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In the south-west of Mauritania, the present provinces of Brakna and Trarza stem from the history of the pre-colonial emirates of the same names. This paper quotes the few but various data at our disposal concerning the landscape history and vegetation and climate evolution during the last centuries. We propose a diachronic approach of this area, to identify the part of the heritage in the current landscape and usefully enlighten environmental and development issues. We can thus identify the main features of the precolonial landscapes of this region as well as the historical roots of the production systems and put into perspective their recent evolutions. Beyond its historical interest, this knowledge can also be one of the grounds of the current environmental approaches. [ABSTRACT FROM AUTHOR]

In Sudanian savannas, frequent fires are required to maintain a mix of trees and grasses. After a century of long conflict over fire utilisation and resource management, arising from colonial scientists reacting against traditional practice, fire has become a management tool used to shape tropical vegetation. Many examples show that fire is allowed and used in protected areas, and more recently, tolerated in West African countrysides. If fires are no longer viewed as 'evil' for African landscapes, fire setting remains a problem. Nowadays, fire ecology and the savanna concept focus on fire seasonal temporality, and create a new and more specific category of contested fires, or late-season fire, referred to in this paper as 'bad fires'. This specific category generally conceives fire as a biophysical element, which leads to savanna degradation. This paper examines the reality of 'bad fires' in the Western Burkina Faso through a space-time analysis to investigate the existence of an annually seasonal pattern of fires created by peasants. Using spatial association ( I_ Moran) on active fire MODIS products, we are able to demonstrate a deterministic regional pattern occurring over six years (from 2004 to 2009). Results of this study confirm the importance of a close study of fire in its temporal dimension with respect to temporality in burning practices. Conclusions show that the details of timing in fire-setting are key and also bring us new perspectives to understanding fire collective management at a local scale and new elements for climate modelling at a global scale. [ABSTRACT FROM AUTHOR]

The island of Madagascar, located in the southern hemisphere between the equator and the Tropic of Capricorn in the Indian Ocean, 450 km from the African continent, is particularly affected by wildfires. The vegetation of the phytogeographic Western Domain of the island consists largely of savannas, wooded grassland, and secondary grassland, maintained by the repeated action of fire operating each year on a seasonal cycle. Rural populations employ fire to manage land use. Depending on the burning practice and the environment in which the fires happen, the impacts vary. This paper supplement the studies that have so far located and quantified wildfires by taking into account their different behaviors, particularly their spread. We analyzed the modalities of the relationship between the two fire products, active fire and burned area, derived from Moderate Resolution Imaging Spectroradiometer (MODIS) data to establish a typology based on fire spread patterns. We identified three general patterns of fire behaviors, as well as their locations in the studied area. Spatial analysis of this patterns enabled us to understand spatial logics better. Type 1 fires are the least frequently observed and have many active fires, but little or no burned area. Type 2 fires are the most common and have areas that burn like a mosaic. Type 3 fires are observed slightly less frequently than the previous type and have few active fires and large burned areas. An inter-annual analysis reveals the spatial stability or variability of these fire types. [ABSTRACT FROM AUTHOR]

In the south-west of Mauritania, the present provinces of Brakna and Trarza stem from the history of the pre-colonial emirates of the same names. This paper quotes the few but various data at our disposal concerning the landscape history and vegetation and climate evolution during the last centuries. We propose a diachronic approach of this area, to identify the part of the heritage in the current landscape and usefully enlighten environmental and development issues. We can thus identify the main features of the precolonial landscapes of this region as well as the historical roots of the production systems and put into perspective their recent evolutions. Beyond its historical interest, this knowledge can also be one of the grounds of the current environmental approaches. [ABSTRACT FROM AUTHOR]

For a long time, fires were regarded as harmful by territory managers, especially by foresters, and today in a context where the protection of the environment debated. European regulations criminalizing fires have been transmitted in the "South" countries during colonization: fires were perceived as a threat to vegetation, which could lead to desertification processes. In that respect, in Madagascar, since its colonization in 1895, "the foresters were alarmed by what they saw as wasteful fires". Back «In the early 19th century, the island's petty kingdoms were transformed into a sophisticated modern state, leading to the first recorded state-level regulation of fires». "The state criminalized burning due to concern that fire destroys the island's natural resources and blocks development».However, recent studies on bushfire in West Africa, have changed this depiction. «Thus, above the image of a powerful constraint on the vegetation, scientific progress in ecology and paleoecology allowed gaining a better understanding that ecologically, fire is part of savannah systems. Fire is an element of the system that forms savannah landscapes in intertropical countries. For West Africa, the authors use the term 'pyroclimax', climax of fire. Generally, in a climax plant vegetation used as reference, unwavering set of operating principles of biophysical processes is required, and an exclusion of human influence. However, it has been admitted that ecosystems need perturbation in order to remove some elements, to make way for young, regenerating stands. Moreover, we notice that plant formations are able to adapt to a new permanent factor ecologic. Systems have the capacity to learn, adapt and self-organize around various factors affected. Human factors can be studied as ecological agents; geosystem determines as a structuring form of natural systems, the anthropisation factor. When the plant vegetation dynamics is 'artificial nature', it's systematically pejorative connotations, whereas heterogenous landscapes generate biodiversity. A number of studies demonstrate the antiquity of anthropogenic actions and the environements resultant have sometimes acquired a patrimonial character. Fire is an example of an agent dictated by the Man actions. His regular and frequent passage change wood plant vegetation into savannah; filter, pyrophiles woody species and grasses. Identify permanent fire spaces could reveal landscapes organised by anthropogenics actions. To study these phenomena, the south-west of Madagascar is a good case. The Public policies have made the choice to strictly prohibit fire because it is identify as the principal agent of degradation of climax wood plant vegetation.Our study aim is to take another look at the role of fire in environmental and landscapes dynamics in south-west of Madagascar on many space and time scales. To account quantitative and qualitative evolutions of surface condition, teledetection method using satellite data Modis and Landsat, are cross whith field observations: quantification of biophysical components and land use, surveys and interviews about uses and their transformations, perceptions and representations. Contribution will draw on a caracterisation of fire spaces and their evolution since 20 years on the Fiherenana and Onilahy watershed, on the South-west of Madagascar. [ABSTRACT FROM AUTHOR]

The research on the mutations of colonial agrarian landscapes aims to provide historical-geographical knowledge on their transformations and evolutionary tendencies during sultan, colonial and postcolonial periods. To achieve it, archive, multidata images and field data were collected, organized, analyzed and compared. It is clear from this that more than 40 years after the Independence, the plantations and the factories which constituted the great symbols of the agrarian colonization are either almost erased from the landscape or in a state of ruin. Of the more than 17 species introduced to Anjouan by Europeans as part of the plantation economy, only clove, ylang-ylang and vanilla are today export and industrial crops. As for traditional food crops, they are part of the agrarian landscapes that are currently under urban pressure. In compensation, Anjouan is subject to agriculture in forest areas. These landscape transformations went together with positive and negative effects as regards socio-spatial, socio-economic and environmental aspects. Among them, there were cases of expropriation, retrocession and land conflicts; rural exodus and migration; duality and complementarity between traditional agricultural economies of self-sufficiency and plantations of capitalist type; export crops as main sources of family incomes; deforestation and degradation of river flows. [ABSTRACT FROM AUTHOR]

The research on the mutations of colonial agrarian landscapes aims to provide historical-geo- graphical knowledge on their transformations and evolutionary tendencies during sultan, colonial and postcolonial periods. To achieve it, archive, multidata images and field data were collected, organized, analyzed and compared. It is clear from this that more than 40 years after the Independence, the plantations and the factories which constituted the great symbols of the agrarian colonization are either almost erased from the landscape or in a state of ruin. Of the more than 17 species introduced to Anjouan by Europeans as part of the plantation economy, only clove, ylang-ylang and vanilla are today export and industrial crops. As for traditional food crops, they are part of the agrarian landscapes that are currently under urban pressure. In compensation, Anjouan is subject to agriculture in forest areas. These landscape transformations went together with positive and negative effects as regards socio-spatial, socio-economic and environmental aspects. Among them, there were cases of expropriation, retrocession and land conflicts; rural exodus and migration; duality and complementarity between traditional agricultural economies of self-sufficiency and plantations of capitalist type; export crops as main sources of family incomes; deforestation and degradation of river flows. [ABSTRACT FROM AUTHOR]

The present study aims to review palaeoecological evidence for environmental changes induced by human activities over the last few millennia in the montane landscapes of Morocco. The study is based on well-dated pollen and geochemical records from the Rif and the Middle Atlas mountains, to show spatial and temporal variation in the onset and intensity of exploitation of forest, soil and mineral resources. Before ca. 2000 BP, anthropogenic impact was minimal. At about that time, abrupt changes of the arboreal pollen proportions, with a decline in all tree taxa, indicate a reduction of the forest cover interpreted as being anthropogenic. In the Rif Mountains, increased influx of carbonates (Ca) in the sedimentary records indicates enhanced soil erosion coincident with the reduction in tree cover. In the Middle Atlas, reduced forest cover is linked to geochemical evidence for mining and metallurgy of lead (Pb), copper (Cu) and zinc (Zn). These industrial activities correspond to the expansion of the Roman Empire into Morocco at around AD 40 and show a decline when the Romans were displaced by the Vandals about five centuries later. [ABSTRACT FROM AUTHOR]

