摘要:

SummaryThe pattern of distribution, in space and time, ofBrachylaena huillensis(Compositae) in two semi‐deciduous forests in Kenya was investigated. Results showed that seedlings and adults are distributed in patches, reflecting the distribution of female trees in the forest. Seedlings of different ages occur within the patches indicating that continuous establishment is ensured on sites under canopy. Other factors, however, seem to influence the degree of patchiness, and an investigation of these is neede

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1991.tb00465.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryFound‐ivory records complement the information provided by aerial surveys to illustrate changes in the Ruaha elephant population between 1973 and 1988. Intense poaching in the late 1970s and early 1980s reduced the numbers of elephants by about 60% and also distorted the age structure of the survivors. There are now few cows>34 years and few bulls>16 years. Footprint measurements in 1989 showed a lack of calves aged 2 to 9 years but many new‐born infa

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1991.tb00466.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryPercentage composition of woody plants in five vegetation types and activity sites of warthog were used to evaluate the spatial distribution ofCochlospermumspp. in Kainji Lake National Park.Cochlospermum planchoniandCochlospermum tinctoriumwere mostly encountered inAcaciaforest. These species constituted between 7% and 18% of the plant species in the activity sites of warthog. The activity site with the highest composition ofCochlospermumspp. contained the lowest density (1–2 km‐1) of warthog. AlthoughC. planchonicontained more nutrients thanC. tinctorium, each of these species may be useful for the total ash (93‐0g kg‐1) and crude fibre (423‐0g kg‐1) quantities that are being utilized as nutrients by warthog. Consequently,Cochlospermumspp. could be established in conservation areas either to eradicate the use of artificial salt licks or to reduce the percentage of bare ground prone to trampling

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1991.tb00467.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryFeeding habits of free‐ranging wildebeest and zebra were monitored in a semi‐arid nature reserve, bordering the southwestern part of Kruger National Park, South Africa. The purpose of study was to distinguish and define the feeding niches of two roughage grazers that occur in similar habitat types. The monthly compositions of diets were evaluated by direct observations of feeding bouts over a period of two years when rainfall patterns were average and animal populations were stable. Other analyses evaluated the standing biomass of grass species in the reserve during the wet summer and dry winter seasons.A considerable overlap of grass species composition was found in the diets of wildebeest and zebra. Ordination of bi‐monthly records of the diet composition showed greater variations in scores of grasses in zebra diet in comparison to wildebeest. Seasonal patterns were more apparent in the wildebeest diet. Preference ranking of grass species indicated that zebra diet remained constant in winter and summer. Wildebeest diet however, alternated with seasons, showing high preferences during the winter months for grass species which were rejected during summer.The combined assessment of results from three separate statistical methods analysing temporal patterns and preferences in diet composition revealed contradictory trends. The solution, however, relied on the initial assumptions posed. Hence, wildebeest and zebra are essentially generalist feeders which show a limited amount of preference in their choice of

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1991.tb00468.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryThe effects of rainfall and temperature on the behavioural ecology of Chanler's mountain reedbuck(Redunca fulvorufula fulvorufulaRothschild) were examined on ranchland near Gilgil, Kenya. Ambient temperature was shown to be the proximate determinant of diurnal activity and rumination patterns. Mountain reedbuck were active during early morning and late afternoon, but rested and abandoned rumination when temperatures peaked at midday. There was close synchrony in levels of activity, rumination and use of cover and shade between males and females. Seasonal variations in time budgets were strongly influenced by rainfall patterns. Analyses revealed a one‐month lag between rainfall and both peak grass growth and a decrease in rumination frequency. The proportion of time allocated to feeding decreased one month later, and was coincident with an increase in the proportion of grass in the diet. Reedbuck may therefore be prevented from exploiting high‐quality new grass, possibly by gut‐fill or induced imbalances in rumen pH. It is suggested that the unexpectedly high levels of browse in the diet is an adaptive response to low rainfall during the preceding two m

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1991.tb00469.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryEmergence, basking behaviour, selected temperature, and critical thermal minimum were studied in warm and cold acclimated groups of two subspecies of the lizardMabuya striata.The high‐altitudeM. s. punctatissimaemerges earlier than the low‐altitudeM. s. striata.Under conditions of warm acclimation,M. s. punctatissimahas a longer initial bask. The two subspecies do not differ in either mean selected temperature or critical thermal minimum, although in both cases values for cold acclimated lizards are lower than for warm acclimated lizards. I have previously demonstrated differences between the subspecies in the pattern of thermal acclimation of rate of oxygen consumption. I thus consider thatM. striatais static in some aspects of its thermal biology but labile in oth

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1991.tb00470.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

SummaryThis paper describes observations on body size, growth, and the timing of births in an individually identified population of oribi (Ourebia ourebi, Zimmermann 1783) in the Serengeti National Park, Tanzania. Females tended to be larger and approximately 2 kg heavier than males. Young oribi grew rapidly, attaining near‐adult size in about 7 months. Horns appeared in male oribi at about 4½ months of age and grew rapidly up to 20 months of age. Births occurred in all months of the year but were most common between March and June. The results provide an observational means of estimating the age of sub‐adult oribi by body size, and the age of adult male oribi, up to 20 months of age, by horn le

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1991.tb00471.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Variation in activities of Senegal kob (Kobus kob kob Erxleben 1777) during daylight period in an enclosure at Kainji Lake Research Institute range farm, New Busa, Nigeria

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1991.tb00472.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY