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Population demography and spatial distribution of the mantis shrimp Squilla biformis (Stomatopoda, Squillidae) from Pacific Costa Rica

HERNAEZ, Patricio; CLARKE, Tayler McLellan; BENAVIDES-VARELA, Catalina; VILLALOBOS-ROJAS, Fresia; NIVIA-RUIZ, Jaime; WEHRTMANN, Ingo S.
Fonte: INTER-RESEARCH Publicador: INTER-RESEARCH
Tipo: Artigo de Revista Científica
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The mantis shrimp Squilla biformis is the most conspicuous and abundant stomatopod captured during benthic trawling operations off the Pacific coast of Costa Rica. Due to its abundance, this species is considered a potential fisheries resource for the region. Nevertheless, its life history is practically unknown. The present study describes the population demography, spatial distribution and behaviour of S. biformis from Pacific Costa Rica. The population was principally composed of individuals between 20 and 32 mm carapace length (CL), forming 2 age groups. Individuals of 35 to 45 mm CL and > 45 mm CL were poorly represented. We assume that larger individuals are more frequent at greater depths (probably on the continental slope), thus out of the reach of the fishing vessels used in our study. Males outnumbered females, as observed in other stomatopods. Visual evidence of their behaviour demonstrates that the adults in this species possess a benthic and pelagic life style. Largest numbers of individuals (50% of the total) were found between 240 to 260 m, the same bathymetric range that was historically occupied by commercial shrimps. This shift may be related to intense fishing activities. We observed a synchronized moulting of females and males during less luminous (third and fourth) lunar phases. The evolutionary development of a group moulting system could confer advantages to S. biformis in comparison to other stomatopods whose moulting process is individual and asynchronous.; Ristic AG (Oberferrieden...

Influência do microhabitat e da densidade e distância de vizinhos na demografia de populações espécies arbóreas; The influence of microhabitat and distance and density of neighborns on the population demography of four woody species

Carolina Bernucci Virillo
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 18/08/2010 Português
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Os mecanismos responsáveis pela alta diversidade de espécies arbóreas em florestas tropicais têm sido alvo de intenso debate na literatura, e dentre os inúmeros mecanismos propostos, dois deles têm encontrado relativo suporte empírico: a dependência de densidade e a diferenciação de nichos. O objetivo deste trabalho foi investigar a ocorrência destes mecanismos na Floresta Ombrófila Densa Atlântica, que apresenta uma enorme diversidade de espécies vegetais, que variam em abundância, e uma grande diversidade de habitats, o que faz deste bioma um local apropriado para buscar evidências da ocorrência desses mecanismos. Foi investigada a influência da densidade de coespecíficos, da vizinhança e do microhábitat na demografia de quatro espécies arbóreas, e esperava-se que estes fatores atuassem de maneira conjunta na determinação da demografia das espécies estudadas. Em cinco áreas de 0,25 ha, duas na Floresta Ombrófila Densa de Terras Baixas (TB) e três na Floresta Ombrófila Densa Submontana (SM), foram marcados e medidos os indivíduos destas espécies, e um recenso foi realizado após dois anos para obtenção de taxas de mortalidade e recrutamento. Indivíduos com PAP (perímetro a altura do peito) > 15 cm foram acompanhados mensalmente para a avaliação da fenologia reprodutiva e do incremento diamétrico. Foi avaliada a influência da densidade de indivíduos e da distância e número de vizinhos coespecíficos na demografia das espécies. Também foi avaliada a relação da demografia com habitats específicos...

Long-term population demography of Trillium recurvatum on loess bluffs in western Tennessee, USA

Moore, James E.; Franklin, Scott B.; Wein, Gary; Collins, Beverly S.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
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The paper uses modified population viability models and spatial structure via block analysis to assess population demography of Trillium recurvatum a clonal understory plant. The population is expanding, a likely outcome of the relatively high proportion of juvenile and non-flowering adult ramets and fast-replicating non-flowering adults. Further work is needed to elucidate the relative contributions of clonal vs seed recruitment to genetic structure and demography.

