Nathan F. Sayre

The Genesis, History, and Limits of Carrying Capacity

The concept of carrying capacity is employed in a remarkably wide range of disciplines and debates, and it has been forcefully critiqued within numerous fields. Yet its historical origins remain obscure. I identify four major types of uses of carrying capacity: (1) as a mechanical or engineered attribute of manufactured objects or systems, beginning around 1840 in the context of international shipping; (2) as an attribute of living organisms and natural systems, beginning in the 1870s and most fully developed in range and game management early in the twentieth century; (3) as K, the intrinsic limit of population increase in organisms, used by population biologists since the mid-twentieth century; and (4) as the number of humans the earth can support, employed by neo-Malthusians, also since midcentury. All four uses persist to the present, although the first has been largely supplanted by other terms such as payload. In all cases, carrying capacity has been conceived as ideal, static, and numerical—characteristics that were appropriate in the first case but increasingly untenable as the concept was extended to systems of larger scale, greater variability, and lesser human control.

Origin, Persistence, and Resolution of the Rotational Grazing Debate: Integrating Human Dimensions Into Rangeland Research

Abstract The debate regarding the benefits of rotational grazing has eluded resolution within the US rangeland profession for more than 60 yr. This forum examines the origin of the debate and the major reasons for its persistence in an attempt to identify common ground for resolution, and to search for meaningful lessons from this central chapter in the history of the US rangeland profession. Rotational grazing was a component of the institutional and scientific response to severe rangeland degradation at the turn of the 20th century, and it has since become the professional norm for grazing management. Managers have found that rotational grazing systems can work for diverse management purposes, but scientific experiments have demonstrated that they do not necessarily work for specific ecological purposes. These interpretations appear contradictory, but we contend that they can be reconciled by evaluation within the context of complex adaptive systems in which human variables such as goal setting, experiential knowledge, and decision making are given equal importance to biophysical variables. The scientific evidence refuting the ecological benefits of rotational grazing is robust, but also narrowly focused, because it derives from experiments that intentionally excluded these human variables. Consequently, the profession has attempted to answer a broad, complex question—whether or not managers should adopt rotational grazing—with necessarily narrow experimental research focused exclusively on ecological processes. The rotational grazing debate persists because the rangeland profession has not yet developed a management and research framework capable of incorporating both the social and biophysical components of complex adaptive systems. We recommend moving beyond the debate over whether or not rotational grazing works by focusing on adaptive management and the integration of experiential and experimental, as well as social and biophysical, knowledge to provide a more comprehensive framework for the management of rangeland systems.

Desertification, land use, and the transformation of global drylands

Desertification is an escalating concern in global drylands, yet assessments to guide management and policy responses are limited by ambiguity concerning the definition of “desertification” and what processes are involved. To improve clarity, we propose that assessments of desertification and land transformation be placed within a state change–land-use change (SC–LUC) framework. This framework considers desertification as state changes occurring within the context of particular land uses (eg rangeland, cropland) that interact with land-use change. State changes that can be readily reversed are distinguished from regime shifts, which are state changes involving persistent alterations to vegetation or soil properties. Pressures driving the transformation of rangelands to other types of land uses may be low, fluctuating, or high, and may influence and be influenced by state change. We discuss how the SC–LUC perspective can guide more effective assessment of desertification and management of drylands.

Conservation Outcomes and Social Relations: A Comparative Study of Private Ranchland Conservation Easements

Conservation easements have increased dramatically but their social and ecological outcomes are largely unknown. To examine the influence of social relations and institutional structure on easement design and conservation outcomes, we compared two regions where land trusts hold conservation easements protecting large areas of private rangeland: Lassen Foothills, California, and Malpai Borderlands, Arizona and New Mexico. We conducted interviews with landowners, land trust staff, and public agency employees, and analyzed easement documents and monitoring reports. Social relations and organization goals influenced easement terms and their direct effects on land use. Furthermore, easements had important indirect conservation-relevant outcomes resulting from increased land management resources, financial incentives, and altered relations among landowners, government agencies, and nongovernmental organizations (NGOs). Easements entail a combination of collaborative and regulatory approaches, and their embedded social relations are important for conservation outcome assessment. These findings have significant implications for how conservation programs are designed, monitored, enforced, and evaluated.

The role of rangelands in diversified farming systems: innovations, obstacles, and opportunities in the USA.

Discussions of diversified farming systems (DFS) rarely mention rangelands: the grasslands, shrublands, and savannas that make up roughly one-third of Earths ice-free terrestrial area, including some 312 million ha of the United States. Although ranching has been criticized by environmentalists for decades, it is probably the most ecologically sustainable segment of the U.S. meat industry, and it exemplifies many of the defining characteristics of DFS: it relies on the functional diversity of natural ecological processes of plant and animal (re)production at multiple scales, based on ecosystem services generated and regenerated on site rather than imported, often nonrenewable, inputs. Rangelands also provide other ecosystem services, including watershed, wildlife habitat, recreation, and tourism. Even where non-native or invasive plants have encroached on or replaced native species, rangelands retain unusually high levels of plant diversity compared with croplands or plantation forests. Innovations in management, marketing, incentives, and easement programs that augment ranch income, creative land tenure arrangements, and collaborations among ranchers all support diversification. Some obstacles include rapid landownership turnover, lack of accessible U.S. Department of Agriculture certified processing facilities, tenure uncertainty, fragmentation of rangelands, and low and variable income, especially relative to land costs. Taking advantage of rancher knowledge and stewardship, and aligning incentives with production of diverse goods and services, will support the sustainability of ranching and its associated public benefits. The creation of positive feedbacks between economic and ecological diversity should be the ultimate goal.

