摘要:

SummaryUtilization of waterholes by wildlife was studied between April, 1973 and July, 1974 in Tsavo National Park (East), south of the Voi river. Seasonality was an important factor which influenced the various aspects of waterhole utilization. The numbers of the herbivores utilizing the waterholes increased during the dry season but fell during the rains. Some ungulates also moved near to the artificial waterholes in the dry season but moved away from them during the rains when they drank from natural water‐holes formed in clay pans filled with rain water.A basic pattern of waterhole utilization dominated by small (adult‐size) species during day‐time 06.00–18.00 hours and larger species at night 18.00–06.00 hours is described. The separation in times of arrival and deparature peaks of waterhole utilization, and average coincidence of percentages of paired species populations are used to show that big‐game attained a measure of time‐spaced ecological separation at the waterholes.The water relations of some day‐time and night‐time drinkers are discussed. From the baseline study the management implications of the development of additional waterholes in the p

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1975.tb00142.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SummaryThe Mkomazi Reserve of northeastern Tanzania encompasses about 3300 km2of semi‐arid steppe between Tsavo National Park on the north and the Usambara Mountains on the south. Analyses of the various components of the ecosystem range from the measurement, synthesis and interpretation of climatic data to indices of large herbivore diversity. An analysis of the whole system and two simulation models are included.Of overriding importance to understanding the ecology of the Mkomazi is the recognition of many east‐west gradients ranging from elevation, solar input and rainfall to physical and biological soil properties. Since the biological communities are greatly affected by these they also reflect gradients but they, in turn, effect changes back on the soils and other variables such as the intensity of fire. With rainfall ranging from 35 cm year1in the east central region to about 60 cm in the west, the central section was found to be about 50% more arid than the west. The soils are all quite fertile with significant differences in cation‐exchange‐capacity, organic carbon, and nitrogen as a function of both depth and position on the slope.Vegetation consists of four major associations: (i)Acacia‐Commiphorabushland; (ii) wooded grassland; (iii) open grassland; and (iv) dry montane forest. Standing crop values range from about 200 g m‐2in the central region to around 600 in the west. Cumulative seasonal accretion values on denuded plots levelled off at about 150 and 300 g m‐2respectively. The maximum measured rate‐of‐change was 6 g m‐2day‐1while the wet season mean was 1 ‐9 g m‐2day‐1.There is a marked gradient of animal numbers from an annual average of only one or two animals knr1in the east to an annual average of twelve in the northwest. Double the annual average occurs around the permanent water during the dry season. Average annual biomass values range from about 5500 g km‐2in the west to about 750 g km‐2in the west central and 100 g km‐2or less in the east central. In addition to the east‐west gradient there is another gradient from very low numbers near the southern boundary settlements to higher numbers along the Tsavo Park boundary. Most of the area is more of a wet season liberation area than a dry season refugium.Even though species richness is high, the actual species diversity is low. For example, in the northwest section three species constitute about 90% of the numbers, 93% of the biomass and 90% of the energy transfer at any particular time or place. Elephants (Loxodonta africanaBlumenbach) alone account for 82% of the entire reserve's wet season biomass.Approximately 20% of the net primary production is estimated to be consumed by the large herbivores. The ratio of large herbivore poundage to large carnivore poundage is about 333: 1 indicating a reasonably slow energy turnover rate. Despite the large animal biomass densities in the savanna ecosystem the energy flow rates are probably not that much greater than other systems because of the large mean body sizes. Water and nutrient cycling are briefly discussed.Simulation results from two different computer models suggest that under existing land use and human population growth conditions elephants will continue to be a habitat degradation threat for several decades. Intermittent

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1975.tb00143.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SummaryThis paper presents a description of the temporal and spatial distribution of rainfall within the Serengeti Ecosystem, Tanzania. Ecosystem and Regional patterns are discussed with respect to synoptic processes, vegetation zonation, phases of primary production and the distribution and migrations of large mammals.

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1975.tb00144.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

摘要:

SummaryFood habit studies on wildebeest (Connochaetes taurinusBurchell) and plains zebra (Equus burchelliGray), using stomach contents analysis, were carried out between April 1972 and October 1973 in the Athi‐Kaputei plains and Nguruman in Kajiado district. Both areas fall within the semi‐arid region of Kenya and are grazed by both Masai stock and wildlife.Wildebeest was highly selective for grass leaves, while zebra took more of the coarse plant materials, viz. sheath and stem. Zebra is more suited to coarse feeding, which enables it to survive the droughts better than wildebeest. The latter is usually hit harder at such times, as it cannot maintain itself on the fibrous materials which can constitute a maintenance diet for ze

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1975.tb00145.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1975.tb00146.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1975.tb00147.x

出版商:Blackwell Publishing Ltd    

年代:1975

数据来源: WILEY