摘要:

A short account is given of the aims and some preliminary results of the author's excavations at Sterkfontein, Transvaal (1966–1991) and at the Buxton Limeworks, Taung, Bophuthatswana (1988–1991). The Piltdown hoax and its relevance to the acceptance ofAustralopithecusare briefly reviewed, as is the role of Sir Arthur Keith, recently incriminated as the probable scientist-member of the team of forgers.

ISSN:0035-919X    

DOI:10.1080/00359199209520253

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The Tierberg Karoo Research Centre near Prince Albert in the southern Karoo is intended for long-term ecological monitoring and manipulative studies. This paper summarizes information on the management history, geology, soils, climate and vegetation and includes preliminary checklists of 189 vascular plant species, 25 ant, 90 bird, 18 reptile and 18 mammal species known to occur on the 1 km2study site. In comparison with arid shrublands in North America, Australia. Israel and elsewhere in southern Africa, grasses and annual forbs are scarce, succulents abundant and there are few alien taxa.

ISSN:0035-919X    

DOI:10.1080/00359199209520254

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The possession by the Royal Society of South Africa of a letter by Faraday supporting the publication of Joule's 1850 paper on the mechanical equivalent of heat is described. There was perhaps a closer relationship between the two men than has hitherto been supposed.

ISSN:0035-919X    

DOI:10.1080/00359199209520255

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The Cape Floristic Region (CFR) contains a disproportionate number of southern Africa's Red Data Book plants (70%), freshwater flsh (57%), amphibians (43%), butterflies (38%), and reptiles (35%), relative to the small area (4%) of the subcontinent which it occupies. With the exception of reptiles, the vast majority of these species are endemic to the CFR, occurring mainly in mountain and lowland fynbos vegetation. Among the threats to the continued survival of these species, agriculture and alien invasive plants rank highest overall, although many scavenging birds and large mammals have been hunted and poisoned to extinction within the CFR. An active reintroduction of these large mammals from outside the CFR has been the dominant strategy of local conservation agencies.The focus on large mammals as target species for conservation strategies has been to the detriment of floral preservation.The geographical distribution of threatened species is not related to the extent to which vegetation types have been transformed. Thus renoster shrubland, which has been reduced to 6 per cent of its original lowland extent, contains few Red Data Book taxa relative to fynbos. By far the largest concentration of Red Data Book species of plants, butterflies, reptiles and amphibians occurs in the greater Cape Town metropolitan area. With 15.1 Red Data Book plant species per km2, this area ranks as one of the most urgent conservation priorities in the world.

ISSN:0035-919X    

DOI:10.1080/00359199209520256

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Two categories of historical change in vertebrate populations are analysed: decreases leading to species being included in local Red Data Books and changes in distribution and abundance of what are often more common species, as revealed by regional surveys. The former category of change tends to reflect radical anthropogenic influences (e.g. habitat transformation, persecution and overuse). The latter generally reflects the more widespread forms of habitat modification (e.g. ‘bush encroachment’, the spread of alien trees into formerly ‘treeless’ biomes, and ‘desertification’ through overgrazing of semi-arid rangelands). Destruction of vleis and marshes has been important throughout the region. Any long-term climatic change that might have occurred over the last two centuries is not reflected by changes in vertebrate populations. Several vertebrate changes do, however, indicate a general tendency for the woody plant component of savanna communities to increase in density. This trend is consistent with the predicted response of these communities to the observed global increase in the atmospheric concentration of carbon dioxide. Short-term variations in annual rainfall have given rise to significant fluctuations in vertebrate populations. Vertebrates could be particularly useful in monitoring future climatic change where the effects of such change can be predicted in terms of alterations in the relative abundance of woody and herbaceous vegetation. Continuous monitoring of bird populations would probably be the most effective approach to detecting such changes. The effects of a wide range of other factors, as detailed in this analysis, must be filtered out before variations in vertebrate populations can be attributed to climatic change.

ISSN:0035-919X    

DOI:10.1080/00359199209520257

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The Palearctic musselMytilus galloprovincialishas recently invaded the southern African coast. Its present range extends from central Namibia to Hermanus, with an outlying population between Port Elizabeth and the Great Fish River. It is most abundant on the southern Benguela coast, where it occurs intertidally. It grows vigorously on suspended mussel ropes, but is absent from subtidal benthic substrata where the silt-tolerantChoromytilus meridionalispredominates. Intertidally, it outcompetes the indigenous musselAulacomya ater, by reason of its superior reproductive output, faster growth rate and greater tolerance to desiccation. It is a superior competitor to the intertidal limpetPatella granularisfor primary rock space, which is a favoured settlement and recruitment medium for this species. The rate ofMytilusinvasion in the Saldanha region between 1979 and 1988 was rapid, as evidenced by major changes in the diets of African black oystercatchersHaematopus moquini.Although at present largely confined to the cold temperate coasts of southern Africa,Mytilusgrows rapidly in warm water and its eventual colonization of the warm temperate and subtropical coasts seems inevitable, as does consequent competition with the indigenous brown musselPerna perna.No control measures are in operation. This species must be considered as out of control and uncontrollable, and research into its potential for commercial exploitation is needed.

ISSN:0035-919X    

DOI:10.1080/00359199209520258

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Because of their small size and limited mobility aquatic insects are seldom recognized as invasive species and only where verifiable historical data exist can introductions of exotic species be confirmed. Records of some generally considered cosmopolitan species could in fact be undocumented introductions. Of the entirely aquatic orders of insects only the Odonata are noted as regular invaders. Trichoptera, Ephemeroptera, Plecoptera and Megaloptera are all poor colonizers. In contrast, the Hemiptera, Diptera and Coleoptera have many species which show excellent colonizer and invader qualities. Diptera are recognized as the most deleterious of introduced aquatic insects because many of the species are pests and disease vectors of man and his livestock. Although no alien aquatic insect pests have been recorded in South Africa, the potential for the introduction of problem species exists.

ISSN:0035-919X    

DOI:10.1080/00359199209520259

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The Darwinian revolution in biological thinking gave priority to individual variation and rendered typological ideas and rigid classifications inappropriate for the study of life. Large biological variability of humans is a fact that must be accepted. In morphological characteristics such as body weight or brain size one half or more of the total variance within the species is produced by differences between individuals within the same populations, slightly less than one quarter by sexual dimorphism, and only about one quarter results from differences between populations. A large portion of variability is heritable; however, environmental influences during individual life play an important role. Perception of human variation is biased by prejudice. This is seen in the ascribing of a larger role to gender differences than really exists.

ISSN:0035-919X    

DOI:10.1080/00359199209520260

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0035-919X    

DOI:10.1080/00359199209520261

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

ISSN:0035-919X    

DOI:10.1080/00359199209520262

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor