南极乔治王岛的苔藓植物

从魏江春博士在1983-1984年于南极乔治王岛所采的苔藓标本及中国南极委员会李振培先生于1985年从该岛所收集的标本中,鉴定了7种苔藓植物,它们分别隶属4科和6属.其中湿原藓属(Calliergon)和镰刀藓属(Drepanocladus)植物在潮湿生境生长,卵叶黑藓(Andreaea obovata)适于干旱石质生境。扭口藓(Barbula unguiculata)和土生墙藓(Tortu-la ruralis)则可忍受非持久干旱的环境。这七个种中除了卵叶黑藓和黄色湿原藓外几乎均系世界广布种,它们可能为南极大陆漂移至目前位置前或由强风把孢子带至南极。     

THE BIRDS OF TASMANIA: ECOLOGY AND EVOLUTION

SUMMARY Tasmania, about the size of Ireland, separated from the Australian mainland by 140 miles of sea, and isolated for about the last 12,000 years, has 104 species of native breeding land-birds, with the addition of ten introduced species. The environment is described; in particular the vegetation is classified into nine natural types and three produced by European man; and the distribution of the bird species among these is defined and discussed. The other vertebrates are briefly considered. No extinction is definitely known to have taken place as a result of European settlement except of the Tasmanian Emu (and of course Tasmanian Man). An attempt is made to reconstruct the Late Pleistocene history of Tasmania and its vegetation, with special reference to the Last Glaciation, when the island would have been joined to the mainland. When the avifauna is divided into categories, water-birds, raptors, etc., it is found to have much the same proportional composition as the Australian mainland avifaunas with which it is compared, though it consists of many fewer species. The vegetation types of the colder and wetter areas of Tasmania house far fewer species of birds than the drier and warmer habitats. The 104 breeding species include 14 endemics, which are considered in detail, and 27 endemic subspecies. As shown by comparison with other islands, the total proportionate endemism is extraordinarily high for a recent continental island (though it is actually lower than that in the remote ecological island formed by the sclerophyll of southwestern Western Australia). A contributory cause may be that Tasmania is not regularly visited by land-birds from the continent (though at least one-fifth of the Tasmanian species are partial or total migrants in winter). The most noteworthy endemics are two monotypic genera, Lathamus and Acanthornis, and the Native Hen Tribonyx mortierii, which has become flightless apparently in the face of a formidable array of local predators. Considerations of climate and habitat suggest that at least half the avifauna, including 19 of the endemic subspecies and six of the members of superspecies, arrived in Tasmania some time after the amelioration of the Last Glaciation began, some 18,000 years ago. Geographical considerations suggest that four of those six members of superspecies existed in their present form when the land-bridge to the mainland was cut, 12,000 years ago. Certain habitats, widespread over southeastern Australia during the glaciation, are now virtually confined to Tasmania where they form the stronghold of certain species, such as the Pink Robin Petroica rodinogaster, which occur only as relicts on the mainland. The endemic Scrub Tit Acanthornis magnus is practically confined to such habitats, where its ecology suggests it would have been well adapted to glacial conditions. Among the local endemics there is a strong tendency for colouration to be more saturated than on the continent of Australia (Gloger's rule) but there is less consistency in tendency to greater size (Bergmann's rule). A noteworthy proportion of the Tasmanian species have duller plumage than their mainland relatives, usually with an assimilation to female or juvenile plumage—unexpected in an island as big as Tasmania with so considerable an avifauna.     

THE SEA-BIRDS OF GOUGH ISLAND

Between November 1955 and May 1956 continuous observations were made on the sea-birds of Gough Island. These have been augmented by further occasional observations during seven subsequent years, and are compared with all previous published records for the island.
A check-list of 30 species of sea-birds has been compiled and substantiated, as far as possible, by a series of skins of 20 species.
Nearly 900 sea-birds cf 20 species were caught and measured, considerably more than at any previous time there; in the case of eight species, these are analysed in detail and some are compared with those from other populations.
The relative status of each species was estimated, together with total breeding populations where possible. In same cases the distribution of nests was mapped.
A detailed sound and photographic record, of 14 and 16 species respectively, was made.
Numbers of Wandering Albatrosses Diomedea exulans dabbenena and skuas Catharacta skua hamiltoni were ringed and colour-marked respectively to enable a more detailed study to be made of them.
General observations were made on the nesting seasons, breeding behaviour and moult of various species which are treated systematically.     

THE BIOLOGY OF THE WAVED ALBATROSS DIOMEDEA IRRORATA OF HOOD ISLAND, GALAPAGOS

As a nesting species, the Waved Albatross Diomedea irrorata is restricted to Hood Island in the Galapagos archipelago where 12,000 pairs bred in 1971. Outside the islands the species occurs over the northern parts of the Humboldt Current. Two colonies were studied in detail (1970–1971). At the start of a season, males returned first to the colonies and defended a small territory. Copulation occurred without any elaborate ceremony and the female spent little time on land before laying. There was no fixed nest-site, even within a season, and birds moved their eggs considerable distances. This resulted in heavy egg losses. Younger birds bred later than older birds and laid longer but narrower eggs. The average incubation spell varied from four to five days at the extremes of the incubation period to 19 days in the middle. The average incubation and fledging periods were 60 and 167 days respectively. Pairs which lost an egg sometimes adopted the abandoned egg of another bird and successfully reared the chick. Most pairs nested in both seasons. Nesting success was extremely variable, both between years and between colonies. Between 1961 and 1971 at Punta Suarez, virtually no young were reared in four seasons. Even in 1970–71, where nesting success was good, some groups of birds deserted their eggs en masse whereas in neighbouring areas up to 80% of the pairs reared young. The main foods of the young were squid and fish. Birds did not moult wing and tail feathers at the breeding colonies, and about 50% retained some primaries for more than one season, suggesting that successful pairs had difficulty in fitting in a complete moult between breeding attempts. Old feathers were normally found among the inner primaries and at the next moult were preferentially replaced, though adjacent newer feathers were sometimes retained for another season. Some birds bred in their fourth years, but most not until a year or two older. Immatures were present at the colonies late in the breeding cycle, the youngest returning latest and remaining until the last young fledged. Survival of adults and young averaged at least 95% and 93% per annum over many years. Adults and young ringed in 1961 survived equally well. The significance of the timing of the return of immatures and of the large-scale desertion of eggs, apparently not due to food shortage or disturbance, is discussed.