The Phylogeography and Population Demography of the Yunnan Caecilian (Ichthyophis bannanicus): Massive Rivers as Barriers to Gene Flow

Wang, Hui; Luo, Xia; Meng, Shaoquan; Bei, Yongjian; Song, Tao; Meng, Tao; Li, Guifen; Zhang, Baowei
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 27/04/2015 Português
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Ichthyophis bannanicus is the only caecilian species in China. In this study, the phylogeography and population demography of I. bannanicus were explored, based on the mitochondrial DNA genes (cyt b and ND2) and 15 polymorphic microsatellite loci. Altogether 158 individuals were collected from five populations in Yunnan province, Guangxi province, Guangdong province, and Northern Vietnam. Phylogeographical and population structure analysis identified either two groups (Xishuangbanna, Northern Vietnam-Yulin-Yangchun-Deqing) or three groups (Xishuangbanna, Northern Vietnam-Yulin-Yangchun, and Deqing), indicating that the Red River and Pearl River systems may have acted as gene-flow barriers for I. bannanicus. Historical population expansion that happened 15–17 Ka ago was detected for mtDNA data and was possibly triggered by warmer weather after the Last Glacial Maximum. However, the Bayesian simulations of population history based on microsatellite data pinpointed population decline in all populations since 19,123 to 1,029 years ago, demonstrating a significant influence of anthropogenic habitat alteration on I. bannanicus.

Low fertility: unifying the theory and the demography

McDonald, Peter
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Working/Technical Paper Formato: 212187 bytes; 359 bytes; application/pdf; application/octet-stream
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The market is very short-term and favors flexible, childless people averse to risk, while the private world of the family requires them to be self-sacrificing and prepared to accept risks. These two areas - which some still consider to be separate - attest to the old division of labor between men and women. The reinforcement of the male breadwinner model of the family is not the solution to the dilemma that we now face in maintaining social reproduction in combination with a free-market approach to production. What is required is no less than a new social contract asserting that children are a social good and not merely a private, optional pleasure. The new social contract also must be one based on gender equity.; Paper prepared for Session 73, Future of Fertility in Low Fertility Countries, 2002 Meeting of the Population Association of America, Atlanta, 9-11 May 2002. Population Futures and Low Fertility: papers by Peter McDonald and Rebecca Kippen.; no

The population of South-East Asia

Jones, Gavin W
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Working/Technical Paper Formato: 186313 bytes; 347 bytes; application/pdf; application/octet-stream
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The population of South-East Asia has recently passed the 500 million mark. Although growth is slowing, another 140 million may be added over the 20-year period 1995-2015. The additional population will be concentrated in the working ages and among the elderly. In many countries of the region – for example, Thailand, Indonesia and Vietnam – there will little or no further growth in the number of children and adolescents. Almost all countries will continue to benefit for some time yet from a decline in dependency ratios that has been in train since the early 1970s. By the mid-1990s, the whole region had progressed three quarters of the way toward replacement fertility in Singapore to continued very high fertility in Lao PDR. A general theory explaining the varied fertility experiences of the different countries remains elusive. Although South-East Asia remains one of the world’s least urbanized regions, urbanization is increasingly rapidly and the region contains some of the world’s largest cities. Because of wide differences between countries in their mortality and fertility transitions, levels of urbanization, systems of governance, and ethnic and cultural background, the key issues facing population policy and approaches to dealing with them remain diverse.; no

Changing patterns of population distribution in Australia

Hugo, G.
Fonte: Australian Population Association Publicador: Australian Population Association
Tipo: Artigo de Revista Científica
Publicado em //2002 Português
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The spatial dimension of Australia's demography has received limited research attention. This is despite evidence of unprecedented concern among policy makers over perceived wide differentials in wellbeing between different parts of the country. This paper seeks to identify recent and emerging trends in Australia's population distribution, and argues that it is one of the most dynamic and policy-relevant dimensions of the contemporary demographic situation. The paper analyses first the changing distribution of population between the states, then the shifting balance between metropolitan and nonmetropolitan areas. Trends in areas classified according to their degree of remoteness are discussed next, the focus then moving to the changing population distributions within nonmetropolitan Australia and within metropolitan areas. It is argued that there is a growing dichotomization in both nonmetropolitan and metropolitan Australia between areas of growth and areas of decline. Some attention is also given to distributional aspects of social wellbeing.; Graeme Hugo; © Australian Population Association

The Future Aged: New Projections of Australia's Elderly Population

Booth, Heather; Tickle, Leonie
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Working/Technical Paper Formato: 63241 bytes; 347 bytes; 347 bytes; application/pdf; application/octet-stream; application/octet-stream
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Objectives: To use new methodology to forecast mortality for use in projections of the elderly population of Australia and to compare them with official projections. Method: The Lee-Carter method is applied to data for Australian females and males for 1968–2000 to forecast mortality to 2031. These forecasts are used with standard population projection methods to produce projections of the elderly population. Results: By 2027, forecast life expectancy is 88.1 and 82.9 years for females and males, compared with official projections of 85.4 and 81.4 years. Over the period to 2031, the populations aged 65+ and 85+ are forecast to increase by factors of 2.3 and 3.4 respectively. Compared with official projections, the forecast elderly population is substantially larger and has higher old-age dependency ratios, higher proportions aged 85+ and lower sex ratios. Conclusion: Official projections underestimate the size of the future elderly population especially the female and oldest-old populations. This article will be published in the Australasian Journal on Ageing.; no

Population futures for Australia: the policy alternatives

McDonald, Peter; Kippen, Rebecca
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Working/Technical Paper Formato: 209015 bytes; 15166 bytes; 12648 bytes; 10239 bytes; 14015 bytes; 14122 bytes; 12742 bytes; 14745 bytes; 15063 bytes; 8253 bytes; 7439 bytes; 13151 bytes; 14827 bytes; 3416 bytes; text/html; image/gif; image/gif; image/gif; image/gif; image/gif; image/gif
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In recent years, there has been intense debate about the population size to which Australia should aim in the 21st century. Some argue for a much lower population than we have now. The environmentalist, Tim Flannery, for example, has suggested that Australians might opt for a future population of between 6 and 12 million people. Others argue for a considerably larger population. For example, former Prime Minister, Malcolm Fraser, would like to see a population of 45 to 50 million people in the next 50 years. This paper shows that the targets specified by both Flannery and Fraser are unattainable in the next 50 years because such targets can only be reached through levels of immigration which are impossibly negative on one side or impossibly large on the other side. The demographic reality is that the options for Australia's future population size are much more limited than the options that are considered in popular debate. The limiting factor is our low, and falling, level of fertility. The powerful demographic effects of low fertility have been little appreciated. One of the aims of this paper is to provide such an appreciation. We show that with zero net migration, Australia's projected levels of fertility and mortality would lead to the population rising initially to 20 million and then falling slowly in the first half of next century and rapidly in the second half. The population would age dramatically and the size of the labour force would fall markedly. We argue that these are not desirable outcomes and that...

Comments on intergenerational report, 2002-2003

McDonald, Peter; Dowrick, S
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Working/Technical Paper Formato: 40924 bytes; application/pdf
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The Government's Intergenerational Report, tabled as one of a series of 2002 Federal Budget papers is the first in what may become a series of reports of this nature. Such a report is now required from time to time by the Government's Charter of Budget Honesty Act 1998 . The report (Table 13) highlights the concern that the future ageing of the Australian population may over-tax the workforce. So-called "demographic spending" on the part of the Commonwealth is predicted to rise from 13.9 percent of GDP in 2000 to 19.2 percent by 2041, a rise of just over five percentage points. This prediction is derived from baseline projections of demographic and economic trends. The impact of alternative demographic and economic scenarios is summarised in Table 15 of the report, with a downside of an additional two-and-a-quarter percentage points and an upside of a reduction in demographic spending of just under one -and-ahalf percentage points, relative to the baseline scenario. 1

The results of the report derive from the application of a complex model of future demography, future people-related federal outlays and future labour force trends, including labour productivity, labour force participation rates and unemployment. Clearly, over a 40-year period...

