Browsing by Author "Harrison, James Adriaan"

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    The Southern African Bird Atlas Project and its relevance to nature conservation
    (Stellenbosch : Stellenbosch University, 1993-09) Harrison, James Adriaan; Van Hensbergen, H. J.; Bigalke, R. C.; Stellenbosch University. Faculty of AgriSciences. Dept. of Forest & Wood Science.
    ENGLISH SUMMARY: The objectives of this thesis are to: (a) describe the Southern African Bird Atlas Project (SABAP), document its progress and assess its success, as a contribution to the planning of future projects; (b) explore the potential of atlas data to answer questions other than those concerned with the ranges of species; (c) investigate the application of bird atlas data to some specific questions which have a bearing on the planning and practice of conservation. The progress and organizational features of SABAP and its databank are described. It is shown that the SABAP has been a success in terms of the large volumes of accurate and up-to-date data on species' distributions and patterns of seasonality acquired. The decision to use amateur volunteers is shown to have been appropriate but not without drawbacks. A methodological point made is that the methods of atlasing and of computerization of the data need to be planned so as to permit statistical analysis of the data. If this is done, reporting rates can provide an index of relative abundance which can, in tum, permit the application of atlas data to many questions beyond that of range extent. The analysis of reporting rates is illuminating in the description of seasonal patterns of occurrence and therefore, of seasonal movement. This is demonstrated for long-distance migration and for local movement. The papers dealing with patterns of seasonality highlight the fact that species with extensive seasonal movements cannot be conserved within, single reserves. The growing demand for access to SABAP data is reported and the applications listed. Improvement of SABAP's relevance to the environmental consultancy user group is achieved by a method of presenting atlas data in a manner which will maximize their usefulness. The approach hinges on the ability to allocate species to habitat categories. This enables one to break down an undifferentiated species list for a grid square into a number of habitat-specific species lists. It is proposed that atlasing could be adapted to achieve population monitoring objectives. One exercise set out to analyse changes in reporting rate through time and to correlate these with a key environmental variable, namely rainfall. The exercise is only a limited success. It is shown that, while potential to use atlas methods for population monitoring does exist, the need to improve the standardization of methods for this purpose is crucial. Interim results of the SABAP in the form of species distribution maps are presented as an aid to the planning of conservation action for cranes. The information for the three species is compiled to produce a map which highlights those grid squares which have the greatest diversity of cranes. It is shown that the combination of atlas information for a suite of species can yield an index of diversity which may hold greater potential for planning the location of reserves than the distribution maps of individual species alone. Trends in bird atlasing and of the use of reporting rate as an index of relative abundance are reviewed as is the use of reporting rates as a population monitoring tool.