A History of North American Rangelands

North America's diverse grassland, savanna, steppe and desert ecosystems evolved in the absence of domesticated livestock. The arrival of cattle, sheep, goats, pigs and horses after 1492 transformed many ecosystems while enabling European soldiers, missionaries and settlers to conquer the continent. The decimation of indige-nous populations by warfare, disease and economic dependency further transformed rangelands by removing Native management practices, especially the use of fire. The history of rangelands since then has been one of recursive efforts to commodify and territorialize rangeland resources-including wildlife, grass, soil fertility and the land itself-for market production and exchange. Many former rangelands have been lost altogether, by conversion to forest cover (due to fire suppression) or to agricultural uses (especially in the Great Plains), and invasive exotic plant species have radically altered large areas of rangelands in California, the Great Basin, and other regions. Nonetheless, North American rangelands remain both vast and invalu-able for wildlife. The Western Range system of public land grazing leases, which emerged from the devastating overgrazing of the late nineteenth century, succeeded in stabilizing range conditions and linking land use and management across large landscapes of mixed ownerships. With accelerating urbanization, the rise of environ-mentalism, and structural shifts in the livestock industry since World War II, however, the Western Range has begun to unravel, exposing rangelands to development and fragmentation. Climatic variability in the form of droughts, floods and extreme fire conditions, more so than aridity per se, has frustrated efforts to extract value from rangelands from the outset, and climate change promises to amplify these phenomena going forward

Climate Change, Scale, and Devaluation: The Challenge of Our Built Environment

Climate debate and policy proposals in the United States have yet to grasp the gravity and magnitude of the challenges posed by global warming. This paper develops three arguments to redress this situation. First, the spatial and temporal scale of the processes linking greenhouse gas (GHG) emissions to climate change is unprecedented in human experience, challenging our abilities to comprehend, let alone act. An adequate understanding of the scale of global warming leads to an unequivocal starting point for all discussions: we must leave as much fossil fuel in the ground as possible, for as long as possible. Second, a policy informed by this insight must focus on the built environment, which mediates economic production, exchange, and consumption in ways that both presuppose and reinforce high rates of GHG emissions, especially in the U.S. A rapid and comprehensive reconfiguration of the built environment is imperative if we are to mitigate and adapt to global warming. Third, the obstacles and opposition to such a reconfiguration are best understood in terms of the devaluation of fixed capital, public and private investments alike, that has been sunk in the built environment of the present. In a fortuitous paradox, these investments are threatened with devaluation whether or not we act to stabilize the atmospheric GHG concentrations; in highly uneven, unpredictable, and potentially abrupt ways, global warming will make our current built environment increasingly untenable and uneconomical. There is, therefore, no reason not to be proactive and to craft policies with the goal of completely redesigning and rebuilding our built environment over the next 20 to 50 years

Putting local knowledge and context to work for Gunnison sage-grouse conservation

Successful conservation requires adequate understanding of focal species and ecology, practices that may assist species survival, and a community of people willing and able to conserve the species. For many species at risk, we operate with imperfect knowledge in complex conservation contexts. In this case study involving the Gunnison sage-grouse (Centrocercus minimus), we interviewed 26 community-defined local experts, including both those with and without related academic degrees, to assess the utility of local knowledge for understanding and informing conservation opportunities.This project suggests several benefits of integrating local knowledge that apply specifically to rare and endemic populations, including the ability to gain (1) access to a deeper temporal perspective, (2) observations made during different seasons and life-history stages, and (3) insights regarding the applicability of management strategies formed and science conducted on similar species. The contributions of local experts also can help identify conflicting narratives of species decline and, therefore, important future research directions. The patterns of expert referrals in this project provide evidence that long-term collaboration in conservation has created a pool of local Gunnison sage-grouse experts with technical training and long-term experience. Systematic assessment of the pool of local experts may improve long-term conservation by providing increased insight into the conservation context

Absence of system xc⁻ on immune cells invading the central nervous system alleviates experimental autoimmune encephalitis

Background: Multiple sclerosis (MS) is an autoimmune demyelinating disease that affects the central nervous system (CNS), leading to neurodegeneration and chronic disability. Accumulating evidence points to a key role for neuroinflammation, oxidative stress, and excitotoxicity in this degenerative process. System x(c)- or the cystine/glutamate antiporter could tie these pathological mechanisms together: its activity is enhanced by reactive oxygen species and inflammatory stimuli, and its enhancement might lead to the release of toxic amounts of glutamate, thereby triggering excitotoxicity and neurodegeneration. Methods: Semi-quantitative Western blotting served to study protein expression of xCT, the specific subunit of system x(c)-, as well as of regulators of xCT transcription, in the normal appearing white matter (NAWM) of MS patients and in the CNS and spleen of mice exposed to experimental autoimmune encephalomyelitis (EAE), an accepted mouse model of MS. We next compared the clinical course of the EAE disease, the extent of demyelination, the infiltration of immune cells and microglial activation in xCT-knockout (xCT(-/-)) mice and irradiated mice reconstituted in xCT(-/-) bone marrow (BM), to their proper wild type (xCT(+/+)) controls. Results: xCT protein expression levels were upregulated in the NAWM of MS patients and in the brain, spinal cord, and spleen of EAE mice. The pathways involved in this upregulation in NAWM of MS patients remain unresolved. Compared to xCT(+/+) mice, xCT(-/-) mice were equally susceptible to EAE, whereas mice transplanted with xCT(-/-) BM, and as such only exhibiting loss of xCT in their immune cells, were less susceptible to EAE. In none of the above-described conditions, demyelination, microglial activation, or infiltration of immune cells were affected. Conclusions: Our findings demonstrate enhancement of xCT protein expression in MS pathology and suggest that system x(c)- on immune cells invading the CNS participates to EAE. Since a total loss of system x(c)- had no net beneficial effects, these results have important implications for targeting system x(c)- for treatment of MS