摘要:

SummaryA description is given of the 11,560 km2Bamingui‐Bangoran National Park situated in the mid‐Sudanian phytogeographic domain of the Central African Republic. Attention is drawn to the interest of the ecology of this little‐known zone, which lies between north‐south and east‐west ecotones, of the sahel‐tropical forest and oriental region west Africa, respectively. Preliminary collections of plants and small mammals were made. An analysis of the flora and the large mammals observed suggests a predominantly West African affinity. The sub‐specific endemism shown by the large mammals appears more probably linked to Pleistocene isolation by the Chari‐Logone river system, than to a mega Lake Chad as has been postu

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1988.tb00959.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummarySeasonal changes in plant biomass in the herb layer were measured at Nairobi National Park and Masai Mara Game Reserve in Kenya from January 1980 to February 1981. Plant biomass fluctuated in response to seasonal rainfall, and live biomass was correlated with rainfall and soil moisture at both locations. Peak values for live biomass at Nairobi National Park occurred at the end of the long rains during the June 1980 sample and ranged from 138 to 197gm‐2. Minimum values for live biomass at Nairobi occurred during a dry season in February 1981 and ranged from 8 to 39 g m‐2. The standing dead and litter compartments were larger than the live compartment during every sample period at Nairobi National Park, and together often comprised more than 80% of the total above‐ground biomass. Probably as a result of higher rainfall, peak values for live biomass at Masai Mara Game Reserve were higher than those at Nairobi. Again, peak biomass occurred during June following the long rains, and ranged from 218 to 294 gm‐2. Minimum values for live biomass occurred during February 1981, and ranged from 10 to 48 g m‐2. Standing dead and litter compartments were much smaller than at Nairobi National Park, reflecting more intense herbivore pressure and a greater frequency of fires at Masai Mara compared with that at Nairobi Nati

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1988.tb00960.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummarySignificant seasonal changes in the concentrations of N, P, K, and Ca were observed in the herb layer vegetation at Nairobi National Park and Masai Mara Game Reserve in Kenya. These changes were related to the alternation of wet and dry seasons. Live forbs typically had the highest concentrations of all nutrients, especially N and Ca, at both locations. Standing dead and litter compartments showed less seasonal variation and had the lowest concentrations of all nutrients except Ca when compared with those of other compartments. Standing stocks of all nutrients were higher at Nairobi National Park than at Masai Mara due to larger litter and standing dead compartments resulting from lower grazing intensity and a lower frequency of fire. Most of the aboveground nutrients at Nairobi National Park appeared to be recycled through the decomposer pathway, while a large proportion of the standing stock at Masai Mara appeared to be recycled through the excreta of large mammalian herbivores and through fires. The crude protein content of the live grass compartment fell below maintenance levels required for ruminants (5% crude protein) during September 1980 and February 1981 at Nairobi National Park and during June and July 1980 at Masai Mara Game Reserve. Thus, herbivore populations in these preserves may be limited by shortages of nutritionally adequate food during dry seasons, as previously reported for other regions in East Africa.

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1988.tb00961.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryPellet group counts, drive counts and track counts were used to estimate population abundances of one small and four large species of duiker (Cephalophussp.) in a moist evergreen forest in northeastern Zaire. Procedures to develop estimates based on line transect counts of pellet groups are described. The Fourier Series estimator proved to be useful for estimating densities of pellet groups. Comparisons were made between population abundance in heavily and lightly hunted areas, and between small and large species. The three census methods were consistent in showing no significant difference between animal abundance in the hunted populations or between abundances of the smaller species relative to the larger species. All methods showed potential as population indices for assessing trends of rare and elusive species in forest environments. Drive counts and pellet group counts may also be useful for estimating densities.

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1988.tb00962.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryEarth mounds at seven sites in upland areas of Kenya were examined. Termite activity was recorded from 91% of mounds and the major termite genus present wasOdontotermes.Generally, signs of the mole rat,Tachyoryctes splendenswere few and were present on only 18% mounds.All termite activity was mound‐centred but only at Kiserian were mounds obvious centres for mole rat activity. At Molo, whereTachyorycteswere abundant, neither mounds nor much sign of termite activity were observed.The data are discussed in relation to the work of Cox and Gakahu. No convincing evidence was found to support the conclusion made by these workers for a mole rat origin of large earth mounds. The weight of the data suggests that a termite origin for these mounds is more likel

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1988.tb00963.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryData were collected in Kenya on the movements of individually recognizable wild eland over a 30‐month period. Further information on movement was obtained from monthly ground counts of Nairobi National Park, and two aerial censuses of the Park and Athi Kapiti plains. Results indicated that adult male eland had restricted home ranges, but that females and juveniles carried out extensive seasonal movements between open grassland and bushed habitats. The numbers of eland in the Park were found to be related to rainfall over the previous two months in the areas outside the Park. It was concluded that females and juveniles were taking advantage of seasonal food abundance in open grassland areas, where the formation of large groups gives protection to small‐sized juveni

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1988.tb00964.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryThe population of lungfish (Protopterus aethiopicus(Heckel)) was sampled by bottom trawling for 12 months from June 1984 to May 1985. A total of 576 lungfish were investigated. The sex ratio in the population was 1 male : 1 ‐98 females. Average size at maturity was found to be 960cm total length (TL) but the smallest matured male measured 72‐9 cm and the female 840 cm TL. It was not possible to establish spawning times and reproductive activity trends either from the variation in relative condition factor ‘kn’ or from gonadosomatic index (GSI). Whereas male lungfish seem to show no further increase in GSI after gonadal maturity stage III, females exhibit GSI values that vary directly with oocyte maturation and ovarian weights. Fat deposited along the gonads was found to be a better basis for assessing maturation and spawning in lungfish. The potential spawning period was found to be from September to May. Absence of lungfish with spent gonads over the 12‐month period and the presence of different egg sizes in ovaries, suggest that the fish is a multiple spawner. Fecundity was found to range from 705 eggs (in 84‐cm TL fish) to 14,922 eggs (in 130

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1988.tb00965.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

SummaryStable carbon isotope ratios have been successfully used to assess modern animal diets and to reconstruct prehistoric diets of animals and humans (Vogel&van der Merwe, 1977; van der Merwe&Vogel, 1978; Burleigh&Brothwell, 1978; Vogel, 1978a; DeNiro&Epstein, 1978; Tieszenet al.,1979; Tieszen&Imbamba, 1980; Chisholm, Nelson&Schwarcz, 1982; Tauber, 1981). We have used13C/12C ratio measurements of bone collagen to study the diets of African elephants in twelve wildlife refuges. These represent most of the habitats in which elephants live, including such diverse plant communities as primary rain forest, savanna woodland and desert. The δ13C values were found to have a simple linear relationship with tree density in most cases. When translated into relative amounts of dietary browse (C3plants) and graze (C4plants), the grass content is seen to be systematically under‐represented, presumably due to inefficient metabolism. This does not affect the relationship between elephant diet and tree density, which has implications for the study of elephant‐woodland interactions, and for reconstructions of past African environm

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1988.tb00966.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1988.tb00967.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Book reviewed in this article:An Introduction to Behavioural Ecology by J. R. Krebs&N. B. Davies. BlackwellThe Savannas. Biogeography and Geobotany by Monica M. Cole.Building Models for Conservation and Wildlife Management. By A. M. Starficld&A. L. Bleloch.

ISSN:0141-6707    

DOI:10.1111/j.1365-2028.1988.tb00968.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY