Beyond Population and Environment: Household Life Cycle Demography and Land Use Allocation among Small Farm Colonists in the Amazon

NASA Technical Reports Server (NTRS)

Perz, Stephen G.; Walker, Robert T.; Caldas, Marcellus M.

2006-01-01

Most research featuring demographic factors in environmental change has focused on processes operating at the level of national or global populations. This paper focuses on household-level demographic life cycles among colonists in the Amazon, and evaluates the impacts on land use allocation. The analysis goes beyond prior research by including a broader suite of demographic variables, and by simultaneously assessing their impacts on multiple land uses with different economic and ecological implications. We estimate a system of structural equations that accounts for endogeneity among land uses, and the findings indicate stronger demographic effects than previous work. These findings bear implications for modeling land use, and the place of demography in environmental research.

Long-term impacts of recurrent logging and fire in Amazon forests: a modeling study using the Ecosystem Demography Model (ED2)

NASA Astrophysics Data System (ADS)

Longo, M.; Keller, M.; Scaranello, M. A., Sr.; dos-Santos, M. N.; Xu, Y.; Huang, M.; Morton, D. C.

2017-12-01

Logging and understory fires are major drivers of tropical forest degradation, reducing carbon stocks and changing forest structure, composition, and dynamics. In contrast to deforested areas, sites that are disturbed by logging and fires retain some, albeit severely altered, forest structure and function. In this study we simulated selective logging using the Ecosystem Demography Model (ED-2) to investigate the impact of a broad range of logging techniques, harvest intensities, and recurrence cycles on the long-term dynamics of Amazon forests, including the magnitude and duration of changes in forest flammability following timber extraction. Model results were evaluated using eddy covariance towers at logged sites at the Tapajos National Forest in Brazil and data on long-term dynamics reported in the literature. ED-2 is able to reproduce both the fast (< 5yr) recovery of water, energy fluxes compared to flux tower, and the typical, field-observed, decadal time scales for biomass recovery when no additional logging occurs. Preliminary results using the original ED-2 fire model show that canopy cover loss of forests under high-intensity, conventional logging cause sufficient drying to support more intense fires. These results indicate that under intense degradation, forests may shift to novel disturbance regimes, severely reducing carbon stocks, and inducing long-term changes in forest structure and composition from recurrent fires.

Political demography: Powerful trends under-attended by demographic science.

PubMed

Teitelbaum, Michael S

2015-01-01

The interconnections between politics and the dramatic demographic changes under way around the world have been neglected by the two research disciplines that could contribute most to their understanding: demography and political science. Instead, this area of 'political demography' has largely been ceded to political activists, pundits, and journalists, leading often to exaggerated or garbled interpretation. The terrain includes some of the most politically sensitive and contested issues: alleged demographically determined shifts in the international balance of power; low fertility, population decline, and demographic ageing; international migration; change in national identity; and compositional shifts in politically sensitive social categories and human rights. Meanwhile many governments and non-governmental actors have actively pursued varieties of 'strategic demography', deploying fertility, mortality, or migration as instruments of domestic or international policy. Political scientists and demographers could and should use their knowledge and analytic techniques to improve understanding and to moderate excessive claims and fears on these topics.

Area Handbook Series: Finland: A Country Study

DTIC Science & Technology

1988-12-01

79 DEMOGRAPHY ................................... 79 External M igration ........................... 81 Internal...blue-collar workers (see Demography ; Social Struc- ture, ch. 2). Along with the changes in social and in economic cir- cumstances went changes in popular...examination of the social forces involved in the for- mation of the Finnish state. C. Leonard Lundin’s Finland in the Second World War was a pioneering work

Integrating Paleodistribution Models and Phylogeography in the Grass-Cutting Ant Acromyrmex striatus (Hymenoptera: Formicidae) in Southern Lowlands of South America

PubMed Central

Cristiano, Maykon Passos; Clemes Cardoso, Danon; Fernandes-Salomão, Tânia Maria; Heinze, Jürgen

2016-01-01

Past climate changes often have influenced the present distribution and intraspecific genetic diversity of organisms. The objective of this study was to investigate the phylogeography and historical demography of populations of Acromyrmex striatus (Roger, 1863), a leaf-cutting ant species restricted to the open plains of South America. Additionally, we modeled the distribution of this species to predict its contemporary and historic habitat. From the partial sequences of the mitochondrial gene cytochrome oxidase I of 128 A. striatus workers from 38 locations we estimated genetic diversity and inferred historical demography, divergence time, and population structure. The potential distribution areas of A. striatus for current and quaternary weather conditions were modeled using the maximum entropy algorithm. We identified a total of 58 haplotypes, divided into five main haplogroups. The analysis of molecular variance (AMOVA) revealed that the largest proportion of genetic variation is found among the groups of populations. Paleodistribution models suggest that the potential habitat of A. striatus may have decreased during the Last Interglacial Period (LIG) and expanded during the Last Maximum Glacial (LGM). Overall, the past potential distribution recovered by the model comprises the current potential distribution of the species. The general structuring pattern observed was consistent with isolation by distance, suggesting a balance between gene flow and drift. Analysis of historical demography showed that populations of A. striatus had remained constant throughout its evolutionary history. Although fluctuations in the area of their potential historic habitat occurred during quaternary climate changes, populations of A. striatus are strongly structured geographically. However, explicit barriers to gene flow have not been identified. These findings closely match those in Mycetophylax simplex, another ant species that in some areas occurs in sympatry with A. striatus. Ecophysiological traits of this species and isolation by distance may together have shaped the phylogeographic pattern. PMID:26734939

Reconstructing the historic demography of an endangered seabird

Treesearch

Steven R. Beissinger; Zachariah M. Peery

2007-01-01

Reducing extinction risk for threatened species requires determining which demographic parameters are depressed and causing population declines. Museum collections may constitute a unique, underutilized resource for measuring demographic changes over long time periods using age-ratio analysis. We reconstruct the historic demography of a U.S. federally endangered...

Mathematical demography of spotted owls in the Pacific Northwest

Treesearch

B.R. Noon; C.M. Biles

1990-01-01

We examined the mathematical demography of northern spotted owls (Strix occidentalis caurina) using simple deterministic population models. Our goals were to gain insights into the life history strategy, to determine demographic attributes most affecting changes in population size, and to provide guidelines for effective management of spotted owl...

Effects of Holocene climate change on the historical demography of migrating sharp-shinned hawks (Accipiter striatus velox) in North America.

PubMed

Hull, Joshua M; Girman, Derek J

2005-01-01

DNA sequences of the mitochondrial control region were analysed from 298 individual sharp-shinned hawks (Accipiter striatus velox) sampled at 12 different migration study sites across North America. The control region proved to be an appropriate genetic marker for identification of continental-scale population genetic structure and for determining the historical demography of population units. These data suggest that sharp-shinned hawks sampled at migration sites in North America are divided into distinct eastern and western groups. The eastern group appears to have recently expanded in response to the retreat of glacial ice at the end of the last glacial maximum. The western group appears to have been strongly effected by the Holocene Hypsithermal dry period, with molecular evidence indicating the most recent expansion following this mid-Holocene climatic event 7000-5000 years before present.

Grand Forks - East Grand Forks Urban Water Resources Study. Background Information Appendix.

DTIC Science & Technology

1981-07-01

Social Organization 121 Introduction 121 Demography 122 Racial Distribution 139 Ethnic Groups 141 Neighborhood Groups 141 Religion 143 Crime 144...of agricultural clearing operations and urban growth. Native tree species are important because of their longevity and now relatively infrequent... Demography Geographic Distribution Governmental Organiization Economy Occupational Structure Education Social Support Services 109 CULTURAL ELEM1ENTS

Alternative glacial-interglacial refugia demographic hypotheses tested on Cephalocereus columna-trajani (Cactaceae) in the intertropical Mexican drylands

PubMed Central

Cornejo-Romero, Amelia; Aguilar-Martínez, Gustavo F.; Medina-Sánchez, Javier; Rendón-Aguilar, Beatriz; Valverde, Pedro Luis; Zavala-Hurtado, Jose Alejandro; Serrato, Alejandra; Rivas-Arancibia, Sombra; Pérez-Hernández, Marco Aurelio; López-Ortega, Gerardo; Jiménez-Sierra, Cecilia

2017-01-01

Historic demography changes of plant species adapted to New World arid environments could be consistent with either the Glacial Refugium Hypothesis (GRH), which posits that populations contracted to refuges during the cold-dry glacial and expanded in warm-humid interglacial periods, or with the Interglacial Refugium Hypothesis (IRH), which suggests that populations contracted during interglacials and expanded in glacial times. These contrasting hypotheses are developed in the present study for the giant columnar cactus Cephalocereus columna-trajani in the intertropical Mexican drylands where the effects of Late Quaternary climatic changes on phylogeography of cacti remain largely unknown. In order to determine if the historic demography and phylogeographic structure of the species are consistent with either hypothesis, sequences of the chloroplast regions psbA-trnH and trnT-trnL from 110 individuals from 10 populations comprising the full distribution range of this species were analysed. Standard estimators of genetic diversity and structure were calculated. The historic demography was analysed using a Bayesian approach and the palaeodistribution was derived from ecological niche modelling to determine if, in the arid environments of south-central Mexico, glacial-interglacial cycles drove the genetic divergence and diversification of this species. Results reveal low but statistically significant population differentiation (FST = 0.124, P < 0.001), although very clear geographic clusters are not formed. Genetic diversity, haplotype network and Approximate Bayesian Computation (ABC) demographic analyses suggest a population expansion estimated to have taken place in the Last Interglacial (123.04 kya, 95% CI 115.3–130.03). The species palaeodistribution is consistent with the ABC analyses and indicates that the potential area of palaedistribution and climatic suitability were larger during the Last Interglacial and Holocene than in the Last Glacial Maximum. Overall, these results suggest that C. columna-trajani experienced an expansion following the warm conditions of interglacials, in accordance with the GRH. PMID:28426818

Alternative glacial-interglacial refugia demographic hypotheses tested on Cephalocereus columna-trajani (Cactaceae) in the intertropical Mexican drylands.

PubMed

Cornejo-Romero, Amelia; Vargas-Mendoza, Carlos Fabián; Aguilar-Martínez, Gustavo F; Medina-Sánchez, Javier; Rendón-Aguilar, Beatriz; Valverde, Pedro Luis; Zavala-Hurtado, Jose Alejandro; Serrato, Alejandra; Rivas-Arancibia, Sombra; Pérez-Hernández, Marco Aurelio; López-Ortega, Gerardo; Jiménez-Sierra, Cecilia

2017-01-01

Historic demography changes of plant species adapted to New World arid environments could be consistent with either the Glacial Refugium Hypothesis (GRH), which posits that populations contracted to refuges during the cold-dry glacial and expanded in warm-humid interglacial periods, or with the Interglacial Refugium Hypothesis (IRH), which suggests that populations contracted during interglacials and expanded in glacial times. These contrasting hypotheses are developed in the present study for the giant columnar cactus Cephalocereus columna-trajani in the intertropical Mexican drylands where the effects of Late Quaternary climatic changes on phylogeography of cacti remain largely unknown. In order to determine if the historic demography and phylogeographic structure of the species are consistent with either hypothesis, sequences of the chloroplast regions psbA-trnH and trnT-trnL from 110 individuals from 10 populations comprising the full distribution range of this species were analysed. Standard estimators of genetic diversity and structure were calculated. The historic demography was analysed using a Bayesian approach and the palaeodistribution was derived from ecological niche modelling to determine if, in the arid environments of south-central Mexico, glacial-interglacial cycles drove the genetic divergence and diversification of this species. Results reveal low but statistically significant population differentiation (FST = 0.124, P < 0.001), although very clear geographic clusters are not formed. Genetic diversity, haplotype network and Approximate Bayesian Computation (ABC) demographic analyses suggest a population expansion estimated to have taken place in the Last Interglacial (123.04 kya, 95% CI 115.3-130.03). The species palaeodistribution is consistent with the ABC analyses and indicates that the potential area of palaedistribution and climatic suitability were larger during the Last Interglacial and Holocene than in the Last Glacial Maximum. Overall, these results suggest that C. columna-trajani experienced an expansion following the warm conditions of interglacials, in accordance with the GRH.

Population inertia and its sensitivity to changes in vital rates and population structure

USGS Publications Warehouse

Koons, David N.; Holmes, Randall R.; Grand, James B.

2007-01-01

Because the (st)age structure of a population may rarely be stable, studies of transient population dynamics and population momentum are becoming ever more popular. Yet, studies of "population momentum" are restricted in the sense that they describe the inertia of population size resulting from a demographic transition to the stationary population growth rate. Although rarely mentioned, inertia in population size is a general phenomenon and can be produced by any demographic transition or perturbation. Because population size is of central importance in demography, conservation, and management, formulas relating the sensitivity of population inertia to changes in underlying vital rates and population structure could provide much-needed insight into the dynamics of populations with unstable (st)age structure. Here, we derive such formulas, which are readily computable, and provide examples of their potential use in studies of life history and applied arenas of population study. ?? 2007 by the Ecological Society of America.

Merced County Streams Project, Bear Reservoir, California. Intensive Cultural Resources Survey.

DTIC Science & Technology

1982-03-01

all shown on the Official Map of Mariposa County for 1897. William A. Grade, a pioneer merchant of Mariposa, began buying ranch lands to the north of...divided into four areas: (1) cultural change, (2) subsistence and settlement, (3) cultural and social interactions, and (4) paleo- demography . Numerous...indicative of the Yosemite region. Other research questions, based upon research domains such as demography , are possible but, given the limitations of a cul

Effect of the Spanish Conquest on coastal change in Northwestern Peru

PubMed Central

Belknap, Daniel F.; Sandweiss, Daniel H.

2014-01-01

When Francisco Pizarro and his small band of Spanish conquistadores landed in northern Peru in A.D. 1532 to begin their conquest of the vast Inca Empire, they initiated profound changes in the culture, language, technology, economics, and demography of western South America. They also altered anthropogenically modulated processes of shoreline change that had functioned for millennia. Beginning with the extirpation of local cultures as a result of the Spanish Conquest, and continuing through today, the intersection of demography, economy, and El Niño-driven beach-ridge formation on the Chira beach-ridge plain of Northwestern Peru has changed the nature of coastal evolution in this region. A similar event may have occurred at about 2800 calibrated y B.P. in association with increased El Niño frequency. PMID:24843118

Effect of the Spanish Conquest on coastal change in Northwestern Peru

NASA Astrophysics Data System (ADS)

Belknap, Daniel F.; Sandweiss, Daniel H.

2014-06-01

When Francisco Pizarro and his small band of Spanish conquistadores landed in northern Peru in A.D. 1532 to begin their conquest of the vast Inca Empire, they initiated profound changes in the culture, language, technology, economics, and demography of western South America. They also altered anthropogenically modulated processes of shoreline change that had functioned for millennia. Beginning with the extirpation of local cultures as a result of the Spanish Conquest, and continuing through today, the intersection of demography, economy, and El Niño-driven beach-ridge formation on the Chira beach-ridge plain of Northwestern Peru has changed the nature of coastal evolution in this region. A similar event may have occurred at about 2800 calibrated y B.P. in association with increased El Niño frequency.

Effect of the Spanish Conquest on coastal change in Northwestern Peru.

PubMed

Belknap, Daniel F; Sandweiss, Daniel H

2014-06-03

When Francisco Pizarro and his small band of Spanish conquistadores landed in northern Peru in A.D. 1532 to begin their conquest of the vast Inca Empire, they initiated profound changes in the culture, language, technology, economics, and demography of western South America. They also altered anthropogenically modulated processes of shoreline change that had functioned for millennia. Beginning with the extirpation of local cultures as a result of the Spanish Conquest, and continuing through today, the intersection of demography, economy, and El Niño-driven beach-ridge formation on the Chira beach-ridge plain of Northwestern Peru has changed the nature of coastal evolution in this region. A similar event may have occurred at about 2800 calibrated y B.P. in association with increased El Niño frequency.

Contrasting patterns of population history and seed-mediated gene flow in two endemic Costa Rican oak species.

PubMed

Rodríguez-Correa, Hernando; Oyama, Ken; Quesada, Mauricio; Fuchs, Eric J; González-Rodríguez, Antonio

2018-03-02

Lower Central America is an important area to study recent population history and diversification of Neotropical species due to its complex and dynamic geology and climate. Phylogeographic studies in this region are few in comparison with other regions and even less for tree species. The aim of the present study was to characterize the phylogeographic structure in two partially co-distributed endemic oak species (Quercus costaricensis and Q. bumelioides) of the Costa Rican mountains using chloroplast short sequence repeats (cpSSRs), and to test for the effect of geological and palaeoclimatic processes on their population history. Genetic diversity and structure, haplotype networks, patterns of seed-mediated gene flow and historical demography were estimated for both species. Results suggested contrasting patterns. Quercus costaricensis exhibited high values of genetic diversity, a marked phylogeographic structure, a north-to-south genetic diversity gradient and evidence of a demographic expansion during the Quaternary. Quercus bumelioides did not show significant genetic structure and the haplotype network and historical demography estimates suggested a recent population expansion probably during the Pleistocene-Holocene transition. Phylogeographic structure of Q. costaricensis seems to be related to Pleistocene altitudinal migration due to its higher altitudinal distribution. Meanwhile, historical seed-mediated gene flow through the lower altitudinal distribution of Q. bumelioides may have promoted the homogenization of genetic variation. Population expansion and stable availability of suitable climatic areas in both species probably indicate that palaeoclimatic changes promoted downwards altitudinal migration and formation of continuous forests allowing oak species to expand their distribution into the Panamanian mountains during glacial stages.

What population studies can do for business.

PubMed

Hugo, G

1991-05-01

This paper examines how specific skills essential to demography, the scientific study of human populations, can be useful in private and public sector planning. Over the past 2 decades, Australia's population has undergone profound transformations -- a shift to below replacement level fertility and a change in ethnic composition, to name a few. And these changes have reshaped the markets for goods, services, and labor. Because demography seeks to analyze and explain changes in the size, composition, and spatial distribution of people, this discipline requires certain skills that can be particularly valuable to both private and public sector planning. These skills include: 1) a sound knowledge of why and how populations change over time; 2) a wide range of concepts (the "cohort," for example) which allow demographers to analyze the dynamics of change in a population; 3) statistical techniques; and 4) life tables techniques. Having named the specific skills of demographers, the author identifies the areas of business and public administration where these skills can be most useful, areas that include the following: strategic long-term planning, marketing, market segmentation, small area analysis, household and family level analysis, projections and estimates, human resources analysis, and international population trends. Finally, the author discusses the implications of applied population analysis on the training of demographers in Australia, emphasizing the role of the Australian Population Association in improving the status of demography as an important planning tool.

[The Impact of Demography, Migration, New Technologies and the Self-Actualization Movement on the Education System and on the Economic System.] Testimony of Jerry L. Fletcher, Prepared for The Joint Economic Committee Special Study on Economic Change, June 1, 1978.

ERIC Educational Resources Information Center

Fletcher, Jerry L.

Demography, urban to rural migration, new educational technologies, and the human potential movement all impact on education. With the decline in number of school-aged children, schools can try to expand the number of students downward (early childhood education/day care), outward (special education, dropouts), or upward (adults), expand service…

Household demography and early childhood mortality in a rice-farming village in Northern Laos.

PubMed

Tomita, Shinsuke; Parker, Daniel M; Jennings, Julia A; Wood, James

2015-01-01

This paper extends Alexandr Chayanov's model of changing household demography (specifically the ratio of food consumers to food producers) and its influence on agricultural behavior so that it includes possible adverse effects of a rising ratio on nutritional status and early childhood mortality within the household. We apply the model to 35 years' worth of longitudinal demographic and economic data collected in the irrigated-rice growing village of Na Savang in northern Laos. When appropriate controls are included for other household variables, unobserved inter-household heterogeneity, and changes in local conditions and national policy over the study period, the analysis suggests that a unit increase in the household's consumer/producer ratio induces something like a nine-fold increase in the risk of death among household members aged less than five years. Monte Carlo simulation studies suggest that this may be an over-estimate but also that the effect is probably real and likely to be an important factor in household demography. At the very least, the results suggest that Chayanov's model still has theoretical relevance and deserves to be revived.

Household Demography and Early Childhood Mortality in a Rice-Farming Village in Northern Laos

PubMed Central

Tomita, Shinsuke; Parker, Daniel M.; Jennings, Julia A.; Wood, James

2015-01-01

This paper extends Alexandr Chayanov’s model of changing household demography (specifically the ratio of food consumers to food producers) and its influence on agricultural behavior so that it includes possible adverse effects of a rising ratio on nutritional status and early childhood mortality within the household. We apply the model to 35 years’ worth of longitudinal demographic and economic data collected in the irrigated-rice growing village of Na Savang in northern Laos. When appropriate controls are included for other household variables, unobserved inter-household heterogeneity, and changes in local conditions and national policy over the study period, the analysis suggests that a unit increase in the household’s consumer/producer ratio induces something like a nine-fold increase in the risk of death among household members aged less than five years. Monte Carlo simulation studies suggest that this may be an over-estimate but also that the effect is probably real and likely to be an important factor in household demography. At the very least, the results suggest that Chayanov’s model still has theoretical relevance and deserves to be revived. PMID:25775467

Bayesian demography 250 years after Bayes

PubMed Central

Bijak, Jakub; Bryant, John

2016-01-01

Bayesian statistics offers an alternative to classical (frequentist) statistics. It is distinguished by its use of probability distributions to describe uncertain quantities, which leads to elegant solutions to many difficult statistical problems. Although Bayesian demography, like Bayesian statistics more generally, is around 250 years old, only recently has it begun to flourish. The aim of this paper is to review the achievements of Bayesian demography, address some misconceptions, and make the case for wider use of Bayesian methods in population studies. We focus on three applications: demographic forecasts, limited data, and highly structured or complex models. The key advantages of Bayesian methods are the ability to integrate information from multiple sources and to describe uncertainty coherently. Bayesian methods also allow for including additional (prior) information next to the data sample. As such, Bayesian approaches are complementary to many traditional methods, which can be productively re-expressed in Bayesian terms. PMID:26902889

The future demographic niche of a declining grassland bird fails to shift poleward in response to climate change

USGS Publications Warehouse

McCauley, Lisa A.; Ribic, Christine; Pomara, Lars Y.; Zuckerberg, Benjamin

2017-01-01

ContextTemperate grasslands and their dependent species are exposed to high variability in weather and climate due to the lack of natural buffers such as forests. Grassland birds are particularly vulnerable to this variability, yet have failed to shift poleward in response to recent climate change like other bird species in North America. However, there have been few studies examining the effect of weather on grassland bird demography and consequent influence of climate change on population persistence and distributional shifts.ObjectivesThe goal of this study was to estimate the vulnerability of Henslow’s Sparrow (Ammodramus henslowii), an obligate grassland bird that has been declining throughout much of its range, to past and future climatic variability.MethodsWe conducted a demographic meta-analysis from published studies and quantified the relationship between nest success rates and variability in breeding season climate. We projected the climate-demography relationships spatially, throughout the breeding range, and temporally, from 1981 to 2050. These projections were used to evaluate population dynamics by implementing a spatially explicit population model.ResultsWe uncovered a climate-demography linkage for Henslow’s Sparrow with summer precipitation, and to a lesser degree, temperature positively affecting nest success. We found that future climatic conditions—primarily changes in precipitation—will likely contribute to reduced population persistence and a southwestward range contraction.ConclusionsFuture distributional shifts in response to climate change may not always be poleward and assessing projected changes in precipitation is critical for grassland bird conservation and climate change adaptation.

The impact of lianas on the carbon cycle of tropical forests: a modeling study using the Ecosystem Demography model

NASA Astrophysics Data System (ADS)

di Porcia e Brugnera, M.; Longo, M.; Verbeek, H.

2017-12-01

Lianas are an important component of tropical forests, constituting up to 40% of the woody stems and about 35% of the woody species. Tropical forests have been experiencing large-scale structural changes, including an increase in liana abundance and biomass. This may eventually reduce the projected carbon sink of tropical forests. Despite their crucial role no single terrestrial ecosystem model has included lianas so far. Here, we present the very first implementation of lianas in the Ecosystem Demography model (ED2). ED2 is able to represent the competition for water and light between different vegetation types at the regional level. Our new implementation of ED2 is hence suitable to address important questions such as the impact of lianas on the tropical forest carbon balance. We validated the model against forest inventory and eddy covariance flux data at a dry seasonal site (Barro Colorado Island, Panama), and at a wet rainforest site (Paracou, French Guiana). The model was able to represent size structure and carbon accumulation rates. We also evaluated the impact of the unique allocation strategy of lianas on their competitive ability. Lianas invest only a small fraction of their carbon for structural tissues when compared to trees. As a result, lianas benefit from an extra amount of available carbon, however the trade-offs of low allocation on structural tissues are not yet well understood. We are currently investigating a number of hypotheses, including the possibility for lianas to have high turnover rates for leaves and fine roots, or to have high mortality rates due to the loss of structural support when trees die. As such our model allows us to get a better understanding of the role of lianas in the tropical forest carbon cycle.

Variation in the biomass density and demography of Antarctic krill in the vicinity of the South Shetland Islands during the 1999/2000 austral summer

NASA Astrophysics Data System (ADS)

Hewitt, R. P.; Kim, S.; Naganobu, M.; Gutierrez, M.; Kang, D.; Takao, Y.; Quinones, J.; Lee, Y.-H.; Shin, H.-C.; Kawaguchi, S.; Emery, J. H.; Demer, D. A.; Loeb, V. J.

2004-06-01

Vessels from Japan, Peru, and the USA conducted four sequential surveys designed to estimate the biomass density and demography of Antarctic krill in the vicinity of the South Shetland Islands between late December 1999 and early March 2000. The surveys were conducted during the same austral summer as the CCAMLR 2000 Survey in the Scotia Sea (Watkins et al., Deep-Sea Research, II, this issue [doi: 10.1016/j.dsr2.2004.06.010]), and the data were analyzed in a similar manner. Biomass densities were not significantly different between the surveys and averaged 49 g m -2. Maps of krill biomass indicate three areas of consistently high density: one near the eastern end of Elephant Island, one mid-way between Elephant Island and King George Island, and one near Cape Shirreff on the north side of Livingston Island. The areas of highest krill density appeared to move closer to the shelf break as the season progressed. This apparent movement was accompanied by a change in the demographic structure of the population, with smaller krill absent and a larger proportion of sexually mature animals present in late summer.

Teaching Business Demography Using Case Studies.

PubMed

Swanson, David A; Morrison, Peter A

2010-02-01

Many faculty members consider using case studies but not all end up using them. We provide a brief review of what cases are intended to do and identify three ways in which they can be used. We then use an example to illustrate how we have used the case study method in teaching business demography. Among other benefits, we note that the case studies method not only encourages the acquisition of skills by students, but can be used to promote "deep structure learning," an approach naturally accommodates other features associated with the case studies method-the development of critical thinking skills, the use of real world problems, the emphasis of concepts over mechanics, writing and presentation skills, active cooperative learning and the "worthwhileness" of a course. As noted by others, we understand the limitations of the case study method. However, given its strengths, we believe it has a place in the instructional toolbox for courses in business demography. The fact that courses we teach is a testament to our perceived efficacy of this tool.

Greening TVET: Qualifications Needs and Implementation Strategies. Report of the UNESCO-UNEVOC Virtual Conference, 12 to 26 November 2013

ERIC Educational Resources Information Center

UNESCO-UNEVOC International Centre for Technical and Vocational Education and Training, 2014

2014-01-01

Technical and vocational education and training (TVET) faces a number of challenges, including technological and societal changes, exemplified by changes in demography, rapidly changing labour markets, persistent social inequalities and conflict. These changes require people to possess skills that are adaptable to the changing nature of work and…

Predicted Water and Carbon Fluxes as well as Vegetation Distribution on the Korean Peninsula in the Future with the Ecosystem Demography Model version 2

NASA Astrophysics Data System (ADS)

Kim, J. B.; Kim, Y.

2017-12-01

This study investigates how the water and carbon fluxes as well as vegetation distribution on the Korean peninsula would vary with climate change. Ecosystem Demography (ED) Model version 2 (ED2) is used in this study, which is an integrated terrestrial biosphere model that can utilize a set of size- and age- structured partial differential equations that track the changing structure and composition of the plant canopy. With using the vegetation distribution data of Jeju Island, located at the southern part of the Korean Peninsula, ED2 is setup and driven for the past 10 years. Then the results of ED2 are evaluated and adjusted with observed forestry data, i.e., growth and mortality, and the flux tower and MODIS satellite data, i.e., evapotranspiration (ET) and gross primary production (GPP). This adjusted ED2 are used to simulate the water and carbon fluxes as well as vegetation dynamics in the Korean Peninsula for the historical period with evaluating the model against the MODIS satellite data. Finally, the climate scenarios of RCP 2.6 and 6.0 are used to predict the fluxes and vegetation distribution of the Korean Peninsula in the future. With using the state-of-art terrestrial ecosystem model, this study would provide us better understanding of the future ecosystem vulnerability of the Korean Peninsula. AcknowledgementsThis work was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning (2015R1C1A2A01054800) and by the Korea Meteorological Administration R&D Program under Grant KMIPA 2015-6180. This work was also supported by the Yonsei University Future-leading Research Initiative of 2015(2016-22-0061).

LATE PLEISTOCENE ENVIRONMENTAL CHANGES LEAD TO UNSTABLE DEMOGRAPHY AND POPULATION DIVERGENCE OF ANOPHELES ALBIMANUS IN THE NORTHERN NEOTROPICS

PubMed Central

Loaiza, Jose R.; Scott, Marilyn E.; Bermingham, Eldredge; Sanjur, Oris I.; Wilkerson, Richard; Rovira, Jose; Gutiérrez, Lina A.; Correa, Margarita M.; Grijalva, Mario; Birnberg, Lotty; Bickersmith, Sara; Conn, Jan E.

2011-01-01

We investigated the historical demography of Anopheles albimanus using mosquitoes from five countries and three different DNA regions, the mitochondrial cytochrome oxidase subunit I gene (COI), the single copy nuclear white gene and the ribosomal internal transcribed spacer two (ITS2). All the molecular markers supported the taxonomic status of a single species of An. albimanus. Furthermore, agreement between the COI and the white genes suggested a scenario of Pleistocene geographic fragmentation (i.e., population contraction) and subsequent range expansion across southern Central America. PMID:20888924

Demographic studies of Joshua trees in Mojave Desert National Parks: demography with emphasis on germination and recruitment

USGS Publications Warehouse

Esque, T.C.; Reynolds, B.; DeFalco, L.A.; Waitman, B.A.; Hughson, Debra

2010-01-01

The study of population change with regard to reproduction, seed dispersal, and germination, establishment, growth, and survival/mortality is known as demography. Demographic studies provide managers with information to assess future trends on the density, distribution, health, and population changes of importance or value, including Joshua trees (Yucca brevifolia). Demographic research provides the potential to understand the combined impacts of climate change and land-use practices and determine if strategies for protecting important species are likely to succeed or fall short of management goals and will identify factors that have the potential to de-stabilize populations outside the realm of natural variation so that management strategies can be developed to circumvent challenges for key species, processes, and ecosystems. The National Park Service and US Geological Survey are collaborating to collect demographic information about the demographics of Joshua tree in the Mojave Desert.

ALM-FATES: Using dynamic vegetation and demography to capture changes in forest carbon cycling and competition at the global scale

NASA Astrophysics Data System (ADS)

Holm, J. A.; Knox, R. G.; Koven, C.; Riley, W. J.; Bisht, G.; Fisher, R.; Christoffersen, B. O.; Dietze, M.; Chambers, J. Q.

2017-12-01

The inclusion of dynamic vegetation demography in Earth System Models (ESMs) has been identified as a critical step in moving ESMs towards more realistic representations of plant ecology and the processes that govern climatically important fluxes of carbon, energy, and water. Successful application of dynamic vegetation models, and process-based approaches to simulate plant demography, succession, and response to disturbances without climate envelopes at the global scale is a challenging endeavor. We integrated demographic processes using the Functionally-Assembled Terrestrial Ecosystem Simulator (FATES) in the newly developed ACME Land Model (ALM). We then use an ALM-FATES globally gridded simulation for the first time to investigate plant functional type (PFT) distributions and dynamic turnover rates. Initial global simulations successfully include six interacting and competing PFTs (ranging from tropical to boreal, evergreen, deciduous, needleleaf and broadleaf); including more PFTs is planned. Global maps of net primary productivity, leaf area index, and total vegetation biomass by ALM-FATES matched patterns and values when compared to CLM4.5-BGC and MODIS estimates. We also present techniques for PFT parameterization based on the Predictive Ecosystem Analyzer (PEcAn), field based turnover rates, improved PFT groupings based on trait-tradeoffs, and improved representation of multiple canopy positions. Finally, we applied the improved ALM-FATES model at a central Amazon tropical and western U.S. temperate sites and demonstrate improvements in predicted PFT size- and age-structure and regional distribution. Results from the Amazon tropical site investigate the ability and magnitude of a tropical forest to act as a carbon sink by 2100 with a doubling of CO2, while results from the temperate sites investigate the response of forest mortality with increasing droughts.

Tree demography suggests multiple directions and drivers for species range shifts in mountains of Northeastern United States.

PubMed

Wason, Jay W; Dovciak, Martin

2017-08-01

Climate change is expected to lead to upslope shifts in tree species distributions, but the evidence is mixed partly due to land-use effects and individualistic species responses to climate. We examined how individual tree species demography varies along elevational climatic gradients across four states in the northeastern United States to determine whether species elevational distributions and their potential upslope (or downslope) shifts were controlled by climate, land-use legacies (past logging), or soils. We characterized tree demography, microclimate, land-use legacies, and soils at 83 sites stratified by elevation (~500 to ~1200 m above sea level) across 12 mountains containing the transition from northern hardwood to spruce-fir forests. We modeled elevational distributions of tree species saplings and adults using logistic regression to test whether sapling distributions suggest ongoing species range expansion upslope (or contraction downslope) relative to adults, and we used linear mixed models to determine the extent to which climate, land use, and soil variables explain these distributions. Tree demography varied with elevation by species, suggesting a potential upslope shift only for American beech, downslope shifts for red spruce (more so in cool regions) and sugar maple, and no change with elevation for balsam fir. While soils had relatively minor effects, climate was the dominant predictor for most species and more so for saplings than adults of red spruce, sugar maple, yellow birch, cordate birch, and striped maple. On the other hand, logging legacies were positively associated with American beech, sugar maple, and yellow birch, and negatively with red spruce and balsam fir - generally more so for adults than saplings. All species exhibited individualistic rather than synchronous demographic responses to climate and land use, and the return of red spruce to lower elevations where past logging originally benefited northern hardwood species indicates that land use may mask species range shifts caused by changing climate. © 2016 John Wiley & Sons Ltd.

Counting Souls: Towards an historical demography of Africa

PubMed Central

Walters, Sarah

2016-01-01

Background Little is known about even the relatively recent demographic history of Africa, because of the lack of data. Elsewhere, historical demographic trends have been reconstructed by applying family reconstitution to church records. Such data also exist throughout Africa from the late 19th century. For the Counting Souls Project, nearly one million records from the oldest Catholic parishes in East and Central Africa have been digitised. These data are currently being processed into a relational database. The aim of this paper is to describe their potential for demographic reconstruction in the region, and to outline how their provenance defines the analytical approach. Results Empirically, religion is correlated with population patterns in contemporary Africa, and, historically, reproduction and family formation were central to Christian mission in the region. Measuring change using sources created by agents of change raises questions of epistemology, causation, and selection bias. This paper describes how these concerns are balanced by missionary determination to follow the intimate lives of their parishioners, to monitor their ‘souls’, and to measure their morality, fidelity, and faith. This intimate recording means that the African parish registers, together with related sources such as missionary diaries and letters and oral histories, describe qualitatively and quantitatively what happens to individual agency (reproductive decision-making) when the moral hegemony shifts (via evangelisation and colonisation), and how the two interact in a reciprocal process of change. Conclusion Reconstructing long-term demographic trends using parish registers in Africa is therefore more than simply generating rates and testing their reliability. It is a bigger description of how ‘decision rules’ are structured and re-structured, unpicking the cognitive seam between individual and culture by exploring dynamic micro-interactions between reproduction, honour, hope, and modernity over the long term. With such a mixed-methods approach, parish registers offer real potential for historical demography in Africa. PMID:27313490

Recent demography drives changes in linked selection across the maize genome

USDA-ARS?s Scientific Manuscript database

The interaction between genetic drift and selection in shaping genetic diversity is not fully understood. In particular, a population's propensity to drift is typically summarized by its long-term e_ective population size (Ne), but rapidly changing population demographics may complicate this relatio...

Impacts of climatic variation on trout: A global synthesis and path forward

USGS Publications Warehouse

Kovach, Ryan; Muhlfeld, Clint C.; Al-Chokhachy, Robert K.; Dunham, Jason B.; Letcher, Benjamin; Kershner, Jeffrey L.

2016-01-01

Despite increasing concern that climate change may negatively impact trout—a globally distributed group of fish with major economic, ecological, and cultural value—a synthetic assessment of empirical data quantifying relationships between climatic variation and trout ecology does not exist. We conducted a systematic review to describe how temporal variation in temperature and streamflow influences trout ecology in freshwater ecosystems. Few studies (n = 42) have quantified relationships between temperature or streamflow and trout demography, growth, or phenology, and nearly all estimates (96 %) were for Salvelinus fontinalis and Salmo trutta. Only seven studies used temporal data to quantify climate-driven changes in trout ecology. Results from these studies were beset with limitations that prohibited quantitatively rigorous meta-analysis, a concerning inadequacy given major investment in trout conservation and management worldwide. Nevertheless, consistent patterns emerged from our synthesis, particularly a positive effect of summer streamflow on trout demography and growth; 64 % of estimates were positive and significant across studies, age classes, species, and locations, highlighting that climate-induced changes in hydrology may have numerous consequences for trout. To a lesser degree, summer and fall temperatures were negatively related to population demography (51 and 53 % of estimates, respectively), but temperature was rarely related to growth. To address limitations and uncertainties, we recommend: (1) systematically improving data collection, description, and sharing; (2) appropriately integrating climate impacts with other intrinsic and extrinsic drivers over the entire lifecycle; (3) describing indirect consequences of climate change; and (4) acknowledging and describing intrinsic resiliency.

Sensitivity of woody carbon stocks to bark investment strategy in Neotropical savannas and forests

NASA Astrophysics Data System (ADS)

Trugman, Anna T.; Medvigy, David; Hoffmann, William A.; Pellegrini, Adam F. A.

2018-01-01

Fire frequencies are changing in Neotropical savannas and forests as a result of forest fragmentation and increasing drought. Such changes in fire regime and climate are hypothesized to destabilize tropical carbon storage, but there has been little consideration of the widespread variability in tree fire tolerance strategies. To test how aboveground carbon stocks change with fire frequency and composition of plants with different fire tolerance strategies, we update the Ecosystem Demography model 2 (ED2) with (i) a fire survivorship module based on tree bark thickness (a key fire-tolerance trait across woody plants in savannas and forests), and (ii) plant functional types representative of trees in the region. With these updates, the model is better able to predict how fire frequency affects population demography and aboveground woody carbon. Simulations illustrate that the high survival rate of thick-barked, large trees reduces carbon losses with increasing fire frequency, with high investment in bark being particularly important in reducing losses in the wettest sites. Additionally, in landscapes that frequently burn, bark investment can broaden the range of climate and fire conditions under which savannas occur by reducing the range of conditions leading to either complete tree loss or complete grass loss. These results highlight that tropical vegetation dynamics depend not only on rainfall and changing fire frequencies but also on tree fire survival strategy. Further, our results indicate that fire survival strategy is fundamentally important in regulating tree size demography in ecosystems exposed to fire, which increases the preservation of aboveground carbon stocks and the coexistence of different plant functional groups.