Although understanding the emergence of agriculture in West Africa has recently benefited from major advances, the reasons for its fast diffusion south of the Sahara remain to be explained. We propose here a reconstruction of African agriculture expansion built from a spatialization of available archaeological data and associated radiocarbon dates. With this approach, we can show that the initial spread of food production occurred with some specific rhythms. From this structure, we discuss the potential underlying processes. Our work suggests that the spread of agriculture in West Africa cannot be explained by a simple response to an abrupt environmental change at the beginning of the Late Holocene, but rather by a combined climate-culture mechanism. In addition, cord-wrapped roulette-impressed pottery appears to be a good indicator of the expansion of agro-pastoralist populations in Sub-Saharan regions. Our results are also consistent with the assumption of a monophyletic origin of domestic pearl millet in south-western Sahara and strengthen the idea that the first cultivators were Saharan pastoralists. [ABSTRACT FROM AUTHOR]

Abstract: Research conducted in the Yamé Valley (Dogon Country, Mali) provides valuable information about the river systems and their Holocene evolution in Sudano-Sahelian West Africa. Past research in the region has relied primarily on marine and lacustrine records. The new results confirm correlation between palaeoclimatic fluctuations recorded in both the river system and in tropical African lakes. They offer a new continental milestone for understanding of the environmental repercussions of Holocene monsoon oscillations. These studies demonstrate the value of river systems as a palaeoenvironmental record and the role of palaeoclimatic and anthropogenic factors in the Holocene dynamics of Sudano-Sahelian hydrosystems. [Copyright &y& Elsevier]

Abstract: The site complex Ounjougou on the Dogon Plateau (Mali) comprises sediments up to 100,000 years old with numerous Pleistocene and Holocene sequences. The site Ravin de la Mouche (11.4–10.2 ka) is of special archaeological significance because in its Early Holocene deposits, pottery sherds have been found which are among the oldest in Africa. For a better understanding of the environmental conditions which might have contributed to the innovation of pottery making, a multi-proxy approach was applied to the sediments of Ravin de la Mouche, including phytoliths, pollen, palynofacies, micromorphology and charcoal. The multi-proxy approach also allows reconstructing the complex taphonomy of the site. In our phytolith study, we applied a combination of the general and the indices approaches. We recorded a maximum of morphotypes and used the summarized data for a calculation of the indices D:P, Ic, and Iph, in comparison with modern surface samples and data from other African phytolith studies. With the general approach, a number of morphotypes could be detected which are useful in describing the Late Pleistocene and the Early Holocene vegetation. Phytoliths were extracted from the Pleistocene base and the early Holocene layers HA1, HA2 and HA3. The Pleistocene sediment samples, with an age of ca. 30–40 ka BP, have no grass short cell phytoliths (GSCP) and their composition is difficult to interpret. HA1 is a coarse fluvial deposit with mainly redeposited phytoliths of Pleistocene origin. The palaeosoil in HA2 contains phytolith assemblages developed in situ from a terrestrial plant cover. The vegetation was an open tropical grassland and a gallery forest with palms and Marantaceae. Annuals from the grass subfamilies Chloridoideae and Panicoideae, probably with a low biomass production, dominated the grassland. This might explain the insignificant role of fire, as indicated by the very low number of micro-charcoals. HA3 results from a rhythmic deposition of alluvial sediments, pointing to pronounced seasonality of rainfall and discharge. It contains pollen, charcoal, and phytolith assemblages with a similar composition as in HA2. The Early Holocene annual grassland on the Dogon Plateau probably harboured a high number of species from the grass subfamily Panicoideae with edible grains. We suggest that the massive expansion of useful Panicoid grasses during the Early Holocene triggered the development of important cultural innovations, mainly pottery production. Cooking wild cereal grains in a ceramic container would have enabled a very effective exploitation of the vast Sahelo–Sudanian grasslands, which remained to be successful until modern times. [Copyright &y& Elsevier]

Biome reconstruction from pollen and plant macrofossil data provides an objective method to reconstruct past vegetation. Biomes for Africa and the Arabian peninsula have been mapped for 6000 years bp and provide a new standard for the evaluation of simulated palaeovegetation distributions. A test using modern pollen data shows the robustness of the biomization method, which is able to predict the major vegetation types with a high confidence level. The application of the procedure to the 6000 years data set (pollen and plant macrofossil analyses) shows systematic differences from the present that are consistent with the numerous previous regional and continental interpretations, while providing a more extensive and more objective basis for such interpretations. Madagascar, eastern, southern and central Africa show only minor changes in terms of biomes, compared to present. Major changes in biome distributions occur north of 15°N, with steppe in many low-elevation sites that are now desert, and temperate xerophytic woods/scrub and warm mixed forest in the Saharan mountains. These shifts in biome distributions imply significant changes in climate, especially precipitation, between 6000 years and present, reflecting a change in monsoon extent combined with a southward expansion of Mediterranean influence. [ABSTRACT FROM AUTHOR]