Search

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. [ABSTRACT FROM AUTHOR]

Rangelands encompass 30-40% of Earth's land surface and support 1 to 2 billion people. Their predominant use is extensive livestock production by pastoralists and ranchers. But rangelands are characterized by ecological, economic, and political marginality, and higher value, more intensive land uses are impinging on rangelands around the world. Earth Stewardship of rangelands must address both livestock management and the broader socioecological dynamics that promote land-use changes, fragmentation, and degradation. We identify specific gradients on which human-rangeland systems can be arrayed, including issues of variability, adaptation to disturbance, commercialization, land-use change, land-tenure security, and effective governance, and we illustrate the gradients' interactions and effects in sites worldwide. The result is a synthetic framework to help in understanding how rangeland Earth Stewardship can be achieved in the face of marginality, globalization, and climate change. [ABSTRACT FROM AUTHOR]

Abstract: Scientific interest in carbon sequestration on rangelands is largely driven by their extent, while the interest of ranchers in the United States centers on opportunities to enhance revenue streams. Rangelands cover approximately 30% of the earth''s ice-free land surface and hold an equivalent amount of the world''s terrestrial carbon. Rangelands are grasslands, shrublands, and savannas and cover 312 million hectares in the United States. On the arid and semi-arid sites typical of rangelands annual fluxes are small and unpredictable over time and space, varying primarily with precipitation, but also with soils and vegetation. There is broad scientific consensus that non-equilibrium ecological models better explain the dynamics of such rangelands than equilibrium models, yet current and proposed carbon sequestration policies and associated grazing management recommendations in the United States often do not incorporate this developing scientific understanding of rangeland dynamics. Carbon uptake on arid and semi-arid rangelands is most often controlled by abiotic factors not easily changed by management of grazing or vegetation. Additionality may be impossible to achieve consistently through management on rangelands near the more xeric end of a rangeland climatic gradient. This point is illustrated by a preliminary examination of efforts to develop voluntary cap and trade markets for carbon credits in the United States, and options including payment for ecosystem services or avoided conversion, and carbon taxation. A preliminary analysis focusing on cap and trade and payment for avoided conversion or ecosystem services illustrates the misalignment between policies targeting vegetation management for enhanced carbon uptake and non-equilibrium carbon dynamics on arid United States rangelands. It is possible that current proposed carbon policy as exemplified by carbon credit exchange or offsets will result in a net increase in emissions, as well as investment in failed management. Rather than focusing on annual fluxes, policy and management initiatives should seek long-term protection of rangelands and rangeland soils to conserve carbon, and a broader range of environmental and social benefits. [Copyright &y& Elsevier]

The article looks at land use and natural history in the Middle San Pedro River Valley in southeastern Arizona. Particular focus is given to the impact of past human activity and other changes to the landscape on conditions and land management goals in the 21st century. Details related to several sources of change include climatic and hydrological factors, the entrenchment of the river channel in the 19th century, and livestock grazing are presented. Other topics include droughts, land tenure, ranching and farming, surface and groundwater rights, and conservation.

The use and management of rangelands involves both ecological and social processes, and it is in the interaction of these that conservation is or is not achieved. Overall, the ecological dimensions of rangelands and rangeland management have been studied in greater detail and are better understood than the social dimensions. This paper argues that qualitative methods are necessary to understand the management of rangelands by ranchers. Existing studies using quantitative methods have found little correlation between ranchers' management practices and a variety of social factors. One consistent finding of these studies, however, is that profit is a secondary or insignificant motivation among ranchers, casting doubt on the premise that economic self-interest motivates ranchers to embrace improved management practices. The theoretical and methodological implications of this finding have not been adequately recognized in rangeland science. With its greater flexibility and attention to context, qualitative research can reveal social, historical, political, and economic factors that affect ranch management but have eluded quantitative studies. In addition, qualitative methods are better suited to capturing both the processes that generate ranchers' ‘mental models’ and the historical information needed in light of recent theoretical advances in rangeland ecology. Suggestions for future research on ranch management include conducting case studies of smaller areas over longer temporal periods, focusing on interactions among ranchers, giving ranchers a greater role in identifying research needs, studying urbanization and other ‘new’ rangeland issues, and drawing on research about pastoralist societies elsewhere. [ABSTRACT FROM AUTHOR]

Environmentalists, scientists, and land managers have long debated the role of ranching in landscape conservation with some contending that ranching represents the major threat to ecological systems, while others believe it is key to long-term conservation. We contrast the impacts of livestock grazing with those of the major alternative land use at this time, suburban and ex-urban development, on the semi-arid Chihuahuan Desert grasslands and savannas of southern Arizona and New Mexico, USA, and northern Chihuahua and Sonora, Mexico. Because landscape change has resulted from complex interactions among natural and anthropogenic disturbances, attempts to identify simple causal relationships resulting from livestock are of limited ecological significance. Far more important is long-term conservation of basic ecological processes at large spatial scales, which in turn requires that certain social conditions be maintained. In the face of rapid, extensive suburban and ex-urban development in the region, conservation of functioning ranch units represents the most viable means of sustaining ecological function. Examples of community-based adaptive management illustrate the potential of coalitions of ranchers, agencies, scientists, and environmentalists to conserve the biodiversity of these landscapes, protecting a matrix of publicly and privately owned land through an extension of UNESCOs biosphere reserve model. [Copyright &y& Elsevier]

The author focuses on Earth's natural resources that has to be planned and managed in order to maintain order and states several recommendations to researchers so that the skills, values, and ambitions of people can be developed to make Earth Stewardship responsibility of most of the inhabitants. He emphasizes that the concept of stewardship must be expanded for all land and waters and advices work should be done along various stakeholders to make future secure and sustainable.