Molecular insights into the historic demography of bowhead whales: understanding the evolutionary basis of contemporary management practices

PubMed Central

Phillips, C D; Hoffman, J I; George, J C; Suydam, R S; Huebinger, R M; Patton, J C; Bickham, J W

2013-01-01

Patterns of genetic variation observed within species reflect evolutionary histories that include signatures of past demography. Understanding the demographic component of species' history is fundamental to informed management because changes in effective population size affect response to environmental change and evolvability, the strength of genetic drift, and maintenance of genetic variability. Species experiencing anthropogenic population reductions provide valuable case studies for understanding the genetic response to demographic change because historic changes in the census size are often well documented. A classic example is the bowhead whale, Balaena mysticetus, which experienced dramatic population depletion due to commercial whaling in the late 19th and early 20th centuries. Consequently, we analyzed a large multi-marker dataset of bowhead whales using a variety of analytical methods, including extended Bayesian skyline analysis and approximate Bayesian computation, to characterize genetic signatures of both ancient and contemporary demographic histories. No genetic signature of recent population depletion was recovered through any analysis incorporating realistic mutation assumptions, probably due to the combined influences of long generation time, short bottleneck duration, and the magnitude of population depletion. In contrast, a robust signal of population expansion was detected around 70,000 years ago, followed by a population decline around 15,000 years ago. The timing of these events coincides to a historic glacial period and the onset of warming at the end of the last glacial maximum, respectively. By implication, climate driven long-term variation in Arctic Ocean productivity, rather than recent anthropogenic disturbance, appears to have been the primary driver of historic bowhead whale demography. PMID:23403722

Stunted by climate

NASA Astrophysics Data System (ADS)

2011-11-01

With expertise in geography and human health, Marta Jankowska and David López-Carr worked with a team of specialists in climate science, statistics, demography and policy to study climate change impacts on child malnutrition in Mali.

Fishing-induced changes in adult length are mediated by skipped-spawning.

PubMed

Wang, Hui-Yu; Chen, Ying-Shiuan; Hsu, Chien-Chung; Shen, Sheng-Feng

2017-01-01

Elucidating fishing effects on fish population dynamics is a critical step toward sustainable fisheries management. Despite previous studies that have suggested age or size truncation in exploited fish populations, other aspects of fishing effects on population demography, e.g., via altering life histories and density, have received less attention. Here, we investigated the fishing effects altering adult demography via shifting reproductive trade-offs in the iconic, overexploited, Pacific bluefin tuna Thunnus orientalis. We found that, contrary to our expectation, mean lengths of catch increased over time in longline fisheries. On the other hand, mean catch lengths for purse seine fisheries did not show such increasing trends. We hypothesized that the size-dependent energetic cost of the spawning migration and elevated fishing mortality on the spawning grounds potentially drive size-dependent skipped spawning for adult tuna, mediating the observed changes in the catch lengths. Using eco-genetic individual-based modeling, we demonstrated that fishing-induced evolution of skipped spawning and size truncation interacted to shape the observed temporal changes in mean catch lengths for tuna. Skipped spawning of the small adults led to increased mean catch lengths for the longline fisheries, while truncation of small adults by the purse seines could offset such a pattern. Our results highlight the eco-evolutionary dynamics of fishing effects on population demography and caution against using demographic traits as a basis for fisheries management of the Pacific bluefin tuna as well as other migratory species. © 2016 by the Ecological Society of America.

Reconceptualizing the Nature of Goals and Outcomes in Language/s Education

ERIC Educational Resources Information Center

Leung, Constant; Scarino, Angela

2016-01-01

Transformations associated with the increasing speed, scale, and complexity of mobilities, together with the information technology revolution, have changed the demography of most countries of the world and brought about accompanying social, cultural, and economic shifts (Heugh, 2013). This complex diversity has changed the very nature of…

The Changing Nature of Work. Trend Analysis Report. TAP 17.

ERIC Educational Resources Information Center

American Council of Life Insurance, New York, NY.

This report on the changing nature of work examines developing issues and potential changes in the world of work relevant to life insurance company management. The main body of the report is divided into three sections. Topics covered in the first section are demography, women, minorities, the young worker, and blurring work roles. Challenges to…

Demography and population dynamics of the mouse opossum (Thylamys elegans) in semi-arid Chile: seasonality, feedback structure and climate.

PubMed Central

Lima, M.; Stenseth, N. C.; Yoccoz, N. G.; Jaksic, F. M.

2001-01-01

Here we present, to the authors' knowledge for the very first time for a small marsupial, a thorough analysis of the demography and population dynamics of the mouse opossum (Thylamys elegans) in western South America. We test the relative importance of feedback structure and climatic factors (rainfall and the Southern Oscillation Index) in explaining the temporal variation in the demography of the mouse opossum. The demographic information was incorporated into a stage-structured population dynamics model and the model's predictions were compared with observed patterns. The mouse opossum's capture rates showed seasonal (within-year) and between-year variability, with individuals having higher capture rates during late summer and autumn and lower capture rates during winter and spring. There was also a strong between-year effect on capture probabilities. The reproductive (the fraction of reproductively active individuals) and recruitment rates showed a clear seasonal and a between-year pattern of variation with the peak of reproductive activity occuring during winter and early spring. In addition, the fraction of reproductive individuals was positively related to annual rainfall, while population density and annual rainfall positively influenced the recruitment rate. The survival rates were negatively related to annual rainfall. The average finite population growth rate during the study period was estimated to be 1.011 +/- 0.0019 from capture-recapture estimates. While the annual growth rate estimated from the seasonal linear matrix models was 1.026, the subadult and adult survival and maturation rates represent between 54% (winter) and 81% (summer) of the impact on the annual growth rate. PMID:11571053

Climate change impacts on marine ecosystems.

PubMed

Doney, Scott C; Ruckelshaus, Mary; Duffy, J Emmett; Barry, James P; Chan, Francis; English, Chad A; Galindo, Heather M; Grebmeier, Jacqueline M; Hollowed, Anne B; Knowlton, Nancy; Polovina, Jeffrey; Rabalais, Nancy N; Sydeman, William J; Talley, Lynne D

2012-01-01

In marine ecosystems, rising atmospheric CO2 and climate change are associated with concurrent shifts in temperature, circulation, stratification, nutrient input, oxygen content, and ocean acidification, with potentially wide-ranging biological effects. Population-level shifts are occurring because of physiological intolerance to new environments, altered dispersal patterns, and changes in species interactions. Together with local climate-driven invasion and extinction, these processes result in altered community structure and diversity, including possible emergence of novel ecosystems. Impacts are particularly striking for the poles and the tropics, because of the sensitivity of polar ecosystems to sea-ice retreat and poleward species migrations as well as the sensitivity of coral-algal symbiosis to minor increases in temperature. Midlatitude upwelling systems, like the California Current, exhibit strong linkages between climate and species distributions, phenology, and demography. Aggregated effects may modify energy and material flows as well as biogeochemical cycles, eventually impacting the overall ecosystem functioning and services upon which people and societies depend.

[The study of unions in demography: from categories to process].

PubMed

Burch, T K; Belanger, D

1999-01-01

For centuries, illegitimate children, those born outside of civil marriage or a marriage conducted within the church, were systematically accorded second-class status by both the law and religion. This attitude toward such children frustrates efforts to change legislation, social structure, and our understanding of new types of union outside of marriage. In Canada, no common term even exists in the two official languages to designate the cohabitation of an unmarried couple. Such unions simply fall through the net of classical demography. Even the more dynamic approaches, such as those seen in multistate models, follow only the movements of individuals in traditional categories. One must understand that the formation of couples is a multidimensional process and that a multidimensional approach to such unions could lead to the creation of a new group of nonethnocentric categories applicable to a number of different societies. The authors also consider the notion of process, in which marriage and cohabitation are merely two states in a range of possible states through which an individual will move during the course of his or her life. Cohabiting situations vary in importance depending upon one¿s states. Better demographic analyses can lead to greater understanding of the human couple and its sexual and reproductive behaviors.

Decadal change of forest biomass carbon stocks and tree demography in the Delaware River Basin

Treesearch

Bing Xu; Yude Pan; Alain F. Plante; Arthur Johnson; Jason Cole; Richard Birdsey

2016-01-01

Quantifying forest biomass carbon (C) stock change is important for understanding forest dynamics and their feedbacks with climate change. Forests in the northeastern U.S. have been a net carbon sink in recent decades, but C accumulation in some northern hardwood forests has been halted due to the impact of emerging stresses such as invasive pests, land use change and...

SPATIALLY AUTOCORRELATED DEMOGRAPHY AND INTERPOND MIGRATION IN THE CALIFORNIA TIGER SALAMANDER (AMBYSTOME CALIFORNIENSE)

EPA Science Inventory

We investigated the metapopulation structure of the California tiger salamander (Ambystoma californiense) using a combination of indirect and direct methods to evaluate two key requirements of modern metapopulation models: 1) that patches support somewhat independent populations ...

DEMOGRAPHY AND SPATIAL POPULATION STRUCTURE IN CALIFORNIA TIGER SALAMANDER

EPA Science Inventory

Although the causes of many amphibian declines remain mysterious, there is general agreement that human habitat alteration represents the greatest threat to amphibian populations. In January 2000 the US Fish and Wildlife Service proposed listing Santa Barbara County California Ti...

The genetical theory of social behaviour

PubMed Central

Lehmann, Laurent; Rousset, François

2014-01-01

We survey the population genetic basis of social evolution, using a logically consistent set of arguments to cover a wide range of biological scenarios. We start by reconsidering Hamilton's (Hamilton 1964 J. Theoret. Biol. 7, 1–16 (doi:10.1016/0022-5193(64)90038-4)) results for selection on a social trait under the assumptions of additive gene action, weak selection and constant environment and demography. This yields a prediction for the direction of allele frequency change in terms of phenotypic costs and benefits and genealogical concepts of relatedness, which holds for any frequency of the trait in the population, and provides the foundation for further developments and extensions. We then allow for any type of gene interaction within and between individuals, strong selection and fluctuating environments and demography, which may depend on the evolving trait itself. We reach three conclusions pertaining to selection on social behaviours under broad conditions. (i) Selection can be understood by focusing on a one-generation change in mean allele frequency, a computation which underpins the utility of reproductive value weights; (ii) in large populations under the assumptions of additive gene action and weak selection, this change is of constant sign for any allele frequency and is predicted by a phenotypic selection gradient; (iii) under the assumptions of trait substitution sequences, such phenotypic selection gradients suffice to characterize long-term multi-dimensional stochastic evolution, with almost no knowledge about the genetic details underlying the coevolving traits. Having such simple results about the effect of selection regardless of population structure and type of social interactions can help to delineate the common features of distinct biological processes. Finally, we clarify some persistent divergences within social evolution theory, with respect to exactness, synergies, maximization, dynamic sufficiency and the role of genetic arguments. PMID:24686929

The genetical theory of social behaviour.

PubMed

Lehmann, Laurent; Rousset, François

2014-05-19

We survey the population genetic basis of social evolution, using a logically consistent set of arguments to cover a wide range of biological scenarios. We start by reconsidering Hamilton's (Hamilton 1964 J. Theoret. Biol. 7, 1-16 (doi:10.1016/0022-5193(64)90038-4)) results for selection on a social trait under the assumptions of additive gene action, weak selection and constant environment and demography. This yields a prediction for the direction of allele frequency change in terms of phenotypic costs and benefits and genealogical concepts of relatedness, which holds for any frequency of the trait in the population, and provides the foundation for further developments and extensions. We then allow for any type of gene interaction within and between individuals, strong selection and fluctuating environments and demography, which may depend on the evolving trait itself. We reach three conclusions pertaining to selection on social behaviours under broad conditions. (i) Selection can be understood by focusing on a one-generation change in mean allele frequency, a computation which underpins the utility of reproductive value weights; (ii) in large populations under the assumptions of additive gene action and weak selection, this change is of constant sign for any allele frequency and is predicted by a phenotypic selection gradient; (iii) under the assumptions of trait substitution sequences, such phenotypic selection gradients suffice to characterize long-term multi-dimensional stochastic evolution, with almost no knowledge about the genetic details underlying the coevolving traits. Having such simple results about the effect of selection regardless of population structure and type of social interactions can help to delineate the common features of distinct biological processes. Finally, we clarify some persistent divergences within social evolution theory, with respect to exactness, synergies, maximization, dynamic sufficiency and the role of genetic arguments.

Population size does not explain past changes in cultural complexity.

PubMed

Vaesen, Krist; Collard, Mark; Cosgrove, Richard; Roebroeks, Wil

2016-04-19

Demography is increasingly being invoked to account for features of the archaeological record, such as the technological conservatism of the Lower and Middle Pleistocene, the Middle to Upper Paleolithic transition, and cultural loss in Holocene Tasmania. Such explanations are commonly justified in relation to population dynamic models developed by Henrich [Henrich J (2004)Am Antiq69:197-214] and Powell et al. [Powell A, et al. (2009)Science324(5932):1298-1301], which appear to demonstrate that population size is the crucial determinant of cultural complexity. Here, we show that these models fail in two important respects. First, they only support a relationship between demography and culture in implausible conditions. Second, their predictions conflict with the available archaeological and ethnographic evidence. We conclude that new theoretical and empirical research is required to identify the factors that drove the changes in cultural complexity that are documented by the archaeological record.

Population size does not explain past changes in cultural complexity

PubMed Central

Vaesen, Krist; Collard, Mark; Cosgrove, Richard; Roebroeks, Wil

2016-01-01

Demography is increasingly being invoked to account for features of the archaeological record, such as the technological conservatism of the Lower and Middle Pleistocene, the Middle to Upper Paleolithic transition, and cultural loss in Holocene Tasmania. Such explanations are commonly justified in relation to population dynamic models developed by Henrich [Henrich J (2004) Am Antiq 69:197–214] and Powell et al. [Powell A, et al. (2009) Science 324(5932):1298–1301], which appear to demonstrate that population size is the crucial determinant of cultural complexity. Here, we show that these models fail in two important respects. First, they only support a relationship between demography and culture in implausible conditions. Second, their predictions conflict with the available archaeological and ethnographic evidence. We conclude that new theoretical and empirical research is required to identify the factors that drove the changes in cultural complexity that are documented by the archaeological record. PMID:27044082

Incorporating variability in simulations of seasonally forced phenology using integral projection models

DOE PAGES

Goodsman, Devin W.; Aukema, Brian H.; McDowell, Nate G.; ...

2017-11-26

Phenology models are becoming increasingly important tools to accurately predict how climate change will impact the life histories of organisms. We propose a class of integral projection phenology models derived from stochastic individual-based models of insect development and demography. Our derivation, which is based on the rate summation concept, produces integral projection models that capture the effect of phenotypic rate variability on insect phenology, but which are typically more computationally frugal than equivalent individual-based phenology models. We demonstrate our approach using a temperature-dependent model of the demography of the mountain pine beetle (Dendroctonus ponderosae Hopkins), an insect that kills maturemore » pine trees. This work illustrates how a wide range of stochastic phenology models can be reformulated as integral projection models. Due to their computational efficiency, these integral projection models are suitable for deployment in large-scale simulations, such as studies of altered pest distributions under climate change.« less

Incorporating variability in simulations of seasonally forced phenology using integral projection models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goodsman, Devin W.; Aukema, Brian H.; McDowell, Nate G.

Phenology models are becoming increasingly important tools to accurately predict how climate change will impact the life histories of organisms. We propose a class of integral projection phenology models derived from stochastic individual-based models of insect development and demography. Our derivation, which is based on the rate summation concept, produces integral projection models that capture the effect of phenotypic rate variability on insect phenology, but which are typically more computationally frugal than equivalent individual-based phenology models. We demonstrate our approach using a temperature-dependent model of the demography of the mountain pine beetle (Dendroctonus ponderosae Hopkins), an insect that kills maturemore » pine trees. This work illustrates how a wide range of stochastic phenology models can be reformulated as integral projection models. Due to their computational efficiency, these integral projection models are suitable for deployment in large-scale simulations, such as studies of altered pest distributions under climate change.« less

[Demography and age-dependency in ophthalmic diseases].

PubMed

Wolfram, C

2015-01-01

This article explains key terms in demography and describes current and future changes in the composition of the German population. The ratio of older persons is greatly increasing as age groups from higher birth rates are growing older and as the life expectancy continues to rise particularly for older age groups. Ophthalmology is highly affected by these societal changes as eye diseases particularly affect the elderly. The prevalence of blindness and low vision is increasing in the older population even though this increase is being overlapped by a general reduction in the risk of blindness. Up to more than 30% more age-related eye diseases are expected in the population by the year 2030, which will lead to an additional roughly 7.7 million ophthalmic consultations in the population of more than 60 years of age. The healthcare units need to be adjusted to the rising demand for ophthalmic care.

Late Holocene Lake Level Fluctuations at Laguna Arapa, Peru and Connections to Human Demography

NASA Astrophysics Data System (ADS)

Hillman, A. L.; Abbott, M. B.; Werne, J. P.; Arkush, E.; Thompson, L. G.; Ferland, T.; Holmes, E.; Puhnaty, C.; Woods, A.

2016-12-01

The relationship between variations in hydroclimate and human demography on the Peruvian Altiplano has significant implications for understanding how people in the past have adapted to changes in freshwater resources. To investigate these human-environmental interactions, this project presents a 2,000 year sediment record from Laguna Arapa, a large lake that is <20 km NW of Lake Titicaca. Using sedimentology and stratigraphy as well as a suite of organic geochemical proxies including fecal 5β-stanols and leaf waxes (long chain n-alkanoic acids), we aim to tie together proxies of human population with indicators of regional hydroclimate. Preliminary results of sedimentology and stratigraphy show notable transitions from sand to silt to clay, suggesting rising lake level sequences at 500 and 700 AD. The last 1,300 years of sediment are characterized by alternating layers of organic rich material with abundant charcoal and black inorganic clay, suggesting intermittent periods of aridity and/or anthropogenic fire-setting. These layers are particularly frequent during the Medieval Climate Anomaly, which was characterized by dry and warm conditions. These results agree well with other records of hydroclimate from regional lakes as well as accumulation rate and temperature from the Quelccaya ice cap. Organic geochemical work is currently in progress and shows promise for linking together proxies of human demography with hydroclimate to understand the relationship between human settlement and climate change.

Population genetic structure and gene flow of Adélie penguins (Pygoscelis adeliae) breeding throughout the western Antarctic Peninsula

USGS Publications Warehouse

Gorman, Kristen B.; Talbot, Sandra L.; Sonsthagen, Sarah A.; Sage, George K.; Gravley, Megan C.; Fraser, William R.; Williams, Tony D.

2017-01-01

Adélie penguins (Pygoscelis adeliae) are responding to ocean–climate variability throughout the marine ecosystem of the western Antarctic Peninsula (WAP) where some breeding colonies have declined by 80%. Nuclear and mitochondrial DNA (mtDNA) markers were used to understand historical population genetic structure and gene flow given relatively recent and continuing reductions in sea ice habitats and changes in numbers of breeding adults at colonies throughout the WAP. Genetic diversity, spatial genetic structure, genetic signatures of fluctuations in population demography and gene flow were assessed in four regional Adélie penguin colonies. The analyses indicated little genetic structure overall based on bi-parentally inherited microsatellite markers (FST =-0.006–0.004). No significant variance was observed in overall haplotype frequency (mtDNA ΦST =0.017; P=0.112). Some comparisons with Charcot Island were significant, suggestive of female-biased philopatry. Estimates of gene flow based on a two-population coalescent model were asymmetrical from the species’ regional core to its northern range. Breeding Adélie penguins of the WAP are a panmictic population and hold adequate genetic diversity and dispersal capacity to be resilient to environmental change.

Annual and spatial variation in shoot demography associated with masting in Betula grossa: comparison between mature trees and saplings

PubMed Central

Ishihara, Masae Iwamoto; Kikuzawa, Kihachiro

2009-01-01

Backgrounds and Aims Shoot demography affects the growth of the tree crown and the number of leaves on a tree. Masting may cause inter-annual and spatial variation in shoot demography of mature trees, which may in turn affect the resource budget of the tree. The aim of this study was to evaluate the effect of masting on the temporal and spatial variations in shoot demography of mature Betula grossa. Methods The shoot demography was analysed in the upper and lower parts of the tree crown in mature trees and saplings over 7 years. Mature trees and saplings were compared to differentiate the effect of masting from the effect of exogenous environment on shoot demography. The fate of different shoot types (reproductive, vegetative, short, long), shoot length and leaf area were investigated by monitoring and by retrospective survey using morphological markers on branches. The effects of year and branch position on demographic parameters were evaluated. Key Results Shoot increase rate, production of long shoots, bud mortality, length of long shoots and leaf area of a branch fluctuated periodically from year to year in mature trees over 7 years, in which two masting events occurred. Branches within a crown showed synchronized annual variation, and the extent of fluctuation was larger in the upper branches than the lower branches. Vegetative shoots varied in their bud differentiation each year and contributed to the dynamic shoot demography as much as did reproductive shoots, suggesting physiological integration in shoot demography through hormonal regulation and resource allocation. Conclusions Masting caused periodic annual variation in shoot demography of the mature trees and the effect was spatially variable within a tree crown. Since masting is a common phenomenon among tree species, annual variation in shoot demography and leaf area should be incorporated into resource allocation models of mature masting trees. PMID:19734164

Integral projection models for finite populations in a stochastic environment.

PubMed

Vindenes, Yngvild; Engen, Steinar; Saether, Bernt-Erik

2011-05-01

Continuous types of population structure occur when continuous variables such as body size or habitat quality affect the vital parameters of individuals. These structures can give rise to complex population dynamics and interact with environmental conditions. Here we present a model for continuously structured populations with finite size, including both demographic and environmental stochasticity in the dynamics. Using recent methods developed for discrete age-structured models we derive the demographic and environmental variance of the population growth as functions of a continuous state variable. These two parameters, together with the expected population growth rate, are used to define a one-dimensional diffusion approximation of the population dynamics. Thus, a substantial reduction in complexity is achieved as the dynamics of the complex structured model can be described by only three population parameters. We provide methods for numerical calculation of the model parameters and demonstrate the accuracy of the diffusion approximation by computer simulation of specific examples. The general modeling framework makes it possible to analyze and predict future dynamics and extinction risk of populations with various types of structure, and to explore consequences of changes in demography caused by, e.g., climate change or different management decisions. Our results are especially relevant for small populations that are often of conservation concern.

Empirical Succession Mapping and Data Assimilation to Constrain Demographic Processes in an Ecosystem Model

NASA Astrophysics Data System (ADS)

Kelly, R.; Andrews, T.; Dietze, M.

2015-12-01

Shifts in ecological communities in response to environmental change have implications for biodiversity, ecosystem function, and feedbacks to global climate change. Community composition is fundamentally the product of demography, but demographic processes are simplified or missing altogether in many ecosystem, Earth system, and species distribution models. This limitation arises in part because demographic data are noisy and difficult to synthesize. As a consequence, demographic processes are challenging to formulate in models in the first place, and to verify and constrain with data thereafter. Here, we used a novel analysis of the USFS Forest Inventory Analysis to improve the representation of demography in an ecosystem model. First, we created an Empirical Succession Mapping (ESM) based on ~1 million individual tree observations from the eastern U.S. to identify broad demographic patterns related to forest succession and disturbance. We used results from this analysis to guide reformulation of the Ecosystem Demography model (ED), an existing forest simulator with explicit tree demography. Results from the ESM reveal a coherent, cyclic pattern of change in temperate forest tree size and density over the eastern U.S. The ESM captures key ecological processes including succession, self-thinning, and gap-filling, and quantifies the typical trajectory of these processes as a function of tree size and stand density. Recruitment is most rapid in early-successional stands with low density and mean diameter, but slows as stand density increases; mean diameter increases until thinning promotes recruitment of small-diameter trees. Strikingly, the upper bound of size-density space that emerges in the ESM conforms closely to the self-thinning power law often observed in ecology. The ED model obeys this same overall size-density boundary, but overestimates plot-level growth, mortality, and fecundity rates, leading to unrealistic emergent demographic patterns. In particular, the current ED formulation cannot capture steady state dynamics evident in the ESM. Ongoing efforts are aimed at reformulating ED to more closely approach overall forest dynamics evident in the ESM, and then assimilating inventory data to constrain model parameters and initial conditions.

Demographic consequences of age-structure in extreme environments: population models for arctic and alpine ptarmigan.

PubMed

Sandercock, Brett K; Martin, Kathy; Hannon, Susan J

2005-11-01

Organisms living in arctic and alpine environments are increasingly impacted by human activities. To evaluate the potential impacts of global change, a better understanding of the demography of organisms in extreme environments is needed. In this study, we compare the age-specific demography of willow ptarmigan (Lagopus lagopus) breeding at arctic and subalpine sites, and white-tailed ptarmigan (L. leucurus) breeding at an alpine site. Rates of egg production improved with age at the alpine and subalpine sites, but the stochastic effects of nest and brood predation led to similar rates of annual fecundity among 1-, 2-, and 3+-year-old females. All populations had short generation times (T<2.7 years) and low net reproductive rates (R0<1.2). Stable age distributions were weighted towards 1-year-old females in willow ptarmigan (>59%), and to 3+-year-old females in white-tailed ptarmigan (>47%). High damping ratios (rho>3.2) indicated that asymptotic estimates were likely to match natural age distributions. Sensitivity and elasticity values indicated that changes in juvenile survival would have the greatest impact on the finite rate of population change (lambda) in willow ptarmigan, whereas changes to the survival of 3+-year-old females would have a greater effect in white-tailed ptarmigan. High survivorship buffers white-tailed ptarmigan in alpine environments against the potential effects of climate change on annual fecundity, but may make the species more sensitive to the effects of pollutants or harvesting on adult survival. Conversely, processes that reduce annual fecundity would have a greater impact on the population viability of willow ptarmigan in arctic and subalpine environments. If these same demographic patterns prove to be widespread among organisms in extreme environments, it may be possible to develop general recommendations for conservation of the biological resources of arctic and alpine ecosystems.

Deep Learning for Population Genetic Inference.

PubMed

Sheehan, Sara; Song, Yun S

2016-03-01

Given genomic variation data from multiple individuals, computing the likelihood of complex population genetic models is often infeasible. To circumvent this problem, we introduce a novel likelihood-free inference framework by applying deep learning, a powerful modern technique in machine learning. Deep learning makes use of multilayer neural networks to learn a feature-based function from the input (e.g., hundreds of correlated summary statistics of data) to the output (e.g., population genetic parameters of interest). We demonstrate that deep learning can be effectively employed for population genetic inference and learning informative features of data. As a concrete application, we focus on the challenging problem of jointly inferring natural selection and demography (in the form of a population size change history). Our method is able to separate the global nature of demography from the local nature of selection, without sequential steps for these two factors. Studying demography and selection jointly is motivated by Drosophila, where pervasive selection confounds demographic analysis. We apply our method to 197 African Drosophila melanogaster genomes from Zambia to infer both their overall demography, and regions of their genome under selection. We find many regions of the genome that have experienced hard sweeps, and fewer under selection on standing variation (soft sweep) or balancing selection. Interestingly, we find that soft sweeps and balancing selection occur more frequently closer to the centromere of each chromosome. In addition, our demographic inference suggests that previously estimated bottlenecks for African Drosophila melanogaster are too extreme.

Deep Learning for Population Genetic Inference

PubMed Central

Sheehan, Sara; Song, Yun S.

2016-01-01

Given genomic variation data from multiple individuals, computing the likelihood of complex population genetic models is often infeasible. To circumvent this problem, we introduce a novel likelihood-free inference framework by applying deep learning, a powerful modern technique in machine learning. Deep learning makes use of multilayer neural networks to learn a feature-based function from the input (e.g., hundreds of correlated summary statistics of data) to the output (e.g., population genetic parameters of interest). We demonstrate that deep learning can be effectively employed for population genetic inference and learning informative features of data. As a concrete application, we focus on the challenging problem of jointly inferring natural selection and demography (in the form of a population size change history). Our method is able to separate the global nature of demography from the local nature of selection, without sequential steps for these two factors. Studying demography and selection jointly is motivated by Drosophila, where pervasive selection confounds demographic analysis. We apply our method to 197 African Drosophila melanogaster genomes from Zambia to infer both their overall demography, and regions of their genome under selection. We find many regions of the genome that have experienced hard sweeps, and fewer under selection on standing variation (soft sweep) or balancing selection. Interestingly, we find that soft sweeps and balancing selection occur more frequently closer to the centromere of each chromosome. In addition, our demographic inference suggests that previously estimated bottlenecks for African Drosophila melanogaster are too extreme. PMID:27018908

What factors shape genetic diversity in cetaceans?

PubMed

Vachon, Felicia; Whitehead, Hal; Frasier, Timothy R

2018-02-01

Understanding what factors drive patterns of genetic diversity is a central aspect of many biological questions, ranging from the inference of historical demography to assessing the evolutionary potential of a species. However, as a larger number of datasets have become available, it is becoming clear that the relationship between the characteristics of a species and its genetic diversity is more complex than previously assumed. This may be particularly true for cetaceans, due to their relatively long lifespans, long generation times, complex social structures, and extensive ranges. In this study, we used microsatellite and mitochondrial DNA data from a systematic literature review to produce estimates of diversity for both markers across 42 cetacean species. Factors relating to demography, distribution, classification, biology, and behavior were then tested using phylogenetic methods and linear models to assess their relative influence on the genetic diversity of both marker types. The results show that while relative nuclear diversity is correlated with population size, mitochondrial diversity is not. This is particularly relevant given the widespread use of mitochondrial DNA to infer historical demography. Instead, mitochondrial diversity was mostly influenced by the range and social structure of the species. In addition to population size, habitat type (neritic vs. oceanic) had a significant correlation with relative nuclear diversity. Combined, these results show that many often-unconsidered factors are likely influencing patterns of genetic diversity in cetaceans, with implications regarding how to interpret, and what can be inferred from, existing patterns of diversity.

Demography and Environment Earth: Teacher Edition.

ERIC Educational Resources Information Center

McCrea, Lester C.; And Others

This document is one in a series of instructional materials on population education developed for the Baltimore public schools. The unit, designed for elementary grades 5 and 6, focuses on demography and human factors and consequences. The first part of the resource unit presents basic information, methodology, and understandings of demography and…

The co-evolution of social institutions, demography, and large-scale human cooperation.

PubMed

Powers, Simon T; Lehmann, Laurent

2013-11-01

Human cooperation is typically coordinated by institutions, which determine the outcome structure of the social interactions individuals engage in. Explaining the Neolithic transition from small- to large-scale societies involves understanding how these institutions co-evolve with demography. We study this using a demographically explicit model of institution formation in a patch-structured population. Each patch supports both social and asocial niches. Social individuals create an institution, at a cost to themselves, by negotiating how much of the costly public good provided by cooperators is invested into sanctioning defectors. The remainder of their public good is invested in technology that increases carrying capacity, such as irrigation systems. We show that social individuals can invade a population of asocials, and form institutions that support high levels of cooperation. We then demonstrate conditions where the co-evolution of cooperation, institutions, and demographic carrying capacity creates a transition from small- to large-scale social groups. © 2013 John Wiley & Sons Ltd/CNRS.

Leaf development and demography explain photosynthetic seasonality in Amazon evergreen forests

USGS Publications Warehouse

Wu, Jin; Albert, Lauren; Lopes, Aline; Restrepo-Coupe, Natalia; Hayek, Matthew; Wiedemann, Kenia T.; Guan, Kaiyu; Stark, Scott C.; Christoffersen, Bradley; Prohaska, Neill; Tavares, Julia V.; Marostica, Suelen; Kobayashi, Hideki; Ferreira, Maurocio L.; Campos, Kleber Silva; da Silva, Rodrigo; Brando, Paulo M.; Dye, Dennis G.; Huxman, Travis E.; Huete, Alfredo; Nelson, Bruce; Saleska, Scott

2016-01-01

In evergreen tropical forests, the extent, magnitude, and controls on photosynthetic seasonality are poorly resolved and inadequately represented in Earth system models. Combining camera observations with ecosystem carbon dioxide fluxes at forests across rainfall gradients in Amazônia, we show that aggregate canopy phenology, not seasonality of climate drivers, is the primary cause of photosynthetic seasonality in these forests. Specifically, synchronization of new leaf growth with dry season litterfall shifts canopy composition toward younger, more light-use efficient leaves, explaining large seasonal increases (~27%) in ecosystem photosynthesis. Coordinated leaf development and demography thus reconcile seemingly disparate observations at different scales and indicate that accounting for leaf-level phenology is critical for accurately simulating ecosystem-scale responses to climate change.

[How municipalities can plan for later life. Regional challenges of a demography-sensitive social planning for later life as exemplified by the administrative district Vechta (Lower Saxony/Germany)].

PubMed

Amrhein, L; Backes, G M

2012-07-01

The demographic ageing of the population confronts towns, municipalities and administrative districts with new sociopolitical challenges. The general view of the demographic and social change requires demography-sensitive social planning that is no longer segregated according to age or life stages. Drawing on the example of a demographic evaluation conducted for the administrative district of Vechta in Lower Saxony, Germany, it will be discussed how a life course-orientated municipal social planning for later life can be developed. Furthermore, which practical research and methodical challenges the gerontological policy development municipalities can expect to be confronted with in the future are discussed.

Indicators of Family and Household Structure of Racial and Ethnic Minorities in the U.S. CDE Working Paper 77-29.

ERIC Educational Resources Information Center

Sweet, James A.

This paper reviews some of the issues and concerns that have prompted the growth of interest in the demography of the family. It also examines a number of aspects of the family and the household structure of racial and ethnic minorities. The five racial minorities discussed are blacks, Chinese, Japanese, Filipinos and American Indians. The…

Long-term effects of fire and fire-return interval on population structure and growth of longleaf pine (Pinus palustris)

Treesearch

Chelcy R. Ford; Emily S. Minor; Gordon A. Fox

2010-01-01

We investigated the effect of fire and fire frequency on stand structure and longleaf pine (Pinus palustris P. Mill.) growth and population demography in an experimental research area in a southwest Florida sandhill community. Data were collected from replicated plots that had prescribed fire-return intervals of 1, 2, 5, or 7 years or were left...

Spatial structure and nest demography reveal the influence of competition, parasitism and habitat quality on slavemaking ants and their hosts

PubMed Central

2011-01-01

Background Natural communities are structured by intra-guild competition, predation or parasitism and the abiotic environment. We studied the relative importance of these factors in two host-social parasite ecosystems in three ant communities in Europe (Bavaria) and North America (New York, West Virginia). We tested how these factors affect colony demography, life-history and the spatial pattern of colonies, using a large sample size of more than 1000 colonies. The strength of competition was measured by the distance to the nearest competitor. Distance to the closest social parasite colony was used as a measure of parasitism risk. Nest sites (i.e., sticks or acorns) are limited in these forest ecosystems and we therefore included nest site quality as an abiotic factor in the analysis. In contrast to previous studies based on local densities, we focus here on the positioning and spatial patterns and we use models to compare our predictions to random expectations. Results Colony demography was universally affected by the size of the nest site with larger and more productive colonies residing in larger nest sites of higher quality. Distance to the nearest competitor negatively influenced host demography and brood production in the Bavarian community, pointing to an important role of competition, while social parasitism was less influential in this community. The New York community was characterized by the highest habitat variability, and productive colonies were clustered in sites of higher quality. Colonies were clumped on finer spatial scales, when we considered only the nearest neighbors, but more regularly distributed on coarser scales. The analysis of spatial positioning within plots often produced different results compared to those based on colony densities. For example, while host and slavemaker densities are often positively correlated, slavemakers do not nest closer to potential host colonies than expected by random. Conclusions The three communities are differently affected by biotic and abiotic factors. Some of the differences can be attributed to habitat differences and some to differences between the two slavemaking-host ecosystems. The strong effect of competition in the Bavarian community points to the scarcity of resources in this uniform habitat compared to the other more diverse sites. The decrease in colony aggregation with scale indicates fine-scale resource hotspots: colonies are locally aggregated in small groups. Our study demonstrates that species relationships vary across scales and spatial patterns can provide important insights into species interactions. These results could not have been obtained with analyses based on local densities alone. Previous studies focused on social parasitism and its effect on host colonies. The broader approach taken here, considering several possible factors affecting colony demography and not testing each one in isolation, shows that competition and environmental variability can have a similar strong impact on demography and life-history of hosts. We conclude that the effects of parasites or predators should be studied in parallel to other ecological influences. PMID:21443778

Spatial structure and nest demography reveal the influence of competition, parasitism and habitat quality on slavemaking ants and their hosts.

PubMed

Scharf, Inon; Fischer-Blass, Birgit; Foitzik, Susanne

2011-03-28

Natural communities are structured by intra-guild competition, predation or parasitism and the abiotic environment. We studied the relative importance of these factors in two host-social parasite ecosystems in three ant communities in Europe (Bavaria) and North America (New York, West Virginia). We tested how these factors affect colony demography, life-history and the spatial pattern of colonies, using a large sample size of more than 1000 colonies. The strength of competition was measured by the distance to the nearest competitor. Distance to the closest social parasite colony was used as a measure of parasitism risk. Nest sites (i.e., sticks or acorns) are limited in these forest ecosystems and we therefore included nest site quality as an abiotic factor in the analysis. In contrast to previous studies based on local densities, we focus here on the positioning and spatial patterns and we use models to compare our predictions to random expectations. Colony demography was universally affected by the size of the nest site with larger and more productive colonies residing in larger nest sites of higher quality. Distance to the nearest competitor negatively influenced host demography and brood production in the Bavarian community, pointing to an important role of competition, while social parasitism was less influential in this community. The New York community was characterized by the highest habitat variability, and productive colonies were clustered in sites of higher quality. Colonies were clumped on finer spatial scales, when we considered only the nearest neighbors, but more regularly distributed on coarser scales. The analysis of spatial positioning within plots often produced different results compared to those based on colony densities. For example, while host and slavemaker densities are often positively correlated, slavemakers do not nest closer to potential host colonies than expected by random. The three communities are differently affected by biotic and abiotic factors. Some of the differences can be attributed to habitat differences and some to differences between the two slavemaking-host ecosystems. The strong effect of competition in the Bavarian community points to the scarcity of resources in this uniform habitat compared to the other more diverse sites. The decrease in colony aggregation with scale indicates fine-scale resource hotspots: colonies are locally aggregated in small groups. Our study demonstrates that species relationships vary across scales and spatial patterns can provide important insights into species interactions. These results could not have been obtained with analyses based on local densities alone. Previous studies focused on social parasitism and its effect on host colonies. The broader approach taken here, considering several possible factors affecting colony demography and not testing each one in isolation, shows that competition and environmental variability can have a similar strong impact on demography and life-history of hosts. We conclude that the effects of parasites or predators should be studied in parallel to other ecological influences.

