Abstract: In recent years in East and Southern Africa, increasing pressure of Man and domesticated animals on the natural environment has caused a rapid deterioration of soil, vegetation, and water resources, together with widespread destruction of wildlife. The use of vegetation by wild animals in semi-arid areas such as the [`]lowveld' of Rhodesia tends to be far more efficient than is its use by cattle. Game ranching --the scientific management of many species of wild animals in their natural habitat--has been carried out successfully in Rhodesia and South Africa for a number of years. In protein-hungry Africa, with its great unsatisfied demand for meat, game ranching, if practised more widely, could help to satisfy some of this demand. This is in addition to the obvious need for the conservation of wild animals for scientific and aesthetic reasons and as a source of delight to, and revenue from, increasing numbers of tourists. Statistical information is given particularly for game ranching in Rhodesia (Table I) and for various provinces and national parks in South Africa.
Abstract: In eastern New Mexico, most of the winter precipitation occurs as low-intensity rain or snow along slow-moving cold fronts, whereas summer rains are produced by short-duration, high-intensity thunderstorms, from purely convective buildup, or from convective cells developing along weak, fast-moving cold fronts. These summer convective storms (May-October) produce about 80 percent of the annual rainfall. Since runoff-producing precipitation on semiarid rangeland watersheds is of primary interest at the Southwest Watershed Research Center, the variability in rainfall affecting runoff has been analyzed for the Alamogordo Creek watershed. The ten-year mean, annual, seasonal, and monthly variations have been analyzed and compared with the long-term averages of nearby weather stations. The distribution and orographic effects have been discussed in detail. Variations in runoff yields were discussed and analyzed for the period of record.
Abstract: This article deals with the most important aspects of nearly twenty years of intensive study of the pollen-and-spore content of Tertiary sediments in some parts of tropical South America, Africa and Asia. For a proper evaluation, the character of the data, including the selection and preparation of the samples, the diversity of previous recording and the statistically achieved uniformity in presentation of these basic data needs a full exposition, given in the introduction. This is directly followed by an explanation of the process of elimination of all stratigraphically unimportant species. The resulting interpretation of climatic and topographical influences on the dispersal of pollen and spores is illustrated with examples from the fossil record. The disturbing effect of redeposition forms a problem, which in some cases can be solved. Now that the main ways of dispersal of pollen and spores are understood, the characteristics of the three major depositional environments can be distinguished by purely statistical analysis, without necessarily having any botanical information from probably related Recent plant species. Additionally botany and palaeontology may bring supporting evidence. This many-sided approach leads to the discrimination between local and regional features of environmental or time-stratigraphical significance which is needed for the evaluation of long-distance correlation. As a result the marker species can be classified into: (1) a restricted number of pantropical marker species; (2) a larger number of marker species which occurred in both the South American and west African regions, tropical today (transatlantic distribution); and (3) a still greater quantity of species which are of significance only within a single botanical province (intracontinental distribution). Thus a broad stratigraphical framework on a pantropical scale is established, which may be further subdivided regionally. These three systems of subzonation are compared with independent zoopalaeontological time-stratigraphical correlation and discussed in great detail, with special emphasis on the Carribean data. The major palynological changes marking the boundaries of the pantropical subzonation are thought to reflect the evolution of new groups of plants. They are mostly marked by a gradual incoming of pollen types. Extinction of plants is stratigraphically of less value, since they may have survived longer in one area than in another. Climatic boundaries are next in importance, but in general they are more restricted to specific regions. Similarly the immigration of plants, although producing sharp and useful boundaries, is only of regional value. Of least significance for regional correlation are the locally restricted boundaries which are caused by changes in habitat or dispersal. They may still be valuable for studies within one basin. An intriguing aspect of the palynological studies is formed by the possible affinity of the fossil type with Recent botanical species. Such affinities are obviously present in many fossil types. Whereas most are restricted to the level of family relationship, some interesting cases of much closer affinity are recorded here. In exceptional cases the morphogenetic development and migration of a restricted group of related pollen types can be traced. In the final section of this paper the species selected for this study have been formally described and illustrated; they include several new ones. The study is further documented by distribution charts and sections showing the stratigraphical significance of the marker types, as discussed in detail in the stratigraphical section.
Abstract: From the time aerial photographs were used in South Africa for the compilation of topographic maps, these maps have included some information on land use. Since the end of the Second World War more specialized studies, based on photo interpretation have been undertaken. These studies include land use, vegetation types, and soil erosion and its relation to land use. A review is given of the different projects, with reference to the kind of aerial photography used, working procedures and tools. The studies have proved that with photo interpretation for producing maps a considerable saving in cost over conventional methods is obtained. Aerial photographs are now being used for surveys for land planning in southern Africa, where up-to-date information on the use of land is required in a relatively short time.