Australia's population futures

McDonald, Peter
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Working/Technical Paper Formato: 248205 bytes; 360 bytes; application/pdf; application/octet-stream
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There are four components that go into the making of population projections: fertility, mortality, migration and the size and age structure of the base population. One of the central demographic lessons is that much of a population's future is contained in its present age structure, which, in turn, is primarily the result of its past fertility history. In broad terms, Australia's fertility was relatively low in the 1930s and 1940s, high in the 1950s and 1960s and very low in the 1980s and 1990s. This 70-year history of fertility is very much reflected in Australia&'s present age structure and is the central reason that we can be absolutely certain that Australia will experience substantial ageing of its population in the coming decades as the large number of births of the 1950s and 1960s replaces the small number born in the 1930s and 1940s at the older ages, while, at younger ages, there is no increase in the size of age cohorts. While it is often stated that post-war immigration has kept Australia's population young, it has been shown that in fact this immigration had no impact at all on the age distribution of the Australian population. Falling mortality rates, particularly in the past 25 years, however, have contributed to population ageing (to a lesser extent than past fertility) and variations in future mortality levels can have a significant impact on the extent of population ageing. The existing age structure is what gives population futures "aircraft carrier" nature...

The impact of immigration on the ageing of Australia's population

McDonald, Peter; Kippen, Rebecca
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Working/Technical Paper Formato: 76225 bytes; 347 bytes; application/pdf; application/octet-stream
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In 1998, just over 12 per cent of Australia’s population were aged 65 years and over. Population projections indicate that this percentage is likely to at least double in the next 40 years. This trend has given rise to concerns about the capacity of our economy in the future to support the older members of our society. In particular, an older population implies increased costs for aged pensions and health and aged care services. As part of the response to this future situation, it has been suggested that we should reduce the extent or speed of ageing through changes to immigration policy. The argument is that, as immigrants are younger on average than the Australian population, an increase in the level of immigration would reduce the ageing of the population. To strengthen the case, it has also been suggested that the immigration program should recruit persons who are younger than the immigrants that enter Australia now. The call is for more and younger immigrants who have skill levels at least equal to those of immigrants at present. In addition, proponents of this position sometimes claim that immigrants have higher fertility than the Australian average, so that higher immigration would increase Australia’s birth rate and...

The impact of long-term visitors on projections of Australia's population

Kippen, Rebecca; McDonald, Peter
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Working/Technical Paper Formato: 192806 bytes; application/pdf
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In 1999 and 2000, for the first time, net long-term visitor migration exceeded net permanent migration, by nine per cent in 1999 and by 21 per cent in 2000. This report focuses on the longer-term demographic implications of this change by constructing an alternative population projection methodology.; no

Delaware Population Consortium: Annual Population Projections

Fonte: Center for Applied Demography & Survey Research Publicador: Center for Applied Demography & Survey Research
Tipo: Outros Formato: 493524 bytes; application/pdf
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This document is divided into three sections following some introductory text. Section A contains the latest version (2000) of the population projections. The projections reflect a slight decrease in the total population over last year’s, largely because of a major review of net migration (see Notes on page 9) and benchmarking to the Census Bureau’s 1999 estimates. These data also incorporate the actual births and deaths since 1990. Section B contains the ever popular “population pyramids” that display in easily digestible fashion, the complexity of the tables found in Section A. Section C includes illustrative population projections by race for the City of Wilmington. Finally, Section D contains total household and population projections for Census County Divisions (CCD’s).