Demic and cultural diffusion in prehistoric Europe in the age of ancient genomes.

PubMed

Harris, Eugene E

2017-09-01

Ancient genomes can help us detect prehistoric migrations, population contractions, and admixture among populations. Knowing the dynamics of demography is invaluable for understanding culture change in prehistory, particularly the roles played by demic and cultural diffusion in transformations of material cultures. Prehistoric Europe is a region where ancient genome analyses can help illuminate the interplay between demography and culture change. In Europe, there is more archeological evidence, in terms of detailed studies, radiometric dates, and explanatory hypotheses that can be evaluated, than in any other region of the world. Here I show some important ways that ancient genomes have given us insights into population movements in European prehistory. I also propose that studies might be increasingly focused on specific questions of culture change, for example in evaluating the makers of "transitional" industries as well as the origins of the Gravettian and spread of the Magdalenian. I also discuss genomic evidence supporting the large role that demic expansion has played in the Neolithization of Europe and the formation of the European population during the Bronze Age. © 2017 Wiley Periodicals, Inc.

Genetic effects of landscape, habitat preference and demography on three co-occurring turtle species.

PubMed

Reid, Brendan N; Mladenoff, David J; Peery, M Zachariah

2017-02-01

Expanding the scope of landscape genetics beyond the level of single species can help to reveal how species traits influence responses to environmental change. Multispecies studies are particularly valuable in highly threatened taxa, such as turtles, in which the impacts of anthropogenic change are strongly influenced by interspecific differences in life history strategies, habitat preferences and mobility. We sampled approximately 1500 individuals of three co-occurring turtle species across a gradient of habitat change (including varying loss of wetlands and agricultural conversion of upland habitats) in the Midwestern USA. We used genetic clustering and multiple regression methods to identify associations between genetic structure and permanent landscape features, past landscape composition and landscape change in each species. Two aquatic generalists (the painted turtle, Chrysemys picta, and the snapping turtle Chelydra serpentina) both exhibited population genetic structure consistent with isolation by distance, modulated by aquatic landscape features. Genetic divergence for the more terrestrial Blanding's turtle (Emydoidea blandingii), on the other hand, was not strongly associated with geographic distance or aquatic features, and Bayesian clustering analysis indicated that many Emydoidea populations were genetically isolated. Despite long generation times, all three species exhibited associations between genetic structure and postsettlement habitat change, indicating that long generation times may not be sufficient to delay genetic drift resulting from recent habitat fragmentation. The concordances in genetic structure observed between aquatic species, as well as isolation in the endangered, long-lived Emydoidea, reinforce the need to consider both landscape composition and demographic factors in assessing differential responses to habitat change in co-occurring species. © 2016 John Wiley & Sons Ltd.

Let's Put Demography Back into Economics: Population Pyramids in Excel

ERIC Educational Resources Information Center

Barreto, Humberto

2018-01-01

The economics curriculum today does not emphasize the study of population. This needs to change immediately because we are in the midst of another demographic sea change, slamming on the brakes right after a rapid acceleration during the last half of the twentieth century. Instead of glibly tossing a dependency ratio onto a slide, this article…

Demographically idiosyncratic responses to climate change and rapid Pleistocene diversification of the walnut genus Juglans (Juglandaceae) revealed by whole-genome sequences

Treesearch

Wei-Ning Bai; Peng-Cheng Yan; Bo-Wen Zhang; Keith E. Woeste; Kui Lin; Da-Yong Zhang

2018-01-01

Whether species demography and diversification are driven primarily by extrinsic environmental changes such as climatic oscillations in the Quaternary or by intrinsic biological interactions like coevolution between antagonists is a matter of active debate. In fact, their relative importance can be assessed by tracking past population fluctuations over considerable...

USSR Report, Life Sciences, Biomedical and Behavioral Sciences

DTIC Science & Technology

1985-02-19

BIBLIOGRAPHY 1. Demografiya vrachebnykh kadrov i potrebnost’ v poslediplomnom ikh obuchenii [ Demography of Physician Personnel and Need for Their...chief of Demography Department^ Scientific Research Institute of the USSR Central Statistical Administration/ /Text/ A sampling sociodemographic...statisticians and social hygienists in studying the pressing problems of demography and social hygiene. COPYRIGH: "Zdravookhraneniye Rössiyskoy

[PRENATAL DIAGNOSIS: EVOLUTION OF CLINICAL INDICATIONS AND THE SOCIETY IN THE PAST 30 YEARS].

PubMed

Sagredo, José Miguel García

2014-01-01

Here we report the results of prenatal diagnosis at the Hospital Universitario Ramón y Cajal since its opening in 1979 to 2010, establishing a parallelism between the different methodologies for screening and prenatal diagnosis, clinical indications, and demographic changes. It shows how the indications have varied as to the structure of the population did. These changes have been possible thanks to the fact that the screening and prenatal diagnosis methods have allowed it. Demonstrating, once again, how procedures evolve with technology and adapt to the demography. This evolution has allowed to make a more effective prenatal diagnosis because the clinical indications have been more precise what has allowed to detect the same number of fetuses with chromosomal abnormalities by performing less invasive procedures, which has led to an optimization of prenatal diagnosis saving resources and personnel and, above all, avoiding unnecessary fetal losses.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Til, J.

This book represents an extension of several earlier works on spatial form by Van Til, an urban sociologist who describes himself as a guarded pessimist about the future. He examines the spatial ramifications on urban, suburban, and rural use of space brought about by changes in the availability of amount and types of energy resources. In the first three chapters, he explores these ideas by structuring the future in terms of four institutional sectors: economy (inflation, unemployment, corporate control, and distribution of wealth); culture (values, demography and life style, information revolution); polity (governance and empowerment); and voluntary action. The secondmore » part of the book explicitly considers geographic space, with a chapter devoted to describing urban, suburban, and nonmetropolitan spatial forms, and one to changes anticipated in these forms given the three future scenarios. This balanced presentation discusses both those who advocate reliance on technological development as well as those who prefer other solutions.« less

The New Demography: Implications for the School Curriculum.

ERIC Educational Resources Information Center

Unks, Gerald

1984-01-01

It is time to free urban education from the standards of rural, agrarian America. Urban education must reflect modern family structures, utilize school buildings to a fuller extent, reflect more autonomy for schools in individual communities, and expand bilingual programs. In short, schools should become the new "settlement houses" for urban…

Cerritos College Information Notebook, 1990-91.

ERIC Educational Resources Information Center

Fillpot, James

This notebook, which provides current statistical and comparative information on Cerritos Community College (CCC), is divided into eight detailed sections. Part I outlines current trends and challenges affecting education in California, focusing on changes in demography, ethnic proportions of students and staff at secondary and postsecondary…

Cerritos College Information Notebook, 1988-89.

ERIC Educational Resources Information Center

Cerritos Coll., Norwalk, CA. Office of Institutional Research.

This notebook, intended to provide current statistical and comparative information on Cerritos Community College (CCC), is divided into eight detailed sections. Part I outlines current trends and challenges affecting education in California, focusing on changes in demography, ethnic proportions of students and staff at the secondary and…

Incorporating variability in simulations of seasonally forced phenology using integral projection models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goodsman, Devin W.; Aukema, Brian H.; McDowell, Nate G.

Phenology models are becoming increasingly important tools to accurately predict how climate change will impact the life histories of organisms. We propose a class of integral projection phenology models derived from stochastic individual-based models of insect development and demography.Our derivation, which is based on the rate-summation concept, produces integral projection models that capture the effect of phenotypic rate variability on insect phenology, but which are typically more computationally frugal than equivalent individual-based phenology models. We demonstrate our approach using a temperature-dependent model of the demography of the mountain pine beetle (Dendroctonus ponderosae Hopkins), an insect that kills mature pine trees.more » This work illustrates how a wide range of stochastic phenology models can be reformulated as integral projection models. Due to their computational efficiency, these integral projection models are suitable for deployment in large-scale simulations, such as studies of altered pest distributions under climate change.« less

Demography, life history, and the evolution of age-dependent social behaviour.

PubMed

Rodrigues, António M M

2018-06-14

Since the inception of modern social evolution theory, a vast majority of studies have sought to explain cooperation using relatedness-driven hypotheses. Natural populations, however, show a substantial amount of variation in social behaviour that is uncorrelated with relatedness. Age offers a major alternative explanation for variation in behaviour that remains unaccounted for. Most natural populations are structured into age-classes, with ageing being a nearly universal feature of most major taxa, including eukaryotic and prokaryotic organisms. Despite this, the theoretical underpinnings of age-dependent social behaviour remain limited. Here, we investigate how group age-composition, demography, and life history shape trajectories of age-dependent behaviours that are expressed conditionally on an actor and recipient's age. We show that demography introduces novel age-dependent selective pressures acting on social phenotypes. Furthermore, we find that life history traits influence the costs and benefits of cooperation directly, but also indirectly. Life history has a strong impact not only on the genetic structure of the population but also on the distribution of group age-compositions, with both of these processes influencing the expression of age-dependent cooperation. Age of peak reproductive performance, in particular, is of chief importance for the evolution of cooperation, as this will largely determine the age and relatedness of social partners. Moreover, our results suggest that later-life reproductive senescence may occur because of demographic effects alone, which opens new vistas on the evolution of menopause and related phenomena. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Demography or selection on linked cultural traits or genes? Investigating the driver of low mtDNA diversity in the sperm whale using complementary mitochondrial and nuclear genome analyses.

PubMed

Morin, Phillip A; Foote, Andrew D; Baker, Charles Scott; Hancock-Hanser, Brittany L; Kaschner, Kristin; Mate, Bruce R; Mesnick, Sarah L; Pease, Victoria L; Rosel, Patricia E; Alexander, Alana

2018-06-01

Mitochondrial DNA has been heavily utilized in phylogeography studies for several decades. However, underlying patterns of demography and phylogeography may be misrepresented due to coalescence stochasticity, selection, variation in mutation rates and cultural hitchhiking (linkage of genetic variation to culturally-transmitted traits affecting fitness). Cultural hitchhiking has been suggested as an explanation for low genetic diversity in species with strong social structures, counteracting even high mobility, abundance and limited barriers to dispersal. One such species is the sperm whale, which shows very limited phylogeographic structure and low mtDNA diversity despite a worldwide distribution and large population. Here, we use analyses of 175 globally distributed mitogenomes and three nuclear genomes to evaluate hypotheses of a population bottleneck/expansion vs. a selective sweep due to cultural hitchhiking or selection on mtDNA as the mechanism contributing to low worldwide mitochondrial diversity in sperm whales. In contrast to mtDNA control region (CR) data, mitogenome haplotypes are largely ocean-specific, with only one of 80 shared between the Atlantic and Pacific. Demographic analyses of nuclear genomes suggest low mtDNA diversity is consistent with a global reduction in population size that ended approximately 125,000 years ago, correlated with the Eemian interglacial. Phylogeographic analysis suggests that extant sperm whales descend from maternal lineages endemic to the Pacific during the period of reduced abundance and have subsequently colonized the Atlantic several times. Results highlight the apparent impact of past climate change, and suggest selection and hitchhiking are not the sole processes responsible for low mtDNA diversity in this highly social species. © 2018 John Wiley & Sons Ltd.

Demographic and life history characteristics influence the cytonuclear composition of mosquitofish populations

USGS Publications Warehouse

Scribner, Kim T.; Avise, John C.; Beaumont, A.

1994-01-01

Experimental laboratory crosses and population experiments reveal significant differences in individual life-history traits and population demography between two related species of mosquitofish, Gambusia affinis and G. holbrooki. With respect to life-history traits, progeny from G. holbrooki exhibit larger size at birth and earlier age at sexual maturity than do progeny from G. affinis parents. With respect to demography, populations of G. holbrooki exhibit higher recruitment and carrying capacity and loser overwinter mortality than do populations of G. affinis. These differences help t explain the dramatic changes in cytonuclear genotype frequency observed in replicated experimental hybrid populations of Gambusia monitored over 52 weeks. These experimental results are interpreted in the context of introgression patterns previously studied indirectly from distributions of cytonuclear genotypes in a natural mosquitofish hybrid zone.

CUMULATIVE EFFECTS OF COASTAL HABITAT ALTERATIONS ON FISHERY RESOURCES: TOWARD PREDICTION AT REGIONAL SCALES

EPA Science Inventory

The integrity of aquatic ecosystems and habitats at the land-sea interface is challeneged by several forces, ranging from plot scale destruction and disturbance, to watershed scale perturbations, to global changes in climate and human demographis. The scientific challenge is to ...

The interplay of demography and selection during maize domestication and expansion

USDA-ARS?s Scientific Manuscript database

The history of maize has been characterized by major demographic events including changes in population size associated with domestication and subsequent range expansion as well as gene flow with wild relatives. This complex demographic history and its interplay with selection have shaped diversity ...

Trends in Schooling: Demography, Performance and Organization.

ERIC Educational Resources Information Center

Mare, Robert D.

1981-01-01

Utilizing "Social Indicators" (1979), discusses growth and distribution of schooling in the U.S., trends in student test performance, and major organizational changes in elementary/secondary education. Comments on quality of available data and suggests improvements for future reporting of educational indicators. (Reprint of article is available…

Population: A Lively Introduction.

ERIC Educational Resources Information Center

McFalls, Joseph A., Jr.

1991-01-01

The study of demography must begin with an understanding of the three sources of population changes: fertility, mortality, and migration. This paper leads prospective demographers--or anyone interested in population--through the dynamics of these three variables, introducing them to the forces that cause populations to grow or decline, and that…

The Changing Demographic Landscape of the Nation: Perspectives on College Opportunities for Asian Americans and Pacific Islanders

ERIC Educational Resources Information Center

Teranishi, Robert T.; Kim, Victoria

2017-01-01

With the rapidly changing demography of the United States, there is a need for greater attention to expanding opportunities and reducing barriers to education for all. This article focuses on one of the nation's fastest-growing immigrant groups--Asian Americans and Pacific Islanders (AAPIs). A case study of a program at a community college shows…

Strong population genetic structuring in an annual fish, Nothobranchius furzeri, suggests multiple savannah refugia in southern Mozambique.

PubMed

Bartáková, Veronika; Reichard, Martin; Janko, Karel; Polačik, Matej; Blažek, Radim; Reichwald, Kathrin; Cellerino, Alessandro; Bryja, Josef

2013-09-12

Intraspecific genetic variation of African fauna has been significantly affected by pronounced climatic fluctuations in Plio-Pleistocene, but, with the exception of large mammals, very limited empirical data on diversity of natural populations are available for savanna-dwelling animals. Nothobranchius furzeri is an annual fish from south-eastern Africa, inhabiting discrete temporary savannah pools outside main river alluvia. Their dispersal is limited and population processes affecting its genetic structure are likely a combination of those affecting terrestrial and aquatic taxa. N. furzeri is a model taxon in ageing research and several populations of known geographical origin are used in laboratory studies. Here, we analysed the genetic structure, diversity, historical demography and temporal patterns of divergence in natural populations of N. furzeri across its entire distribution range. Genetic structure and historical demography of N. furzeri were analysed using a combination of mitochondrial (partial cytochrome b sequences, 687 bp) and nuclear (13 microsatellites) markers in 693 fish from 36 populations. Genetic markers consistently demonstrated strong population structuring and suggested two main genetic groups associated with river basins. The split was dated to the Pliocene (>2 Mya). The northern group inhabits savannah pools across the basin of the intermittent river Chefu in south-western Mozambique and eastern Zimbabwe. The southern group (from southernmost Mozambique) is subdivided, with the River Limpopo forming a barrier (maximum divergence time 1 Mya). A strong habitat fragmentation (isolated temporary pools) is reflected in significant genetic structuring even between adjacent pools, with a major influence of genetic drift and significant isolation-by-distance. Analysis of historical demography revealed that the expansion of both groups is ongoing, supported by frequent founder effects in marginal parts of the range and evidence of secondary contact between Chefu and Limpopo populations. We demonstrated: (1) ancient (pre-Pleistocene) divergence between the two main N. furzeri lineages, their recent secondary contact and lack of reproductive isolation; (2) important genetic structuring attributed to the fragmented nature of their environment and isolation-by-distance, suggesting that dispersal is limited, occurs over short distances and is not directly associated with river routes; (3) an apparent role of the River Limpopo as a barrier to dispersal and gene flow.

Growth and demography of Pinaleno high elevation forests

Treesearch

Christopher O' Connor; Donald A. Falk; Ann M. Lynch; Craig P. Wilcox; Thomas W. Swetnam; Tyson L. Swetnam

2010-01-01

The project goal is to understand how multiple disturbance events including fire, insect outbreaks, and climate variability interact in space and time, and how they combine to influence forest species composition, spatial structure, and tree population dynamics in high elevation forests of the Pinaleno Mountains. Information from each of these components is needed in...

The Demography of Urban Poverty: North and Latin America.

ERIC Educational Resources Information Center

Farkas, George

The similar structure of present-day North American cities makes it impossible to study urban poverty as anything other than a concomitant of the possession of certain demographic characteristics the penalty for which is imposed on a society-wide level. By shifting our focus, however, to incorporate both Latin American cities and North American…

Managing structural and compositional diversity with silviculture.

Treesearch

S.S. Hummel

2003-01-01

Ecology, economy, and demography interact to affect forest management objectives. In the temperate rainforests of northwestern North America (Franklin and Halpern 1988), the outcome of this interaction for most of the 20th century was a management emphasis on wood production (Curtis et al. 1998, Haynes et al. 2003). Because of production efficiencies, even-aged,...

Demography, Social Structure and Learning through Life

ERIC Educational Resources Information Center

van der Veen, Ruud

2010-01-01

The modernisation of the Western world during the last two centuries has been a mix of industrialisation/computerisation and urbanisation. Consequently, reports on the future of adult learning and adult education have been a mix on the one hand of the learning requirements that follow from industrialisation/computerisation and on the other hand,…

Contrasts in genetic structure and historical demography of marine and riverine populations of Atherina at similar geographical scales

NASA Astrophysics Data System (ADS)

Francisco, Sara M.; Cabral, Henrique; Vieira, Maria Natividade; Almada, Vítor C.

2006-09-01

In this paper, we compare the genetic structure and the historical demography of two populations of the sand smelt Atherina boyeri from the rivers Tagus and Mondego (Portugal) with two groups of samples of the closely related marine Atherina presbyter collected on the shore at comparable latitudes. A. presbyter is a pelagic marine inshore fish, while A. boyeri is typically found in coastal lagoons, estuaries and freshwaters bodies. Analysis of mtDNA control region sequences showed that the marine A. presbyter did not display signs of genetic differentiation between sites some hundreds of kilometers apart. On the contrary, A. boyeri showed clear differences between populations. The populations of A. boyeri showed a much lower genetic diversity and younger coalescence times when compared with A. presbyter. We suggest that these differences reflect the interplay between differences in ecology between the two species and the historical impact of the glaciations. While A. presbyter likely moved to the south evading the cold periods, A. boyeri probably went extinct and its populations in Western Europe are recent recolonizations from western Mediterranean refugia.

Stochastic demography and the neutral substitution rate in class-structured populations.

PubMed

Lehmann, Laurent

2014-05-01

The neutral rate of allelic substitution is analyzed for a class-structured population subject to a stationary stochastic demographic process. The substitution rate is shown to be generally equal to the effective mutation rate, and under overlapping generations it can be expressed as the effective mutation rate in newborns when measured in units of average generation time. With uniform mutation rate across classes the substitution rate reduces to the mutation rate.

Impacts of changing rainfall regime on the demography of tropical birds

NASA Astrophysics Data System (ADS)

Brawn, Jeffrey D.; Benson, Thomas J.; Stager, Maria; Sly, Nicholas D.; Tarwater, Corey E.

2017-02-01

Biodiversity in tropical regions is particularly high and may be highly sensitive to climate change. Unfortunately, a lack of long-term data hampers understanding of how tropical species, especially animals, may react to projected environmental changes. The amount and timing of rainfall is key to the function of tropical ecosystems and, although specific model predictions differ, there is general agreement that rainfall regimes will change over large areas of the tropics. Here, we estimate associations between dry season length (DSL) and the population biology of 20 bird species sampled in central Panama over a 33-year period. Longer dry seasons decreased the population growth rates and viability of nearly one-third of the species sampled. Simulations with modest increases in DSL suggest that consistently longer dry seasons will change the structure of tropical bird communities. Such change may occur even without direct loss of habitat--a finding with fundamental implications for conservation planning. Systematic changes in rainfall regime may threaten some populations and communities of tropical animals even in large tracts of protected habitat. These findings suggest the need for collaboration between climate scientists and conservation biologists to identify areas where rainfall regimes will be able to plausibly maintain wildlife populations.

Shaping Graduate Education's Future: Improving the Doctoral Experience.

ERIC Educational Resources Information Center

Beeler, Karl J.

A discussion of graduate higher education suggests that shifts in demography of graduate school students and changes in traditional doctoral programs will lead to increased participation in doctoral study by the nation's best and brightest students. Declines in doctoral program participation due to demographic shifts, decreasing financial support,…

Probabilistic and spatially variable niches inferred from demography

Treesearch

Jeffrey M. Diez; Itamar Giladi; Robert Warren; H. Ronald Pulliam

2014-01-01

Summary 1. Mismatches between species distributions and habitat suitability are predicted by niche theory and have important implications for forecasting how species may respond to environmental changes. Quantifying these mismatches is challenging, however, due to the high dimensionality of species niches and the large spatial and temporal variability in population...

Bulgaria: The Double Edge of Economy and Demography

ERIC Educational Resources Information Center

Georgieva, Patricia

2004-01-01

The higher education and research sector in Bulgaria is undergoing a gradual change. Whether this transformation will bring success or failure depends on how prepared stakeholders are to meet associated challenges and opportunities. The mobility of academics and the related phenomenon of brain drain need careful investigation. Academic teachers…

Increasing Minority Student Enrollment in Counselor Education

ERIC Educational Resources Information Center

Robinson, Mona C.; Lewis, Denise; Henderson, DeAnna; Flowers, Carl R.

2009-01-01

Counselor education programs across the country often fail to attract, enroll and graduate students in proportion that reflects the diversity of the nation. As our country's demography changes, the impact of race and ethnicity within the client-counselor relationship is likely to have greater importance and, as such, counselor education programs…

A simple, sufficient, and consistent method to score the status of threats and demography of imperiled species

PubMed Central

Webber, Whitney M.; Li, Ya-Wei

2016-01-01

Managers of large, complex wildlife conservation programs need information on the conservation status of each of many species to help strategically allocate limited resources. Oversimplifying status data, however, runs the risk of missing information essential to strategic allocation. Conservation status consists of two components, the status of threats a species faces and the species’ demographic status. Neither component alone is sufficient to characterize conservation status. Here we present a simple key for scoring threat and demographic changes for species using detailed information provided in free-form textual descriptions of conservation status. This key is easy to use (simple), captures the two components of conservation status without the cost of more detailed measures (sufficient), and can be applied by different personnel to any taxon (consistent). To evaluate the key’s utility, we performed two analyses. First, we scored the threat and demographic status of 37 species recently recommended for reclassification under the Endangered Species Act (ESA) and 15 control species, then compared our scores to two metrics used for decision-making and reports to Congress. Second, we scored the threat and demographic status of all non-plant ESA-listed species from Florida (54 spp.), and evaluated scoring repeatability for a subset of those. While the metrics reported by the U.S. Fish and Wildlife Service (FWS) are often consistent with our scores in the first analysis, the results highlight two problems with the oversimplified metrics. First, we show that both metrics can mask underlying demographic declines or threat increases; for example, ∼40% of species not recommended for reclassification had changes in threats or demography. Second, we show that neither metric is consistent with either threats or demography alone, but conflates the two. The second analysis illustrates how the scoring key can be applied to a substantial set of species to understand overall patterns of ESA implementation. The scoring repeatability analysis shows promise, but indicates thorough training will be needed to ensure consistency. We propose that large conservation programs adopt our simple scoring system for threats and demography. By doing so, program administrators will have better information to monitor program effectiveness and guide their decisions. PMID:27478713

A simple, sufficient, and consistent method to score the status of threats and demography of imperiled species.

PubMed

Malcom, Jacob W; Webber, Whitney M; Li, Ya-Wei

2016-01-01

Managers of large, complex wildlife conservation programs need information on the conservation status of each of many species to help strategically allocate limited resources. Oversimplifying status data, however, runs the risk of missing information essential to strategic allocation. Conservation status consists of two components, the status of threats a species faces and the species' demographic status. Neither component alone is sufficient to characterize conservation status. Here we present a simple key for scoring threat and demographic changes for species using detailed information provided in free-form textual descriptions of conservation status. This key is easy to use (simple), captures the two components of conservation status without the cost of more detailed measures (sufficient), and can be applied by different personnel to any taxon (consistent). To evaluate the key's utility, we performed two analyses. First, we scored the threat and demographic status of 37 species recently recommended for reclassification under the Endangered Species Act (ESA) and 15 control species, then compared our scores to two metrics used for decision-making and reports to Congress. Second, we scored the threat and demographic status of all non-plant ESA-listed species from Florida (54 spp.), and evaluated scoring repeatability for a subset of those. While the metrics reported by the U.S. Fish and Wildlife Service (FWS) are often consistent with our scores in the first analysis, the results highlight two problems with the oversimplified metrics. First, we show that both metrics can mask underlying demographic declines or threat increases; for example, ∼40% of species not recommended for reclassification had changes in threats or demography. Second, we show that neither metric is consistent with either threats or demography alone, but conflates the two. The second analysis illustrates how the scoring key can be applied to a substantial set of species to understand overall patterns of ESA implementation. The scoring repeatability analysis shows promise, but indicates thorough training will be needed to ensure consistency. We propose that large conservation programs adopt our simple scoring system for threats and demography. By doing so, program administrators will have better information to monitor program effectiveness and guide their decisions.

Stress and body condition are associated with climate and demography in Asian elephants.

PubMed

Mumby, Hannah S; Mar, Khyne U; Thitaram, Chatchote; Courtiol, Alexandre; Towiboon, Patcharapa; Min-Oo, Zaw; Htut-Aung, Ye; Brown, Janine L; Lummaa, Virpi

2015-01-01

Establishing links between ecological variation, physiological markers of stress and demography is crucial for understanding how and why changes in environmental conditions affect population dynamics, and may also play a key role for conservation efforts of endangered species. However, detailed longitudinal studies of long-lived species are rarely available. We test how two markers of stress and body condition vary through the year and are associated with climatic conditions and large-scale mortality and fertility variation in the world's largest semi-captive population of Asian elephants employed in the timber industry in Myanmar. Glucocorticoid metabolites (used as a proxy for stress levels in 75 elephants) and body weight (used as a proxy for condition in 116 elephants) were monitored monthly across a typical monsoon cycle and compared with birth and death patterns of the entire elephant population over half a century (n = 2350). Our results show seasonal variation in both markers of stress and condition. In addition, this variation is correlated with population-level demographic variables. Weight is inversely correlated with population mortality rates 1 month later, and glucocorticoid metabolites are negatively associated with birth rates. Weight shows a highly positive correlation with rainfall 1 month earlier. Determining the factors associated with demography may be key to species conservation by providing information about the correlates of mortality and fertility patterns. The unsustainability of the studied captive population has meant that wild elephants have been captured and tamed for work. By elucidating the correlates of demography in captive elephants, our results offer management solutions that could reduce the pressure on the wild elephant population in Myanmar.

Phylogeography in Galaxias maculatus (Jenyns, 1848) along Two Biogeographical Provinces in the Chilean Coast

PubMed Central

González-Wevar, Claudio A.; Salinas, Pilar; Hüne, Mathias; Segovia, Nicolás I.; Vargas-Chacoff, Luis; Astorga, Marcela; Cañete, Juan I.; Poulin, Elie

2015-01-01

Major geologic and climatic changes during the Quaternary exerted a major role in shaping past and contemporary distribution of genetic diversity and structure of aquatic organisms in southern South America. In fact, the northern glacial limit along the Pacific coast, an area of major environmental changes in terms of topography, currents, and water salinity, represents a major biogeographic transition for marine and freshwater species. We used mitochondrial DNA sequences (D-loop) to investigate the consequences of Quaternary glacial cycles over the pattern of genetic diversity and structure of G. maculatus (Pisces: Galaxiidae) along two biogeographical provinces in the Chilean coast. Extreme levels of genetic diversity and strong phylogeographic structure characterize the species suggesting a low amount of influence of the last glacial cycle over its demography. However, we recognized contrasting patterns of genetic diversity and structure between main biogeographical areas here analyzed. Along the Intermediate Area (38°–41° S) each estuarine population constitutes a different unit. In contrast, Magellanic populations (43°–53° S) exhibited low levels of genetic differentiation. Contrasting patterns of genetic diversity and structure recorded in the species between the analyzed biogeographic areas are consistent with the marked differences in abiotic factors (i.e., different coastal configurations, Quaternary glacial histories, and oceanographic regimes) and to inherent characteristics of the species (i.e., salt-tolerance, physiology, and reproductive behavior). PMID:26161896

The impact of forest structure and light utilization on carbon cycling in tropical forests

NASA Astrophysics Data System (ADS)

Morton, D. C.; Longo, M.; Leitold, V.; Keller, M. M.

2015-12-01

Light competition is a fundamental organizing principle of forest ecosystems, and interactions between forest structure and light availability provide an important constraint on forest productivity. Tropical forests maintain a dense, multi-layered canopy, based in part on abundant diffuse light reaching the forest understory. Climate-driven changes in light availability, such as more direct illumination during drought conditions, therefore alter the potential productivity of forest ecosystems during such events. Here, we used multi-temporal airborne lidar data over a range of Amazon forest conditions to explore the influence of forest structure on gross primary productivity (GPP). Our analysis combined lidar-based observations of canopy illumination and turnover in the Ecosystem Demography model (ED, version 2.2). The ED model was updated to specifically account for regional differences in canopy and understory illumination using lidar-derived measures of canopy light environments. Model simulations considered the influence of forest structure on GPP over seasonal to decadal time scales, including feedbacks from differential productivity between illuminated and shaded canopy trees on mortality rates and forest composition. Finally, we constructed simple scenarios with varying diffuse and direct illumination to evaluate the potential for novel plant-climate interactions under scenarios of climate change. Collectively, the lidar observations and model simulations underscore the need to account for spatial heterogeneity in the vertical structure of tropical forests to constrain estimates of tropical forest productivity under current and future climate conditions.

Innovation and Change in American Education. Kensington Revisited: A Fifteen Year Follow-Up of an Innovative Elementary School and Its Faculty. Volume III--Community and School: Patterns of Development and Annals of Change. Final Report.

ERIC Educational Resources Information Center

Prunty, John J.; And Others

This third volume of a six-volume study of a school district code-named "Milford" shifts attention to the Kensington School itself. To explain the "profound changes" this "once innovative school" went through, the authors begin with such wider topics as demography, neighborhoods, and political jurisdiction. Chapter 1 traces Milford's "Native…

Future premature mortality due to O3, secondary inorganic aerosols and primary PM in Europe--sensitivity to changes in climate, anthropogenic emissions, population and building stock.

PubMed

Geels, Camilla; Andersson, Camilla; Hänninen, Otto; Lansø, Anne Sofie; Schwarze, Per E; Skjøth, Carsten Ambelas; Brandt, Jørgen

2015-03-04

Air pollution is an important environmental factor associated with health impacts in Europe and considerable resources are used to reduce exposure to air pollution through emission reductions. These reductions will have non-linear effects on exposure due, e.g., to interactions between climate and atmospheric chemistry. By using an integrated assessment model, we quantify the effect of changes in climate, emissions and population demography on exposure and health impacts in Europe. The sensitivity to the changes is assessed by investigating the differences between the decades 2000-2009, 2050-2059 and 2080-2089. We focus on the number of premature deaths related to atmospheric ozone, Secondary Inorganic Aerosols and primary PM. For the Nordic region we furthermore include a projection on how population exposure might develop due to changes in building stock with increased energy efficiency. Reductions in emissions cause a large significant decrease in mortality, while climate effects on chemistry and emissions only affects premature mortality by a few percent. Changes in population demography lead to a larger relative increase in chronic mortality than the relative increase in population. Finally, the projected changes in building stock and infiltration rates in the Nordic indicate that this factor may be very important for assessments of population exposure in the future.

Future Premature Mortality Due to O3, Secondary Inorganic Aerosols and Primary PM in Europe — Sensitivity to Changes in Climate, Anthropogenic Emissions, Population and Building Stock

PubMed Central

Geels, Camilla; Andersson, Camilla; Hänninen, Otto; Lansø, Anne Sofie; Schwarze, Per E.; Ambelas Skjøth, Carsten; Brandt, Jørgen

2015-01-01

Air pollution is an important environmental factor associated with health impacts in Europe and considerable resources are used to reduce exposure to air pollution through emission reductions. These reductions will have non-linear effects on exposure due, e.g., to interactions between climate and atmospheric chemistry. By using an integrated assessment model, we quantify the effect of changes in climate, emissions and population demography on exposure and health impacts in Europe. The sensitivity to the changes is assessed by investigating the differences between the decades 2000–2009, 2050–2059 and 2080–2089. We focus on the number of premature deaths related to atmospheric ozone, Secondary Inorganic Aerosols and primary PM. For the Nordic region we furthermore include a projection on how population exposure might develop due to changes in building stock with increased energy efficiency. Reductions in emissions cause a large significant decrease in mortality, while climate effects on chemistry and emissions only affects premature mortality by a few percent. Changes in population demography lead to a larger relative increase in chronic mortality than the relative increase in population. Finally, the projected changes in building stock and infiltration rates in the Nordic indicate that this factor may be very important for assessments of population exposure in the future. PMID:25749320

The impacts of climate, land use, and demography on fires during the 21st century simulated by CLM-CN

NASA Astrophysics Data System (ADS)

Kloster, S.; Mahowald, N. M.; Randerson, J. T.; Lawrence, P. J.

2012-01-01

Landscape fires during the 21st century are expected to change in response to multiple agents of global change. Important controlling factors include climate controls on the length and intensity of the fire season, fuel availability, and fire management, which are already anthropogenically perturbed today and are predicted to change further in the future. An improved understanding of future fires will contribute to an improved ability to project future anthropogenic climate change, as changes in fire activity will in turn impact climate. In the present study we used a coupled-carbon-fire model to investigate how changes in climate, demography, and land use may alter fire emissions. We used climate projections following the SRES A1B scenario from two different climate models (ECHAM5/MPI-OM and CCSM) and changes in population. Land use and harvest rates were prescribed according to the RCP 45 scenario. In response to the combined effect of all these drivers, our model estimated, depending on our choice of climate projection, an increase in future (2075-2099) fire carbon emissions by 17 and 62% compared to present day (1985-2009). The largest increase in fire emissions was predicted for Southern Hemisphere South America for both climate projections. For Northern Hemisphere Africa, a region that contributed significantly to the global total fire carbon emissions, the response varied between a decrease and an increase depending on the climate projection. We disentangled the contribution of the single forcing factors to the overall response by conducting an additional set of simulations in which each factor was individually held constant at pre-industrial levels. The two different projections of future climate change evaluated in this study led to increases in global fire carbon emissions by 22% (CCSM) and 66% (ECHAM5/MPI-OM). The RCP 45 projection of harvest and land use led to a decrease in fire carbon emissions by -5%. The RCP 26 and RCP 60 harvest and landuse projections caused decreases around -20%. Changes in human ignition led to an increase of 20%. When we also included changes in fire management efforts to suppress fires in densely populated areas, global fire carbon emission decreased by -6% in response to changes in population density. We concluded from this study that changes in fire emissions in the future are controlled by multiple interacting factors. Although changes in climate led to an increase in future fire emissions this could be globally counterbalanced by coupled changes in land use, harvest, and demography.

Reproductive efficiency and herd demography of Nguni cattle in village-owned and group-owned enterprises under low-input communal production systems.

PubMed

Tada, Obert; Muchenje, Voster; Dzama, Kennedy

2013-08-01

The objective of the study was to determine the herd demography and reproductive efficiency of the Nguni cattle in village-owned and group-owned enterprises under low-input communal production systems. Data on husbandry practices, reason of cattle entry/exist, herd structure, bulling rates, breeding females, age at first calving and calving interval were obtained from 22 village-owned and 19 group-owned enterprises in a cross-sectional survey of an ecologically controlled low-input cattle production system. Descriptive statistics and chi-square tests of association were computed on enterprise ownership patterns, husbandry practices and herd demography. An AN(C)OVA was used to determine significant factors affecting herd structure, mortality, age at first calving and calving interval in the enterprises. Village-owned enterprises had higher (p < 0.05) dipping frequency per season than group enterprises. The herd sizes were significantly higher (p < 0.05) in group-owned (29.9 ± 3.23) than in village-owned (23.6 ± 2.40) enterprises. Mortality rate was significantly lower (p < 0.05) in group-owned (10.8%) than in village-owned enterprises (26.4 %). Group-owned enterprises had significantly more sales and programme retains than the village-owned enterprises (p < 0.05). There were no significant differences between enterprise ownership pattern on cattle production potential and age at first calving (p > 0.05). Significant differences were observed on the calving interval (p < 0.05) where the group-owned enterprises performed better (16.0 ± 1.10 months) than village-owned enterprises (22.7 ± 1.07 months). The bulling rate was higher in village-owned enterprises, while the proportion of breeding females was higher in group-owned enterprises. Farmers with a college education had Nguni animals with the shortest calving interval. It was concluded that group-owned enterprises had significantly better calving intervals, mortality rates and overall herd structure than village-owned enterprises.

Work and Family: An Annotated Bibliography

DTIC Science & Technology

1984-01-01

8217 with the rest of society. t..- _ 81. Collver, 0. A. Women’s work participation and fertility in metropolitan are’as. Demography , 1968, 5, 55-60. This...In the United States. Demography , 1979, 16, 177-197. The central concept of microeconomic theories of fertility is opportunity cost-the product of...Convenience of work and the job constraint of children. Demography , 1975,1 12, 245-258. This paper investigates whether convenient working conditions reduce

Gendered Authorship and Demographic Research: An Analysis of 50 Years of Demography.

PubMed

Krapf, Sandra; Kreyenfeld, Michaela; Wolf, Katharina

2016-08-01

Demography, the official journal of the Population Association of America, has been given the highest rating among demographic journals by the Social Sciences Citation Index (SSCI). Our aim here is to investigate the development of research subfields and female authorship in Demography over the last 50 years. We find that female authorship in Demography has risen considerably since the 1980s and that currently a woman is about as likely as a man to be the sole or the first author of a paper published in the journal. However, we find some differences by subfield. Women seem to be overrepresented in the "family and household" research subfield but underrepresented in the "mortality and health" and "data and methods" categories.

