattle Co. implemented a method-driven rotational grazing system in 1996. Initial results were neutral or negative. In 1999 we created specific ecological goals and monitoring that drove adaptation of the grazing system. A key adaptation tied length of recovery periods to plant physiology; allowing desired species to reach maturity between defoliation events. Other important adaptations were the consideration of animal selectivity and seasonality in grazing decisions. Under adaptive management from 2004 to 2012 economic and ecological indicators improved significantly. This case study illustrates that adaptive grazing management can produce desired outcomes where rotational grazing systems fail.
Grazing Distribution in Space
The applied science. Norton et al. describe the uneven distribution of grazing under extensive conditions, and how grazing management can increase forage availability and therefore grazing capacity.
|Brien "Ben" Norton|
Distribution of grazing animals can become more even by creating smaller paddocks that collectively include areas that were previously neglected or ignored. Rather than stock all small paddocks simultaneously for a long time, it is far simpler to amalgamate stock into one large herd that moves from one small paddock to the next in a cycle that covers the entire ranch. There are ecological benefits to smoothing out the extremes of overgrazing and under-utilization that occur in large, conservatively stocked paddocks, and production benefits from the increased amount of forage made accessible to livestock by using many smaller paddocks.
The art of management. Barnes and Howell present a case study in the southern Rocky Mountains of western Colorado, where planned grazing with multiple paddocks is used to even out distribution between preferred areas that were previously grazed heavily and repeatedly, and steep slopes that were previously avoided, thus increasing forage availability and grazing capacity.
Planned grazing has improved the spatial distribution of utilization on the Howell Ranch with shorter grazing periods, higher stocking density, and smaller paddocks than the extensive management practiced previously on the ranch and currently on many ranches. Cattle regularly graze steep mountainsides and plants often considered unpalatable, without damaging riparian areas, at moderate overall utilization. Monitoring from 1997-2011 shows increased plant and litter cover, and decreased bare ground, while the stocking rate averaged about 50% higher than under previous seasonlong grazing. This supports recent experimental evidence that multiple-paddock grazing can improve grazing distribution and thus grazing capacity.
The art of management. Peterson et al. present a viewpoint based on their experience with extremely high stocking densities in tall-grass pasture in Missouri. They have found that higher stocking density promotes even utilization of plant species, including lower-quality forage.
Stocking density is a powerful tool to manage grazing land resources, as demonstrated on prairie and pasture in Missouri. Utilizing different stocking densities, we can achieve different goals, including affecting diet selection, weed and brush control, improving utilization and manure distribution, and even improving seed-to-soil contact. We allow sufficient recovery periods between grazing events to increase plant diversity and develop as much above- and below-ground biomass as possible. During grazing periods we use stocking density to manipulate the amount of forage trampling that occurs. Trampling can have a very positive impact on water and mineral cycles, building soil and increasing fertility in our perennial grasslands.
I thank Tim Steffens (West Texas A&M University) for beginning the process that culminated in this issue, and the sponsors, especially the Colorado Section Society for Range Management, as well as the Colorado and Texas Grazing Lands Conservation Initiatives, and the Caesar Kleburg Wildlife Research Institute, for supporting the symposia and this issue. Editor-in-Chief Lori Hidinger (Arizona State University), and Associate Editor Ann Hild of the Rangelands Steering Committee (University of Wyoming) coordinated the review process, significantly improving all of the manuscripts.
The Rangelands issue is available at: http://www.srmjournals.org/toc/rala/35/5.
The Rangelands issue is available at: http://www.srmjournals.org/toc/rala/35/5.
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