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PORTAIL D'INFORMATION GÉOGRAPHIQUE

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  • Macro and micro botanical remains point to a Holocene environment of open grass and Chenopodiaceae vegetation, with varied herbs and some shrubs. The plant cover could have been somewhat denser than nowadays to explain the geomorphological
  • Vegetation changes in the Reserve have been quantified using 1937, 1960 and 1975 aerial photographs, and related to management history. Intensive woody plant removal operations and controlled burning applications have not been effective in retarding
  • the long term rate of shrub and tree encroachment. Significant reductions in tall grass cover attributed to sustained overgrazing have occurred. (AJC).
  • Although the paper covers the whole of Africa, useful information on West African countries is included. (EMS).
  • A comprehensive guide to Grahamstown and its environs covering prehistory, history, development, excursion routes in and around the town, birds, mammals, reptiles, amphibians, fishes and nature reserves. - (AJC)
  • Publications in English and French between 1960 and 1979, in German and Portuguese and unpublished doctoral theses are covered, and include a geographical section on West Africa. (EMS).
  • Remote sensing is at present of limited value in geographical research in Nigeria, except for repetitive covering and temporal thematic changes. (EMS).
  • The existence of four slope terraces from the freeface over the southern slope of the Magaliesberg was ascertained by means of slope analysis. These terraces are covered by colluvium which has had no significant influence on the prominence
  • of the terrace. In the same vicinity, on the Daspoortrand pediment, it was possible to deduce that the fine sediments originating from the Daspoort quartzite totally covered a small valley as well as a terrace on the middle pediment of the Daspoortrand
  • Change of vegetation cover and morphodynamics: a study in applied geomorphology in the semi-arid lands of northern Kenya in Applied geomorphology.
  • Estimating and mapping grass cover and biomass from low-level photographic sampling
  • Although eighty per cent of the land area of Nigeria is covered with savanna woodland, there is a shortage of wood and wood products. The Savanna Forestry Research Project has studied the conditions necessary for increased tree growth. Some problems
  • and the switch to interglacial conditions at about 12,000 yr B.P. The record also covers the period of maximum rainfall in East Africa, 9 000 to 5 000 yr B.P., a time marked by high lake levels.
  • This study examines data for Nile flood indicators (water level, sediment load, and discharge) covering the same time span as that of the examined shoreline positions. The AA. also report on more recent shoreline positions to study the long-term
  • The standard conditions of erosion rates (on albaqualps respective argiudolls soils) is considered to be described by two areas with undisturbed grass cover. Measured sediment concentration in runoff from these were compared with two study areas
  • At the beginning of the Holocene the inner parts of the Congo shelf were covered by clear and relatively warm waters. About 12,000 yr BP deposits show a high carbonate content. Sedimentation rates have decreased from 2-3 m to 0.07-0.3 m per 1000
  • of the CO-ion which comes from the atmosphere, the salts are most probably formed during weathering of the basaltic lava covering the obstruction and crystallizing at or near the face of the cliffs where the water evaporates. The loosened sandgrains
  • The area covered by pans in the Orange Free State varies from nul in some parts to more than nine percent per quarter degree square. The highest incidence is found in the western parts of the province. Percentages exceeding 1,5 percent per unit area
  • forests still cover most of the mountain slopes between 700 and 1300m above sea level, although some tree species have suffered from overexploitation in the past. The open forest of the endemic tree, le Tamarin des hauts (Acacia heterophylla), is found
  • : peak elevations Ras Dejen 4543 m). Thus, the most likely palaeoclimate was about 7 C cooler, and poor in run off and rainfall. It had a tendency towards winter precipitation and only occasional summer cloud cover, without monsoon activity, and remained
  • covers the time span of approximately 40 000 to 6 000 years BP. The pollen spectra give indications of semi-arid and more humid periods while colder intervals may have occurred. The results are correlated with changes in lake levels.