Mismatch Between Birth Date and Vegetation Phenology Slows the Demography of Roe Deer

PubMed Central

Plard, Floriane; Gaillard, Jean-Michel; Coulson, Tim; Hewison, A. J. Mark; Delorme, Daniel; Warnant, Claude; Bonenfant, Christophe

2014-01-01

Marked impacts of climate change on biodiversity have frequently been demonstrated, including temperature-related shifts in phenology and life-history traits. One potential major impact of climate change is the modification of synchronization between the phenology of different trophic levels. High phenotypic plasticity in laying date has allowed many bird species to track the increasingly early springs resulting from recent environmental change, but although changes in the timing of reproduction have been well studied in birds, these questions have only recently been addressed in mammals. To track peak resource availability, large herbivores like roe deer, with a widespread distribution across Europe, should also modify their life-history schedule in response to changes in vegetation phenology over time. In this study, we analysed the influence of climate change on the timing of roe deer births and the consequences for population demography and individual fitness. Our study provides a rare quantification of the demographic costs associated with the failure of a species to modify its phenology in response to a changing world. Given these fitness costs, the lack of response of roe deer birth dates to match the increasingly earlier onset of spring is in stark contrast with the marked phenotypic responses to climate change reported in many other mammals. We suggest that the lack of phenotypic plasticity in birth timing in roe deer is linked to its inability to track environmental cues of variation in resource availability for the timing of parturition. PMID:24690936

Effects of sample size on estimates of population growth rates calculated with matrix models.

PubMed

Fiske, Ian J; Bruna, Emilio M; Bolker, Benjamin M

2008-08-28

Matrix models are widely used to study the dynamics and demography of populations. An important but overlooked issue is how the number of individuals sampled influences estimates of the population growth rate (lambda) calculated with matrix models. Even unbiased estimates of vital rates do not ensure unbiased estimates of lambda-Jensen's Inequality implies that even when the estimates of the vital rates are accurate, small sample sizes lead to biased estimates of lambda due to increased sampling variance. We investigated if sampling variability and the distribution of sampling effort among size classes lead to biases in estimates of lambda. Using data from a long-term field study of plant demography, we simulated the effects of sampling variance by drawing vital rates and calculating lambda for increasingly larger populations drawn from a total population of 3842 plants. We then compared these estimates of lambda with those based on the entire population and calculated the resulting bias. Finally, we conducted a review of the literature to determine the sample sizes typically used when parameterizing matrix models used to study plant demography. We found significant bias at small sample sizes when survival was low (survival = 0.5), and that sampling with a more-realistic inverse J-shaped population structure exacerbated this bias. However our simulations also demonstrate that these biases rapidly become negligible with increasing sample sizes or as survival increases. For many of the sample sizes used in demographic studies, matrix models are probably robust to the biases resulting from sampling variance of vital rates. However, this conclusion may depend on the structure of populations or the distribution of sampling effort in ways that are unexplored. We suggest more intensive sampling of populations when individual survival is low and greater sampling of stages with high elasticities.

A stand-alone tree demography and landscape structure module for Earth system models: integration with global forest data

NASA Astrophysics Data System (ADS)

Haverd, V.; Smith, B.; Nieradzik, L. P.; Briggs, P. R.

2014-02-01

Poorly constrained rates of biomass turnover are a key limitation of Earth system models (ESM). In light of this, we recently proposed a new approach encoded in a model called Populations-Order-Physiology (POP), for the simulation of woody ecosystem stand dynamics, demography and disturbance-mediated heterogeneity. POP is suitable for continental to global applications and designed for coupling to the terrestrial ecosystem component of any ESM. POP bridges the gap between first generation Dynamic Vegetation Models (DVMs) with simple large-area parameterisations of woody biomass (typically used in current ESMs) and complex second generation DVMs, that explicitly simulate demographic processes and landscape heterogeneity of forests. The key simplification in the POP approach, compared with second-generation DVMs, is to compute physiological processes such as assimilation at grid-scale (with CABLE or a similar land surface model), but to partition the grid-scale biomass increment among age classes defined at sub grid-scale, each subject to its own dynamics. POP was successfully demonstrated along a savanna transect in northern Australia, replicating the effects of strong rainfall and fire disturbance gradients on observed stand productivity and structure. Here, we extend the application of POP to a range of forest types around the globe, employing paired observations of stem biomass and density from forest inventory data to calibrate model parameters governing stand demography and biomass evolution. The calibrated POP model is then coupled to the CABLE land surface model and the combined model (CABLE-POP) is evaluated against leaf-stem allometry observations from forest stands ranging in age from 3 to 200 yr. Results indicate that simulated biomass pools conform well with observed allometry. We conclude that POP represents a preferable alternative to large-area parameterisations of woody biomass turnover, typically used in current ESMs.

A longevity record for Canada lynx, Lynx canadensis, in western Montana

Treesearch

Jay A. Kolbe; John R. Squires

2006-01-01

The Canada lynx (Lynx canadensis) was listed as a threatened species under the Endangered Species Act (USDI Fish and Wildlife Service 2000) in 2000 and is a species of conservation concern in the United States. New insights into the basic demography of southern lynx populations are needed. Data describing population age structures, including maximum ages, will...

Women Teachers in Western Australian "Bush" Schools, 1900-1939: Passive Victims of Oppressive Structures?

ERIC Educational Resources Information Center

Trotman, Janina

2006-01-01

Demography, distance, and the expansion of settlements created problems for the State Department of Education in Western Australia and other Australian states in the nineteenth and early twentieth centuries. Educational administration in Canada and parts of the United States faced similar issues with regard to the provision of schools. A common…

Native ungulates of diverse body sizes collectively regulate long-term woody plant demography and structure of a semi-arid savanna

USDA-ARS?s Scientific Manuscript database

Large mammalian herbivores and fire are both well recognized to play important roles in regulating tree cover and biomass in savannas. However, the extent to which browsing ungulates are capable of regulating tree populations in the absence of other synergistic disturbances such as fire is unclear. ...

America's Future: Latino Child Well-Being in Numbers and Trends

ERIC Educational Resources Information Center

Mather, Mark; Foxen, Patricia

2010-01-01

This data book offers a comprehensive overview of the state of Latino children by integrating a range of key factors and outcomes in the areas of demography, citizenship, family structure, poverty, health, education, and juvenile justice. It provides an overview of current national and state-level trends for Latino children under age 18 relative…

The Role of Parental Involvement in India: A Context-Based Review

ERIC Educational Resources Information Center

Saravanabhavan, Rc; Saravanabhavan, Sheila; Muthaiah, N.

2012-01-01

The article presents a historical overview of education in India, followed by a background on current demography, governance structures, and status. The role of parent involvement is traced from ancient times to the modern era to highlight how this phenomenon has evolved. A review of recent national policies stemming from the 2009 Right of…

Attitudes of Major Soviet Nationalities. Volume IV. Central Asia. Kazakhstan, Kirgizistan, Turkmenistan, Uzbekistan, Tadzhikistan.

DTIC Science & Technology

1973-06-01

attitudes. IV. Demography Although Uzbekistan is somewhat smaller in area than neighboring Turkmenistan, it has nearly six times the population--close...Uzbekistan - Demography - 2 Table A.2. National Composition of Uzbek SSR 19 26a 19 39b 1959 c 1 970c T number % number % number % number % Total . Uzbek...Mullyadzbanov, Narodo naseleniye Ilzbekskoi SSR (Tashkent, 1967): 177. c Pravda Vostoka (April 28), 1971: 2. 4 Uzbekistan - Demography - 3 the extraordinary

Challenges in Improving Latino College Enrollment: Opportunities for Systemic Change Viewpoints from California

ERIC Educational Resources Information Center

Tomas Rivera Policy Institute, 2005

2005-01-01

This document includes presentation summaries and policy recommendations from the 2004 Tomas Rivera Policy Institute (TRPI) Education Conference: (1) The Present and Coming Crisis: Demography and Education (Dowell Myers and Estela Mara Bensimon); (2) A View from the Academic Community (Moderators: Jorge Haynes and Jamilah Moore; Presenters:…

Children at Risk: The Work of the States.

ERIC Educational Resources Information Center

Council of Chief State School Officers, Washington, DC.

This study of at-risk youth and children highlights the states' interest in this problem, sparked by changing demographies, new state educational reform policies, the concerns of business and industry, and increasing national awareness. The nature of at-risk youth is examined and the obstacles to meeting their needs are discussed. Findings are…

A Status Report from the Task Force on Marketing Research.

ERIC Educational Resources Information Center

Keim, William A.; And Others

Concerned with changes in enrollment and credit hour patterns, the chancellor of the Kansas City Metropolitan Community Colleges (MCC) created a special Task Force to consider recommendations for marketing strategies for the 1978-79 academic year. The Task Force reviewed regional and district demography, area population trends and density, age and…

A Portrait of Race and Ethnicity in California: An Assessment of Social and Economic Well-Being.

ERIC Educational Resources Information Center

Reyes, Belinda I., Ed.

This document examines differences in socioeconomic status by racial and ethnic groups in California, exploring changing patterns over time. It analyzes trends and outcomes in demography, geographic distribution, health, education, crime, labor markets, economic status, and political participation. Data on educational outcomes include: education…

Abstracts and program proceedings of the 1994 meeting of the International Society for Ecological Modelling North American Chapter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kercher, J.R.

1994-06-01

This document contains information about the 1994 meeting of the International Society for Ecological Modelling North American Chapter. The topics discussed include: extinction risk assessment modelling, ecological risk analysis of uranium mining, impacts of pesticides, demography, habitats, atmospheric deposition, and climate change.

Behavioral and Social Science Research: A National Resource. Part II.

ERIC Educational Resources Information Center

Adams, Robert McC., Ed.; And Others

Areas of behavioral and social science research that have achieved significant breakthroughs in knowledge or application or that show future promise of achieving such breakthroughs are discussed in 12 papers. For example, the paper on formal demography shows how mathematical or statistical techniques can be used to explain and predict change in…

From System Expansion to System Contraction: Access to Higher Education in Poland

ERIC Educational Resources Information Center

Kwiek, Marek

2013-01-01

Access to higher education in Poland is changing due to the demography of smaller cohorts of potential students. Following a demand-driven educational expansion after the collapse of communism in 1989, the higher education system is now contracting. Such expansion/contraction and growth/decline in European higher education has rarely been…

The devil is in the dispersers: Predictions of landscape connectivity change with demography

Treesearch

Nicholas B. Elliot; Samuel A. Cushman; David W. Macdonald; Andrew J. Loveridge

2014-01-01

Concern about the effects of habitat fragmentation has led to increasing interest in dispersal and connectivity modelling. Most modern techniques for connectivity modelling have resistance surfaces as their foundation. However, resistance surfaces for animal movement are frequently estimated without considering dispersal, despite being the principal natural mechanism...

High Selection Pressure Promotes Increase in Cumulative Adaptive Culture

PubMed Central

Vegvari, Carolin; Foley, Robert A.

2014-01-01

The evolution of cumulative adaptive culture has received widespread interest in recent years, especially the factors promoting its occurrence. Current evolutionary models suggest that an increase in population size may lead to an increase in cultural complexity via a higher rate of cultural transmission and innovation. However, relatively little attention has been paid to the role of natural selection in the evolution of cultural complexity. Here we use an agent-based simulation model to demonstrate that high selection pressure in the form of resource pressure promotes the accumulation of adaptive culture in spite of small population sizes and high innovation costs. We argue that the interaction of demography and selection is important, and that neither can be considered in isolation. We predict that an increase in cultural complexity is most likely to occur under conditions of population pressure relative to resource availability. Our model may help to explain why culture change can occur without major environmental change. We suggest that understanding the interaction between shifting selective pressures and demography is essential for explaining the evolution of cultural complexity. PMID:24489724

Population differentiation in the context of Holocene climate change for a migratory marine species, the southern elephant seal.

PubMed

Corrigan, L J; Fabiani, A; Chauke, L F; McMahon, C R; de Bruyn, M; Bester, M N; Bastos, A; Campagna, C; Muelbert, M M C; Hoelzel, A R

2016-09-01

Understanding observed patterns of connectivity requires an understanding of the evolutionary processes that determine genetic structure among populations, with the most common models being associated with isolation by distance, allopatry or vicariance. Pinnipeds are annual breeders with the capacity for extensive range overlap during seasonal migrations, establishing the potential for the evolution of isolation by distance. Here, we assess the pattern of differentiation among six breeding colonies of the southern elephant seal, Mirounga leonina, based on mtDNA and 15 neutral microsatellite DNA markers, and consider measures of their demography and connectivity. We show that all breeding colonies are genetically divergent and that connectivity in this highly mobile pinniped is not strongly associated with geographic distance, but more likely linked to Holocene climate change and demographic processes. Estimates of divergence times between populations were all after the last glacial maximum, and there was evidence for directional migration in a clockwise pattern (with the prevailing current) around the Antarctic. We discuss the mechanisms by which climate change may have contributed to the contemporary genetic structure of southern elephant seal populations and the broader implications. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Leaf ontogeny and demography explain photosynthetic seasonality in Amazon evergreen forests

NASA Astrophysics Data System (ADS)

Wu, J.; Albert, L.; Lopes, A. P.; Restrepo-Coupe, N.; Hayek, M.; Wiedemann, K. T.; Guan, K.; Stark, S. C.; Prohaska, N.; Tavares, J. V.; Marostica, S. F.; Kobayashi, H.; Ferreira, M. L.; Campos, K.; Silva, R. D.; Brando, P. M.; Dye, D. G.; Huxman, T. E.; Huete, A. R.; Nelson, B. W.; Saleska, S. R.

2015-12-01

Photosynthetic seasonality couples the evolutionary ecology of plant leaves to large-scale rhythms of carbon and water exchanges that are important feedbacks to climate. However, the extent, magnitude, and controls on photosynthetic seasonality of carbon-rich tropical forests are poorly resolved, controversial in the remote sensing literature, and inadequately represented in most earth system models. Here we show that ecosystem-scale phenology (measured by photosynthetic capacity), rather than environmental seasonality, is the primary driver of photosynthetic seasonality at four Amazon evergreen forests spanning gradients in rainfall seasonality, forest composition, and flux seasonality. We further demonstrate that leaf ontogeny and demography explain most of this ecosystem phenology at two central Amazon evergreen forests, using a simple leaf-cohort canopy model that integrates eddy covariance-derived CO2 fluxes, novel near-surface camera-detected leaf phenology, and ground observations of litterfall and leaf physiology. The coordination of new leaf growth and old leaf divestment (litterfall) during the dry season shifts canopy composition towards younger leaves with higher photosynthetic efficiency, driving large seasonal increases (~27%) in ecosystem photosynthetic capacity. Leaf ontogeny and demography thus reconciles disparate observations of forest seasonality from leaves to eddy flux towers to satellites. Strategic incorporation of such whole-plant coordination processes as phenology and ontogeny will improve ecological, evolutionary and earth system theories describing tropical forests structure and function, allowing more accurate representation of forest dynamics and feedbacks to climate in earth system models.

Toward a mechanistic understanding of human-induced rapid environmental change: A case study linking energy development, avian nest predation, and predators

USGS Publications Warehouse

Hethcoat, Matthew G.; Chalfoun, Anna D.

2015-01-01

Synthesis and applications. We demonstrate one mechanism, that is the local augmentation of predators, by which human-induced rapid environmental change can influence the demography of local populations. Given the accelerating trajectory of global energy demands, an important next step will be to understand why the activity and/or abundance of rodent predators increased with surrounding habitat loss from energy development activities.

Water Operations Technical Support Program: Techniques for Evaluating Aquatic Habitats in Rivers, Streams, and Reservoirs. Proceedings of a Workshop Held in Vicksburg, Mississippi on 8-10 August 1989.

DTIC Science & Technology

1991-08-01

cohorts). The abundance of individuals greater than 20 mm SL and the complexity of size demography indicated longevity of 2 to 3 years for a substantial...Richard Kasul ......... ......................... . 86 DATA ANALYSIS AND INTERPRETATION ...... ................... 93 Measurement of Size Demography ...Experi- ment Station, Vicksburg, MS. Miller, A. C., and Payne, B. S. 1988. "The Need for Quantitative Sampling to Characterize Size Demography and Density

Coupling mammalian demography to climate through satellite time series of plant phenology

NASA Astrophysics Data System (ADS)

Stoner, D.; Sexton, J. O.; Nagol, J. R.; Ironside, K.; Choate, D.; Longshore, K.; Edwards, T., Jr.

2016-12-01

The seasonality of plant productivity governs the demography of primary and secondary consumers, and in arid ecosystems primary production is constrained by water availability. We relate the behavior, demography, and spatial distribution of large mammalian herbivores and their principal predator to remotely sensed indices of climate and vegetation across the western United States from 2000-2014. Terrain and plant community composition moderate the effects of climatological drought on primary productivity, resulting in spatial variation in ecosystem susceptibility to water stress. Herbivores track these patterns through habitat selection during key periods such as birthing and migration. Across a broad climatological gradient, timing of the start of growing season explains 75% of the variation in herbivore birth timing and 56% of the variation in neonatal survival rates. Initiation of autumn migration corresponds with the end of the growing season. Although indirectly coupled to primary production, carnivore home range size and population density are strongly correlated with plant productivity and growing-season length. Satellite measures of green reflectance during the peak of the growing season explain over 84% of the variation in carnivore home range size and 59% of the variation in density. Climate projections for the western United States predict warming temperatures and shifts in the timing and form of precipitation. Our analyses suggest that increased climatological variability will contribute to fluctuations in the composition and phenology of plant communities. These changes will propagate through consumer trophic levels, manifesting as increased home range area, shifts in the timing of migration, and greater volatility in large mammal populations. Combined with expansion and amplification of human land uses, these changes will likely have economic implications stemming from increased human-wildlife conflict and loss of ecosystem services.

Evaluating within-population variability in behavior and demography for the adaptive potential of a dispersal-limited species to climate change

USGS Publications Warehouse

Muñoz, David J.; Miller Hesed, Kyle; Grant, Evan H. Campbell; Miller, David A.W.

2016-01-01

Multiple pathways exist for species to respond to changing climates. However, responses of dispersal-limited species will be more strongly tied to ability to adapt within existing populations as rates of environmental change will likely exceed movement rates. Here, we assess adaptive capacity in Plethodon cinereus, a dispersal-limited woodland salamander. We quantify plasticity in behavior and variation in demography to observed variation in environmental variables over a 5-year period. We found strong evidence that temperature and rainfall influence P. cinereus surface presence, indicating changes in climate are likely to affect seasonal activity patterns. We also found that warmer summer temperatures reduced individual growth rates into the autumn, which is likely to have negative demographic consequences. Reduced growth rates may delay reproductive maturity and lead to reductions in size-specific fecundity, potentially reducing population-level persistence. To better understand within-population variability in responses, we examined differences between two common color morphs. Previous evidence suggests that the color polymorphism may be linked to physiological differences in heat and moisture tolerance. We found only moderate support for morph-specific differences for the relationship between individual growth and temperature. Measuring environmental sensitivity to climatic variability is the first step in predicting species' responses to climate change. Our results suggest phenological shifts and changes in growth rates are likely responses under scenarios where further warming occurs, and we discuss possible adaptive strategies for resulting selective pressures.

Large-scale climatic anomalies affect marine predator foraging behaviour and demography.

PubMed

Bost, Charles A; Cotté, Cedric; Terray, Pascal; Barbraud, Christophe; Bon, Cécile; Delord, Karine; Gimenez, Olivier; Handrich, Yves; Naito, Yasuhiko; Guinet, Christophe; Weimerskirch, Henri

2015-10-27

Determining the links between the behavioural and population responses of wild species to environmental variations is critical for understanding the impact of climate variability on ecosystems. Using long-term data sets, we show how large-scale climatic anomalies in the Southern Hemisphere affect the foraging behaviour and population dynamics of a key marine predator, the king penguin. When large-scale subtropical dipole events occur simultaneously in both subtropical Southern Indian and Atlantic Oceans, they generate tropical anomalies that shift the foraging zone southward. Consequently the distances that penguins foraged from the colony and their feeding depths increased and the population size decreased. This represents an example of a robust and fast impact of large-scale climatic anomalies affecting a marine predator through changes in its at-sea behaviour and demography, despite lack of information on prey availability. Our results highlight a possible behavioural mechanism through which climate variability may affect population processes.

Large-scale climatic anomalies affect marine predator foraging behaviour and demography

NASA Astrophysics Data System (ADS)

Bost, Charles A.; Cotté, Cedric; Terray, Pascal; Barbraud, Christophe; Bon, Cécile; Delord, Karine; Gimenez, Olivier; Handrich, Yves; Naito, Yasuhiko; Guinet, Christophe; Weimerskirch, Henri

2015-10-01

Determining the links between the behavioural and population responses of wild species to environmental variations is critical for understanding the impact of climate variability on ecosystems. Using long-term data sets, we show how large-scale climatic anomalies in the Southern Hemisphere affect the foraging behaviour and population dynamics of a key marine predator, the king penguin. When large-scale subtropical dipole events occur simultaneously in both subtropical Southern Indian and Atlantic Oceans, they generate tropical anomalies that shift the foraging zone southward. Consequently the distances that penguins foraged from the colony and their feeding depths increased and the population size decreased. This represents an example of a robust and fast impact of large-scale climatic anomalies affecting a marine predator through changes in its at-sea behaviour and demography, despite lack of information on prey availability. Our results highlight a possible behavioural mechanism through which climate variability may affect population processes.

Demography and Public Health Emergency Preparedness: Making the Connection

PubMed Central

Katz, Rebecca

2009-01-01

The tools and techniques of population sciences are extremely relevant to the discipline of public health emergency preparedness: protecting and securing the population’s health requires information about that population. While related fields such as security studies have successfully integrated demographic tools into their research and literature, the theoretical and practical connection between the methods of demography and the practice of public health emergency preparedness is weak. This article suggests the need to further the interdisciplinary use of demography by examining the need for a systematic use of population science techniques in public health emergency preparedness. Ultimately, we demonstrate how public health emergency preparedness can incorporate demography to develop more effective preparedness plans. Important policy implications emerge: demographers and preparedness experts need to collaborate more formally in order to facilitate community resilience and mitigate the consequences of public health emergencies. PMID:20694030

Fine-scale population structure in a desert amphibian: landscape genetics of the black toad (Bufo exsul).

PubMed

Wang, Ian J

2009-09-01

Environmental variables can strongly influence a variety of intra- and inter-population processes, including demography, population structure and gene flow. When environmental conditions are particularly harsh for a certain species, investigating these effects is important to understanding how populations persist under difficult conditions. Furthermore, species inhabiting challenging environments present excellent opportunities to examine the effects of complex landscapes on population processes because these effects will often be more pronounced. In this study, I use 16 microsatellite loci to examine population structure, gene flow and demographic history in the black toad, Bufo exsul, which has one of the most restricted natural ranges of any amphibian. Bufo exsul inhabits four springs in the Deep Springs Valley high desert basin and has never been observed more than several meters from any source of water. My results reveal limited gene flow and moderately high levels of population structure (F(ST) = 0.051-0.063) between all but the two closest springs. I found that the geographic distance across the arid scrub habitat between springs is significantly correlated with genetic structure when distance accounts for topography and barriers to dispersal. I also found very low effective population sizes (N(e) = 7-30) and substantial evidence for historical population bottlenecks in all four populations. Together, these results suggest that the desert landscape and B. exsul's high habitat specificity contribute significantly to population structure and demography in this species and emphasize the importance of considering behavioural and landscape data in conservation genetic studies of natural systems.

Life-stage differences in spatial genetic structure in an irruptive forest insect: implications for dispersal and spatial synchrony

Treesearch

Patrick M.A. James; Barry Cooke; Bryan M.T. Brunet; Lisa M. Lumley; Felix A.H. Sperling; Marie-Josee Fortin; Vanessa S. Quinn; Brian R. Sturtevant

2015-01-01

Dispersal determines the flux of individuals, energy and information and is therefore a key determinant of ecological and evolutionary dynamics. Yet, it remains difficult to quantify its importance relative to other factors. This is particularly true in cyclic populations in which demography, drift and dispersal contribute to spatio-temporal variability in genetic...

Acceleration of vegetation turnover and element cycling by mammalian herbivory in riparian ecosystems

Treesearch

Lem G. Butler; Knut Kielland

2008-01-01

1. We examined the effects of browsing by moose and snowshoe hares on vegetation structure, species composition, plant demography and element cycling in 25 riparian (willow) vegetation stands along the Tanana River, interior Alaska, across a 250-km gradient that represented a fivefold range in moose densities (0.2 to 1.0 km-2). 2. Browsing...

"Should I Stay or Should I Go?": Dilemmas and Decisions among UK Undergraduates

ERIC Educational Resources Information Center

Bradley, Harriet

2017-01-01

There is increasing concern about high rates of dropout from universities, especially among students from disadvantaged backgrounds. In the UK this is related to recent changes in higher education policy, especially the imposition of a higher fees regime and the uncapping of student numbers. While recent research has explored the demography of…

An Assessment of Long-Term Changes in Anthropometric Dimensions: Secular Trends of U.S. Army Males

DTIC Science & Technology

1990-12-01

17. COSATI CODES 18 SUBJECT TERMS (Continue on reverse if necessary and identify by block number) FIELD GROUP SUB-GROUP Anthropometry Demography... Elderly Population. Human Bioloxy 60:917-925. Clauser, C, I Tebbetts, B Bradtmiller, J McConville and CC Gordon (1988) Measurer’s Handbook: U.S. Army

American Higher Education: Journalistic and Policy Perspectives from "National CrossTalk"

ERIC Educational Resources Information Center

Trombley, William H., Ed.; Sallo, Todd, Ed.

2012-01-01

In the first decade of the 21st century, the nation, the states, and colleges and universities began to grapple with the challenges of globalization, changing demography, the implications of the digital era, and of a less expansive public sector. Although not a transformative period for higher education, the decade saw significant innovations in…

Maintaining Credibility and Authority as an Instructor of Color in Diversity-Education Classrooms: A Qualitative Inquiry

ERIC Educational Resources Information Center

Perry, Gary; Moore, Helen; Edwards, Crystal; Acosta, Katherine; Frey, Connie

2009-01-01

The movement for multicultural or diversity-centered education has resulted in changes to the academic demography of the United States. Institutions of higher education have integrated the voices, knowledge, and lived experiences of various underrepresented cultures and excluded groups into their formal academic curriculum. A recent survey by the…

Climate, not Aboriginal landscape burning, controlled the historical demography and distribution of fire-sensitive conifer populations across Australia

PubMed Central

Sakaguchi, Shota; Bowman, David M. J. S.; Prior, Lynda D.; Crisp, Michael D.; Linde, Celeste C.; Tsumura, Yoshihiko; Isagi, Yuji

2013-01-01

Climate and fire are the key environmental factors that shape the distribution and demography of plant populations in Australia. Because of limited palaeoecological records in this arid continent, however, it is unclear as to which factor impacted vegetation more strongly, and what were the roles of fire regime changes owing to human activity and megafaunal extinction (since ca 50 kya). To address these questions, we analysed historical genetic, demographic and distributional changes in a widespread conifer species complex that paradoxically grows in fire-prone regions, yet is very sensitive to fire. Genetic demographic analysis showed that the arid populations experienced strong bottlenecks, consistent with range contractions during the Last Glacial Maximum (ca 20 kya) predicted by species distribution models. In southern temperate regions, the population sizes were estimated to have been mostly stable, followed by some expansion coinciding with climate amelioration at the end of the last glacial period. By contrast, in the flammable tropical savannahs, where fire risk is the highest, demographic analysis failed to detect significant population bottlenecks. Collectively, these results suggest that the impact of climate change overwhelmed any modifications to fire regimes by Aboriginal landscape burning and megafaunal extinction, a finding that probably also applies to other fire-prone vegetation across Australia. PMID:24174110

Schooling in modern Europe exploring major issues and their ramifications

NASA Astrophysics Data System (ADS)

Husén, Torsten

1993-11-01

Basing its arguments on a major study conducted on behalf of the Academia Europaea by a study group coordinated by the author, this paper sets out a number of important findings concerning problems besetting schooling in modern Europe. The paper begins by stressing the importance of studying the state of European education at a particularly significant time when major political changes are taking place, trade and labour markets are in a process of rapid integration, schools as institutions are becoming increasingly complex and there is a need to establish a new European identity and consciousness. The main questions examined, against the current background of industrialization, urbanization, changing demography and growing European integration, are those relating particularly to educational response to growing international competition and the consequences of changing family structure. Among problems considered are those arising from the changing capacity of schools to provide a substitute for the family and other influences in modern society at a time when, for various reasons, these are declining and schooling is generally being prolonged. Priority areas proposed for school education in the new circumstances include the promotion of European citizenship, the teaching of foreign languages to all, a preparation for working life geared to its rapidly changing structure and the expansion of appropriate scientific and technological education. The need to find solutions to the problems of educating immigrant groups and to develop evaluation systems in order to monitor quality maintenance are particularly highlighted.

Genetic diversity and differentiation in a wide ranging anadromous fish, American shad (Alosa sapidissima), is correlated with latitude.

PubMed

Hasselman, Daniel J; Ricard, Daniel; Bentzen, Paul

2013-03-01

Studies that span entire species ranges can provide insight into the relative roles of historical contingency and contemporary factors that influence population structure and can reveal patterns of genetic variation that might otherwise go undetected. American shad is a wide ranging anadromous clupeid fish that exhibits variation in demographic histories and reproductive strategies (both semelparity and iteroparity) and provides a unique perspective on the evolutionary processes that govern the genetic architecture of anadromous fishes. Using 13 microsatellite loci, we examined the magnitude and spatial distribution of genetic variation among 33 populations across the species' range to (i) determine whether signals of historical demography persist among contemporary populations and (ii) assess the effect of different reproductive strategies on population structure. Patterns of genetic diversity and differentiation among populations varied widely and reflect the differential influences of historical demography, microevolutionary processes and anthropogenic factors across the species' range. Sequential reductions of diversity with latitude among formerly glaciated rivers are consistent with stepwise postglacial colonization and successive population founder events. Weak differentiation among U.S. iteroparous populations may be a consequence of human-mediated gene flow, while weak differentiation among semelparous populations probably reflects natural gene flow. Evidence for an effect of reproductive strategy on population structure suggests an important role for environmental variation and suggests that the factors that are responsible for shaping American shad life history patterns may also influence population genetic structure. © 2013 Blackwell Publishing Ltd.

Rapid genetic divergence in response to 15 years of simulated climate change.

PubMed

Ravenscroft, Catherine H; Whitlock, Raj; Fridley, Jason D

2015-11-01

Genetic diversity may play an important role in allowing individual species to resist climate change, by permitting evolutionary responses. Our understanding of the potential for such responses to climate change remains limited, and very few experimental tests have been carried out within intact ecosystems. Here, we use amplified fragment length polymorphism (AFLP) data to assess genetic divergence and test for signatures of evolutionary change driven by long-term simulated climate change applied to natural grassland at Buxton Climate Change Impacts Laboratory (BCCIL). Experimental climate treatments were applied to grassland plots for 15 years using a replicated and spatially blocked design and included warming, drought and precipitation treatments. We detected significant genetic differentiation between climate change treatments and control plots in two coexisting perennial plant study species (Festuca ovina and Plantago lanceolata). Outlier analyses revealed a consistent signature of selection associated with experimental climate treatments at individual AFLP loci in P. lanceolata, but not in F. ovina. Average background differentiation at putatively neutral AFLP loci was close to zero, and genomewide genetic structure was associated neither with species abundance changes (demography) nor with plant community-level responses to long-term climate treatments. Our results demonstrate genetic divergence in response to a suite of climatic environments in reproductively mature populations of two perennial plant species and are consistent with an evolutionary response to climatic selection in P. lanceolata. These genetic changes have occurred in parallel with impacts on plant community structure and may have contributed to the persistence of individual species through 15 years of simulated climate change at BCCIL. © 2015 The Authors. Global Change Biology Bioenergy Published by John Wiley & Sons Ltd.

Interactions between social structure, demography, and transmission determine disease persistence in primates.

PubMed

Ryan, Sadie J; Jones, James H; Dobson, Andrew P

2013-01-01

Catastrophic declines in African great ape populations due to disease outbreaks have been reported in recent years, yet we rarely hear of similar disease impacts for the more solitary Asian great apes, or for smaller primates. We used an age-structured model of different primate social systems to illustrate that interactions between social structure and demography create 'dynamic constraints' on the pathogens that can establish and persist in primate host species with different social systems. We showed that this varies by disease transmission mode. Sexually transmitted infections (STIs) require high rates of transmissibility to persist within a primate population. In particular, for a unimale social system, STIs require extremely high rates of transmissibility for persistence, and remain at extremely low prevalence in small primates, but this is less constrained in longer-lived, larger-bodied primates. In contrast, aerosol transmitted infections (ATIs) spread and persist at high prevalence in medium and large primates with moderate transmissibility;, establishment and persistence in small-bodied primates require higher relative rates of transmissibility. Intragroup contact structure - the social network - creates different constraints for different transmission modes, and our model underscores the importance of intragroup contacts on infection prior to intergroup movement in a structured population. When alpha males dominate sexual encounters, the resulting disease transmission dynamics differ from when social interactions are dominated by mother-infant grooming events, for example. This has important repercussions for pathogen spread across populations. Our framework reveals essential social and demographic characteristics of primates that predispose them to different disease risks that will be important for disease management and conservation planning for protected primate populations.

Acorns and acorn woodpeckers: ups and downs in a long-term relationship

Treesearch

Walter D. Koenig; Eric L. Walters; Johannes M.H. Knops; William J. Carmen

2015-01-01

Acorn woodpeckers are one of the most conspicuous and abundant birds in California oak forests due to their unique dependence on acorns, a food resource eaten directly and stored in specialized structures on their territories for later use when acorns are no longer present on trees. Parallel long-term studies of the demography and behavior of this species and of...

Integrating bioclimate with population models to improve forecasts of species extinctions under climate change.

PubMed

Brook, Barry W; Akçakaya, H Resit; Keith, David A; Mace, Georgina M; Pearson, Richard G; Araújo, Miguel B

2009-12-23

Climate change is already affecting species worldwide, yet existing methods of risk assessment have not considered interactions between demography and climate and their simultaneous effect on habitat distribution and population viability. To address this issue, an international workshop was held at the University of Adelaide in Australia, 25-29 May 2009, bringing leading species distribution and population modellers together with plant ecologists. Building on two previous workshops in the UK and Spain, the participants aimed to develop methodological standards and case studies for integrating bioclimatic and metapopulation models, to provide more realistic forecasts of population change, habitat fragmentation and extinction risk under climate change. The discussions and case studies focused on several challenges, including spatial and temporal scale contingencies, choice of predictive climate, land use, soil type and topographic variables, procedures for ensemble forecasting of both global climate and bioclimate models and developing demographic structures that are realistic and species-specific and yet allow generalizations of traits that make species vulnerable to climate change. The goal is to provide general guidelines for assessing the Red-List status of large numbers of species potentially at risk, owing to the interactions of climate change with other threats such as habitat destruction, overexploitation and invasive species.

Simulating changes in ecosystem structure and composition in response to climate change: a case study focused on tropical nitrogen-fixing trees (Invited)

NASA Astrophysics Data System (ADS)

Medvigy, D.; Levy, J.; Xu, X.; Batterman, S. A.; Hedin, L.

2013-12-01

Ecosystems, by definition, involve a community of organisms. These communities generally exhibit heterogeneity in their structure and composition as a result of local variations in climate, soil, topography, disturbance history, and other factors. Climate-driven shifts in ecosystems will likely include an internal re-organization of community structure and composition and as well as the introduction of novel species. In terms of vegetation, this ecosystem heterogeneity can occur at relatively small scales, sometimes of the order of tens of meters or even less. Because this heterogeneous landscape generally has a variable and nonlinear response to environmental perturbations, it is necessary to carefully aggregate the local competitive dynamics between individual plants to the large scales of tens or hundreds of kilometers represented in climate models. Accomplishing this aggregation in a computationally efficient way has proven to be an extremely challenging task. To meet this challenge, the Ecosystem Demography 2 (ED2) model statistically characterizes a distribution of local resource environments, and then simulates the competition between individuals of different sizes and species (or functional groupings). Within this framework, it is possible to explicitly simulate the impacts of climate change on ecosystem structure and composition, including both internal re-organization and the introduction of novel species or functional groups. This presentation will include several illustrative applications of the evolution of ecosystem structure and composition under climate change. One application pertains to the role of nitrogen-fixing species in tropical forests. Will increasing CO2 concentrations increase the demand for nutrients and perhaps give a competitive edge to nitrogen-fixing species? Will potentially warmer and drier conditions make some tropical forests more water-limited, reducing the demand for nitrogen, thereby giving a competitive advantage to non-nitrogen-fixing species? Will the response of nitrogen-fixing species to climate change be sensitive to local disturbance histories?

The dynamics and ethnic composition of the population of Russia in the era of imperialism (from the end of the 19th century to 1917).

PubMed

Bruk, S I; Kabuzan, V M

1989-02-01

"The authors critically survey tsarist censuses before the October Revolution and Soviet works on historical demography, and they re-estimate population numbers, natural and mechanical increase, and internal and external migration between 1897 and 1917, as well as changes in ethnic composition." excerpt

Bottom-up processes influence the demography and life-cycle phenology of Hawaiian bird communities

Treesearch

Jared D. Wolfe; C. John Ralph; Andrew Wiegardt

2017-01-01

Changes in climate can indirectly regulate populations at higher trophic levels by influencing the availability of food resources in the lower reaches of the food web. As such, species that rely on fruit and nectar food resources may be particularly sensitive to these bottom-up perturbations due to the strength of their trophic linkages with climatically-...

Changes in ash tree demography associated with emerld ash borer invasion, indicated by regional forest inventory data from the Great Lakes States

Treesearch

Scott A. Pugh; Andrew M. Liebhold; Randall S. Morin

2011-01-01

The emerald ash borer (EAB) (Agrilus planipennis Fairmaire) is a nonnative phloem-feeding beetle that was accidentally introduced near Detroit, Michigan, two to three decades ago. North American ash (Fraxinus spp.) exhibit little or no resistance, and as this insect species expands its range, extensive mortality results. Previous...

Six States, One Destiny: Critical Issues for New England

ERIC Educational Resources Information Center

Mass, William; Soule, David C.

2005-01-01

Midway through the first decade of the 21st century, New England innovation and creative capacity are being challenged by other regions of the nation and the world. New England needs foresight to understand what its emerging economic sectors need to thrive in a changing demography. The region is losing 20- to 34-year-olds and seeing a growing…

The context for great lakes silviculture in the 21st century

Treesearch

David D. Reed

2004-01-01

Great Lakes forests were subject to a severe pulse of disturbance from the mid-19th century through the early 20th century that resulted from extensive harvesting and subsequent fires following European settlement. Today?s forest, in many ways, is exhibiting changes in area and demography that reflect recovery from this pulse of disturbance, as well as response to...

Middle Rio Grande Cooperative Water Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tidwell, Vince; Passell, Howard

2005-11-01

This is computer simulation model built in a commercial modeling product Called Studio Expert, developed by Powersim, Inc. The simulation model is built in a system dynamics environment, allowing the simulation of the interaction among multiple systems that are all changing over time. The model focuses on hydrology, ecology, demography, and economy of the Middle Rio Grande, with Water as the unifying feature.

Teaching Large Classes in an Increasingly Internationalising Higher Education Environment: Pedagogical, Quality and Equity Issues

ERIC Educational Resources Information Center

Maringe, Felix; Sing, Nevensha

2014-01-01

Marketisation, increased student mobility, the massification of Higher Education (HE) and stagnating staff numbers in universities have combined to cause a ripple effect of change both in the demography and size of university classes across the world. This has implications for the quality and equity of learning and the need to examine and to…

78 FR 67103 - Request for Nominations of Members To Serve on the Census Scientific Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-08

... analysis, survey methodology, geospatial analysis, econometrics, cognitive psychology, and computer science... following disciplines: demography, economics, geography, psychology, statistics, survey methodology, social... expertise in such areas as demography, economics, geography, psychology, statistics, survey methodology...

77 FR 1454 - Request for Nominations of Members To Serve on the Census Scientific Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-10

..., statistical analysis, survey methodology, geospatial analysis, econometrics, cognitive psychology, and... following disciplines: Demography, economics, geography, psychology, statistics, survey methodology, social... technical expertise in such areas as demography, economics, geography, psychology, statistics, survey...

The Impact of Policies Influencing the Demography of Age-Structured Populations: Lessons from Academies of Sciences

PubMed Central

Riosmena, Fernando; Winkler-Dworak, Maria; Prskawetz, Alexia; Feichtinger, Gustav

2013-01-01

In this paper, we assess the role of policies aimed at regulating the number and age structure of elections on the size and age structure of five European Academies of Sciences. We show the recent pace of ageing and the degree of variation in policies across them and discuss the implications of different policies on the size and age structure of academies. We also illustrate the potential effect of different election regimes (fixed vs. linked) and age structures of election (younger vs. older) by contrasting the steady-state dynamics of different projections of Full Members in each academy into 2070 and measuring the size and age-compositional effect of changing a given policy relative to a status quo policy scenario. Our findings suggest that academies with linked intake (i.e., where the size of the academy below a certain age is fixed and the number of elections is set to the number of members becoming that age) may be a more efficient approach to curb growth without suffering any ageing trade-offs relative to the faster growth of academies electing a fixed number of members per year. We further discuss the implications of our results in the context of stable populations open to migration. PMID:23843677

Life history and past demography maintain genetic structure, outcrossing rate, contemporary pollen gene flow of an understory herb in a highly fragmented rainforest

PubMed Central

Suárez-Montes, Pilar; Chávez-Pesqueira, Mariana

2016-01-01

Introduction Theory predicts that habitat fragmentation, by reducing population size and increasing isolation among remnant populations, can alter their genetic diversity and structure. A cascade of effects is expected: genetic drift and inbreeding after a population bottleneck, changes in biotic interactions that may affect, as in the case of plants, pollen dynamics, mating system, reproductive success. The detection of the effects of contemporary habitat fragmentation on the genetic structure of populations are conditioned by the magnitude of change, given the few number of generations since the onset of fragmentation, especially for long-lived organisms. However, the present-day genetic structure of populations may bear the signature of past demography events. Here, we examine the effects of rainforest fragmentation on the genetic diversity, population structure, mating system (outcrossing rate), indirect gene flow and contemporary pollen dynamics in the understory herb Aphelandra aurantiaca. Also, we assessed its present-day genetic structure under different past demographic scenarios. Methods Twelve populations of A. aurantiaca were sampled in large (4), medium (3), and small (5) forest fragments in the lowland tropical rainforest at Los Tuxtlas region. Variation at 11 microsatellite loci was assessed in 28–30 reproductive plants per population. In two medium- and two large-size fragments we estimated the density of reproductive plants, and the mating system by analyzing the progeny of different mother plants per population. Results Despite prevailing habitat fragmentation, populations of A. aurantiaca possess high genetic variation (He = 0.61), weak genetic structure (Rst = 0.037), and slight inbreeding in small fragments. Effective population sizes (Ne) were large, but slightly lower in small fragments. Migrants derive mostly from large and medium size fragments. Gene dispersal is highly restricted but long distance gene dispersal events were detected. Aphelandra aurantiaca shows a mixed mating system (tm = 0.81) and the outcrossing rate have not been affected by habitat fragmentation. A strong pollen pool structure was detected due to few effective pollen donors (Nep) and low distance pollen movement, pointing that most plants received pollen from close neighbors. Past demographic fluctuations may have affected the present population genetic structure as Bayesian coalescent analysis revealed the signature of past population expansion, possibly during warmer conditions after the last glacial maximum. Discussion Habitat fragmentation has not increased genetic differentiation or reduced genetic diversity of A. aurantiaca despite dozens of generations since the onset of fragmentation in the region of Los Tuxtlas. Instead, past population expansion is compatible with the lack of observed genetic structure. The predicted negative effects of rainforest fragmentation on genetic diversity and population structure of A. aurantiaca seem to have been buffered owing to its large effective populations and long-distance dispersal events. In particular, its mixed-mating system, mostly of outcrossing, suggests high efficiency of pollinators promoting connectivity and reducing inbreeding. However, some results point that the effects of fragmentation are underway, as two small fragments showed higher membership probabilities to their population of origin, suggesting genetic isolation. Our findings underscore the importance of fragment size to maintain genetic connectivity across the landscape. PMID:28028460

Teaching Demography to Undergraduates: A Pedagogical Dilemma.

ERIC Educational Resources Information Center

Abowitz, Deborah A.

1990-01-01

Describes a course based on the interdisciplinary approach to demography linked to environmental issues. Analytic and interpretive skills are an integral element in the study of population-related problems. Points out that the interdisciplinary approach maintains demographic literacy while analyzing population problems. (SLM)

A stand-alone tree demography and landscape structure module for Earth system models: integration with inventory data from temperate and boreal forests

NASA Astrophysics Data System (ADS)

Haverd, V.; Smith, B.; Nieradzik, L. P.; Briggs, P. R.

2014-08-01

Poorly constrained rates of biomass turnover are a key limitation of Earth system models (ESMs). In light of this, we recently proposed a new approach encoded in a model called Populations-Order-Physiology (POP), for the simulation of woody ecosystem stand dynamics, demography and disturbance-mediated heterogeneity. POP is suitable for continental to global applications and designed for coupling to the terrestrial ecosystem component of any ESM. POP bridges the gap between first-generation dynamic vegetation models (DVMs) with simple large-area parameterisations of woody biomass (typically used in current ESMs) and complex second-generation DVMs that explicitly simulate demographic processes and landscape heterogeneity of forests. The key simplification in the POP approach, compared with second-generation DVMs, is to compute physiological processes such as assimilation at grid-scale (with CABLE (Community Atmosphere Biosphere Land Exchange) or a similar land surface model), but to partition the grid-scale biomass increment among age classes defined at sub-grid-scale, each subject to its own dynamics. POP was successfully demonstrated along a savanna transect in northern Australia, replicating the effects of strong rainfall and fire disturbance gradients on observed stand productivity and structure. Here, we extend the application of POP to wide-ranging temporal and boreal forests, employing paired observations of stem biomass and density from forest inventory data to calibrate model parameters governing stand demography and biomass evolution. The calibrated POP model is then coupled to the CABLE land surface model, and the combined model (CABLE-POP) is evaluated against leaf-stem allometry observations from forest stands ranging in age from 3 to 200 year. Results indicate that simulated biomass pools conform well with observed allometry. We conclude that POP represents an ecologically plausible and efficient alternative to large-area parameterisations of woody biomass turnover, typically used in current ESMs.

Genetic consequences of Quaternary climatic oscillations in the Himalayas: Primula tibetica as a case study based on restriction site-associated DNA sequencing.

PubMed

Ren, Guangpeng; Mateo, Rubén G; Liu, Jianquan; Suchan, Tomasz; Alvarez, Nadir; Guisan, Antoine; Conti, Elena; Salamin, Nicolas

2017-02-01

The effects of Quaternary climatic oscillations on the demography of organisms vary across regions and continents. In taxa distributed in Europe and North America, several paradigms regarding the distribution of refugia have been identified. By contrast, less is known about the processes that shaped the species' spatial genetic structure in areas such as the Himalayas, which is considered a biodiversity hotspot. Here, we investigated the phylogeographic structure and population dynamics of Primula tibetica by combining genomic phylogeography and species distribution models (SDMs). Genomic data were obtained for 293 samples of P. tibetica using restriction site-associated DNA sequencing (RADseq). Ensemble SDMs were carried out to predict potential present and past distribution ranges. Four distinct lineages were identified. Approximate Bayesian computation analyses showed that each of them have experienced both expansions and bottlenecks since their divergence, which occurred during or across the Quaternary glacial cycles. The two lineages at both edges of the distribution were found to be more vulnerable and responded in different ways to past climatic changes. These results illustrate how past climatic changes affected the demographic history of Himalayan organisms. Our findings highlight the significance of combining genomic approaches with environmental data when evaluating the effects of past climatic changes. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

Phylogeography on the rocks: The contribution of current and historical factors in shaping the genetic structure of Chthamalus montagui (Crustacea, Cirripedia).

PubMed

Pannacciulli, Federica G; Maltagliati, Ferruccio; de Guttry, Christian; Achituv, Yair

2017-01-01

The model marine broadcast-spawner barnacle Chthamalus montagui was investigated to understand its genetic structure and quantify levels of population divergence, and to make inference on historical demography in terms of time of divergence and changes in population size. We collected specimens from rocky shores of the north-east Atlantic Ocean (4 locations), Mediterranean Sea (8) and Black Sea (1). The 312 sequences 537 bp) of the mitochondrial cytochrome c oxidase I allowed to detect 130 haplotypes. High within-location genetic variability was recorded, with haplotype diversity ranging between h = 0.750 and 0.967. Parameters of genetic divergence, haplotype network and Bayesian assignment analysis were consistent in rejecting the hypothesis of panmixia. C. montagui is genetically structured in three geographically discrete populations, which corresponded to north-eastern Atlantic Ocean, western-central Mediterranean Sea, and Aegean Sea-Black Sea. These populations are separated by two main effective barriers to gene flow located at the Almeria-Oran Front and in correspondence of the Cyclades Islands. According to the 'isolation with migration' model, adjacent population pairs diverged during the early to middle Pleistocene transition, a period in which geological events provoked significant changes in the structure and composition of palaeocommunities. Mismatch distributions, neutrality tests and Bayesian skyline plots showed past population expansions, which started approximately in the Mindel-Riss interglacial, in which ecological conditions were favourable for temperate species and calcium-uptaking marine organisms.

Phylogeography on the rocks: The contribution of current and historical factors in shaping the genetic structure of Chthamalus montagui (Crustacea, Cirripedia)

PubMed Central

Pannacciulli, Federica G.; de Guttry, Christian; Achituv, Yair

2017-01-01

The model marine broadcast-spawner barnacle Chthamalus montagui was investigated to understand its genetic structure and quantify levels of population divergence, and to make inference on historical demography in terms of time of divergence and changes in population size. We collected specimens from rocky shores of the north-east Atlantic Ocean (4 locations), Mediterranean Sea (8) and Black Sea (1). The 312 sequences 537 bp) of the mitochondrial cytochrome c oxidase I allowed to detect 130 haplotypes. High within-location genetic variability was recorded, with haplotype diversity ranging between h = 0.750 and 0.967. Parameters of genetic divergence, haplotype network and Bayesian assignment analysis were consistent in rejecting the hypothesis of panmixia. C. montagui is genetically structured in three geographically discrete populations, which corresponded to north-eastern Atlantic Ocean, western-central Mediterranean Sea, and Aegean Sea-Black Sea. These populations are separated by two main effective barriers to gene flow located at the Almeria-Oran Front and in correspondence of the Cyclades Islands. According to the ‘isolation with migration’ model, adjacent population pairs diverged during the early to middle Pleistocene transition, a period in which geological events provoked significant changes in the structure and composition of palaeocommunities. Mismatch distributions, neutrality tests and Bayesian skyline plots showed past population expansions, which started approximately in the Mindel-Riss interglacial, in which ecological conditions were favourable for temperate species and calcium-uptaking marine organisms. PMID:28594840

Coalescent Processes with Skewed Offspring Distributions and Nonequilibrium Demography.

PubMed

Matuszewski, Sebastian; Hildebrandt, Marcel E; Achaz, Guillaume; Jensen, Jeffrey D

2018-01-01

Nonequilibrium demography impacts coalescent genealogies leaving detectable, well-studied signatures of variation. However, similar genomic footprints are also expected under models of large reproductive skew, posing a serious problem when trying to make inference. Furthermore, current approaches consider only one of the two processes at a time, neglecting any genomic signal that could arise from their simultaneous effects, preventing the possibility of jointly inferring parameters relating to both offspring distribution and population history. Here, we develop an extended Moran model with exponential population growth, and demonstrate that the underlying ancestral process converges to a time-inhomogeneous psi-coalescent. However, by applying a nonlinear change of time scale-analogous to the Kingman coalescent-we find that the ancestral process can be rescaled to its time-homogeneous analog, allowing the process to be simulated quickly and efficiently. Furthermore, we derive analytical expressions for the expected site-frequency spectrum under the time-inhomogeneous psi-coalescent, and develop an approximate-likelihood framework for the joint estimation of the coalescent and growth parameters. By means of extensive simulation, we demonstrate that both can be estimated accurately from whole-genome data. In addition, not accounting for demography can lead to serious biases in the inferred coalescent model, with broad implications for genomic studies ranging from ecology to conservation biology. Finally, we use our method to analyze sequence data from Japanese sardine populations, and find evidence of high variation in individual reproductive success, but few signs of a recent demographic expansion. Copyright © 2018 by the Genetics Society of America.

Response of South American Ecosystems to Precipitation Variability

NASA Astrophysics Data System (ADS)

Knox, R. G.; Kim, Y.; Longo, M.; Medvigy, D.; Wang, J.; Moorcroft, P. R.; Bras, R. L.

2009-12-01

The Ecosystem Demography Model 2 is a dynamic ecosystem model and land surface energy balance model. ED2 discretizes landscapes of particular terrain and meteorology into fractional areas of unique disturbance history. Each fraction, defined by a shared vertical soil column and canopy air space, contains a stratum of plant groups unique in functional type, size and number density. The result is a vertically distributed representation of energy transfer and plant dynamics (mortality, productivity, recruitment, disturbance, resource competition, etc) that successfully approximates the behaviour of individual-based vegetation models. In previous exercises simulating Amazonian land surface dynamics with ED 2, it was observed that when using grid averaged precipitation as an external forcing the resulting water balance typically over-estimated leaf interception and leaf evaporation while under estimating through-fall and transpiration. To investigate this result, two scenario were conducted in which land surface biophysics and ecosystem demography over the Northern portion of South America are simulated over ~200 years: (1) ED2 is forced with grid averaged values taken from the ERA40 reanalysis meteorological dataset; (2) ED2 is forced with ERA40 reanalysis, but with its precipitation re-sampled to reflect statistical qualities of point precipitation found at rain gauge stations in the region. The findings in this study suggest that the equilibrium moisture states and vegetation demography are co-dependent and show sensitivity to temporal variability in precipitation. These sensitivities will need to be accounted for in future projections of coupled climate-ecosystem changes in South America.

Standing variation in spatially growing populations

NASA Astrophysics Data System (ADS)

Fusco, Diana; Gralka, Matti; Kayser, Jona; Hallatschek, Oskar

Patterns of genetic diversity not only reflect the evolutionary history of a species but they can also determine the evolutionary response to environmental change. For instance, the standing genetic diversity of a microbial population can be key to rescue in the face of an antibiotic attack. While genetic diversity is in general shaped by both demography and evolution, very little is understood when both factors matter, as e.g. for biofilms with pronounced spatial organization. Here, we quantitatively explore patterns of genetic diversity by using microbial colonies and well-mixed test tube populations as antipodal model systems with extreme and very little spatial structure, respectively. We find that Eden model simulations and KPZ theory can remarkably reproduce the genetic diversity in microbial colonies obtained via population sequencing. The excellent agreement allows to draw conclusions on the resilience of spatially-organized populations and to uncover new strategies to contain antibiotic resistance.

The Dependencies of Ecosystem Pattern, Structure, and Dynamics on Climate, Climate Variability, and Climate Change

NASA Astrophysics Data System (ADS)

Flanagan, S.; Hurtt, G. C.; Fisk, J. P.; Rourke, O.

2012-12-01

A robust understanding of the sensitivity of the pattern, structure, and dynamics of ecosystems to climate, climate variability, and climate change is needed to predict ecosystem responses to current and projected climate change. We present results of a study designed to first quantify the sensitivity of ecosystems to climate through the use of climate and ecosystem data, and then use the results to test the sensitivity of the climate data in a state-of the art ecosystem model. A database of available ecosystem characteristics such as mean canopy height, above ground biomass, and basal area was constructed from sources like the National Biomass and Carbon Dataset (NBCD). The ecosystem characteristics were then paired by latitude and longitude with the corresponding climate characteristics temperature, precipitation, photosynthetically active radiation (PAR) and dew point that were retrieved from the North American Regional Reanalysis (NARR). The average yearly and seasonal means of the climate data, and their associated maximum and minimum values, over the 1979-2010 time frame provided by NARR were constructed and paired with the ecosystem data. The compiled results provide natural patterns of vegetation structure and distribution with regard to climate data. An advanced ecosystem model, the Ecosystem Demography model (ED), was then modified to allow yearly alterations to its mechanistic climate lookup table and used to predict the sensitivities of ecosystem pattern, structure, and dynamics to climate data. The combined ecosystem structure and climate data results were compared to ED's output to check the validity of the model. After verification, climate change scenarios such as those used in the last IPCC were run and future forest structure changes due to climate sensitivities were identified. The results of this study can be used to both quantify and test key relationships for next generation models. The sensitivity of ecosystem characteristics to climate data shown in the database construction and by the model reinforces the need for high-resolution datasets and stresses the importance of understanding and incorporating climate change scenarios into earth system models.

Dispersal responses override density effects on genetic diversity during post-disturbance succession

PubMed Central

Landguth, Erin L.; Bull, C. Michael; Banks, Sam C.; Gardner, Michael G.; Driscoll, Don A.

2016-01-01

Dispersal fundamentally influences spatial population dynamics but little is known about dispersal variation in landscapes where spatial heterogeneity is generated predominantly by disturbance and succession. We tested the hypothesis that habitat succession following fire inhibits dispersal, leading to declines over time in genetic diversity in the early successional gecko Nephrurus stellatus. We combined a landscape genetics field study with a spatially explicit simulation experiment to determine whether successional patterns in genetic diversity were driven by habitat-mediated dispersal or demographic effects (declines in population density leading to genetic drift). Initial increases in genetic structure following fire were likely driven by direct mortality and rapid population expansion. Subsequent habitat succession increased resistance to gene flow and decreased dispersal and genetic diversity in N. stellatus. Simulated changes in population density alone did not reproduce these results. Habitat-mediated reductions in dispersal, combined with changes in population density, were essential to drive the field-observed patterns. Our study provides a framework for combining demographic, movement and genetic data with simulations to discover the relative influence of demography and dispersal on patterns of landscape genetic structure. Our results suggest that succession can inhibit connectivity among individuals, opening new avenues for understanding how disturbance regimes influence spatial population dynamics. PMID:27009225

Changing pattern of landslide risk in Europe - The SafeLand project

NASA Astrophysics Data System (ADS)

Nadim, F.; Kalsnes, B.

2012-04-01

The need to protect people and property with a changing pattern of landslide hazard and risk caused by climate change and changes in demography, and the reality for societies in Europe to live with the risk associated with natural hazards, were the motives for the project SafeLand: "Living with landslide risk in Europe: Assessment, effects of global change, and risk management strategies." SafeLand is a large, integrating research project under the European Commission's 7th Framework Programme (FP7). The project started on 1 May 2009 and will end on 30 April 2012. It involves 27 partners from 12 European countries, and has international collaborators and advisers from China, India, USA, Japan and Hong Kong. SafeLand also involves 25 End-Users from 11 countries. SafeLand is coordinated by the International Centre for Geohazards (ICG) at Norwegian Geotechnical Institute in Norway. Further information on the SafeLand project can be found at its web site http://safeland-fp7.eu/. Main results achieved in SafeLand include: - Various guidelines related to landslide triggering processes and run-out modelling. - Development and testing of several empirical methods for predicting the characteristics of threshold rainfall events for triggering of precipitation-induced landslides, and development of an empirical model for assessing the changes in landslide frequency (hazard) as a function of changes in the demography and population density. - Guideline for landslide susceptibility, hazard and risk assessment and zoning. - New methodologies for physical and societal vulnerability assessment. - Identification of landslide hazard and risk hotspots for Europe. The results show clearly where areas with the largest landslide risk are located in Europe and the objective approach allows a ranking of the countries by exposed area and population. - Different regional and local climate model simulations over selected regions of Europe at spatial resolutions of 10x10 km and 2.8x2.8 km. These simulations were used to perform an extreme value analysis for trends in heavy precipitation events, and subsequent effects on landslide hazard and risk trends. - Guidelines for use of remote sensing techniques, monitoring and early warning systems. - Development of a prototype web-based "toolbox" of innovative and technically appropriate prevention and mitigation measures. The toolbox does a preliminary assessment and ranking of up to 60 structural and non-structural landslide risk mitigation options. - Case histories and "hotspots" of European Land¬slides have been collected and documented. Data for close to fifty potential case study sites have been compiled and summarized. Most of the case study sites are located in Europe (Italy, France, Norway, Switzerland, Austria, Andorra, and Romania); but they also include one site in Canada and one in India. Almost every type of landslide and every type of movement is represented in these sites. - Research on stakeholder workshops and participatory processes to involve the population exposed to landslide risk in the decision-making process for choosing the most appropriate risk mitigation measure(s).

Population dynamics of sugar maple through the southern portion of its range: implications for range migration

Treesearch

Justin L. Hart; Christopher M. Oswalt; Craig M. Turberville

2014-01-01

The range of sugar maple (Acer saccharum Marsh.) is expected to shift northward in accord with changing climate. However, a pattern of increased sugar maple abundance has been reported from sites throughout the eastern US. The goal of our study was to examine the stability of the sugar maple southern range boundary by analyzing its demography through...

The Fiscal Crisis of the State: A Case Study of Education in Detroit.

ERIC Educational Resources Information Center

Hill, Richard Child

In this case study, the effect of the Detroit fiscal crisis on the city's public school system is analyzed in terms of the history of the fiscal crisis, the reasons for the crisis, and State, teacher, public and city reaction to the situation. The changing demography of Detroit and the events leading up to the financial crisis are described. Such…

Culture and Demography: From Reluctant Bedfellows to Committed Partners

PubMed Central

Bachrach, Christine A.

2015-01-01

Demography and culture have had a long but ambivalent relationship. Cultural influences are widely recognized as important for demographic outcomes, but are often “backgrounded” in demographic research. I argue that progress towards a more successful integration is feasible and suggest a network model of culture as a potential tool. The network model bridges both traditional (holistic and institutional) and contemporary (tool kit) models of culture used in the social sciences and offers a simple vocabulary for the diverse set of cultural concepts such as attitudes, beliefs and norms, and quantitative measures of how culture is organized. The proposed model conceptualizes culture as a nested network of meanings which are represented by schemas that range in complexity from simple concepts to multifaceted cultural models. I illustrate the potential value of a model using accounts of the cultural changes underpinning the transformation of marriage in the U.S. and point to developments in the social, cognitive and computational sciences that could facilitate the application of the model in empirical demographic research. PMID:24338643

Culture and demography: from reluctant bedfellows to committed partners.

PubMed

Bachrach, Christine A

2014-02-01

Demography and culture have had a long but ambivalent relationship. Cultural influences are widely recognized as important for demographic outcomes but are often "backgrounded" in demographic research. I argue that progress toward a more successful integration is feasible and suggest a network model of culture as a potential tool. The network model bridges both traditional (holistic and institutional) and contemporary (tool kit) models of culture used in the social sciences and offers a simple vocabulary for a diverse set of cultural concepts, such as attitudes, beliefs, and norms, as well as quantitative measures of how culture is organized. The proposed model conceptualizes culture as a nested network of meanings represented by schemas that range in complexity from simple concepts to multifaceted cultural models. I illustrate the potential value of a model using accounts of the cultural changes underpinning the transformation of marriage in the United States and point to developments in the social, cognitive, and computational sciences that could facilitate the application of the model in empirical demographic research.

Some demographic issues affecting private health insurance.

PubMed

Hanning, Brian

2004-01-01

There will be significant changes in the demography of persons with Private Health Insurance (PHI). Two methods of projecting PHI coverage are discussed in this paper. The first assumes the only factors affecting PHI coverage are demographic change and mortality and facilitates comparisons between actual and projected PHI coverage. The second projects the percentage of the population insured in each five year age cohort, and makes allowance for changes in PHI coverage due to all factors. Demographic change will increase Registered Health Benefit Organization (RHBO) premiums by 1.7% per annum. The role of these projections in analysing the effect of future premium increases on PHI retention rates is also discussed.

Childbearing and Economic Work: The Health Balance of Women in Accra, Ghana.

PubMed

Waterhouse, Philippa; Hill, Allan G; Hinde, Andrew

2016-02-01

This study aims to investigate (1) whether the health of working women with young children differs from that of working women without young children, and (2) which social factors mediate the relationship between economic and maternal role performance and health among mothers with young children. The analyses uses panel data from 697 women present in both waves of the Women's Health Study for Accra (WHSA-I and WHSA-II); a community based study of women aged 18 years and older in the Accra Metropolitan Area of Ghana conducted in 2003 and 2008-2009. Change in physical and mental health between the survey waves is compared between women with a biological child alive at WHSA-II and born since WHSA-I and women without a living biological child at WHSA-II born in the interval. To account for attrition between the two survey waves selection models were used with unconditional change score models being used as the outcome model. We found in our sample of working women that those who had a child born between WHSA-I and WHSA-II who was still alive at WHSA-II did not experience a change in mental or physical health different from other women. Among working women with young children, educational status, relationship to the household head and household demography were associated with change in mental health at the 5 % level, whilst migration status and household demography was associated with change in physical health scores. The results suggest there are no health penalties of combining work and childbearing among women with young children in Accra, Ghana.

Emperor penguins and climate change.

PubMed

Barbraud, C; Weimerskirch, H

2001-05-10

Variations in ocean-atmosphere coupling over time in the Southern Ocean have dominant effects on sea-ice extent and ecosystem structure, but the ultimate consequences of such environmental changes for large marine predators cannot be accurately predicted because of the absence of long-term data series on key demographic parameters. Here, we use the longest time series available on demographic parameters of an Antarctic large predator breeding on fast ice and relying on food resources from the Southern Ocean. We show that over the past 50 years, the population of emperor penguins (Aptenodytes forsteri) in Terre Adélie has declined by 50% because of a decrease in adult survival during the late 1970s. At this time there was a prolonged abnormally warm period with reduced sea-ice extent. Mortality rates increased when warm sea-surface temperatures occurred in the foraging area and when annual sea-ice extent was reduced, and were higher for males than for females. In contrast with survival, emperor penguins hatched fewer eggs when winter sea-ice was extended. These results indicate strong and contrasting effects of large-scale oceanographic processes and sea-ice extent on the demography of emperor penguins, and their potential high susceptibility to climate change.

Demography of Disadvantage in Tennessee.

ERIC Educational Resources Information Center

Jones, Lewis W., Comp.; And Others

In this report, demography conceptualizes significant characteristics to serve as a basis for more intensive study, planning, and procedures focusing on the target group. A compilation of the latest reports available and primarily tabular in form, identifies and locates Tennessee's disadvantaged people, ranking the 95 counties on each of 8…

Impacts of insect disturbance on the structure, composition, and functioning of oak-pine forests

NASA Astrophysics Data System (ADS)

Medvigy, D.; Schafer, K. V.; Clark, K. L.

2011-12-01

Episodic disturbance is an essential feature of terrestrial ecosystems, and strongly modulates their structure, composition, and functioning. However, dynamic global vegetation models that are commonly used to make ecosystem and terrestrial carbon budget predictions rarely have an explicit representation of disturbance. One reason why disturbance is seldom included is that disturbance tends to operate on spatial scales that are much smaller than typical model resolutions. In response to this problem, the Ecosystem Demography model 2 (ED2) was developed as a way of tracking the fine-scale heterogeneity arising from disturbances. In this study, we used ED2 to simulate an oak-pine forest that experiences episodic defoliation by gypsy moth (Lymantria dispar L). The model was carefully calibrated against site-level data, and then used to simulate changes in ecosystem composition, structure, and functioning on century time scales. Compared to simulations that include gypsy moth defoliation, we show that simulations that ignore defoliation events lead to much larger ecosystem carbon stores and a larger fraction of deciduous trees relative to evergreen trees. Furthermore, we find that it is essential to preserve the fine-scale nature of the disturbance. Attempts to "smooth out" the defoliation event over an entire grid cells led to large biases in ecosystem structure and functioning.

Testing for effects of climate change on competitive relationships and coexistence between two bird species.

PubMed

Stenseth, Nils Chr; Durant, Joël M; Fowler, Mike S; Matthysen, Erik; Adriaensen, Frank; Jonzén, Niclas; Chan, Kung-Sik; Liu, Hai; De Laet, Jenny; Sheldon, Ben C; Visser, Marcel E; Dhondt, André A

2015-05-22

Climate change is expected to have profound ecological effects, yet shifts in competitive abilities among species are rarely studied in this context. Blue tits (Cyanistes caeruleus) and great tits (Parus major) compete for food and roosting sites, yet coexist across much of their range. Climate change might thus change the competitive relationships and coexistence between these two species. Analysing four of the highest-quality, long-term datasets available on these species across Europe, we extend the textbook example of coexistence between competing species to include the dynamic effects of long-term climate variation. Using threshold time-series statistical modelling, we demonstrate that long-term climate variation affects species demography through different influences on density-dependent and density-independent processes. The competitive interaction between blue tits and great tits has shifted in one of the studied sites, creating conditions that alter the relative equilibrium densities between the two species, potentially disrupting long-term coexistence. Our analyses show that long-term climate change can, but does not always, generate local differences in the equilibrium conditions of spatially structured species assemblages. We demonstrate how long-term data can be used to better understand whether (and how), for instance, climate change might change the relationships between coexisting species. However, the studied populations are rather robust against competitive exclusion. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Phylogeography and historical demography of the anadromous fish Leucopsarion petersii in relation to geological history and oceanography around the Japanese Archipelago.

PubMed

Kokita, Tomoyuki; Nohara, Kenji

2011-01-01

Phylogeographical patterns of marine and diadromous organisms are often influenced by dynamic ocean histories. For example, the marine realm around the Japanese Archipelago is an interesting area for phylogeographical research because of the wide variation in the environments driven by repeated shifts in sea level in the Quaternary. We analysed mitochondrial cyt b gene and nuclear myh6 gene sequences for individuals collected from throughout the range of the anadromous fish Leucopsarion petersii to assess the lineage divergence, phylogeographical pattern and historical demography in relation to geological history and oceanographic features around the archipelago. Leucopsarion petersii has two major lineages (the Japan Sea and Pacific Ocean lineages), which diverged during the late-early to middle Pleistocene. Geographical distributions of the two lineages were closely related to the pathways of the two warm currents, the Tsushima Current and the Kuroshio Current, that flow past the archipelago. Evidence of introgressive hybridization between these lineages was found at two secondary contact zones. Demographic tests suggested that the Japan Sea and Pacific Ocean lineages carried the genetic signal of different historical demographic processes, and these signals are probably associated with differences in habitat stability during recent glacial periods. The Japan Sea lineage has a larger body-size and more vertebrae, probably in relation to severe habitat conditions through Pleistocene climatic oscillations. Thus, the two lineages have long independent evolutionary histories, and the phylogeographical structure and demography of this species have been influenced both by historical events and the present-day oceanography around the Japanese Archipelago. © 2010 Blackwell Publishing Ltd.

Uncloaking a cryptic, threatened rail with molecular markers: origins, connectivity and demography of a recently-discovered population

USGS Publications Warehouse

Girard, Philippe; Takekawa, John Y.; Beissinger, Steven R.

2010-01-01

The threatened California Black Rail lives under dense marsh vegetation, is rarely observed, flies weakly and has a highly disjunct distribution. The largest population of rails is found in 8–10 large wetlands in San Francisco Bay (SF Bay), but a population was recently discovered in the foothills of the Sierra Nevada Mountains (Foothills), within a wetland network comprised of over 200 small marshes. Using microsatellite and mitochondrial analyses, our objectives were to determine the origins, connectivity and demography of this recently-discovered population. Analyses of individuals from the Foothills (n = 31), SF Bay (n = 31), the Imperial Valley (n = 6) and the East Coast (n = 3), combined with rigorous power evaluations, provided valuable insights into past history and current dynamics of the species in Northern California that challenge conventional wisdom about the species. The Foothills and SF Bay populations have diverged strongly from the Imperial Valley population, even more strongly than from individuals of the East Coast subspecies. The data also suggest a historical presence of the species in the Foothills. The SF Bay and Foothills populations had similar estimated effective population size over the areas sampled and appeared linked by a strongly asymmetrical migration pattern, with a greater probability of movement from the Foothills to SF Bay than vice versa. Random mating was inferred in the Foothills, but local substructure among marshes and inbreeding were detected in SF Bay, suggesting different dispersal patterns within each location. The unexpected dimensions of Black Rail demography and population structure suggested by these analyses and their potential importance for management are discussed.

Whole-genome sequence, SNP chips and pedigree structure: building demographic profiles in domestic dog breeds to optimize genetic-trait mapping.

PubMed

Dreger, Dayna L; Rimbault, Maud; Davis, Brian W; Bhatnagar, Adrienne; Parker, Heidi G; Ostrander, Elaine A

2016-12-01

In the decade following publication of the draft genome sequence of the domestic dog, extraordinary advances with application to several fields have been credited to the canine genetic system. Taking advantage of closed breeding populations and the subsequent selection for aesthetic and behavioral characteristics, researchers have leveraged the dog as an effective natural model for the study of complex traits, such as disease susceptibility, behavior and morphology, generating unique contributions to human health and biology. When designing genetic studies using purebred dogs, it is essential to consider the unique demography of each population, including estimation of effective population size and timing of population bottlenecks. The analytical design approach for genome-wide association studies (GWAS) and analysis of whole-genome sequence (WGS) experiments are inextricable from demographic data. We have performed a comprehensive study of genomic homozygosity, using high-depth WGS data for 90 individuals, and Illumina HD SNP data from 800 individuals representing 80 breeds. These data were coupled with extensive pedigree data analyses for 11 breeds that, together, allowed us to compute breed structure, demography, and molecular measures of genome diversity. Our comparative analyses characterize the extent, formation and implication of breed-specific diversity as it relates to population structure. These data demonstrate the relationship between breed-specific genome dynamics and population architecture, and provide important considerations influencing the technological and cohort design of association and other genomic studies. © 2016. Published by The Company of Biologists Ltd.

Whole-genome sequence, SNP chips and pedigree structure: building demographic profiles in domestic dog breeds to optimize genetic-trait mapping

PubMed Central

Dreger, Dayna L.; Rimbault, Maud; Davis, Brian W.; Bhatnagar, Adrienne; Parker, Heidi G.

2016-01-01

ABSTRACT In the decade following publication of the draft genome sequence of the domestic dog, extraordinary advances with application to several fields have been credited to the canine genetic system. Taking advantage of closed breeding populations and the subsequent selection for aesthetic and behavioral characteristics, researchers have leveraged the dog as an effective natural model for the study of complex traits, such as disease susceptibility, behavior and morphology, generating unique contributions to human health and biology. When designing genetic studies using purebred dogs, it is essential to consider the unique demography of each population, including estimation of effective population size and timing of population bottlenecks. The analytical design approach for genome-wide association studies (GWAS) and analysis of whole-genome sequence (WGS) experiments are inextricable from demographic data. We have performed a comprehensive study of genomic homozygosity, using high-depth WGS data for 90 individuals, and Illumina HD SNP data from 800 individuals representing 80 breeds. These data were coupled with extensive pedigree data analyses for 11 breeds that, together, allowed us to compute breed structure, demography, and molecular measures of genome diversity. Our comparative analyses characterize the extent, formation and implication of breed-specific diversity as it relates to population structure. These data demonstrate the relationship between breed-specific genome dynamics and population architecture, and provide important considerations influencing the technological and cohort design of association and other genomic studies. PMID:27874836

Land Conversion in Amazonia and Northern South America; Influences on Regional Hydrology and Ecosystem Response

NASA Astrophysics Data System (ADS)

Knox, Ryan Gary

A numerical model of the terrestrial biosphere (Ecosystem Demography Model) is compbined with an atmospheric model (Brazilian Regional Atmospheric Modeling System) to investigate how land conversion in the Amazon and Northern South America have changed the hydrology of the region, and to see if those changes are significant enough to produce an ecological response. Two numerical realizations of the structure and composition of terrestrial vegetation are used as boundary conditions in a simulation of the regional land surface and atmosphere. One realization seeks to capture the present day vegetation condition that includes human deforestation and land-conversion, the other is an estimate of the potential structure and composition of the region without human influence. Model output is assessed for consistent and significant differences in hydrometeorology. Locations that show compelling differences are taken as case studies. The seasonal biases in precipitation at these locations are then used to create perturbations to long-term climate datasets. These perturbations then drive long-term simulations of dynamic vegetation to see if the climate consistent with a potential regional vegetation could elicit a change in the vegetation equilibrium at the site. Results show that South American land conversion has had consistent impacts on the regional patterning of precipitation. At some locations, changes in precipitation are persistent and constitute a significant fraction of total precipitation. Land-conversion has decreased mean continental evaporation and increased mean moisture convergence. Case study simulations of long term vegetation dynamic indicate that a hydrologic climate consistent with regional potential vegetation can indeed have significant influence on ecosystem structure and composition, particularly in water limited growth conditions. (Copies available exclusively from MIT Libraries, libraries.mit.edu/docs - docs@mit.edu)

Effect of extreme sea surface temperature events on the demography of an age-structured albatross population.

PubMed

Pardo, Deborah; Jenouvrier, Stéphanie; Weimerskirch, Henri; Barbraud, Christophe

2017-06-19

Climate changes include concurrent changes in environmental mean, variance and extremes, and it is challenging to understand their respective impact on wild populations, especially when contrasted age-dependent responses to climate occur. We assessed how changes in mean and standard deviation of sea surface temperature (SST), frequency and magnitude of warm SST extreme climatic events (ECE) influenced the stochastic population growth rate log( λ s ) and age structure of a black-browed albatross population. For changes in SST around historical levels observed since 1982, changes in standard deviation had a larger (threefold) and negative impact on log( λ s ) compared to changes in mean. By contrast, the mean had a positive impact on log( λ s ). The historical SST mean was lower than the optimal SST value for which log( λ s ) was maximized. Thus, a larger environmental mean increased the occurrence of SST close to this optimum that buffered the negative effect of ECE. This 'climate safety margin' (i.e. difference between optimal and historical climatic conditions) and the specific shape of the population growth rate response to climate for a species determine how ECE affect the population. For a wider range in SST, both the mean and standard deviation had negative impact on log( λ s ), with changes in the mean having a greater effect than the standard deviation. Furthermore, around SST historical levels increases in either mean or standard deviation of the SST distribution led to a younger population, with potentially important conservation implications for black-browed albatrosses.This article is part of the themed issue 'Behavioural, ecological and evolutionary responses to extreme climatic events'. © 2017 The Author(s).

Population ecology of polar bears in Davis Strait, Canada and Greenland

USGS Publications Warehouse

Peacock, Elizabeth; Taylor, Mitchell K.; Laake, Jeffrey L.; Stirling, Ian

2013-01-01

Until recently, the sea ice habitat of polar bears was understood to be variable, but environmental variability was considered to be cyclic or random, rather than progressive. Harvested populations were believed to be at levels where density effects were considered not significant. However, because we now understand that polar bear demography can also be influenced by progressive change in the environment, and some populations have increased to greater densities than historically lower numbers, a broader suite of factors should be considered in demographic studies and management. We analyzed 35 years of capture and harvest data from the polar bear (Ursus maritimus) subpopulation in Davis Strait, including data from a new study (2005–2007), to quantify its current demography. We estimated the population size in 2007 to be 2,158 ± 180 (SE), a likely increase from the 1970s. We detected variation in survival, reproductive rates, and age-structure of polar bears from geographic sub-regions. Survival and reproduction of bears in southern Davis Strait was greater than in the north and tied to a concurrent dramatic increase in breeding harp seals (Pagophilus groenlandicus) in Labrador. The most supported survival models contained geographic and temporal variables. Harp seal abundance was significantly related to polar bear survival. Our estimates of declining harvest recovery rate, and increasing total survival, suggest that the rate of harvest declined over time. Low recruitment rates, average adult survival rates, and high population density, in an environment of high prey density, but deteriorating and variable ice conditions, currently characterize the Davis Strait polar bears. Low reproductive rates may reflect negative effects of greater densities or worsening ice conditions.

Using demography and movement behavior to predict range expansion of the southern sea otter.

USGS Publications Warehouse

Tinker, M.T.; Doak, D.F.; Estes, J.A.

2008-01-01

In addition to forecasting population growth, basic demographic data combined with movement data provide a means for predicting rates of range expansion. Quantitative models of range expansion have rarely been applied to large vertebrates, although such tools could be useful for restoration and management of many threatened but recovering populations. Using the southern sea otter (Enhydra lutris nereis) as a case study, we utilized integro-difference equations in combination with a stage-structured projection matrix that incorporated spatial variation in dispersal and demography to make forecasts of population recovery and range recolonization. In addition to these basic predictions, we emphasize how to make these modeling predictions useful in a management context through the inclusion of parameter uncertainty and sensitivity analysis. Our models resulted in hind-cast (1989–2003) predictions of net population growth and range expansion that closely matched observed patterns. We next made projections of future range expansion and population growth, incorporating uncertainty in all model parameters, and explored the sensitivity of model predictions to variation in spatially explicit survival and dispersal rates. The predicted rate of southward range expansion (median = 5.2 km/yr) was sensitive to both dispersal and survival rates; elasticity analysis indicated that changes in adult survival would have the greatest potential effect on the rate of range expansion, while perturbation analysis showed that variation in subadult dispersal contributed most to variance in model predictions. Variation in survival and dispersal of females at the south end of the range contributed most of the variance in predicted southward range expansion. Our approach provides guidance for the acquisition of further data and a means of forecasting the consequence of specific management actions. Similar methods could aid in the management of other recovering populations.

Effects of stand age on the demography of a temperate forest herb in post-agricultural forests.

PubMed

Jacquemyn, Hans; Brys, Rein

2008-12-01

Changes in land use have been shown to have profound effects on forest plant community structure and diversity. Dispersal limitation has been invoked as a major factor hampering colonization of forest plant species, while seed-sowing experiments and performance observations have provided some evidence for recruitment limitation determining forest plant distribution in post-agricultural forests. However, most of these studies were relatively short-term, and very few studies have investigated long-term growth rates of populations occurring in recent and ancient forests. In this study, matrix models using demographic data collected for four consecutive years were used to study the effect of forest age on population dynamics of the temperate forest herb Primula elatior. A life table response experiment (LTRE) and elasticity analysis were used to analyze the effect of forest age on population growth rate (lambda) and to decompose the effect of forest age on lambda into contributions from each matrix element. Population growth increased logarithmically with increasing forest age. Bootstrap analyses showed that populations located in very recent forests (< 50-years-old) had growth rates that were significantly < 1, whereas populations located in forests > 150-years-old had growth rates that were significantly > 1. Summed elasticities for individual growth significantly decreased with increasing forest age, whereas summed elasticities for survival and fertility significantly increased with increasing forest age. The LTRE analysis showed that the increase in lambda with increasing forest age was mainly due to increased seedling and juvenile growth and increased juvenile and adult survival. Our results indicate that past agricultural land use has long-lasting effects on the demography of forest herbs and may provide an additional mechanistic explanation for the poor colonization capacity of many forest herbs in post-agricultural forests.

Assimilation of Leaf and Canopy Spectroscopic Data to Improve the Representation of Vegetation Dynamics in Terrestrial Ecosystem Models

NASA Astrophysics Data System (ADS)

Serbin, S. P.; Dietze, M.; Desai, A. R.; LeBauer, D.; Viskari, T.; Kooper, R.; McHenry, K. G.; Townsend, P. A.

2013-12-01

The ability to seamlessly integrate information on vegetation structure and function across a continuum of scales, from field to satellite observations, greatly enhances our ability to understand how terrestrial vegetation-atmosphere interactions change over time and in response to disturbances. In particular, terrestrial ecosystem models require detailed information on ecosystem states and canopy properties in order to properly simulate the fluxes of carbon (C), water and energy from the land to the atmosphere as well as address the vulnerability of ecosystems to environmental and other perturbations. Over the last several decades the amount of available data to constrain ecological predictions has increased substantially, resulting in a progressively data-rich era for global change research. In particular remote sensing data, specifically optical data (leaf and canopy), offers the potential for an important and direct data constraint on ecosystem model projections of C and energy fluxes. Here we highlight the utility of coupling information provided through the Ecosystem Spectral Information System (EcoSIS) with complex process models through the Predictive Ecosystem Analyzer (PEcAn; http://www.pecanproject.org/) eco-informatics framework as a means to improve the description of canopy optical properties, vegetation composition, and modeled radiation balance. We also present this an efficient approach for understanding and correcting implicit assumptions and model structural deficiencies. We first illustrate the challenges and issues in adequately characterizing ecosystem fluxes with the Ecosystem Demography model (ED2, Medvigy et al., 2009) due to improper parameterization of leaf and canopy properties, as well as assumptions describing radiative transfer within the canopy. ED2 is especially relevant to these efforts because it contains a sophisticated structure for scaling ecological processes across a range of spatial scales: from the tree-level (demography, physiology) to the distribution of stands across a landscape, which allows for the direct use of remotely sensed data at the appropriate spatial scale. A sensitivity analysis is employed within PEcAn to illustrate the influence of ED2 parameterizations on modeled C and energy fluxes for a northern temperate forest ecosystem as an example of the need for more detailed information on leaf and canopy optical properties. We then demonstrate a data assimilation approach to synthesize spectral data contained within EcoSIS in order to update model parameterizations across key vegetation plant functional types, as well as a means to update vegetation state information (i.e. composition, LAI) and improve the description of radiation transfer through model structural updates. A better understanding of the radiation balance of ecosystems will improve regional and global scale C and energy balance projections.

Demography of northern flying squirrels informs ecosystem management of western interior forests.

Treesearch

John F. Lehmkuhl; Keith D. Kistler; James S. Begley; John. Boulanger

2006-01-01

We studied northern flying squirrel (Glaucomys sabrinus) demography in the eastern Washington Cascade Range to test hypotheses about regional and local abundance patterns and to inform managers of the possible effects of fire and fuels management on flying squirrels. We quantified habitat characteristics and squirrel density, population trends, and...

Seasonal productivity and nest survival of Golden-cheeked Warblers vary with forest type and edge density

Treesearch

Rebecca G. Peak; Frank R., III Thompson

2014-01-01

Knowledge of the demography and habitat requirements of the endangered Golden-cheeked Warbler (Setophaga chrysoparia) is needed for its recovery, including measures of productivity instead of reproductive indices. We report on breeding phenology and demography, calculate model-based estimates of nest survival and seasonal productivity and evaluate...

The demography of a small population of yellow columbines in the Organ Mountains

Treesearch

Chris J. Stubben; Brook G. Milligan

2001-01-01

Yellow-flowered columbines (Aquilegia chrysantha Gray) are usually found in small, isolated populations near streams and pools in mountain ranges throughout the southwestern United States. To study the long-term dynamics of these populations, which are vulnerable to extinction, we have monitored the demography of a population in Fillmore Canyon in the Organ Mountains...

Demography of Mexican spotted owls in the Sacramento Mountains, New Mexico

Treesearch

Joseph L. Ganey; Gary C. White; James P. Ward; Sean C. Kyle; Darrell L. Apprill; Todd A. Rawlinson; Ryan S. Jonnes

2014-01-01

Information on population dynamics is key to gauging the status of threatened or endangered species. We monitored demography of a population of threatened Mexican spotted owls (Strix occidentalis lucida) in the Sacramento Mountains, New Mexico from 2003 to 2011. We estimated reproductive output for territorial pairs of owls; used mark-recapture methodology and Pradel...

[Romanian demography (1975-1989)].

PubMed

Trebici, V

1990-01-01

The author describes developments in the study of demography in Romania over the period 1975-1989. The books and articles mentioned are classified by subject. The author notes that although few full-length monographs were published during the Ceausescu years, a steady stream of demographic articles appeared, most of which were published in the journal Viitorul Social, now retitled Sociologie Romaneasca.

Demography and life history characteristics of two honey bee races (Apis mellifera).

PubMed

Winston, Mark L; Dropkin, Jennifer A; Taylor, Orley R

1981-03-01

Intra-colony demography and life history characteristics of neotropical Africanized and temperate European honey bearaces were compared under simulated feral conditions. Major differences in colony demography were found which nevertheless resulted in some similar reproductive characteristics. European colonies were larger than Africanized colonies, had more rapid initral growth rates of worker populations, showed better survivorship of brood and adult workers, and differed in patterns of worker age distribution. However, both races were similar in the brood and adult populations when colonies swarmed, the frequency and timing of swarming, and the number of workers in prime swarms. The factors most important in determining these colony growth and reproductive patterns were likely worker mortality rates, climate, and resource availability.

Temporal and taxonomic contrasts in coral growth at Davies Reef, central Great Barrier Reef, Australia

NASA Astrophysics Data System (ADS)

Anderson, Kristen D.; Cantin, Neal E.; Heron, Scott F.; Lough, Janice M.; Pratchett, Morgan S.

2018-06-01

Demographic processes, such as growth, can have an important influence on the population and community structure of reef-building corals. Importantly, ongoing changes in environmental conditions (e.g. ocean warming) are expected to affect coral growth, contributing to changes in the structure of coral populations and communities. This study quantified contemporary growth rates (linear extension and calcification) for the staghorn coral, Acropora muricata, at Davies Reef, central Great Barrier Reef, Australia. Growth rates were measured at three different depths (5, 10, and 15 m) over 2 yr (2012-2014) assessing both seasonal and inter-annual variability. Results of this study were compared to equivalent measurements made in 1980-1982 at the same location. To assist in understanding inter-annual variability in coral growth, we also examined annual growth bands from massive Porites providing continuous growth and records of flooding history for Davies Reef over the period 1979-2012. Linear extension rates of A. muricata were substantially (11-62%) lower in 2012-2014 compared to 1980-1982, especially at 10 and 15 m depths. These declines in growth coincide with a + 0.14 °C change in annual mean temperature. For massive Porites, however, calcification rates were highly variable among years and there was no discernible long-term change in growth despite sustained increases in temperature of 0.064 °C per decade. Apparent differences in the growth rates of Acropora between 1980-1982 and 2012-2014 may reflect inter-annual variation in coral growth (as seen for massive Porites), though it is known branching Acropora is much more sensitive to changing environmental conditions than massive corals. There are persistent issues in assessing the sensitivities of branching corals to environmental change due to limited capacity for retrospective analyses of growth, but given their disproportionate contribution to habitat complexity and reef structure, it is critical to ascertain whether there are increasing impacts on their demography.

Climate change, biodiversity, ticks and tick-borne diseases: The butterfly effect.

PubMed

Dantas-Torres, Filipe

2015-12-01

We have killed wild animals for obtaining food and decimated forests for many reasons. Nowadays, we are burning fossil fuels as never before and even exploring petroleum in deep waters. The impact of these activities on our planet is now visible to the naked eye and the debate on climate change is warming up in scientific meetings and becoming a priority on the agenda of both scientists and policy decision makers. On the occasion of the Impact of Environmental Changes on Infectious Diseases (IECID) meeting, held in the 2015 in Sitges, Spain, I was invited to give a keynote talk on climate change, biodiversity, ticks and tick-borne diseases. The aim of the present article is to logically extend my rationale presented on the occasion of the IECID meeting. This article is not intended to be an exhaustive review, but an essay on climate change, biodiversity, ticks and tick-borne diseases. It may be anticipated that warmer winters and extended autumn and spring seasons will continue to drive the expansion of the distribution of some tick species (e.g., Ixodes ricinus) to northern latitudes and to higher altitudes. Nonetheless, further studies are advocated to improve our understanding of the complex interactions between landscape, climate, host communities (biodiversity), tick demography, pathogen diversity, human demography, human behaviour, economics, and politics, also considering all ecological processes (e.g., trophic cascades) and other possible interacting effects (e.g., mutual effects of increased greenhouse gas emissions and increased deforestation rates). The multitude of variables and interacting factors involved, and their complexity and dynamism, make tick-borne transmission systems beyond (current) human comprehension. That is, perhaps, the main reason for our inability to precisely predict new epidemics of vector-borne diseases in general.

Climate change, biodiversity, ticks and tick-borne diseases: The butterfly effect

PubMed Central

Dantas-Torres, Filipe

2015-01-01

We have killed wild animals for obtaining food and decimated forests for many reasons. Nowadays, we are burning fossil fuels as never before and even exploring petroleum in deep waters. The impact of these activities on our planet is now visible to the naked eye and the debate on climate change is warming up in scientific meetings and becoming a priority on the agenda of both scientists and policy decision makers. On the occasion of the Impact of Environmental Changes on Infectious Diseases (IECID) meeting, held in the 2015 in Sitges, Spain, I was invited to give a keynote talk on climate change, biodiversity, ticks and tick-borne diseases. The aim of the present article is to logically extend my rationale presented on the occasion of the IECID meeting. This article is not intended to be an exhaustive review, but an essay on climate change, biodiversity, ticks and tick-borne diseases. It may be anticipated that warmer winters and extended autumn and spring seasons will continue to drive the expansion of the distribution of some tick species (e.g., Ixodes ricinus) to northern latitudes and to higher altitudes. Nonetheless, further studies are advocated to improve our understanding of the complex interactions between landscape, climate, host communities (biodiversity), tick demography, pathogen diversity, human demography, human behaviour, economics, and politics, also considering all ecological processes (e.g., trophic cascades) and other possible interacting effects (e.g., mutual effects of increased greenhouse gas emissions and increased deforestation rates). The multitude of variables and interacting factors involved, and their complexity and dynamism, make tick-borne transmission systems beyond (current) human comprehension. That is, perhaps, the main reason for our inability to precisely predict new epidemics of vector-borne diseases in general. PMID:26835253

Transforming public health through distance learning.

PubMed

Hirano, D; Dillenberg, J

1998-09-01

Public health agencies face old and new problems in the next century: emerging infectious and chronic diseases, health problems related to personal behaviors, a changing demography, and a deteriorating physical and social environment. To meet these challenges, public health agencies should consider the following: the advent of new communications technologies, the need for a strong workforce, and the need for new partnerships. Distance learning can serve as a means to facilitate a strong workforce and new partnerships.

Non-Traditional Learners in Higher Education: Comparison of a Traditional MCQ Examination with Concept Mapping to Assess Learning in a Dental Radiological Science Course

ERIC Educational Resources Information Center

Hay, David B.; Tan, Po Li; Whaites, Eric

2010-01-01

The aim of this study is to argue for alternative assessment methods (i.e. concept map) considering the changes in demography in higher education. In the case of school of dentistry, for example, there is an urgent call for a catalyst for new assessment methods in dental education in view of the drive to comprehensively assess professional…

Coping with Change: United States Policy Toward South Africa,

DTIC Science & Technology

1982-01-01

Division, Directorate of Plans, Headquarters US Air Force. Colonel Fisher designed and introduced the Sub-"aharan African history program at the US...He also holds M.A. and C. Phil. degrees in Sub- Saharan African history from the University of California at Los Angel63. Colonel Fisher is a...not only fundamentally reorder South Africa but will also affect the entire African continent. Both the history and demography of the United States

The changing epidemiology and demography of cystic fibrosis.

PubMed

Stephenson, Anne L; Stanojevic, Sanja; Sykes, Jenna; Burgel, Pierre-Regis

2017-06-01

Once considered a pediatric disease with a poor prognosis, individuals born with cystic fibrosis (CF) today can expect to live well into adulthood. The implementation of multidisciplinary care, novel treatments and newborn screening has resulted in the rapid evolution in the demographics of the CF population. The purpose of this review is to highlight the evolving epidemiology and demographics of the CF population internationally. Copyright © 2017. Published by Elsevier Masson SAS.

Summary Reports of Naval Academy Research Council Sponsored Faculty Projects 1983-1984.

DTIC Science & Technology

1984-11-01

family reconstruction, semantic studies of key terms such as ŕceor 1" and "fyrd," and a pioneer analysis of the geography of Anglo-Saxon lordship...last two decades, however, monographs on aristocratic finance, the changing composition of political and professional elites, demography of the peerage...either glycerol or aliphatic alcohols do not inhibit color response and tend to increase longevity in water; (2) long chain atlipatic alcohols neither

Headache associated with sexual activity: demography, clinical features, and comorbidity.

PubMed

Frese, A; Eikermann, A; Frese, K; Schwaag, S; Husstedt, I-W; Evers, S

2003-09-23

S: To provide data on the demography, clinical features, and comorbidity of headache associated with sexual activity (HSA). Between 1996 and 2001, 51 patients with the diagnosis of HSA were questioned using a structured interview. The mean age at onset was 39.2 (+/-11.1) years. There was a clear male preponderance (2.9:1). The age at onset had two peaks, with a first peak between the 20th and 24th (n = 13) years of life and a second peak between the 35th and 44th (n = 20) years of life. Eleven patients had HSA type 1 (dull subtype), which gradually increased with increasing sexual excitement. The remaining (n = 40) had HSA type 2 (explosive subtype). The pain was predominantly bilateral (67%), and diffuse or occipital (76%). The quality was nearly equally distributed among dull, throbbing, and stabbing. HSA was not dependent on specific sexual habits and most often occurred during sexual activity with the usual partner (94%) and during masturbation (35%). There was a high comorbidity with migraine (25%), benign exertional headache (29%), and tension-type headache (45%). HSA types 1 and 2 did not significantly differ in demography, clinical features, or comorbidity, except for a higher probability of stopping the attack by breaking off sexual activity in HSA type 1. There were no cases with HSA type 3 (postural subtype). Mean age at onset, a male preponderance, a predominantly bilateral and occipital pain, and a high comorbidity with other primary headaches are in concordance with case reports in the literature. The authors found two peaks for the age at onset, however. There was no clinical evidence proving subtypes 1 and 2 to be distinct disorders. HSA types 1 and 2 may be different manifestations of the same disease rather than distinct entities.

Demography, Identity and the 2016 Presidential Election

ERIC Educational Resources Information Center

Davidson, Fiona M.; Sours, Tad; Moll, Rebecca Luebker

2016-01-01

Demography is the study of human population statistics. The United States Census Bureau has measured the demographics of the U.S. population since 1790. Why? The main purpose was for division of representatives of the people in government and for taxes. As time has gone on, it gives us a better picture of who we are as a nation and how to better…

A Study of the U.S. Capacity to Address Tropical Disease Problems

DTIC Science & Technology

1986-04-01

TROPICAL DISEASE SPECIALISTS. ............... 3-1 DEMOGRAPHY .. ....................... 3-4 Size of the Work Force .. .................. 3-5 Age...tropical disease research experience. This is an increasingly important talent pool. - 3-4 - DEMOGRAPHY Data on the number of tropical disease specialists...lines pioneered in the agricultural field in the institutions supported by the Consultative Group for International Agricultural Research. That model

Eastern wood-pewee (Contopus virens) breeding demography across a gradient of savanna, woodland, and forest in the Missouri Ozarks

Treesearch

Sarah W. Kendrick; Frank R. Thompson; Jennifer L. Reidy

2013-01-01

Better knowledge of bird response to savanna and woodland restoration is needed to inform management of these communities. We related temporal and habitat variables to breeding demography and densities of the Eastern Wood-Pewee (Contopus virens) across a gradient of savanna, woodland, and forest. We determined nest success, clutch size, young fledged...

Improving Predictions of Tree Drought Mortality in the Community Land Model Using Hydraulic Physiology Theory and its Effects on Carbon Metabolism

NASA Astrophysics Data System (ADS)

McNellis, B.; Hudiburg, T. W.

2017-12-01

Tree mortality due to drought is predicted to have increasing impacts on ecosystem structure and function during the 21st century. Models can attempt to predict which forests are most at risk from drought, but novel environments may preclude analysis that relies on past observations. The inclusion of more mechanistic detail may reduce uncertainty in predictions, but can also compound model complexity, especially in global models. The Community Land Model version 5 (CLM5), itself a component of the Community Earth System Model (CESM), has recently integrated cohort-based demography into its dynamic vegetation component and is in the process of coupling this demography to a model of plant hydraulic physiology (FATES-Hydro). Previous treatment of drought stress and plant mortality within CLM has been relatively broad, but a detailed hydraulics module represents a key step towards accurate mortality prognosis. Here, we examine the structure of FATES-Hydro with respect to two key physiological attributes: tissue osmotic potentials and embolism refilling. Specifically, we ask how FATES-Hydro captures mechanistic realism within each attribute and how much support there is within the physiological literature for its further elaboration within the model structure. Additionally, connections to broader aspects of carbon metabolism within FATES are explored to better resolve emergent consequences of drought stress on ecosystem function and tree demographics. An on-going field experiment in managed stands of Pinus ponderosa and mixed conifers is assessed for model parameterization and performance across PNW forests, with important implications for future forest management strategy.

Assessing migration patterns in Passerina ciris using the world’s bird collections as an aggregated resource

PubMed Central

Bridge, Eli S.; Duckles, Jonah M.; Navarro-Sigüenza, Adolfo G.; Rohwer, Sievert

2016-01-01

Natural history museum collections (NHCs) represent a rich and largely untapped source of data on demography and population movements. NHC specimen records can be corrected to a crude measure of collecting effort and reflect relative population densities with a method known as abundance indices. We plotted abundance index values from georeferenced NHC data in a 12-month series for the new world migratory passerine Passerina ciris across its molting and wintering range in Mexico and Central America. We illustrated a statistically significant change in abundance index values across regions and months that suggests a quasi-circular movement around its non-breeding range, and used enhanced vegetation index (EVI) analysis of remote sensing plots to demonstrate non-random association of specimen record abundance with areas of high primary productivity. We demonstrated how abundance indices from NHC specimen records can be applied to infer previously unknown migratory behavior, and be integrated with remote sensing data to provide a deeper understanding of demography and behavioral ecology across time and space. PMID:27077001

Changing pattern of landslide risk in Europe - The SafeLand project

NASA Astrophysics Data System (ADS)

Nadim, F.; Kalsnes, B. G.; SafeLand Research Consortium

2011-12-01

The changing pattern of landslide hazard and risk caused by climate change and changes in demography, the need to protect people and property, the reality for society in Europe to live with hazard and risk and the need to manage risk were the motives for the project SafeLand: "Living with landslide risk in Europe: Assessment, effects of global change, and risk management strategies." SafeLand is a large, integrating research project under the European Commission's 7th Framework Programme (FP7). It started on 1 May 2009 and will go on for 3 years, ending on 30 April 2012. There project involves 27 partners from 12 European countries, and has international collaborators and advisers from China, India, USA, Japan and Hong Kong. SafeLand also involves 25 End-Users from 11 countries. SafeLand is coordinated by the International Centre for Geohazards (ICG) at Norwegian Geotechnical Institute in Norway. Further information on the SafeLand project can be found at its web site http://www.safeland-fp7.eu/ . SafeLand is an ongoing project, which results will be finalized in 2012. This lecture summarizes the SafeLand's activities and achievements until November 2011. The main results achieved so far include: - Development and testing of several empirical methods for predicting the characteristics of threshold rainfall events for triggering of precipitation-induced landslides. - Identification of landslide hazard and risk hotspots by an objective, GIS-based analysis for Europe. The results show clearly where landslides pose the largest hazard in Europe and the objective approach allows a ranking of the countries by exposed area and population. - Different regional climate model simulations over Europe (from the EU FP6 project ENSEMBLES) at a spatial resolution of 25 x 25 km have been used to perform an extreme value analysis for trends in heavy precipitation events. In winter a general trend towards more heavy precipitation events across all analyzed regional climate model simulations is found. For summer, a slight increase of heavy precipitation in Northern Europe and a general decrease in southern Europe is found in all regional climate model simulations. - The prototype of a web-based "toolbox" of innovative and technically appropriate prevention and mitigation measures was developed. The toolbox does a preliminary assessment and ranking of up to 60 structural and non-structural landslide risk mitigation options. - Development of an empirical model for assessing the changes in landslide frequency (hazard) as a function of changes in the demography and population density. - Case histories and "hotspots" of European Land¬slides have been collected and documented. Data for 41 potential case study sites have been compiled and summarized. These comprise 39 sites in Europe located in Italy, France, Norway, Switzerland, Austria, Andorra, and Romania; as well as one site in Canada and one in India. Almost every type of landslide and every type of movement is represented in these sites. - Research on stakeholder workshops and participatory processes to involve the population exposed to landslide risk in the decision-making process for choosing the most appropriate risk mitigation measure(s).

Using satellite telemetry to define spatial population structure in polar bears in the Norwegian and western Russian Arctic

USGS Publications Warehouse

Mauritzen, Mette; Derocher, Andrew E.; Wiig, Øystein; Belikov, Stanislav; Boltunov, Andrei N.; Garner, Gerald W.

2002-01-01

1. Animal populations, defined by geographical areas within a species’ distribution where population dynamics are largely regulated by births and deaths rather than by migration from surrounding areas, may be the correct unit for wildlife management. However, in heterogeneous landscapes varying habitat quality may yield subpopulations with distinct patterns in resource use and demography significant to the dynamics of populations.2. To define the spatial population structure of polar bears Ursus maritimus in the Norwegian and western Russian Arctic, and to assess the existence of a shared population between the two countries, we analysed satellite telemetry data obtained from 105 female polar bears over 12 years.3. Using both cluster analyses and home-range estimation methods, we identified five population units inhabiting areas with different sea-ice characteristics and prey availability.4. The continuous distribution of polar bear positions indicated that the different subpopulations formed one continuous polar bear population in the Norwegian and western Russian Arctic. Hence, Norway and Russia have a shared management responsibility.5. The spatial population structure identified will provide a guide for evaluating geographical patterns in polar bear ecology, the dynamics of polar bear–seal relationships and the effects of habitat alteration due to climate change. The work illustrates the importance of defining population borders and subpopulation structure in understanding the dynamics and management of larger animals.

Demography of the Pacific walrus (Odobenus rosmarus divergens): 1974-2006

USGS Publications Warehouse

Taylor, Rebecca L.; Udevitz, Mark S.

2015-01-01

Global climate change may fundamentally alter population dynamics of many species for which baseline population parameter estimates are imprecise or lacking. Historically, the Pacific walrus is thought to have been limited by harvest, but it may become limited by global warming-induced reductions in sea ice. Loss of sea ice, on which walruses rest between foraging bouts, may reduce access to food, thus lowering vital rates. Rigorous walrus survival rate estimates do not exist, and other population parameter estimates are out of date or have well-documented bias and imprecision. To provide useful population parameter estimates we developed a Bayesian, hidden process demographic model of walrus population dynamics from 1974 through 2006 that combined annual age-specific harvest estimates with five population size estimates, six standing age structure estimates, and two reproductive rate estimates. Median density independent natural survival was high for juveniles (0.97) and adults (0.99), and annual density dependent vital rates rose from 0.06 to 0.11 for reproduction, 0.31 to 0.59 for survival of neonatal calves, and 0.39 to 0.85 for survival of older calves, concomitant with a population decline. This integrated population model provides a baseline for estimating changing population dynamics resulting from changing harvests or sea ice.

America's Demography in the New Century: Aging Baby Boomers and New Immigrants as Major Players. Milken Institute Policy Brief.

ERIC Educational Resources Information Center

Frey, William H.; DeVol, Ross C.

America's demography in the new century will be affected by the aging baby boom generation and by new immigrants. Focus on just the national implications of aging baby boomers and the new immigrants is inadequate. This policy brief takes a regional perspective, examining recent trends and population statistics and making the case that aging baby…

Research, Teaching Training in Demography: A Directory of Institutions in the ESCAP Region. Asian Population Studies Series No. 8, Supplement No. 3.

ERIC Educational Resources Information Center

United Nations Economic and Social Commission for Asia and the Pacific, Bangkok (Thailand).

This directory contains information on 39 institutions and 108 projects of research teaching and training in demography in Asia and the Pacific. Eight countries are represented: Australia, Bangladesh, Hong Kong, India, Iran, Japan, New Zealand, and Pakistan. The following information is given for each institution: name, address, person in charge,…

Introduction: demography and cultural macroevolution.

PubMed

Steele, James; Shennan, Stephen

2009-04-01

The papers in this special issue of Human Biology, which derive from a conference sponsored by the Arts and Humanities Research Council (AHRC) Center for the Evolution of Cultural Diversity, lay some of the foundations for an empirical macroevolutionary analysis of cultural dynamics. Our premise here is that cultural dynamics-including the stability of traditions and the rate of origination of new variants-are influenced by independently occurring demographic processes (population size, structure, and distribution as these vary over time as a result of changes in rates of fertility, mortality, and migration). The contributors focus on three sets of problems relevant to empirical studies of cultural macroevolution: large-scale reconstruction of past population dynamics from archaeological and genetic data; juxtaposition of models and evidence of cultural dynamics using large-scale archaeological and historical data sets; and juxtaposition of models and evidence of cultural dynamics from large-scale linguistic data sets. In this introduction we outline some of the theoretical and methodological issues and briefly summarize the individual contributions.

Exploring eco-hydrological consequences of the Amazonian ecosystems under climate and land-use changes in the 21st century

NASA Astrophysics Data System (ADS)

Zhang, K.; Castanho, A. D.; Moghim, S.; Bras, R. L.; Coe, M. T.; Costa, M. H.; Levine, N. M.; Longo, M.; McKnight, S.; Wang, J.; Moorcroft, P. R.

2012-12-01

Deforestation and drought have imposed regional-scale perturbations onto Amazonian ecosystems and are predicted to cause larger negative impacts on the Amazonian ecosystems and associated regional carbon dynamics in the 21st century. However, global climate models (GCMs) vary greatly in their projections of future climate change in Amazonia, giving rise to uncertainty in the expected fate of the Amazon over the coming century. In this study, we explore the possible eco-hydrological consequences of the Amazonian ecosystems under projected climate and land-use changes in the 21st century using two state-of-the-art terrestrial ecosystem models—Ecosystem Demography Model 2.1(ED2.1) and Integrated Biosphere Simulator model (IBIS)—driven by three representative, bias-corrected climate projections from three IPCC GCMs (NCARPCM1, NCARCCSM3 and HadCM3), coupled with two land-use change scenarios (a business-as-usual and a strict governance scenario). We also analyze the relative roles of climate change, CO2 fertilization, land-use change and fire in driving the projected composition and structure of the Amazonian ecosystems. Our results show that CO2 fertilization enhances vegetation productivity and above-ground biomass (AGB) in the region, while land-use change and fire cause AGB loss and the replacement of forests by the savanna-like vegetation. The impacts of climate change depend strongly on the direction and severity of projected precipitation changes in the region. In particular, when intensified water stress is superimposed on unregulated deforestation, both ecosystem models predict large-scale dieback of Amazonian rainforests.

Supermassive black-hole growth over cosmic time: active galaxy demography, physics, and ecology from Chandra surveys.

PubMed

Brandt, W N; Alexander, D M

2010-04-20

Extragalactic X-ray surveys over the past decade have dramatically improved understanding of the majority populations of active galactic nuclei (AGNs) over most of the history of the universe. Here we briefly highlight some of the exciting discoveries about AGN demography, physics, and ecology, with a focus on results from Chandra. We also discuss some key unresolved questions and future prospects.

Supermassive black-hole growth over cosmic time: Active galaxy demography, physics, and ecology from Chandra surveys

PubMed Central

Brandt, W. N.; Alexander, D. M.

2010-01-01

Extragalactic X-ray surveys over the past decade have dramatically improved understanding of the majority populations of active galactic nuclei (AGNs) over most of the history of the universe. Here we briefly highlight some of the exciting discoveries about AGN demography, physics, and ecology, with a focus on results from Chandra. We also discuss some key unresolved questions and future prospects. PMID:20404160

Functional traits help predict post-disturbance demography of tropical trees.

PubMed

Flores, Olivier; Hérault, Bruno; Delcamp, Matthieu; Garnier, Éric; Gourlet-Fleury, Sylvie

2014-01-01

How tropical tree species respond to disturbance is a central issue of forest ecology, conservation and resource management. We define a hierarchical model to investigate how functional traits measured in control plots relate to the population change rate and to demographic rates for recruitment and mortality after disturbance by logging operations. Population change and demographic rates were quantified on a 12-year period after disturbance and related to seven functional traits measured in control plots. The model was calibrated using a Bayesian Network approach on 53 species surveyed in permanent forest plots (37.5 ha) at Paracou in French Guiana. The network analysis allowed us to highlight both direct and indirect relationships among predictive variables. Overall, 89% of interspecific variability in the population change rate after disturbance were explained by the two demographic rates, the recruitment rate being the most explicative variable. Three direct drivers explained 45% of the variability in recruitment rates, including leaf phosphorus concentration, with a positive effect, and seed size and wood density with negative effects. Mortality rates were explained by interspecific variability in maximum diameter only (25%). Wood density, leaf nitrogen concentration, maximum diameter and seed size were not explained by variables in the analysis and thus appear as independent drivers of post-disturbance demography. Relationships between functional traits and demographic parameters were consistent with results found in undisturbed forests. Functional traits measured in control conditions can thus help predict the fate of tropical tree species after disturbance. Indirect relationships also suggest how different processes interact to mediate species demographic response.

Potential trophic cascades triggered by the barred owl range expansion

USGS Publications Warehouse

Holm, Samantha R.; Noon, Barry R.; Wiens, David; Ripple, William J.

2016-01-01

Recently, the barred owl (Strix varia) has expanded its range into the Pacific Northwest of the United States resulting in pronounced effects on the demography and behavior of the northern spotted owl (S. occidentalis caurina). The range expansion has brought together historically allopatric species, creating the potential for significant changes in the avian predator community with possible cascading effects on food-web dynamics. The adverse effects of the barred owl on the behavior and demography of the northern spotted owl are well-documented, but little is known about the immediate and long-term effects changes in the predator community may have on native species composition and ecosystem processes. Based on northern spotted owl and barred owl selection for diet and habitat resources, there is a potential for trophic cascades within the region's predator and prey communities, differing responses by their shared and unique prey species, and possible direct and indirect effects on ecosystem processes. We explored the possible ecological consequences of the barred owl range expansion to wildlife communities of the Pacific Northwest based on the theoretical underpinnings of predator–prey relationships, interspecific competition, intraguild predation, and potential cascading trophic interactions. Negative effects on fitness of northern spotted owls because of interspecific competition with barred owls are strong selection forces that may contribute to the regional extinction of the northern spotted owl. In addition, we posit that shared prey species and those uniquely consumed by barred owls, along with other competing native predators, may experience changes in behavior, abundance, and distribution as a result of increased rates of predation by rapidly expanding populations of barred owls.

Disturbance Distance: Using a process based ecosystem model to estimate and map potential thresholds in disturbance rates that would give rise to fundamentally altered ecosystems

NASA Astrophysics Data System (ADS)

Dolan, K. A.; Hurtt, G. C.; Fisk, J.; Flanagan, S.; LePage, Y.; Sahajpal, R.

2014-12-01

Disturbance plays a critical role in shaping the structure and function of forested ecosystems as well as the ecosystem services they provide, including but not limited to: carbon storage, biodiversity habitat, water quality and flow, and land atmosphere exchanges of energy and water. As recent studies highlight novel disturbance regimes resulting from pollution, invasive pests and climate change, there is a need to include these alterations in predictions of future forest function and structure. The Ecosystem Demography (ED) model is a mechanistic model of forest ecosystem dynamics in which individual-based forest dynamics can be efficiently implemented over regional to global scales due to advanced scaling methods. We utilize ED to characterize the sensitivity of potential vegetation structure and function to changes in rates of density independent mortality. Disturbance rate within ED can either be altered directly or through the development of sub-models. Disturbance sub-models in ED currently include fire, land use and hurricanes. We use a tiered approach to understand the sensitivity of North American ecosystems to changes in background density independent mortality. Our first analyses were conducted at half-degree spatial resolution with a constant rate of disturbance in space and time, which was altered between runs. Annual climate was held constant at the site level and the land use and fire sub-models were turned off. Results showed an ~ 30% increase in non-forest area across the US when disturbance rates were changed from 0.6% a year to 1.2% a year and a more than 3.5 fold increase in non-forest area when disturbance rates doubled again from 1.2% to 2.4%. Continued runs altered natural background disturbance rates with the existing fire and hurricane sub models turned on as well as historic and future land use. By quantify differences between model outputs that characterize ecosystem structure and function related to the carbon cycle across the US, we are identifying areas and characteristics that display higher sensitivities to change in disturbance rates.

Use of a Climate Change Vulnerability Index for Assessing Species at Risk on Military Lands

DTIC Science & Technology

2011-09-01

in northern Florida. Journal of Herpetology 26:158-165. Diemer, J. E. 1992b. Demography of the tortoise Gopherus polyphemus in northern Florida...Journal of Herpetology 26:281-289. Ennen, J. R., B. R. Kreiser, and C. P. Qualls. 2010. Low genetic diversity in several gopher tortoise (Gopherus...effects on a coastal population of gopher tortoises. Journal of Herpetology 18:231-239. Landers, J. L., and D. L. Speake. 1980. Management needs of

Direct and indirect effects of environmental variability on growth and survivorship of pre-reproductive Joshua trees, Yucca brevifolia Engelm (Agavaceae)

USGS Publications Warehouse

Esque, Todd C.; Medica, Phil A.; Shryock, Daniel F.; Defalco, Lesley A.; Webb, Robert H.; Hunter, Richard B.

2015-01-01

• Conclusions: A rare establishment event for Y. brevifolia during 1983–1984, triggered by above-average summer rainfall, provided a unique opportunity to track early survival and growth. Infrequent but acute episodes of herbivory during drought influenced demography for decades. Variability in survival among young Y. brevifolia indicates that size-dependent demographic variables will improve forecasts for this long-lived desert species under predicted regional climate change.

