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Dryland regions are particularly challenging for human survival over the course of deep time. This is true for institutionally complex communities as well as small-scale societies that have existed in semi-arid regions throughout the Holocene. This paper examines some of the successful strategies employed by small-scale mobile communities which enhanced their ability to thrive in drylands over the course of thousands of years. Small-scale societies living in drylands must rely on the transmission of Traditional Ecological Knowledge across generations. Some of this knowledge relates to the availability and use of wetlands and other more ephemeral water sources, the exploitation of a diverse range of resources, and the potential for natural storage of food resources as a buffer against regularly occurring drought years in these regions. We compare this understanding with our environmental archeological findings at the Mid-Holocene site of Zaraa Uul in the eastern Gobi Desert of Mongolia. At the site of Zaraa Uul, we show how hunter-gatherer groups returned to a campsite near the edge of a wetland environment over the course of at least two phases during the Mid-Holocene. Here they took advantage of a greater diversity of animal species and plants, including small-grained-grasses and sedges, which could enhance their caloric intake and increase the potential for storable commodities which could be collected as needed from their natural habitat. [ABSTRACT FROM AUTHOR]

The prediction of the impact of anthropogenic land use change on the climate system hinges on the ability to properly model the interaction between the heterogeneous land surface and the atmosphere in global climate models. This paper contains a review of techniques in general use for modeling this interaction in general circulation models (GCMs) that have been used to assess the impact of land use change on climate. The review includes a summary of GCM simulations of land cover change using these techniques, along with a description of the simulated physical mechanisms by which land cover change affects the climate. The vertical extent to which surface heterogeneities retain their individual character is an important consideration for the land-atmosphere coupling, and the description of a recently developed technique that improves this aspect of the coupling is presented. The differences in the simulated climate between this new technique and a technique in general use include the presence of a boundary layer feedback mechanism that is not present in simulations with the standard technique. We postulate that the new technique when implemented in a GCM has the potential to guide an improved understanding of the mechanisms by which anthropogenic land use change affects climate. [ABSTRACT FROM AUTHOR]

The origins of the word ‘desertification’, most commonly attributed to Aubréville's 1949 work on tropical African forests, may be traced back much earlier, to nineteenth-century French colonial North Africa. The concept of desertification was central to French colonial thinking about the North African environment. This paper argues that an environmental history of the Maghreb was constructed during the French colonial period which blamed local North Africans, especially pastoralists, for the deforestation and desertification of what was erroneously believed to have been a fertile, forested landscape in antiquity. This environmental narrative of destruction and decline was first fabricated during the early years of the French occupation of Algeria, and was invoked in Tunisia and Morocco as they were occupied. Founded on historical inaccuracies and environmental misunderstandings, this narrative helped to justify land expropriation, changes in land tenure, forest appropriation and the criminalization of traditional land use, all of which facilitated the colonial venture in the three Maghreb countries. [ABSTRACT FROM AUTHOR]

Wind erosion is one of the most important processes associated with land degradation and desertification in the arid, semi-arid and portions of the subhumid regions of China. The total land area experiencing wind erosion is approximately 160.74 x 104 km2, which is 16.7% of the national territory. Wind erosion is recognized as a great threat to land utilization and sustainable social and economic development. Documentation of wind erosion and its negative impacts in China dates back over 2000 years. Since the 1950s Chinese scientists have carried out an integrated investigation of the principal lands susceptible to wind erosion, and have undertaken many laboratory tests and field observations with respect to the stabilization and utilization of soil in desert areas. Since the late 1970s there has been an increasing concern worldwide regarding land desertification caused by climatic changes and human activities. Hence, wind erosion, one of the main processes of desertification, has attracted the attention of Chinese scientists to an even greater extent. Studies have been conducted to investigate the mechanics, causes and control techniques related to wind erosion using wind tunnel simulation tests and field observations in typical areas. Some encouraging achievements have been made. In this paper we summarize the main research results on wind erosion that have come to light in China in recent decades, and put forward some perspectives and suggestions to deal with problems in both research into and control practices of wind erosion in China. [ABSTRACT FROM AUTHOR]

This paper examines the mid- to late-Holocene (c. 6850-1160 cal. yr BP) environmental history of Sierra de Gádor in southern Spain. The local vegetation dynamics are reconstructed through the palaeoecological record obtained from a lacustrine deposit situated at 1530 m. Various hypotheses are considered to explain the vegetation dynamics apparent in the palaeoecological evidence, including climatic change, fire occurrence and human activity. Although the vegetation in this region is sensitive to climatic change, threshold events driven by ecological factors are also apparent. Climatic events include a thermo-mesophytic optimum with abundance of deciduous trees and maximum lake water level found from c. 6850 to 5500 cal. yr BP. In contrast, changes in the frequency of major fire episodes appear to have shaped interspecific relationships and vegetation change, especially from c. 4200 cal. yr BP onwards. Biotic properties of the ecosystem such as the inertia of established tree populations, interconnected with competition adjustments, appear also to have played a role. Over the last two millennia, overgrazing, combined with natural and/or human-set fires, appears to have pushed mountain forests over a threshold leading to the spread of grassland, thorny scrub, junipers and nitrophilous communities. [ABSTRACT FROM AUTHOR]

Mediterranean ecosystems contain some of the highest levels of plant diversity of any region on Earth and are amongst those believed to be most at risk from the consequences of global warming. Yet such ecosystems are not static and have responded to environmental changes at a variety of scales and from a variety of causes, particularly climatic and anthropogenic. The purpose of this paper is to review recent research on environmental change and ecosystem response. Long-term records are available to analyse changes over glacial-interglacial cycles, while high resolution records show the sensitivity and coupling of Mediterranean, North Atlantic and Greenland records. For the Holocene, there is continued debate about the relative impact of anthropogenic activity, but there is also increasing recognition that mediterraneantype ecosystems should not be regarded as fragile, degraded landscapes, but are disturbanceadapted. Nevertheless, conservation measures face increasing challenges from contemporary climate change and human pressures. Some insights into the identification of refugial areas, either in glacial times or for present-day conservation purposes, come from molecular biogeographical studies of past faunal and floral distribution. [ABSTRACT FROM AUTHOR]