Potential Effects of United States‐Mexico Border Hardening on Ecological and Human Communities in the Malpai Borderlands

Between 17 October and 29 December 2008, contractors working for the U.S. Department of Homeland Security (DHS) constructed approximately 19 km of contiguous barrier along the United States-Mexico border in the Malpai Borderlands region of southeastern Arizona. The construction was part of the U.S. Secure Fence Act of 2006, which mandated installation of fences, barriers, roads, and surveillance technology on five segments of the United States-Mexican border, totaling approximately 1120 km (or 35% of the entire border) by December 2008. To expedite implementation of the act, Congress authorized the secretary of Homeland Security to waive all or parts of 37 federal statutes pertaining to the conservation of cultural and environmental resources, including the National Environmental Policy Act, the Endangered Species Act (ESA), the Clean Air and Clean Water acts, and the Antiquities Act. Secretary Michael Chertoff exercised this authority on 1 April 2008. According to the Associated Press (28 January 2009), 962 km of barriers had been completed as of January 2009; DHS maps indicate that nearly all of the new construction is located between San Diego, California, and El Paso, Texas. The Malpai Borderlands region harbors significant cultural and ecological resources and has been the site of extraordinary conservation efforts in recent decades (Curtin 2002; Sayre 2006). Cultural sites and artifacts are ubiquitous, reflecting aboriginal human use from the Clovis period to the last days of the Apaches as well as historical Euro-American settlement. Judging from natural heritage data, there are more species of plants and animals in the borderlands than in any other place of comparable size

Speaking through the aspens : Basque tree carvings in California and Nevada

This text looks at the solitary Basque sheepherders who helped to create a major agricultural industry. It analyzes the content of thousands of arboglyphs in the mountains of Nevada and California by topic: language; politics; the Basque homeland; the sheepherders life; sex; and pictorial themes.

The Coyote-Proof Pasture Experiment How fences replaced predators and labor on US rangelands

Few scientific experiments have influenced more land than one conducted in the Wallowa Mountains of eastern Oregon by the US Department of Agriculture’s Bureau of Plant Industry and US Forest Service in 1907–1909. Four square miles of land were enclosed with a “coyote-proof fence,” guarded by a hunter, and stocked with an untended band of sheep. Data were collected on vegetation and sheep performance inside and outside the fence, and two years later success was declared. By 1910, the Forest Service had wrested range research from the Bureau of Plant Industry, subordinating the emerging field to timber production and fire suppression for decades to come. The young scientist who conducted the experiment, James Jardine, was promoted to Inspector of Grazing for the fledgling Forest Service, while his Wallowa collaborator, Arthur Sampson, went on to become “the father” of range science. The model of range management that they pioneered was applied across the US West and, later, on many rangelands in the developing world. Fencing and predator control are now generally viewed as unrelated management practices, but in the Forest Service model they were intimately connected. A critical physical geography of the Wallowa experiment reveals that the institutional context in which it occurred was more important than the findings themselves, and that although the results appeared to be scientifically rigorous and ecological, the methods were weak and the real criteria for “success” were economic. The high costs of fencing could be justified only if they were offset by a reduction in labor costs for herders. But without herders to guard the livestock, predators would have to be eliminated. Enormous public subsidies were required to implement the model, which continues to affect rangelands around the world.

Climax and “Original Capacity”: The Science and Aesthetics of Ecological Restoration in the Southwestern USA

This paper examines the historical origins of ecological restoration in the arid and semiarid deserts of the southwestern USA. Scientific knowledge and aesthetic valuations both emerged during a period of acute environmental degradation between 1893 and 1905, strongly influencing subsequent debates and practices. In science and aesthetics alike, the historical nature of southwestern landscapes was occluded: Clementsian ecology and range science posited a climax condition and an “original capacity” for livestock, while aesthetic treatments such as those of John Van Dyke saw transcendent and timeless beauty in the dramatic dynamics of actively degrading landscapes. In recent decades, southwestern ecologists have renounced Clementsian ecology and its implied telos of “pristine” presettlement conditions. But aesthetic ideals continue to influence broader debates and practices of ecological restoration in the region, specifically with regard to grasslands, riparian areas, livestock grazing, and fire.

Birds, beasts and bovines: three cases of pastoralism and wildlife in the USA

BackgroundPastoralism in the USA began coincidently with the initiation of profound ecological change resulting from colonization in the sixteenth century. Relationships between pastoralism and wildlife conservation in three different contexts of land tenure, environmental legacy, and geography are examined.ResultsOn the federal rangelands of the Intermountain West, based on limited scientific information, wildlife policy has been interpreted to require separation of native bighorn sheep from livestock to prevent disease transmission. Ignored are the possible long term and broad scale impacts of removing grazing on the ecosystem and the ‘social disturbance’ to local communities. In southwestern deserts, the implementation of wildlife policy exemplifies the contradictions between conservation of individuals versus populations, and fire suppression and grazing removal as ‘inactions’ requiring no review versus grazing and burning as ‘actions’ requiring regulation and control. In California’s Mediterranean rangeland, wildlife policy under the Endangered Species Act is at once a regulatory burden and an opportunity for ranchers. The opportunities result from an evolving recognition that cessation of grazing can harm wildlife.ConclusionsIn all three cases, the environment has changed and is changing due to ecosystem engineering that alters the resources available to wildlife and plant species. Grazing offers potential benefits as a management tool, and pastoralism a means of maintaining un-fragmented landscapes. Yet, absent adequate ecological information, the assumptions of innate conflict between livestock and wildlife, and that cessation of grazing is not an action, as well as the norms of a politically popular yet ecologically unsupportable discourse of restoration, fill in the gaps.