Phylogeography of a Habitat Specialist with High Dispersal Capability: The Savi’s Warbler Locustella luscinioides

PubMed Central

Neto, Júlio M.; Arroyo, José L.; Bargain, Bruno; Monrós, Juan S.; Mátrai, Norbert; Procházka, Petr; Zehtindjiev, Pavel

2012-01-01

In order to describe the influence of Pleistocene glaciations on the genetic structure and demography of a highly mobile, but specialized, passerine, the Savi’s Warbler (Locustella luscinioides), mitochondrial DNA sequences (ND2) and microsatellites were analysed in c.330 individuals of 17 breeding and two wintering populations. Phylogenetic, population genetics and coalescent methods were used to describe the genetic structure, determine the timing of the major splits and model the demography of populations. Savi’s Warblers split from its sister species c.8 million years ago and have two major haplotype groups that diverged in the early/middle Pleistocene. One of these clades originated in the Balkans and is currently widespread, showing strong evidence for population expansion; whereas the other is restricted to Iberia and remained stable. Microsatellites agreed with a genetic break around the Pyrenees, but showed considerable introgression and a weaker genetic structure. Both genetic markers showed an isolation-by-distance pattern associated with the population expansion of the eastern clade. Breeding populations seem to be segregated at the wintering sites, but results on migratory connectivity are preliminary. Savi’s Warbler is the only known migratory bird species in which Iberian birds did not expand beyond the Pyrenees after the last glaciation. Despite the long period of independent evolution of western and eastern populations, complete introgression occurred when these groups met in Iberia. Mitochondrial sequences indicated the existence of refugia-within-refugia in the Iberian Peninsula during the last glacial period, which is surprising given the high dispersal capacity of this species. Plumage differences of eastern subspecies seemed to have evolved recently through natural selection, in agreement with the glacial expansion hypothesis. This study supports the great importance of the Iberian Peninsula and its role for the conservation of genetic variation. PMID:22701653

Evolution of stochastic demography with life history tradeoffs in density-dependent age-structured populations.

PubMed

Lande, Russell; Engen, Steinar; Sæther, Bernt-Erik

2017-10-31

We analyze the stochastic demography and evolution of a density-dependent age- (or stage-) structured population in a fluctuating environment. A positive linear combination of age classes (e.g., weighted by body mass) is assumed to act as the single variable of population size, [Formula: see text], exerting density dependence on age-specific vital rates through an increasing function of population size. The environment fluctuates in a stationary distribution with no autocorrelation. We show by analysis and simulation of age structure, under assumptions often met by vertebrate populations, that the stochastic dynamics of population size can be accurately approximated by a univariate model governed by three key demographic parameters: the intrinsic rate of increase and carrying capacity in the average environment, [Formula: see text] and [Formula: see text], and the environmental variance in population growth rate, [Formula: see text] Allowing these parameters to be genetically variable and to evolve, but assuming that a fourth parameter, [Formula: see text], measuring the nonlinearity of density dependence, remains constant, the expected evolution maximizes [Formula: see text] This shows that the magnitude of environmental stochasticity governs the classical trade-off between selection for higher [Formula: see text] versus higher [Formula: see text] However, selection also acts to decrease [Formula: see text], so the simple life-history trade-off between [Formula: see text]- and [Formula: see text]-selection may be obscured by additional trade-offs between them and [Formula: see text] Under the classical logistic model of population growth with linear density dependence ([Formula: see text]), life-history evolution in a fluctuating environment tends to maximize the average population size. Published under the PNAS license.

Implications of the circumpolar genetic structure of polar bears for their conservation in a rapidly warming Arctic.

PubMed

Peacock, Elizabeth; Sonsthagen, Sarah A; Obbard, Martyn E; Boltunov, Andrei; Regehr, Eric V; Ovsyanikov, Nikita; Aars, Jon; Atkinson, Stephen N; Sage, George K; Hope, Andrew G; Zeyl, Eve; Bachmann, Lutz; Ehrich, Dorothee; Scribner, Kim T; Amstrup, Steven C; Belikov, Stanislav; Born, Erik W; Derocher, Andrew E; Stirling, Ian; Taylor, Mitchell K; Wiig, Øystein; Paetkau, David; Talbot, Sandra L

2015-01-01

We provide an expansive analysis of polar bear (Ursus maritimus) circumpolar genetic variation during the last two decades of decline in their sea-ice habitat. We sought to evaluate whether their genetic diversity and structure have changed over this period of habitat decline, how their current genetic patterns compare with past patterns, and how genetic demography changed with ancient fluctuations in climate. Characterizing their circumpolar genetic structure using microsatellite data, we defined four clusters that largely correspond to current ecological and oceanographic factors: Eastern Polar Basin, Western Polar Basin, Canadian Archipelago and Southern Canada. We document evidence for recent (ca. last 1-3 generations) directional gene flow from Southern Canada and the Eastern Polar Basin towards the Canadian Archipelago, an area hypothesized to be a future refugium for polar bears as climate-induced habitat decline continues. Our data provide empirical evidence in support of this hypothesis. The direction of current gene flow differs from earlier patterns of gene flow in the Holocene. From analyses of mitochondrial DNA, the Canadian Archipelago cluster and the Barents Sea subpopulation within the Eastern Polar Basin cluster did not show signals of population expansion, suggesting these areas may have served also as past interglacial refugia. Mismatch analyses of mitochondrial DNA data from polar and the paraphyletic brown bear (U. arctos) uncovered offset signals in timing of population expansion between the two species, that are attributed to differential demographic responses to past climate cycling. Mitogenomic structure of polar bears was shallow and developed recently, in contrast to the multiple clades of brown bears. We found no genetic signatures of recent hybridization between the species in our large, circumpolar sample, suggesting that recently observed hybrids represent localized events. Documenting changes in subpopulation connectivity will allow polar nations to proactively adjust conservation actions to continuing decline in sea-ice habitat.

Implications of the Circumpolar Genetic Structure of Polar Bears for Their Conservation in a Rapidly Warming Arctic

PubMed Central

Peacock, Elizabeth; Sonsthagen, Sarah A.; Obbard, Martyn E.; Boltunov, Andrei; Regehr, Eric V.; Ovsyanikov, Nikita; Aars, Jon; Atkinson, Stephen N.; Sage, George K.; Hope, Andrew G.; Zeyl, Eve; Bachmann, Lutz; Ehrich, Dorothee; Scribner, Kim T.; Amstrup, Steven C.; Belikov, Stanislav; Born, Erik W.; Derocher, Andrew E.; Stirling, Ian; Taylor, Mitchell K.; Wiig, Øystein; Paetkau, David; Talbot, Sandra L.

2015-01-01

We provide an expansive analysis of polar bear (Ursus maritimus) circumpolar genetic variation during the last two decades of decline in their sea-ice habitat. We sought to evaluate whether their genetic diversity and structure have changed over this period of habitat decline, how their current genetic patterns compare with past patterns, and how genetic demography changed with ancient fluctuations in climate. Characterizing their circumpolar genetic structure using microsatellite data, we defined four clusters that largely correspond to current ecological and oceanographic factors: Eastern Polar Basin, Western Polar Basin, Canadian Archipelago and Southern Canada. We document evidence for recent (ca. last 1–3 generations) directional gene flow from Southern Canada and the Eastern Polar Basin towards the Canadian Archipelago, an area hypothesized to be a future refugium for polar bears as climate-induced habitat decline continues. Our data provide empirical evidence in support of this hypothesis. The direction of current gene flow differs from earlier patterns of gene flow in the Holocene. From analyses of mitochondrial DNA, the Canadian Archipelago cluster and the Barents Sea subpopulation within the Eastern Polar Basin cluster did not show signals of population expansion, suggesting these areas may have served also as past interglacial refugia. Mismatch analyses of mitochondrial DNA data from polar and the paraphyletic brown bear (U. arctos) uncovered offset signals in timing of population expansion between the two species, that are attributed to differential demographic responses to past climate cycling. Mitogenomic structure of polar bears was shallow and developed recently, in contrast to the multiple clades of brown bears. We found no genetic signatures of recent hybridization between the species in our large, circumpolar sample, suggesting that recently observed hybrids represent localized events. Documenting changes in subpopulation connectivity will allow polar nations to proactively adjust conservation actions to continuing decline in sea-ice habitat. PMID:25562525

Implications of the circumpolar genetic structure of polar bears for their conservation in a rapidly warming Arctic

USGS Publications Warehouse

Peacock, Elizabeth; Sonsthagen, Sarah A.; Obbard, Martyn E.; Boltunov, Andrei N.; Regehr, Eric V.; Ovsyanikov, Nikita; Aars, Jon; Atkinson, Stephen N.; Sage, George K.; Hope, Andrew G.; Zeyl, Eve; Bachmann, Lutz; Ehrich, Dorothee; Scribner, Kim T.; Amstrup, Steven C.; Belikov, Stanislav; Born, Erik W.; Derocher, Andrew E.; Stirling, Ian; Taylor, Mitchell K.; Wiig, Øystein; Paetkau, David; Talbot, Sandra L.

2015-01-01

We provide an expansive analysis of polar bear (Ursus maritimus) circumpolar genetic variation during the last two decades of decline in their sea-ice habitat. We sought to evaluate whether their genetic diversity and structure have changed over this period of habitat decline, how their current genetic patterns compare with past patterns, and how genetic demography changed with ancient fluctuations in climate. Characterizing their circumpolar genetic structure using microsatellite data, we defined four clusters that largely correspond to current ecological and oceanographic factors: Eastern Polar Basin, Western Polar Basin, Canadian Archipelago and Southern Canada. We document evidence for recent (ca. last 1–3 generations) directional gene flow from Southern Canada and the Eastern Polar Basin towards the Canadian Archipelago, an area hypothesized to be a future refugium for polar bears as climate-induced habitat decline continues. Our data provide empirical evidence in support of this hypothesis. The direction of current gene flow differs from earlier patterns of gene flow in the Holocene. From analyses of mitochondrial DNA, the Canadian Archipelago cluster and the Barents Sea subpopulation within the Eastern Polar Basin cluster did not show signals of population expansion, suggesting these areas may have served also as past interglacial refugia. Mismatch analyses of mitochondrial DNA data from polar and the paraphyletic brown bear (U. arctos) uncovered offset signals in timing of population expansion between the two species, that are attributed to differential demographic responses to past climate cycling. Mitogenomic structure of polar bears was shallow and developed recently, in contrast to the multiple clades of brown bears. We found no genetic signatures of recent hybridization between the species in our large, circumpolar sample, suggesting that recently observed hybrids represent localized events. Documenting changes in subpopulation connectivity will allow polar nations to proactively adjust conservation actions to continuing decline in sea-ice habitat.

An Archaeological an Bioarchaeological Perspective. The Tucker (41DT104) and Sinclair (41DT105) Cemeteries of Delta County, Texas

DTIC Science & Technology

1988-01-01

Gilbert and Mielke 1985). The adaptive efficiency will be measured here by demography , childhood mortality, adult longevity , disease, and fiequency of...Episodes of childhood stress through time by individual 6-month intervals .... ............ .. 105 15. The demography of the Tucker Cemetery...tradition, it represented a very practical position among many pioneer , rural families where: few churches existed in the early years of settlement

Grand Forks - East Grand Forks Urban Water Resources Study. Social and Environmental Inventory.

DTIC Science & Technology

1979-01-01

61 Introduction 57IPrehistoric 58 Historic 58-61 Social Organization 62-72 Introduction 62 Demography 62-63 Population Distribution by Age 64-65 Urban...programs, native timber is decreasing due to agricultural clearing operatings and urban growth. Native tree species are important because of their longevity ... Demography 62-63 Population Distribution by Age 64-65 Urban-Rural Distribution 66 Population Projections 67-68 Racial Distribution 69 Ethnic Groups 70

Influence of Land Cover Heterogeneity, Land-Use Change and Management on the Regional Carbon Cycle in the Upper Midwest USA as Evaluated by High-Density Observations and a Dynamic Ecosystem Model

NASA Astrophysics Data System (ADS)

Desai, A. R.; Bolstad, P. V.; Moorcroft, P. R.; Davis, K. J.

2005-12-01

The interplay between land use change, forest management and land cover variability complicates the ability to characterize regional scale (10-1000 km) exchange of carbon dioxide between the land surface and atmosphere in heterogeneous landscapes. An attempt was made to observe and model these factors and their influence on the regional carbon cycle across the upper Midwest USA. A high density of eddy-covariance carbon flux, micrometeorology, carbon dioxide mixing ratio, stand-scale biometry and canopy component flux observations have been occurring in this area as part of the Chequamegon Ecosystem-Atmosphere Study. Observations limited to sampling only dominant stands and coarse-resolution biogeochemical models limited to biome-scale parameterization neither accurately capture the variability of carbon fluxes measured by the network of eddy covariance towers nor match the regional-scale carbon flux inferred from very tall tower eddy covariance measurements and multi-site upscaling. Analysis of plot level biometric data, U.S. Forest Service Forest Inventory Analysis data and high-resolution land cover data around the tall tower revealed significant variations in vegetation type, stand age, canopy stocking and structure. Wetlands, clearcuts and recent natural disturbances occur in characteristic small non-uniformly distributed patches that aggregate to form more than 30% of the landscape. The Ecosystem Demography model, a dynamic ecosystem model that incorporates vegetation heterogeneity, canopy structure, stand age, disturbance, land use change and forest management, was parameterized with regional biometric data and meteorology, historical records of land management and high-resolution satellite land cover maps. The model will be used to examine the significance of past land use change, natural disturbance history and current forest management in explaining landscape structure and regional carbon fluxes observed in the region today.

Mesoscale disturbance and ecological response to decadal climatic variability in the American Southwest

USGS Publications Warehouse

Swetnam, T.W.; Betancourt, J.L.

1998-01-01

Ecological responses to climatic variability in the Southwest include regionally synchronized fires, insect outbreaks, and pulses in tree demography (births and deaths). Multicentury, tree-ring reconstructions of drought, disturbance history, and tree demography reveal climatic effects across scales, from annual to decadal, and from local (<102 km2) to mesoscale (104-106 km2). Climate-disturbance relations are more variable and complex than previously assumed. During the past three centuries, mesoscale outbreaks of the western spruce budworm (Choristoneura occidentalis) were associated with wet, not dry episodes, contrary to conventional wisdom. Regional fires occur during extreme droughts but, in some ecosystems, antecedent wet conditions play a secondary role by regulating accumulation of fuels. Interdecadal changes in fire-climate associations parallel other evidence for shifts in the frequency or amplitude of the Southern Oscillation (SO) during the past three centuries. High interannual, fire-climate correlations (r = 0.7 to 0.9) during specific decades (i.e., circa 1740-80 and 1830-60) reflect periods of high amplitude in the SO and rapid switching from extreme wet to dry years in the Southwest, thereby entraining fire occurrence across the region. Weak correlations from 1780 to 1830 correspond with a decrease in SO frequency or amplitude inferred from independent tree-ring width, ice core, and coral isotope reconstructions. Episodic dry and wet episodes have altered age structures and species composition of woodland and conifer forests. The scarcity of old, living conifers established before circa 1600 suggests that the extreme drought of 1575-95 had pervasive effects on tree populations. The most extreme drought of the past 400 years occurred in the mid-twentieth century (1942-57). This drought resulted in broadscale plant dieoffs in shrublands, woodlands, and forests and accelerated shrub invasion of grasslands. Drought conditions were broken by the post-1976 shift to the negative SO phase and wetter cool seasons in the Southwest. The post-1976 period shows up as an unprecedented surge in tree-ring growth within millennia-length chronologies. This unusual episode may have produced a pulse in tree recruitment and improved rangeland conditions (e.g., higher grass production), though additional study is needed to disentangle the interacting roles of land use and climate. The 1950s drought and the post-1976 wet period and their aftermaths offer natural experiments to study long-term ecosystem response to interdecadal climate variability.Ecological responses to climatic variability in the Southwest include regionally synchronized fires, insect outbreaks, and pulses in tree demography (births and deaths). Multicentury, tree-ring reconstructions of drought, disturbance history, and tree demography reveal climatic effects across scales, from annual to decadal, and from local (<102 km2) to mesoscale (104-106 km2). Climate-disturbance relations are more variable and complex than previously assumed. During the past three centuries, mesoscale outbreaks of the western spruce budworm (Choristoneura occidentalis) were associated with wet, not dry episodes, contrary to conventional wisdom. Regional fires occur during extreme droughts but, in some ecosystems, antecedent wet conditions play a secondary role by regulating accumulation of fuels. Interdecadal changes in fire-climate associations parallel other evidence for shifts in the frequency or amplitude of the Southern Oscillation (SO) during the past three centuries. High interannual, fire-climate correlations (r = 0.7 to 0.9) during specific decades (i.e., circa 1740-80 and 1830-60) reflect periods of high amplitude in the SO and rapid switching from extreme wet to dry years in the Southwest, thereby entraining fire occurrence across the region. Weak correlations from 1780 to 1830 correspond with a decrease in SO frequency or amplitude inferred from independent tree-ring width, ic

Archived DNA reveals fisheries and climate induced collapse of a major fishery.

PubMed

Bonanomi, Sara; Pellissier, Loïc; Therkildsen, Nina Overgaard; Hedeholm, Rasmus Berg; Retzel, Anja; Meldrup, Dorte; Olsen, Steffen Malskær; Nielsen, Anders; Pampoulie, Christophe; Hemmer-Hansen, Jakob; Wisz, Mary Susanne; Grønkjær, Peter; Nielsen, Einar Eg

2015-10-22

Fishing and climate change impact the demography of marine fishes, but it is generally ignored that many species are made up of genetically distinct locally adapted populations that may show idiosyncratic responses to environmental and anthropogenic pressures. Here, we track 80 years of Atlantic cod (Gadus morhua) population dynamics in West Greenland using DNA from archived otoliths in combination with fish population and niche based modeling. We document how the interacting effects of climate change and high fishing pressure lead to dramatic spatiotemporal changes in the proportions and abundance of different genetic populations, and eventually drove the cod fishery to a collapse in the early 1970s. Our results highlight the relevance of fisheries management at the level of genetic populations under future scenarios of climate change.

Archived DNA reveals fisheries and climate induced collapse of a major fishery

PubMed Central

Bonanomi, Sara; Pellissier, Loïc; Therkildsen, Nina Overgaard; Hedeholm, Rasmus Berg; Retzel, Anja; Meldrup, Dorte; Olsen, Steffen Malskær; Nielsen, Anders; Pampoulie, Christophe; Hemmer-Hansen, Jakob; Wisz, Mary Susanne; Grønkjær, Peter; Nielsen, Einar Eg

2015-01-01

Fishing and climate change impact the demography of marine fishes, but it is generally ignored that many species are made up of genetically distinct locally adapted populations that may show idiosyncratic responses to environmental and anthropogenic pressures. Here, we track 80 years of Atlantic cod (Gadus morhua) population dynamics in West Greenland using DNA from archived otoliths in combination with fish population and niche based modeling. We document how the interacting effects of climate change and high fishing pressure lead to dramatic spatiotemporal changes in the proportions and abundance of different genetic populations, and eventually drove the cod fishery to a collapse in the early 1970s. Our results highlight the relevance of fisheries management at the level of genetic populations under future scenarios of climate change. PMID:26489934

Archived DNA reveals fisheries and climate induced collapse of a major fishery

NASA Astrophysics Data System (ADS)

Bonanomi, Sara; Pellissier, Loïc; Therkildsen, Nina Overgaard; Hedeholm, Rasmus Berg; Retzel, Anja; Meldrup, Dorte; Olsen, Steffen Malskær; Nielsen, Anders; Pampoulie, Christophe; Hemmer-Hansen, Jakob; Wisz, Mary Susanne; Grønkjær, Peter; Nielsen, Einar Eg

2015-10-01

Fishing and climate change impact the demography of marine fishes, but it is generally ignored that many species are made up of genetically distinct locally adapted populations that may show idiosyncratic responses to environmental and anthropogenic pressures. Here, we track 80 years of Atlantic cod (Gadus morhua) population dynamics in West Greenland using DNA from archived otoliths in combination with fish population and niche based modeling. We document how the interacting effects of climate change and high fishing pressure lead to dramatic spatiotemporal changes in the proportions and abundance of different genetic populations, and eventually drove the cod fishery to a collapse in the early 1970s. Our results highlight the relevance of fisheries management at the level of genetic populations under future scenarios of climate change.

Predicting evolutionary rescue via evolving plasticity in stochastic environments

PubMed Central

Baskett, Marissa L.

2016-01-01

Phenotypic plasticity and its evolution may help evolutionary rescue in a novel and stressful environment, especially if environmental novelty reveals cryptic genetic variation that enables the evolution of increased plasticity. However, the environmental stochasticity ubiquitous in natural systems may alter these predictions, because high plasticity may amplify phenotype–environment mismatches. Although previous studies have highlighted this potential detrimental effect of plasticity in stochastic environments, they have not investigated how it affects extinction risk in the context of evolutionary rescue and with evolving plasticity. We investigate this question here by integrating stochastic demography with quantitative genetic theory in a model with simultaneous change in the mean and predictability (temporal autocorrelation) of the environment. We develop an approximate prediction of long-term persistence under the new pattern of environmental fluctuations, and compare it with numerical simulations for short- and long-term extinction risk. We find that reduced predictability increases extinction risk and reduces persistence because it increases stochastic load during rescue. This understanding of how stochastic demography, phenotypic plasticity, and evolution interact when evolution acts on cryptic genetic variation revealed in a novel environment can inform expectations for invasions, extinctions, or the emergence of chemical resistance in pests. PMID:27655762

Demography and diagnosis of patients encountered at Qassim University Polyclinics, Central Saudi Arabia.

PubMed

Al-Harbi, Meshari M; Al-Mogbel, Hassan A; Al-Amro, Abdalla M; Al-Mofadhi, Abdulaziz A; Al-Homaid, Ahmed F; Al-Harbi, Salman H; Al-Rosaini, Sami A; Al-Suhaibani, Turki A; Imam, Abdelmageed

2016-09-01

To provide current data on the demography and diagnosis of patients encountered at the Internal Medicine Outpatient Department of Qassim University Polyclinics (QUP), Qassim, Kingdom of Saudi Arabia (KSA).  A cross-sectional descriptive study conducted at QUP, Qassim, KSA, during the period November 2014 and December 2015. The record files of the study patients who were sampled by convenience method, were reviewed and analyzed. A standardized questionnaire was designed by the authors to collect data from the patients' records. Percentage descriptive statistics were used for data analysis.   A total of 115 patients were studied. Males were 61.8%. The age range was 1.5-83 years (mean 42.3). The predominant age group was 31-60 years (59.4%). The identified top 5 diseases were: hypertension 40 (34.7%), diabetes mellitus 39 (33.9%), dyslipidemia 17 (14.7%), vitamin D deficiency 13 (11.3%), and arthritic disease 6 (5.2%).  Non-communicable diseases, in the present study, were the common causes for patients to attend QUP, Qassim, KSA. Changing lifestyle of the population is one possible explanation for such a trend. Prospective studies are advisable toward an in-depth understanding of this trend.

Effects of climate change on polar bears.

PubMed

Wiig, Øystein; Aars, Jon; Born, Erik W

2008-01-01

In this article, we review the effects on polar bears of global warming that have already been observed, and try to evaluate what may happen to the polar bears in the future. Many researchers have predicted a wide range of impacts of climate change on polar bear demography and conditions. A predicted major reduction in sea ice habitat will reduce the availability of ice associated seals, the main prey of polar bears, and a loss and fragmentation of polar bear habitat will ultimately lead to large future reductions in most subpopulations. It is likely that polar bears will be lost from many areas where they are common today and also that the total population will change into a few more distinctly isolated populations.

Complexity and demographic explanations of cumulative culture.

PubMed

Querbes, Adrien; Vaesen, Krist; Houkes, Wybo

2014-01-01

Formal models have linked prehistoric and historical instances of technological change (e.g., the Upper Paleolithic transition, cultural loss in Holocene Tasmania, scientific progress since the late nineteenth century) to demographic change. According to these models, cumulation of technological complexity is inhibited by decreasing--while favoured by increasing--population levels. Here we show that these findings are contingent on how complexity is defined: demography plays a much more limited role in sustaining cumulative culture in case formal models deploy Herbert Simon's definition of complexity rather than the particular definitions of complexity hitherto assumed. Given that currently available empirical evidence doesn't afford discriminating proper from improper definitions of complexity, our robustness analyses put into question the force of recent demographic explanations of particular episodes of cultural change.

An integrated map of structural variation in 2,504 human genomes.

PubMed

Sudmant, Peter H; Rausch, Tobias; Gardner, Eugene J; Handsaker, Robert E; Abyzov, Alexej; Huddleston, John; Zhang, Yan; Ye, Kai; Jun, Goo; Fritz, Markus Hsi-Yang; Konkel, Miriam K; Malhotra, Ankit; Stütz, Adrian M; Shi, Xinghua; Casale, Francesco Paolo; Chen, Jieming; Hormozdiari, Fereydoun; Dayama, Gargi; Chen, Ken; Malig, Maika; Chaisson, Mark J P; Walter, Klaudia; Meiers, Sascha; Kashin, Seva; Garrison, Erik; Auton, Adam; Lam, Hugo Y K; Mu, Xinmeng Jasmine; Alkan, Can; Antaki, Danny; Bae, Taejeong; Cerveira, Eliza; Chines, Peter; Chong, Zechen; Clarke, Laura; Dal, Elif; Ding, Li; Emery, Sarah; Fan, Xian; Gujral, Madhusudan; Kahveci, Fatma; Kidd, Jeffrey M; Kong, Yu; Lameijer, Eric-Wubbo; McCarthy, Shane; Flicek, Paul; Gibbs, Richard A; Marth, Gabor; Mason, Christopher E; Menelaou, Androniki; Muzny, Donna M; Nelson, Bradley J; Noor, Amina; Parrish, Nicholas F; Pendleton, Matthew; Quitadamo, Andrew; Raeder, Benjamin; Schadt, Eric E; Romanovitch, Mallory; Schlattl, Andreas; Sebra, Robert; Shabalin, Andrey A; Untergasser, Andreas; Walker, Jerilyn A; Wang, Min; Yu, Fuli; Zhang, Chengsheng; Zhang, Jing; Zheng-Bradley, Xiangqun; Zhou, Wanding; Zichner, Thomas; Sebat, Jonathan; Batzer, Mark A; McCarroll, Steven A; Mills, Ryan E; Gerstein, Mark B; Bashir, Ali; Stegle, Oliver; Devine, Scott E; Lee, Charles; Eichler, Evan E; Korbel, Jan O

2015-10-01

Structural variants are implicated in numerous diseases and make up the majority of varying nucleotides among human genomes. Here we describe an integrated set of eight structural variant classes comprising both balanced and unbalanced variants, which we constructed using short-read DNA sequencing data and statistically phased onto haplotype blocks in 26 human populations. Analysing this set, we identify numerous gene-intersecting structural variants exhibiting population stratification and describe naturally occurring homozygous gene knockouts that suggest the dispensability of a variety of human genes. We demonstrate that structural variants are enriched on haplotypes identified by genome-wide association studies and exhibit enrichment for expression quantitative trait loci. Additionally, we uncover appreciable levels of structural variant complexity at different scales, including genic loci subject to clusters of repeated rearrangement and complex structural variants with multiple breakpoints likely to have formed through individual mutational events. Our catalogue will enhance future studies into structural variant demography, functional impact and disease association.

Property structures, demography and the crisis of the agrarian economy of colonial Bombay Presidency.

PubMed

Kaiwar, V

1992-01-01

Reasons for the relative failure of agricultural development in India during the colonial period are analyzed, and the effects of the scarcity of capital, the absence of suitable technology, and the growth of the population are assessed. "The article explores the manner in which peasant possession of land and other means of subsistence limited productive utilisation of capital and technology, triggered a certain demographic regime and, in turn, disrupted further developmental possibilities." The geographical focus is on the area coinciding with the modern states of Maharashtra and Gujarat. excerpt

[Population, ethics and equity].

PubMed

Berlinguer, G

1997-01-01

"Demography is, explicitly and not, imbued with an [ethical] content.... As demography involves both public policies and individual choices, the [ethical] slant should be [examined]. Thus, what we have on the one hand is an [ethical] state, which dictates its citizens' personal behaviour and, on the other, a state based on liberty, backed up by three shared values: human rights, pluralism and equality. This article looks at how today these may be reinterpreted when making decisions regarding the population." (EXCERPT)

Altered resource availability and the population dynamics of tree species in Amazonian secondary forests.

PubMed

Fortini, Lucas Berio; Bruna, Emilio M; Zarin, Daniel J; Vasconcelos, Steel S; Miranda, Izildinha S

2010-04-01

Despite research demonstrating that water and nutrient availability exert strong effects on multiple ecosystem processes in tropical forests, little is known about the effect of these factors on the demography and population dynamics of tropical trees. Over the course of 5 years, we monitored two common Amazonian secondary forest species-Lacistema pubescens and Myrcia sylvatica-in dry-season irrigation, litter-removal and control plots. We then evaluated the effects of altered water and nutrient availability on population demography and dynamics using matrix models and life table response experiments. Our results show that despite prolonged experimental manipulation of water and nutrient availability, there were nearly no consistent and unidirectional treatment effects on the demography of either species. The patterns and significance of observed treatment effects were largely dependent on cross-year variability not related to rainfall patterns, and disappeared once we pooled data across years. Furthermore, most of these transient treatment effects had little effect on population growth rates. Our results suggest that despite major experimental manipulations of water and nutrient availability-factors considered critical to the ecology of tropical pioneer tree species-autogenic light limitation appears to be the primary regulator of tree demography at early/mid successional stages. Indeed, the effects of light availability may completely override those of other factors thought to influence the successional development of Amazonian secondary forests.

Demographic drivers of age-dependent sexual selection.

PubMed

Martin, A M; Festa-Bianchet, M; Coltman, D W; Pelletier, F

2016-07-01

Sexual selection has a critical role in evolution, and it is fundamental to identify what ecological factors drive its variation. Disentangling the ecological correlates of sexual selection over the long term, however, is challenging and has rarely been done in nature. We sought to assess how demographic changes influenced the intensity, direction and form of sexual selection and whether selective pressures varied with age. We tested whether breeder sex ratio, number of competitors and age structure influenced selection differentials on horn length of wild bighorn rams (Ovis canadensis) of different age classes on Ram Mountain, Alberta. We used 21 years of data including a detailed pedigree, demographic parameters and repeated morphological measurements. Sexual selection on horn length of males of all ages was directional and positive. Selection intensity increased with the number of competitors, reflecting male-male encounter rate during the rut, but was independent of breeder sex ratio or age structure. This result can also be linked to changes in population size because the number of competitors was highly correlated to total number of sheep. This demographic effect likely arises from age-dependent mating tactics. Males aged 2-4 years are weakly competitive and experienced stronger sexual selection as they accounted for a greater proportion of all males. Selection experienced by mature males appeared independent of demography. Our study provides a rare description of the demographic determinants of sexual selection in nature. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

Scaling Forest Management Practices in Earth System Models: Case Study of Southeast and Pacific Northwest Forests

NASA Astrophysics Data System (ADS)

Pourmokhtarian, A.; Becknell, J. M.; Hall, J.; Desai, A. R.; Boring, L. R.; Duffy, P.; Staudhammer, C. L.; Starr, G.; Dietze, M.

2014-12-01

A wide array of human-induced disturbances can alter the structure and function of forests, including climate change, disturbance and management. While there have been numerous studies on climate change impacts on forests, interactions of management with changing climate and natural disturbance are poorly studied. Forecasts of the range of plausible responses of forests to climate change and management are need for informed decision making on new management approaches under changing climate, as well as adaptation strategies for coming decades. Terrestrial biosphere models (TBMs) provide an excellent opportunity to investigate and assess simultaneous responses of terrestrial ecosystems to climatic perturbations and management across multiple spatio-temporal scales, but currently do not represent a wide array of management activities known to impact carbon, water, surface energy fluxes, and biodiversity. The Ecosystem Demography model 2 (ED2) incorporates non-linear impacts of fine-scale (~10-1 km) heterogeneity in ecosystem structure both horizontally and vertically at a plant level. Therefore it is an ideal candidate to incorporate different forest management practices and test various hypotheses under changing climate and across various spatial scales. The management practices that we implemented were: clear-cut, conversion, planting, partial harvest, low intensity fire, restoration, salvage, and herbicide. The results were validated against observed data across 8 different sites in the U.S. Southeast (Duke Forest, Joseph Jones Ecological Research Center, North Carolina Loblolly Pine, and Ordway-Swisher Biological Station) and Pacific Northwest (Metolius Research Natural Area, H.J. Andrews Experimental Forest, Wind River Field Station, and Mount Rainier National Park). These sites differ in regards to climate, vegetation, soil, and historical land disturbance as well as management approaches. Results showed that different management practices could successfully and realistically be implemented in the ED2 model at a site level. Moreover, sensitivity analyses determined the most important processes at different spatial scales, and also those which could be ignored while minimizing overall error.

Modeling multiple resource limitation in tropical dry forests

NASA Astrophysics Data System (ADS)

Medvigy, D.; Xu, X.; Zarakas, C.

2015-12-01

Tropical dry forests (TDFs) are characterized by a long dry season when little rain falls. At the same time, many neotropical soils are highly weathered and relatively nutrient poor. Because TDFs are often subject to both water and nutrient constraints, the question of how they will respond to environmental perturbations is both complex and highly interesting. Models, our basic tools for projecting ecosystem responses to global change, can be used to address this question. However, few models have been specifically parameterized for TDFs. Here, we present a new version of the Ecosystem Demography 2 (ED2) model that includes a new parameterization of TDFs. In particular, we focus on the model's framework for representing limitation by multiple resources (carbon, water, nitrogen, and phosphorus). Plant functional types are represented in terms of a dichotomy between "acquisitive" and "conservative" resource acquisition strategies. Depending on their resource acquisition strategy and basic stoichiometry, plants can dynamically adjust their allocation to organs (leaves, stem, roots), symbionts (e.g. N2-fixing bacteria), and mycorrhizal fungi. Several case studies are used to investigate how resource acquisition strategies affect ecosystem responses to environmental perturbations. Results are described in terms of the basic setting (e.g., rich vs. poor soils; longer vs. shorter dry season), and well as the type and magnitude of environmental perturbation (e.g., changes in precipitation or temperature; changes in nitrogen deposition). Implications for ecosystem structure and functioning are discussed.

Direct and indirect effects of climate on demography and early growth of Pinus sylvestris at the rear edge: changing roles of biotic and abiotic factors.

PubMed

Benavides, Raquel; Rabasa, Sonia G; Granda, Elena; Escudero, Adrián; Hódar, José A; Martínez-Vilalta, Jordi; Rincón, Ana M; Zamora, Regino; Valladares, Fernando

2013-01-01

Global change triggers shifts in forest composition, with warming and aridification being particularly threatening for the populations located at the rear edge of the species distributions. This is the case of Scots pine (Pinus sylvestris) in the Mediterranean Basin where uncertainties in relation to its dynamics under these changing scenarios are still high. We analysed the relative effect of climate on the recruitment patterns of Scots pine and its interactions with local biotic and abiotic variables at different spatial scales. Number of seedlings and saplings was surveyed, and their annual shoot growth measured in 96 plots located across altitudinal gradients in three different regions in the Iberian Peninsula. We found a significant influence of climate on demography and performance of recruits, with a non-linear effect of temperature on the presence of juveniles, and a positive effect of precipitation on their survival. Abundance of juveniles of P. sylvestris that underwent their first summer drought was skewed towards higher altitudes than the altitudinal mean range of the conspecific adults and the optimum elevation for seedlings' emergence. At local level, light availability did not influence juveniles' density, but it enhanced their growth. Biotic interactions were found between juveniles and the herb cover (competition) and between the number of newly emerged seedlings and shrubs (facilitation). Results also highlighted the indirect effect that climate exerts over the local factors, modulating the interactions with the pre-existing vegetation that were more evident at more stressful sites. This multiscale approach improves our understanding of the dynamics of these marginal populations and some management criteria can be inferred to boost their conservation under the current global warming.

Climatic conditions produce contrasting influences on demographic traits in a long-distance Arctic migrant.

PubMed

Cleasby, Ian R; Bodey, Thomas W; Vigfusdottir, Freydis; McDonald, Jenni L; McElwaine, Graham; Mackie, Kerry; Colhoun, Kendrew; Bearhop, Stuart

2017-03-01

The manner in which patterns of variation and interactions among demographic rates contribute to population growth rate (λ) is key to understanding how animal populations will respond to changing climatic conditions. Migratory species are likely to be particularly sensitive to climatic conditions as they experience a range of different environments throughout their annual cycle. However, few studies have provided fully integrated demographic analyses of migratory populations in response to changing climatic conditions. Here, we employed integrated population models to demonstrate that the environmental conditions experienced during a short but critical period play a central role in the demography of a long-distance migrant, the light-bellied Brent goose (Branta bernicla hrota). Female survival was positively associated with June North Atlantic Oscillation (NAO) values, whereas male survival was not. In contrast, breeding productivity was negatively associated with June NAO, suggesting a trade-off between female survival and reproductive success. Both adult female and adult male survival showed low temporal variation, whereas there was high temporal variation in recruitment and breeding productivity. In addition, while annual population growth was positively correlated with annual breeding productivity, a sensitivity analysis revealed that population growth was most sensitive to changes in adult survival. Our results demonstrate that the environmental conditions experienced during a relatively short-time window at the start of the breeding season play a critical role in shaping the demography of a long-distant Arctic migrant. Crucially, different demographic rates responded in opposing directions to climatic variation, emphasising the need for integrated analysis of multiple demographic traits when understanding population dynamics. © 2016 The Authors. Journal of Animal Ecology © 2016 British Ecological Society.

Process-based modeling of species' responses to climate change - a proof of concept using western North American trees

NASA Astrophysics Data System (ADS)

Evans, M. E.; Merow, C.; Record, S.; Menlove, J.; Gray, A.; Cundiff, J.; McMahon, S.; Enquist, B. J.

2013-12-01

Current attempts to forecast how species' distributions will change in response to climate change suffer under a fundamental trade-off: between modeling many species superficially vs. few species in detail (between correlative vs. mechanistic models). The goals of this talk are two-fold: first, we present a Bayesian multilevel modeling framework, dynamic range modeling (DRM), for building process-based forecasts of many species' distributions at a time, designed to address the trade-off between detail and number of distribution forecasts. In contrast to 'species distribution modeling' or 'niche modeling', which uses only species' occurrence data and environmental data, DRMs draw upon demographic data, abundance data, trait data, occurrence data, and GIS layers of climate in a single framework to account for two processes known to influence range dynamics - demography and dispersal. The vision is to use extensive databases on plant demography, distributions, and traits - in the Botanical Information and Ecology Network, the Forest Inventory and Analysis database (FIA), and the International Tree Ring Data Bank - to develop DRMs for North American trees. Second, we present preliminary results from building the core submodel of a DRM - an integral projection model (IPM) - for a sample of dominant tree species in western North America. IPMs are used to infer demographic niches - i.e., the set of environmental conditions under which population growth rate is positive - and project population dynamics through time. Based on >550,000 data points derived from FIA for nine tree species in western North America, we show IPM-based models of their current and future distributions, and discuss how IPMs can be used to forecast future forest productivity, mortality patterns, and inform efforts at assisted migration.

Red River barrier and Pleistocene climatic fluctuations shaped the genetic structure of Microhyla fissipes complex (Anura: Microhylidae) in southern China and Indochina

PubMed Central

Yuan, Zhi-Yong; Suwannapoom, Chatmongkon; Yan, Fang; Poyarkov, Nikolay A.; Nguyen, Sang Ngoc; Chen, Hong-man; Chomdej, Siriwadee; Murphy, Robert W.

