摘要:

Summary(1) Food habits of elephant and giraffe were recorded in short sample periods over several years using the feeding minutes technique. (2) Twelve species of common plants were collected on these occasions, separated into their main parts and analysed chemically. (3) Damage to trees was also recorded at intervals. (4) Fifty‐nine species of plant were eaten by elephant. During wet months their diet was predominantly grass but during dry months woody vegetation became more important. Giraffe were observed eating from thirty‐nine species of plant which were almost entirely browse throughout the year. At least eighteen of these species were also eaten by elephant. (5) Three of the browse species most important to giraffe were also important to elephant in dry seasons. In the driest month the species eaten by giraffe formed more than two‐thirds of the observed diet of elephants. (6) Chemical analyses of plants show that browse leaves had a higher level of protein, fat and minerals than most other plants. (7) The trunk of an elephant and the tongue of a giraffe are highly sensitive organs which permit food selection. Elephant in particular appeared to alter their food habits seasonally and it is suggested that this may be an attempt to obtain a balanced intake of nutrients. (8) Due to the effect of elephant and other agencies there is an accelerating decline inAcacia gerrardiiwoodlands. Browsing and fire are independently preventing their regeneration. (9) The extensive overlap of food requirements on preferred but diminishing browse resources implies potential if not already existing competition between elephant and giraffe. (See Part

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1976.tb00148.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SummarySixteen wildebeest were marked with radio transmitters and tracked for varying lengths of time during the period between late November, 1971, and mid‐July 1972. They were repeatedly radiofixed from an aircraft prior to, during and after their annual wet season visit to the Serengeti Plain. Fix‐to‐fix tracks of animals showed that each hurried to the Plain at the onset of the rains, performed oscillatory movements over an individually distinct, elliptically shaped, fractional part of the Plain area, and departed into the woodland as the Plain dried out. Average fix‐to‐fix rate of travel approximated 3–75 km/day. Large aggregations of animals,armies, were smaller and more restless in the woodlands than on the Plain. Smaller aggregations included within armies,troops, varied in size as a function of activity. They were small when feeding and large when marching. Troops averaged larger in the woodlands mostly because they were more often marching there than on the plain. The tracked animals were equally successful in finding green forage in the presence of water in both habitats. The item in shortest supply appeared to be the presence of green forage in the woodlands and of water on the Plain. It is concluded that structural attributes of the woodlands, by lowering the security level of animals, played a part in making the Serengeti Plain attractive to

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1976.tb00149.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SummaryCensuses indicated similar elephant densities in some habitats to those in certain other East African Parks where woodland has been almost completely destroyed. Giraffe densities were low. Herd structure indicated a healthy elephant population; but poor recruitment in the giraffe population.Policy for the national parks is discussed. It is suggested that it is not in the interests of Uganda or science to allow Kidepo Valley Park to become dominated by elephant in the same way as Kabalega and Rwenzori Park. Evidence that this is happening under current elephant use is strong. Cropping of two thirds of the elephant in the Narus valley is recommended. The revenue from cropping should be used for essential fire control measures and for a monitoring programme to ascertain optimum elephant numbers. Elephant should not be cropped in the absence of fire control.

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1976.tb00150.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SummaryIn view of the substantial vegetation changes in Tsavo National Park and their possible effects on the herbivore fauna, this study was undertaken to obtain quantitative information on densities of several ungulate species and their biomass. Road strip counts (belt transects) constituted the main method used, supplemented by aerial counts in parts of the study area. Densities of most ungulate species are rather low, the maximum of 2–25 per km2being attained by zebra in the southern poition of the study area. There are significant differences between two parts of the study area, related to differences in vegetation types. Mean biomass density is around 4000 kg/km2, of which ⅔‐¾ is made up of elephants. Total biomass density compares well with that in areas of similar climatic conditions but is much lower than that in moist savannas of western Uganda and Zaire with higher ra

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1976.tb00151.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SummaryA method of collecting rumen fluid from free‐living antelope is presented, together with thein vitroprocedure used to try to estimate the digestibility of the herbage grazed by them. Modifications to this procedure are suggested, which it is thought would allow the calculation of a meaningful equation relating these data to digestibility estimates obtained by a chemical metho

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1976.tb00152.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

SummaryThe lappet‐faced and white‐headed vulture nests in a 1636 km2study area on the Serengeti Plains were kept under observation from June 1972 to August 1973. Active nests were inspected from a light aircraft at intervals of approximately 2 weeks.The inverse nesting densities were estimated as 43 km2/pair for the lappet‐faced vulture and 409 km2/pair for the white‐headed vulture. Nests were built of sticks in exposed sites on the crowns of trees,Acacia tortilisbeing the most popular species. Where the previous history was known, 44% of lappet‐faced vulture nests were newly constructed, and the rest re‐used from the previous year.The incubation period was about 55 days and the fledging period about 100 days in both species. Juveniles continued to frequent their nests after they could fly, sometimes for several months.Most lappet‐faced vultures laid their eggs in April‐May, the white‐headed vultures in June‐August. This means that the lappet‐faced vultures raised their young during the dry season, when Grant's and Thomson's gazelles were the only animals present in any numbers on the plains. By contrast, the Ruppell's griffons nesting in the nearby Gol Escarpment colony raise their young during February‐May, when the wildebeest and zebra herds are normally on the plains.The survival rate of lappet‐faced vultures from laying to fledging was about 40%. The chicks are thought to be vulnerable to predation by tawny eagles, and one was known to have been killed by a leopard. Three adult vultures were killed on their nests, from unknown causes.Food remains from lappet‐faced vulture nests showed a heavy preponderance of Grant's and Thomson's gazelles in all cases, with golden jackal the next most commonly occurring species. No food remains were obtained from white‐headed vulture nests.The possibility of using aerial counts of vulture nests as an indicator

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1976.tb00153.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1976.tb00154.x

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY