10 research outputs found

    Population trends of Gentoo Penguins Pygoscelis Papua breeding at the Falkland Islands

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    The fourth archipelago-wide census of Gentoo Penguins Pygoscelis papua breeding at the Falkland Islands was conducted from 24 October to 8 December 2010. The number of Gentoo Penguins breeding in 2010 was estimated to be 132 321 ± 2 015, the highest number of breeding pairs recorded for this species at the Falkland Islands since the first survey in 1933. The global population of Gentoo Penguins is conservatively estimated to be about 384 000 breeding pairs, of which the Falkland Islands accounts for 34%, probably the largest component of the global population. Annually monitored study colonies accounted for 20% of the total number of Gentoo Penguin breeding pairs at the Falkland Islands in 2010 and proved to be a reliable proxy for archipelago-wide changes in the number of breeding pairs. Recent trends at annually monitored study colonies, combined with archipelago-wide trends, indicate that the number of Gentoo Penguins breeding at the Falkland Islands has increased between 2005 to 2010. However, annual monitoring data also revealed large inter-annual variability in the number of breeding pairs, which makes assessing systematic population changes challenging

    The distribution, abundance, status and global importance of giant petrels (Macronectes giganteus and M. halli) breeding at South Georgia

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    Information on the status of giant petrels breeding at South Georgia was previously based on studies at a small number of the archipelago's breeding sites. Here, we report the results of the first complete archipelago-wide survey of breeding northern Macronectes halli and southern M. giganteus giant petrels in the austral summers 2005/2006 and 2006/2007. We estimate that 15,398 pairs of northern and 8803 pairs of southern giant petrels bred at South Georgia. These are the largest and second largest populations at any island group, representing 71.0% and 17.3%, respectively, of updated global estimates of 21,682 pairs of northern and 50,819 pairs of southern giant petrels. A comparison of counts at locations surveyed in both 1986/1987–1987/1988 and 2005/2006–2006/2007 indicated increases of 74% and 27% in northern and southern giant petrels, respectively, over the intervening 18–20 years. The greater increase in northern giant petrels was likely influenced by the recovery of the Antarctic fur seal Arctocephalus gazella population at South Georgia, which provides an abundant but transient food resource (carrion). Due to allochrony, this provides greater benefits to northern giant petrels. The large, and increasing, population of king penguins Aptenodytes patagonicus at South Georgia also provides a potentially valuable food resource. The flexible and opportunistic foraging behaviour of giant petrels has contributed to their positive population trends. Other, more specialised, seabirds such as albatrosses have declined at South Georgia in recent decades mainly because of problems at sea, compounded by greater predation pressure from the increasing populations of giant petrels

    Recent trends in numbers of wandering (Diomedea exulans), black-browed (Thalassarche melanophris) and grey-headed (T. chrysostoma) albatrosses breeding at South Georgia

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    South Georgia supports globally important populations of seabirds, including the wandering albatross Diomedea exulans, black-browed albatross Thalassarche melanophris and grey-headed albatross T. chrysostoma, currently classified by the world Conservation Union (IUCN) as vulnerable, near threatened and endangered, respectively. Surveys of these species at South Georgia were conducted during the incubation stage in November 2014 to January 2015, repeating previous surveys conducted in the 2003/2004 season. Numbers of wandering albatrosses breeding annually at South Georgia decreased by 18% (1.8% per year) from 1553 pairs in 2003/2004 to an estimated 1278 pairs in 2014/2015. Over the same period, black-browed and grey-headed albatrosses decreased by 19% (1.9% per year) and 43% (5% per year), respectively. These represent a continuation of negative trends at South Georgia since the 1970s and are in contrast to some populations elsewhere, which have shown signs of recent recovery. Given the importance of South Georgia for these species, the ongoing population declines, and in the case of grey-headed albatrosses, an acceleration of the decline is of major conservation concern. Incidental fisheries mortality (bycatch) is currently considered to be the main threat. Although seabird bycatch has been reduced to negligible levels in the fisheries operating around South Georgia, wider implementation of effective seabird bycatch mitigation measures is required to improve the conservation status of the South Georgia populations of wandering, black-browed and grey-headed albatrosses. In addition, more research is required to investigate the respective roles of bycatch and climate change in driving these population trends

    Phenological Changes in the Southern Hemisphere

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    Current evidence of phenological responses to recent climate change is substantially biased towards northern hemisphere temperate regions. Given regional differences in climate change, shifts in phenology will not be uniform across the globe, and conclusions drawn from temperate systems in the northern hemisphere might not be applicable to other regions on the planet. We conduct the largest meta-analysis to date of phenological drivers and trends among southern hemisphere species, assessing 1208 long-term datasets from 89 studies on 347 species. Data were mostly from Australasia (Australia and New Zealand), South America and the Antarctic/subantarctic, and focused primarily on plants and birds. This meta-analysis shows an advance in the timing of spring events (with a strong Australian data bias), although substantial differences in trends were apparent among taxonomic groups and regions. When only statistically significant trends were considered, 82% of terrestrial datasets and 42% of marine datasets demonstrated an advance in phenology. Temperature was most frequently identified as the primary driver of phenological changes; however, in many studies it was the only climate variable considered. When precipitation was examined, it often played a key role but, in contrast with temperature, the direction of phenological shifts in response to precipitation variation was difficult to predict a priori. We discuss how phenological information can inform the adaptive capacity of species, their resilience, and constraints on autonomous adaptation. We also highlight serious weaknesses in past and current data collection and analyses at large regional scales (with very few studies in the tropics or from Africa) and dramatic taxonomic biases. If accurate predictions regarding the general effects of climate change on the biology of organisms are to be made, data collection policies focussing on targeting data-deficient regions and taxa need to be financially and logistically supported. Copyright: 2013 Chambers et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

    Return to Robben Island of African Penguins that were rehabilitated, relocated or reared in captivity following the Treasure oil spill of 2000

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    Following an oil spill from the Treasure off the coast of South Africa in June 2000, about 19 000 oiled African Penguins Spheniscus demersus, including 14 825 from Robben Island, were caught for rehabilitation and subsequent release. A further 19 500 penguins that were not oiled — mostly birds in adult plumage, including 7 000 from Robben Island — were relocated some 700km to the east, to prevent them becoming oiled. Additionally, 3 350 orphaned chicks, including 2 643 from Robben Island — were collected for rearing in captivity and release to the wild. Some four years later — by the end of December 2004 — 70% of rehabilitated adults, 40% of relocated birds and 34% of captive-reared chicks had been seen back at Robben Island. Another 7% of birds relocated from Robben Island had been sighted at other localities. Rates of resighting rehabilitated birds were similar at Robben and Dassen Islands, but a greater proportion of relocated birds was seen at Dassen Island, where birds collected for relocation were mostly from breeding areas. The lower proportion of relocated birds seen at Robben Island is thought to result from this intervention causing some pre-breeding birds to move to other colonies. All three conservation interventions are considered to have been successful, but it is premature to assess their relative contributions to the conservation of the species. Three relocated birds tracked by satellite took 15–21 days to return to their home colonies. This rapid return may have resulted from breeding attempts being interrupted. After remaining at their home islands for 4–5 days, two of the tracked birds then left these islands for 19–36 days. We surmise that, after they had searched unsuccessfully for their mates, they abandoned breeding for the year 2000. Ostrich 2006, 77(3&4): 202–20

    Summary of southern hemisphere phenological data by region.

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    <p>N is the number of datasets with a span of at least 10 years of data; 1208 data sets in total. N* is the number of datasets where trends over time [days/decade] were assessed – the three columns (earlier, later and no change [i.e. trend was calculated but was not considered statistical significant]; confidence level as reported in original papers, generally 5% level) sum to N*. Notes: * subantarctic regions under the jurisdiction of South America, Africa and Australia are included in Antarctic/subantarctic (e.g. Marion Island, Falkland Islands, Macquarie Island). <sup>†</sup> Freshwater species comprise Ardeidae (bitterns, herons and egrets), Anatidae (ducks and geese), Podicipedidea (grebes), Anhingidae (darters), and Phalacrocoracidae (cormorants). Marine species comprise penguins, seals, terns, gulls, albatrosses, petrels and shearwaters. <sup>§</sup> Range is based on 5<sup>th</sup> to 95<sup>th</sup> percentiles.</p

    Southern hemisphere phenological data set summaries.

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    <p>(a) Number of southern hemisphere phenological data sets by taxon and main foraging habitat, (b) Summary of direction of trends in southern hemisphere phenological data (%) by main season of phenological event, as a percentage of cases.</p><p>(c) Summary of southern hemisphere phenological data (number) by phenophase.</p><p>Not all datasets had published trends (and those that did were predominantly from Australia, see text for details) or directions of change and only those which explicitly tested for temporal trends are included here. A subset of these, which also recorded the standard error of the trend estimate, is analysed in more detail in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0075514#pone.0075514.s002" target="_blank">Appendix S2</a>. No change indicates a trend was calculated but was not considered statistical significant (confidence level as reported in original papers, generally 5% level). Mean trend in days per decade. <sup>§</sup> Range is based on 5<sup>th</sup> to 95<sup>th</sup> percentiles. Ratio (−/+) is the ratio of the number of negative to the number of positive trends observed, irrespective of the significance of the trend. Not all studies provided trends estimates [e.g. days/year] so the sum of the two ratio values do not equal the sum of Earlier, Later, No Change (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0075514#pone-0075514-t002" target="_blank">Table 2a</a>), N in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0075514#pone-0075514-t002" target="_blank">Table 2b</a> or the sum of the two ratio values. South American plant datasets were classified as wet or dry season but, as none had trends recorded, they have been excluded from this table.</p
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