Annual Population Projections by Delaware Population Consortium 2008 (DPC)

Ratledge, Edward C.
Fonte: Center for Applied Demography & Survey Research Publicador: Center for Applied Demography & Survey Research
Tipo: Outros
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The Delaware Population Consortium was formed in 1975, with the goal of "providing a continuing forum for debate and discussion of matters relating to state and local population growth.; The Delaware Population Consortium (DPC) is pleased to continue its program of providing 30-year population and employment projections for the State, the counties, and for selected municipalities. These projections incorporate new information that has been provided to or generated by DPC members and other agencies at the federal, state, and local level.

Annual Population Projections by Delaware Population Consortium 2007 (DPC)

Ratledge, Edward C.
Fonte: Center for Applied Demography & Survey Research Publicador: Center for Applied Demography & Survey Research
Tipo: Outros
Português
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46.05%
The Delaware Population Consortium was formed in 1975, with the goal of "providing a continuing forum for debate and discussion of matters relating to state and local population growth.; The Delaware Population Consortium (DPC) is pleased to continue its program of providing 30-year population and employment projections for the State, the counties, and for selected municipalities. These projections incorporate new information that has been provided to or generated by DPC members and other agencies at the federal, state, and local level.

Annual Population Projections by Delaware Population Consortium 2006 (DPC)

Ratledge, Edward C.
Fonte: Center for Applied Demography & Survey Research Publicador: Center for Applied Demography & Survey Research
Tipo: Outros
Português
Relevância na Pesquisa
46.05%
The Delaware Population Consortium was formed in 1975, with the goal of "providing a continuing forum for debate and discussion of matters relating to state and local population growth.; The Delaware Population Consortium (DPC) is pleased to continue its program of providing 30-year population and employment projections for the State, the counties, and for selected municipalities. These projections incorporate new information that has been provided to or generated by DPC members and other agencies at the federal, state, and local level.

Annual Population Projections by Delaware Population Consortium 2005 (DPC)

Ratledge, Edward C.; Center for Applied Demography & Survey Research
Fonte: Center for Applied Demography & Survey Research Publicador: Center for Applied Demography & Survey Research
Tipo: Outros
Português
Relevância na Pesquisa
56.24%
The Delaware Population Consortium (DPC) is pleased to continue its program of providing 30-year population and employment projections for the State, the counties, and for selected municipalities. These projections incorporate new information that has been provided to or generated by DPC members and other agencies at the federal, state, and local level.

Delaware Demographics

Center for Applied Demography & Survey Research
Fonte: Center for Applied Demography & Survey Research Publicador: Center for Applied Demography & Survey Research
Tipo: Conferência ou Objeto de Conferência
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A public service by the Center for Applied Demography and Survey Research.

Life history and demography of an uncooperative Australian passerine, the brown thornbill

Green, David; Cockburn, Andrew
Fonte: CSIRO Publishing Publicador: CSIRO Publishing
Tipo: Artigo de Revista Científica
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The genus Acanthiza may be important in understanding the evolution of avian mating systems because while brown thornbills, Acanthiza pusilla, are thought to breed only in pairs, a recent phylogenetic analysis suggests that cooperative breeding is the ancestral trait within this genus. We provide a detailed account of the breeding biology of the brown thornbill, confirm that they breed exclusively in pairs, and compare their population demography with what is known for other members of the Pardalotidae. We found that brown thornbills produced small clutches (3 eggs) with a two-day laying interval, had a long incubation period (declining from 19 to 16 days through the season), and had a long breeding season (4.0 months) that allowed females to occasionally raise two successful broods. Brown thornbills, in our study, produced an average of 1.57 fledglings per pair and had relatively high annual survival rates (c. 63%). We found no evidence to suggest that the evolution of pair-breeding within the Pardalotidae is associated with a reduction in annual survival rates, a short breeding season with reduced productivity, or high levels of predation post-fledging. Since there also appear to be no ecological correlates with mating system in the Pardalotidae we suggest that examination of reproductive conflict between parents and young may shed light on the evolution of pair-breeding in this family.