2016-01-01

South China and Indochina host striking species diversity and endemism. Complex tectonic and climatic evolutions appear to be the main drivers of the biogeographic patterns. In this study, based on the geologic history of this region, we test 2 hypotheses using the evolutionary history of Microhyla fissipes species complex. Using DNA sequence data from both mitochondrial and nuclear genes, we first test the hypothesis that the Red River is a barrier to gene flow and dispersal. Second, we test the hypothesis that Pleistocene climatic cycling affected the genetic structure and population history of these frogs. We detect 2 major genetic splits that associate with the Red River. Time estimation suggests that late Miocene tectonic movement associated with the Red River drove their diversification. Species distribution modeling (SDM) resolves significant ecological differences between sides of the Red River. Thus, ecological divergence also probably promoted and maintained the diversification. Genogeography, historical demography, and SDM associate patterns in southern China with climate changes of the last glacial maximum (LGM), but not Indochina. Differences in geography and climate between the 2 areas best explain the discovery. Responses to the Pleistocene glacial–interglacial cycling vary among species and regions. PMID:29491943

Yellow-bellied marmots: insights from an emergent view of sociality.

PubMed

Blumstein, Daniel T

2013-05-19

Ecological factors explain variation in sociality both within and between species of marmots-large alpine ground squirrels. Fifty years of study, by me and my colleagues, of the yellow-bellied marmots (Marmota flaviventris) at the Rocky Mountain Biological Laboratory, near Crested Butte, CO, USA, has created opportunities to see how sociality changes with population and group size. Over the past decades, we have witnessed a natural experiment whereby the population tripled in size. If we view sociality as an emergent process, then demography acts as a constraint on interactions between individuals, and the threefold increase in population size should have consequences for group structure. We have used social network statistics to study the causes and consequences of social interactions by capitalizing on this demographic variation. Such an emergent view is ideally studied in an integrative Tinbergian way that focuses on both mechanism and function. We have determined that some social attributes are heritable, that social cohesion is established through age and kin structure, that well-embedded females (but not males) are less likely to disperse, and that there are fitness consequences of social attributes. Together, this integrative relationship-centred view expands on the traditional ecological model of sociality and offers a framework that can be applied to other systems.

Red River barrier and Pleistocene climatic fluctuations shaped the genetic structure of Microhyla fissipes complex (Anura: Microhylidae) in southern China and Indochina.

PubMed

Yuan, Zhi-Yong; Suwannapoom, Chatmongkon; Yan, Fang; Poyarkov, Nikolay A; Nguyen, Sang Ngoc; Chen, Hong-Man; Chomdej, Siriwadee; Murphy, Robert W; Che, Jing

2016-12-01

South China and Indochina host striking species diversity and endemism. Complex tectonic and climatic evolutions appear to be the main drivers of the biogeographic patterns. In this study, based on the geologic history of this region, we test 2 hypotheses using the evolutionary history of Microhyla fissipes species complex. Using DNA sequence data from both mitochondrial and nuclear genes, we first test the hypothesis that the Red River is a barrier to gene flow and dispersal. Second, we test the hypothesis that Pleistocene climatic cycling affected the genetic structure and population history of these frogs. We detect 2 major genetic splits that associate with the Red River. Time estimation suggests that late Miocene tectonic movement associated with the Red River drove their diversification. Species distribution modeling (SDM) resolves significant ecological differences between sides of the Red River. Thus, ecological divergence also probably promoted and maintained the diversification. Genogeography, historical demography, and SDM associate patterns in southern China with climate changes of the last glacial maximum (LGM), but not Indochina. Differences in geography and climate between the 2 areas best explain the discovery. Responses to the Pleistocene glacial-interglacial cycling vary among species and regions.

Yellow-bellied marmots: insights from an emergent view of sociality

PubMed Central

Blumstein, Daniel T.

2013-01-01

Ecological factors explain variation in sociality both within and between species of marmots—large alpine ground squirrels. Fifty years of study, by me and my colleagues, of the yellow-bellied marmots (Marmota flaviventris) at the Rocky Mountain Biological Laboratory, near Crested Butte, CO, USA, has created opportunities to see how sociality changes with population and group size. Over the past decades, we have witnessed a natural experiment whereby the population tripled in size. If we view sociality as an emergent process, then demography acts as a constraint on interactions between individuals, and the threefold increase in population size should have consequences for group structure. We have used social network statistics to study the causes and consequences of social interactions by capitalizing on this demographic variation. Such an emergent view is ideally studied in an integrative Tinbergian way that focuses on both mechanism and function. We have determined that some social attributes are heritable, that social cohesion is established through age and kin structure, that well-embedded females (but not males) are less likely to disperse, and that there are fitness consequences of social attributes. Together, this integrative relationship-centred view expands on the traditional ecological model of sociality and offers a framework that can be applied to other systems. PMID:23569297

Multilocus nuclear DNA markers reveal population structure and demography of Anopheles minimus.

PubMed

Dixit, Jyotsana; Arunyawat, Uraiwan; Huong, Ngo Thi; Das, Aparup

2014-11-01

Utilization of multiple putatively neutral DNA markers for inferring evolutionary history of species population is considered to be the most robust approach. Molecular population genetic studies have been conducted in many species of Anopheles genus, but studies based on single nucleotide polymorphism (SNP) data are still very scarce. Anopheles minimus is one of the principal malaria vectors of Southeast (SE) Asia including the Northeastern (NE) India. Although population genetic studies with mitochondrial genetic variation data have been utilized to infer phylogeography of the SE Asian populations of this species, limited information on the population structure and demography of Indian An. minimus is available. We herewith have developed multilocus nuclear genetic approach with SNP markers located in X chromosome of An. minimus in eight Indian and two SE Asian population samples (121 individual mosquitoes in total) to infer population history and test several hypotheses on the phylogeography of this species. While the Thai population sample of An. minimus presented the highest nucleotide diversity, majority of the Indian samples were also fairly diverse. In general, An. minimus populations were moderately substructured in the distribution range covering SE Asia and NE India, largely falling under three distinct genetic clusters. Moreover, demographic expansion events could be detected in the majority of the presently studied populations of An. minimus. Additional DNA sequencing of the mitochondrial COII region in a subset of the samples (40 individual mosquitoes) corroborated the existing hypothesis of Indian An. minimus falling under the earlier reported mitochondrial lineage B. © 2014 John Wiley & Sons Ltd.

Adaptive responses and disruptive effects: how major wildfire influences kinship-based social interactions in a forest marsupial.

PubMed

Banks, Sam C; Blyton, Michaela D J; Blair, David; McBurney, Lachlan; Lindenmayer, David B

2012-02-01

Environmental disturbance is predicted to play a key role in the evolution of animal social behaviour. This is because disturbance affects key factors underlying social systems, such as demography, resource availability and genetic structure. However, because natural disturbances are unpredictable there is little information on their effects on social behaviour in wild populations. Here, we investigated how a major wildfire affected cooperation (sharing of hollow trees) by a hollow-dependent marsupial. We based two alternative social predictions on the impacts of fire on population density, genetic structure and resources. We predicted an adaptive social response from previous work showing that kin selection in den-sharing develops as competition for den resources increases. Thus, kin selection should occur in burnt areas because the fire caused loss of the majority of hollow-bearing trees, but no detectable mortality. Alternatively, fire may have a disruptive social effect, whereby postfire home range-shifts 'neutralize' fine-scale genetic structure, thereby removing opportunities for kin selection between neighbours. Both predictions occurred: the disruptive social effect in burnt habitat and the adaptive social response in adjacent unburnt habitat. The latter followed a massive demographic influx to unburnt 'refuge' habitat that increased competition for dens, leading to a density-related kin selection response. Our results show remarkable short-term plasticity of animal social behaviour and demonstrate how the social effects of disturbance extend into undisturbed habitat owing to landscape-scale demographic shifts. We predicted long-term changes in kinship-based cooperative behaviour resulting from the genetic and resource impacts of forecast changes to fire regimes in these forests. © 2011 Blackwell Publishing Ltd.

Scale-dependent portfolio effects explain growth inflation and volatility reduction in landscape demography

PubMed Central

2017-01-01

Population demography is central to fundamental ecology and for predicting range shifts, decline of threatened species, and spread of invasive organisms. There is a mismatch between most demographic work, carried out on few populations and at local scales, and the need to predict dynamics at landscape and regional scales. Inspired by concepts from landscape ecology and Markowitz’s portfolio theory, we develop a landscape portfolio platform to quantify and predict the behavior of multiple populations, scaling up the expectation and variance of the dynamics of an ensemble of populations. We illustrate this framework using a 35-y time series on gypsy moth populations. We demonstrate the demography accumulation curve in which the collective growth of the ensemble depends on the number of local populations included, highlighting a minimum but adequate number of populations for both regional-scale persistence and cross-scale inference. The attainable set of landscape portfolios further suggests tools for regional population management for both threatened and invasive species. PMID:29109261

Demography and the shaping of Israel's borders.

PubMed

Soffer, A

1989-01-01

"This paper will show that the demographic map of the Land of Israel in its present form is essentially the principal factor in shaping the extent of Jewish settlement in this generation, and that there is little possibility of changing this pattern except for making small and insignificant adjustments." The author describes the changing demographic picture in Palestine from the late nineteenth century to the present day, particularly changes in the ethnic composition of the population. He concludes that the presence of a majority Arab population in the Occupied Territories of Judea, Samaria, and the Gaza Strip will oblige Israel to compromise with regard to granting cultural and political autonomy. Furthermore, three large Arab enclaves in Israel proper--Galilee, the triangle, and the Bedouin Negev--will have to be given up if current settlement patterns do not radically change, which is itself unlikely. excerpt

Genetic variation and evolutionary demography of Fenneropenaeus chinensis populations, as revealed by the analysis of mitochondrial control region sequences

PubMed Central

2010-01-01

Genetic variation and evolutionary demography of the shrimp Fenneropenaeus chinensis were investigated using sequence data of the complete mitochondrial control region (CR). Fragments of 993 bp of the CR were sequenced for 93 individuals from five localities over most of the species' range in the Yellow Sea and the Bohai Sea. There were 84 variable sites defining 68 haplotypes. Haplotype diversity levels were very high (0.95 ± 0.03-0.99 ± 0.02) in F. chinensis populations, whereas those of nucleotide diversity were moderate to low (0.66 ± 0.36%-0.84 ± 0.46%). Analysis of molecular variance and conventional population statistics (FST ) revealed no significant genetic structure throughout the range of F. chinensis. Mismatch distribution, estimates of population parameters and neutrality tests revealed that the significant fluctuations and shallow coalescence of mtDNA genealogies observed were coincident with estimated demographic parameters and neutrality tests, in implying important past-population size fluctuations or range expansion. Isolation with Migration (IM) coalescence results suggest that F. chinensis, distributed along the coasts of northern China and the Korean Peninsula (about 1000 km apart), diverged recently, the estimated time-split being 12,800 (7,400-18,600) years ago. PMID:21637498

"Sustaining the Shrinking City: Concepts, Dynamics and ...

EPA Pesticide Factsheets

Sustainability can be broadly defined as the resilient outcome of the interaction among social equity, economic stability, and environmental quality factors. For example, the utilization of natural resource capitals are constrained by economic forces, and further modulated by social norms and perceptions. Nowhere is this more apparent than in cities, where the social, economic and environmental capital within the city and in its supporting region may wax and wane due to internal dynamics and external drivers. These changes may be charted as shifts in land use, the type and qualities of infrastructure, population and its demography, and other characteristics that drive the trajectory of a city toward shrinkage. Our authors will discuss how fluxes of different capitals (social, cultural, financial, technological, natural resources, governance/political) might align or substitute for each other to create conditions in the structure and function of city to attain a sustainable size after undergoing a rapid depopulation. Other authors focus on how the misalignment of capitals can doom a city to shrink uncontrollably, and in combination with shifts in environmental quality, the may destroy a city’s ability to function as an integrative center for social and economic interactions. We see this special issue as an attractive venue for data-based research on environmental factors as they impact change in the socio-cultural, economic, political, and physiographic feature

Interfaith education: A new model for today's interfaith families

NASA Astrophysics Data System (ADS)

Gordon, Sheila C.; Arenstein, Benjamin

2017-04-01

With societal changes rapidly transforming cultures that had been largely homogenous, today's multi-cultural - and in particular interfaith - families need new educational strategies to help them understand their cultural roots and identify and clarify what aspects of their heritages they wish to nurture and transmit to their children. This paper focuses on a new model for religious education, namely non-doctrinaire "dual-faith" education, which the principal author has helped to develop in the United States (US) through the Interfaith Community (IFC), a small, independent non-profit organisation created and led by dual-faith Jewish/Christian families. The model is premised on the notion that families can have two different faiths in one household and that - with respect and education - families can be harmonious, religion can be transmitted, and tolerance broadly nurtured. While the model is particular to the US and to families with Jewish and Christian heritages, its premises and structure have significant potential to be adaptable to other religious combinations and other cultures and countries. After reviewing relevant literature and situating the IFC model in the global and US contexts, the paper sets out to clarify the importance of the concept, describe its elements, and discuss its implications for religious education in this time of changing ethos and demography.

Asymmetric changes of growth and reproductive investment herald altitudinal and latitudinal range shifts of two woody species.

PubMed

Matías, Luis; Jump, Alistair S

2015-02-01

Ongoing changes in global climate are altering ecological conditions for many species. The consequences of such changes are typically most evident at the edge of the geographical distribution of a species, where range expansions or contractions may occur. Current demographical status at geographical range limits can help us to predict population trends and their implications for the future distribution of the species. Thus, understanding the comparability of demographical patterns occurring along both altitudinal and latitudinal gradients would be highly informative. In this study, we analyse the differences in the demography of two woody species through altitudinal gradients at their southernmost distribution limit and the consistency of demographical patterns at the treeline across a latitudinal gradient covering the complete distribution range. We focus on Pinus sylvestris and Juniperus communis, assessing their demographical structure (density, age and mortality rate), growth, reproduction investment and damage from herbivory on 53 populations covering the upper, central and lower altitudes as well as the treeline at central latitude and northernmost and southernmost latitudinal distribution limits. For both species, populations at the lowermost altitude presented older age structure, higher mortality, decreased growth and lower reproduction when compared to the upper limit, indicating higher fitness at the treeline. This trend at the treeline was generally maintained through the latitudinal gradient, but with a decreased growth at the northern edge for both species and lower reproduction for P. sylvestris. However, altitudinal and latitudinal transects are not directly comparable as factors other than climate, including herbivore pressure or human management, must be taken into account if we are to understand how to infer latitudinal processes from altitudinal data. © 2014 John Wiley & Sons Ltd.

Spatial and temporal dynamics of fucoid populations (Ascophyllum nodosum and Fucus serratus): a comparison between central and range edge populations.

PubMed

Araújo, Rita M; Serrão, Ester A; Sousa-Pinto, Isabel; Åberg, Per

2014-01-01

Persistence of populations at range edges relies on local population dynamics and fitness, in the case of geographically isolated populations of species with low dispersal potential. Focusing on spatial variations in demography helps to predict the long-term capability for persistence of populations across the geographical range of species' distribution. The demography of two ecological and phylogenetically close macroalgal species with different life history characteristics was investigated by using stochastic, stage-based matrix models. Populations of Ascophyllum nodosum and Fucus serratus were sampled for up to 4 years at central locations in France and at their southern range limits in Portugal. The stochastic population growth rate (λ(s)) of A. nodosum was lower and more variable in central than in southern sites whilst for F. serratus this trend was reversed with λ(s) much lower and more variable in southern than in central populations. Individuals were larger in central than in southern populations for both species, which was reflected in the lower transition probabilities of individuals to larger size classes and higher probability of shrinkage in the southern populations. In both central and southern populations elasticity analysis (proportional sensitivity) of population growth rate showed that fertility elements had a small contribution to λ(s) that was more sensitive to changes in matrix transitions corresponding to survival. The highest elasticities were found for loop transitions in A. nodosum and for growth to larger size classes in F. serratus. Sensitivity analysis showed high selective pressure on individual growth for both species at both locations. The results of this study highlight the deterministic role of species-specific life-history traits in population demography across the geographical range of species. Additionally, this study demonstrates that individuals' life-transitions differ in vulnerability to environmental variability and shows the importance of vegetative compared to reproductive stages for the long-term persistence of populations.

Demography, Education, and Democracy: global trends and the case of Iran.

PubMed

Lutz, Wolfgang; Cuaresma, Jesús Crespo; Abbasi-Shavazi, Mohammad Jalal

2010-01-01

Reconstructions and projections of populations by age, sex, and educational attainment for 120 countries since 1970 are used to assess the global relationship between improvements in human capital and democracy. Democracy is measured by the Freedom House indicator of political rights. Similar to an earlier study on the effects of improving educational attainment on economic growth, the greater age detail of this new dataset resolves earlier ambiguities about the effect of improving education as assessed using a global set of national time series. The results show consistently strong effects of improving overall levels of educational attainment, of a narrowing gender gap in education, and of fertility declines and the subsequent changes in age structure on improvements in the democracy indicator. This global relationship is then applied to the Islamic Republic of Iran. Over the past two decades Iran has experienced the world's most rapid fertility decline associated with massive increases in female education. The results show that based on the experience of 120 countries since 1970, Iran has a high chance of significant movement toward more democracy over the following two decades.

Complexity and Demographic Explanations of Cumulative Culture

PubMed Central

Querbes, Adrien; Vaesen, Krist; Houkes, Wybo

2014-01-01

Formal models have linked prehistoric and historical instances of technological change (e.g., the Upper Paleolithic transition, cultural loss in Holocene Tasmania, scientific progress since the late nineteenth century) to demographic change. According to these models, cumulation of technological complexity is inhibited by decreasing— while favoured by increasing—population levels. Here we show that these findings are contingent on how complexity is defined: demography plays a much more limited role in sustaining cumulative culture in case formal models deploy Herbert Simon's definition of complexity rather than the particular definitions of complexity hitherto assumed. Given that currently available empirical evidence doesn't afford discriminating proper from improper definitions of complexity, our robustness analyses put into question the force of recent demographic explanations of particular episodes of cultural change. PMID:25048625

Understanding the biological underpinnings of ecohydrological processes

NASA Astrophysics Data System (ADS)

Huxman, T. E.; Scott, R. L.; Barron-Gafford, G. A.; Hamerlynck, E. P.; Jenerette, D.; Tissue, D. T.; Breshears, D. D.; Saleska, S. R.

2012-12-01

Climate change presents a challenge for predicting ecosystem response, as multiple factors drive both the physical and life processes happening on the land surface and their interactions result in a complex, evolving coupled system. For example, changes in surface temperature and precipitation influence near-surface hydrology through impacts on system energy balance, affecting a range of physical processes. These changes in the salient features of the environment affect biological processes and elicit responses along the hierarchy of life (biochemistry to community composition). Many of these structural or process changes can alter patterns of soil water-use and influence land surface characteristics that affect local climate. Of the many features that affect our ability to predict the future dynamics of ecosystems, it is this hierarchical response of life that creates substantial complexity. Advances in the ability to predict or understand aspects of demography help describe thresholds in coupled ecohydrological system. Disentangling the physical and biological features that underlie land surface dynamics following disturbance are allowing a better understanding of the partitioning of water in the time-course of recovery. Better predicting the timing of phenology and key seasonal events allow for a more accurate description of the full functional response of the land surface to climate. In addition, explicitly considering the hierarchical structural features of life are helping to describe complex time-dependent behavior in ecosystems. However, despite this progress, we have yet to build an ability to fully account for the generalization of the main features of living systems into models that can describe ecohydrological processes, especially acclimation, assembly and adaptation. This is unfortunate, given that many key ecosystem services are functions of these coupled co-evolutionary processes. To date, both the lack of controlled measurements and experimentation has precluded determination of sufficient theoretical development. Understanding the land-surface response and feedback to climate change requires a mechanistic understanding of the coupling of ecological and hydrological processes and an expansion of theory from the life sciences to appropriately contribute to the broader Earth system science goal.

Demography of a population collapse: the Northern Idaho ground squirrel (Spermophilus brunneus brunneus)

USGS Publications Warehouse

Sherman, P.W.; Runge, M.C.

2002-01-01

We studied the demography of a population of Northern Idaho ground squirrels (Spermophilus brunneus brunneus) in Adams Co., Idaho. The population was completely censused yearly from 1987 to 1999, during which time it declined from 272 to 10 animals. The finite population growth rate, based on a Leslie matrix model of average life-history parameters, was only 0.72 (i.e., significantly <1.0). Growth rate was more sensitive to proportional changes in juvenile female survival than to any other single life-history parameter. Comparisons with self-sustaining populations of closely related ground squirrel species revealed that juvenile survival and breeding rates of yearling females were anomalously low. We believe that the ultimate cause of the population's collapse was inadequacy of food resources, particularly seeds, due to drying of the habitat and changes in plant species composition, likely the result of fire suppression and grazing. No 'rescue' by immigration occurred, probably because S. b. brunneus seldom disperse long distances and fire suppression has allowed conifers to encroach on inhabited meadows, shrinking them and closing dispersal routes. The proximate cause of the population's collapse was mortality of older breeding females, which reduced the mean age of breeders. Younger females had lower average pregnancy rates and litter sizes. To place our results in context we developed a new, general classification of anthropogenic population declines, based on whether they are caused by changes in the means of the life-history parameters (blatant disturbances), their variances (inappropriate variations), or the correlations among them (evolutionary traps). Many S. b. brunneus populations have disappeared in recent years, apparently due to blatant disturbances, especially loss of habitat and changes in food-plant composition, resulting in inadequate prehibernation nutrition and starvation overwinter. In addition, our study population may have been caught in an evolutionary trap, because the vegetational cues that could potentially enable the animals to adjust reproduction to the anticipated food supply no longer correlate with availability of fat-laden seeds.

Organization of the Saudi health system.

PubMed

Al-Yousuf, M; Akerele, T M; Al-Mazrou, Y Y

2002-01-01

Using existing data, we reviewed the organizational structure of the Saudi Arabian health system: its demography and history, principal health indicators, organization and management, type and distribution of facilities, financial base, and the impact on it of the Haj. We noted duplication of services, inadequate coordination between some health industry sectors, and the need for a more extensive and rational health centre network with improved information systems and data collection. We also noted scope for a greater role for the private health sector and increased cooperation between it and the public sector to improve health service delivery and population health.

A PHENOMENOLOGICAL STUDY OF DELUSIONS IN SCHIZOPHRENIA

PubMed Central

Kulhara, P.; Chandiramani, K.; Mattoo, S.K.; Awasthi, A.

1986-01-01

SUMMARY 112 patients with final clinical diagnosis of schizophrenia were subjected to detailed mental sums examination using, a structured interview schedule the present state examination. Phenomenology of delusions was determined according to the definitions and criteria of this schedule. The relationships of phenomenology will) socio-demography variables were also studied. It was seen that delusions of persecution were significantly more in males and in patients above the age of 30 years. Educated patients had more delusional misinterpretation, delusions of references and delusions of thoughts being read. Systematization of delusions was more in younger patients. Married patients had more delusions of reference. PMID:21927190

Mountain landscapes offer few opportunities for high-elevation tree species migration

USGS Publications Warehouse

Bell, David M.; Bradford, John B.; Lauenroth, William K.

2014-01-01

Climate change is anticipated to alter plant species distributions. Regional context, notably the spatial complexity of climatic gradients, may influence species migration potential. While high-elevation species may benefit from steep climate gradients in mountain regions, their persistence may be threatened by limited suitable habitat as land area decreases with elevation. To untangle these apparently contradictory predictions for mountainous regions, we evaluated the climatic suitability of four coniferous forest tree species of the western United States based on species distribution modeling (SDM) and examined changes in climatically suitable areas under predicted climate change. We used forest structural information relating to tree species dominance, productivity, and demography from an extensive forest inventory system to assess the strength of inferences made with a SDM approach. We found that tree species dominance, productivity, and recruitment were highest where climatic suitability (i.e., probability of species occurrence under certain climate conditions) was high, supporting the use of predicted climatic suitability in examining species risk to climate change. By predicting changes in climatic suitability over the next century, we found that climatic suitability will likely decline, both in areas currently occupied by each tree species and in nearby unoccupied areas to which species might migrate in the future. These trends were most dramatic for high elevation species. Climatic changes predicted over the next century will dramatically reduce climatically suitable areas for high-elevation tree species while a lower elevation species, Pinus ponderosa, will be well positioned to shift upslope across the region. Reductions in suitable area for high-elevation species imply that even unlimited migration would be insufficient to offset predicted habitat loss, underscoring the vulnerability of these high-elevation species to climatic changes.

The human core of the shared socioeconomic pathways: Population scenarios by age, sex and level of education for all countries to 2100.

PubMed

Kc, Samir; Lutz, Wolfgang

2017-01-01

This paper applies the methods of multi-dimensional mathematical demography to project national populations based on alternative assumptions on future, fertility, mortality, migration and educational transitions that correspond to the five shared socioeconomic pathways (SSP) storylines. In doing so it goes a significant step beyond past population scenarios in the IPCC context which considered only total population size. By differentiating the human population not only by age and sex-as is conventionally done in demographic projections-but also by different levels of educational attainment the most fundamental aspects of human development and social change are being explicitly addressed through modeling the changing composition of populations by these three important individual characteristics. The scenarios have been defined in a collaborative effort of the international Integrated Assessment Modeling community with the medium scenario following that of a major new effort by the Wittgenstein Centre for Demography and Global Human Capital (IIASA, OEAW, WU) involving over 550 experts from around the world. As a result, in terms of total world population size the trajectories resulting from the five SSPs stay very close to each other until around 2030 and by the middle of the century already a visible differentiation appears with the range between the highest (SSP3) and the lowest (SSP1) trajectories spanning 1.5 billion. The range opens up much more with the SSP3 reaching 12.6 billion in 2100 and SSP1 falling to 6.9 billion which is lower than today's world population.

Climate change and the effects of temperature extremes on Australian flying-foxes.

PubMed

Welbergen, Justin A; Klose, Stefan M; Markus, Nicola; Eby, Peggy

2008-02-22

Little is known about the effects of temperature extremes on natural systems. This is of increasing concern now that climate models predict dramatic increases in the intensity, duration and frequency of such extremes. Here we examine the effects of temperature extremes on behaviour and demography of vulnerable wild flying-foxes (Pteropus spp.). On 12 January 2002 in New South Wales, Australia, temperatures exceeding 42 degrees C killed over 3500 individuals in nine mixed-species colonies. In one colony, we recorded a predictable sequence of thermoregulatory behaviours (wing-fanning, shade-seeking, panting and saliva-spreading, respectively) and witnessed how 5-6% of bats died from hyperthermia. Mortality was greater among the tropical black flying-fox, Pteropus alecto (10-13%) than the temperate grey-headed flying-fox, Pteropus poliocephalus (less than 1%), and young and adult females were more affected than adult males (young, 23-49%; females, 10-15%; males, less than 3%). Since 1994, over 30000 flying-foxes (including at least 24500 P. poliocephalus) were killed during 19 similar events. Although P. alecto was relatively less affected, it is currently expanding its range into the more variable temperature envelope of P. poliocephalus, which increases the likelihood of die-offs occurring in this species. Temperature extremes are important additional threats to Australian flying-foxes and the ecosystem services they provide, and we recommend close monitoring of colonies where temperatures exceeding 42.0 degrees C are predicted. The effects of temperature extremes on flying-foxes highlight the complex implications of climate change for behaviour, demography and species survival.

Age and growth of the mutton hamlet Alphestes afer, with a review of the size and age of sex change among epinephelids.

PubMed

Marques, S; Ferreira, B P

2016-07-01

This paper presents results on the age, growth and population structure of a small grouper, the mutton hamlet Alphestes afer, and discusses the observed size and age structure patterns in relation to reproductive strategies among the epinephelids. Ages were determined by examination of sectioned otoliths, which showed a distinct pattern of alternating translucent and opaque zones that formed annually, as validated with tetracycline labelling. The von Bertalanffy growth function was adjusted to the length-at-age data of the males and females, but no significant differences were observed between the resulting parameters. The females, however, were older at given sizes and attained larger sizes and ages, with a maximum observed longevity of 13 years and a total length (LT ) of 26 cm, while the males attained maximum longevities of only 10 years and a 22 cm maximum LT . The LT and age range for the sex change was 16-25 cm and 3-11 years. The total mortality rate (Z) was estimated to be 0·55 for females and 0·82 for males. With the males younger and smaller than the females, this species differed from the pattern commonly observed for protogynous epinephelids. Males had slower growth after maturation, probably due to energy allocation to sperm production during sexual development. This study shows that demography is an important tool to understand the pathways for reproductive strategies in grouper populations. © 2016 The Fisheries Society of the British Isles.

Historical demography of common carp estimated from individuals collected from various parts of the world using the pairwise sequentially markovian coalescent approach.

PubMed

Yuan, Zihao; Huang, Wei; Liu, Shikai; Xu, Peng; Dunham, Rex; Liu, Zhanjiang

2018-04-01

The inference of historical demography of a species is helpful for understanding species' differentiation and its population dynamics. However, such inference has been previously difficult due to the lack of proper analytical methods and availability of genetic data. A recently developed method called Pairwise Sequentially Markovian Coalescent (PSMC) offers the capability for estimation of the trajectories of historical populations over considerable time periods using genomic sequences. In this study, we applied this approach to infer the historical demography of the common carp using samples collected from Europe, Asia and the Americas. Comparison between Asian and European common carp populations showed that the last glacial period starting 100 ka BP likely caused a significant decline in population size of the wild common carp in Europe, while it did not have much of an impact on its counterparts in Asia. This was probably caused by differences in glacial activities in East Asia and Europe, and suggesting a separation of the European and Asian clades before the last glacial maximum. The North American clade which is an invasive population shared a similar demographic history as those from Europe, consistent with the idea that the North American common carp probably had European ancestral origins. Our analysis represents the first reconstruction of the historical population demography of the common carp, which is important to elucidate the separation of European and Asian common carp clades during the Quaternary glaciation, as well as the dispersal of common carp across the world.

Distinct population structure for co-occurring Anopheles goeldii and Anopheles triannulatus in Amazonian Brazil

PubMed Central

McKeon, Sascha Naomi; Moreno, Marta; Sallum, Maria Anise; Povoa, Marinete Marins; Conn, Jan Evelyn

2013-01-01

To evaluate whether environmental heterogeneity contributes to the genetic heterogeneity in Anopheles triannulatus, larval habitat characteristics across the Brazilian states of Roraima and Pará and genetic sequences were examined. A comparison with Anopheles goeldii was utilised to determine whether high genetic diversity was unique to An. triannulatus. Student t test and analysis of variance found no differences in habitat characteristics between the species. Analysis of population structure of An. triannulatus and An. goeldii revealed distinct demographic histories in a largely overlapping geographic range. Cytochrome oxidase I sequence parsimony networks found geographic clustering for both species; however nuclear marker networks depicted An. triannulatus with a more complex history of fragmentation, secondary contact and recent divergence. Evidence of Pleistocene expansions suggests both species are more likely to be genetically structured by geographic and ecological barriers than demography. We hypothesise that niche partitioning is a driving force for diversity, particularly in An. triannulatus. PMID:23903977

Mitochondrial population genomic analyses reveal population structure and demography of Indian Plasmodium falciparum.

PubMed

Tyagi, Suchi; Das, Aparup

2015-09-01

Inference on the genetic diversity of Plasmodium falciparum populations could help in better management of malaria. A very recent study with mitochondrial (mt) genomes in global P. falciparum had revealed interesting evolutionary genetic patterns of Indian isolates in comparison to global ones. However, no population genetic study using the whole mt genome sequences of P. falciparum isolates collected in the entire distribution range in India has yet been performed. We herewith have analyzed 85 whole mt genomes (48 already published and 37 entirely new) sampled from eight differentially endemic Indian locations to estimate genetic diversity and infer population structure and historical demography of Indian P. falciparum. We found 19 novel Indian-specific Single Nucleotide Polymorphisms (SNPs) and 22 novel haplotypes segregating in Indian P. falciparum. Accordingly, high haplotype and nucleotide diversities were detected in Indian P. falciparum in comparison to many other global isolates. Indian P. falciparum populations were found to be moderately sub-structured with four different genetic clusters. Interestingly, group of local populations aggregate to form each cluster; while samples from Jharkhand and Odisha formed a single cluster, P. falciparum isolates from Asom formed an independent one. Similarly, Surat, Bilaspur and Betul formed a single cluster and Goa and Mangalore formed another. Interestingly, P. falciparum isolates from the two later populations were significantly genetically differentiated from isolates collected in other six Indian locations. Signature of historical population expansion was evident in five population samples, and the onset of expansion event was found to be very similar to African P. falciparum. In agreement with the previous finding, the estimated Time to Most Recent Common Ancestor (TMRCA) and the effective population size were high in Indian P. falciparum. All these genetic features of Indian P. falciparum with high mt genome diversity are somehow similar to Africa, but quite different from other Asian population samples. Copyright © 2015 © Elsevier B.V. and Mitochondria Research Society. Published by Elsevier B.V. All rights reserved.

Selective logging: does the imprint remain on tree structure and composition after 45 years?

PubMed

Osazuwa-Peters, Oyomoare L; Chapman, Colin A; Zanne, Amy E

2015-01-01

Selective logging of tropical forests is increasing in extent and intensity. The duration over which impacts of selective logging persist, however, remains an unresolved question, particularly for African forests. Here, we investigate the extent to which a past selective logging event continues to leave its imprint on different components of an East African forest 45 years later. We inventoried 2358 stems ≥10 cm in diameter in 26 plots (200 m × 10 m) within a 5.2 ha area in Kibale National Park, Uganda, in logged and unlogged forest. In these surveys, we characterized the forest light environment, taxonomic composition, functional trait composition using three traits (wood density, maximum height and maximum diameter) and forest structure based on three measures (stem density, total basal area and total above-ground biomass). In comparison to unlogged forests, selectively logged forest plots in Kibale National Park on average had higher light levels, different structure characterized by lower stem density, lower total basal area and lower above-ground biomass, and a distinct taxonomic composition driven primarily by changes in the relative abundance of species. Conversely, selectively logged forest plots were like unlogged plots in functional composition, having similar community-weighted mean values for wood density, maximum height and maximum diameter. This similarity in functional composition irrespective of logging history may be due to functional recovery of logged forest or background changes in functional attributes of unlogged forest. Despite the passage of 45 years, the legacy of selective logging on the tree community in Kibale National Park is still evident, as indicated by distinct taxonomic and structural composition and reduced carbon storage in logged forest compared with unlogged forest. The effects of selective logging are exerted via influences on tree demography rather than functional trait composition.

Selective logging: does the imprint remain on tree structure and composition after 45 years?

PubMed Central

Osazuwa-Peters, Oyomoare L.; Chapman, Colin A.; Zanne, Amy E.

2015-01-01

Selective logging of tropical forests is increasing in extent and intensity. The duration over which impacts of selective logging persist, however, remains an unresolved question, particularly for African forests. Here, we investigate the extent to which a past selective logging event continues to leave its imprint on different components of an East African forest 45 years later. We inventoried 2358 stems ≥10 cm in diameter in 26 plots (200 m × 10 m) within a 5.2 ha area in Kibale National Park, Uganda, in logged and unlogged forest. In these surveys, we characterized the forest light environment, taxonomic composition, functional trait composition using three traits (wood density, maximum height and maximum diameter) and forest structure based on three measures (stem density, total basal area and total above-ground biomass). In comparison to unlogged forests, selectively logged forest plots in Kibale National Park on average had higher light levels, different structure characterized by lower stem density, lower total basal area and lower above-ground biomass, and a distinct taxonomic composition driven primarily by changes in the relative abundance of species. Conversely, selectively logged forest plots were like unlogged plots in functional composition, having similar community-weighted mean values for wood density, maximum height and maximum diameter. This similarity in functional composition irrespective of logging history may be due to functional recovery of logged forest or background changes in functional attributes of unlogged forest. Despite the passage of 45 years, the legacy of selective logging on the tree community in Kibale National Park is still evident, as indicated by distinct taxonomic and structural composition and reduced carbon storage in logged forest compared with unlogged forest. The effects of selective logging are exerted via influences on tree demography rather than functional trait composition. PMID:27293697

Past climate change and recent anthropogenic activities affect genetic structure and population demography of the greater long-tailed hamster in northern China.

PubMed

Ye, Junbin; Xiao, Zhenlong; Li, Chuanhai; Wang, Fusheng; Liao, Jicheng; Fu, Jinzhong; Zhang, Zhibin

2015-09-01

The genetic diversity and the spatial structure of a species are likely consequences of both past and recent evolutionary processes, but relevant studies are still rare in East Asia where the Pleistocene climate has unique influences. In this study, we examined the impact of past climate change and recent anthropogenic activities on the genetic structure and population size of the greater long-tailed hamster (Tscherskia triton), an agricultural rodent pest species in northern China. DNA sequence data of 2 mitochondrial genes and genotypic data of 11 microsatellite DNA loci from 41 populations (545 individuals) were gathered. Phylogenetic and population genetic analyses, as well as species distribution modeling and coalescent simulations, were conducted to infer its historical and demographic patterns and processes. Two deeply diverged mitochondrial clades were recovered. A small one was restricted to the Shandong Peninsula while the main clade was further divided into 3 geographic clusters by their microsatellite DNA genotypes: Northwest, North-center and Northeast. Divergence dating indicated a Middle-to-Late Pleistocene divergence between the 2 clades. Demographic analysis indicated that all 3 and pooled populations showed consistent long-period expansions during last glacial period; but not during the Holocene, probably due to the impact of climate warming and human disturbances. Conflicting patterns between mtDNA and microsatellite markers imply an anthropogenic impact on North-center populations due to intensified agricultural cultivation in this region. Our study demonstrated that the impact of past glaciation on organisms in East Asia significantly differs from that of Europe and North America, and human activity is an important factor in determining the genetic diversity of a species, as well as its spatial structure. © 2015 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and Wiley Publishing Asia Pty Ltd.

The carbon debt from Amazon forest degradation: integrating airborne lidar, field measurements, and an ecosystem demography model.

NASA Astrophysics Data System (ADS)

Longo, M.; Keller, M. M.; dos-Santos, M. N.; Scaranello, M. A., Sr.; Pinagé, E. R.; Leitold, V.; Morton, D. C.

2016-12-01

Amazon deforestation has declined over the last decade, yet forest degradation from logging, fire, and fragmentation continue to impact forest carbon stocks and fluxes. The magnitude of this impact remains uncertain, and observation-based studies are often limited by short time intervals or small study areas. To better understand the long-term impact of forest degradation and recovery, we have been developing a framework that integrates field plot measurements and airborne lidar surveys into an individual- and process-based model (Ecosystem Demography model, ED). We modeled forest dynamics for three forest landscapes in the Amazon with diverse degradation histories: conventional and reduced-impact logging, logging and burning, and multiple burns. Based on the initialization with contemporary forest structure and composition, model results suggest that degraded forests rapidly recover (30 years) water and energy fluxes compared with old-growth, even at sites that were affected by multiple fires. However, degraded forests maintained different carbon stocks and fluxes even after 100 years without further disturbances, because of persistent differences in forest structure and composition. Recurrent disturbances may hinder the recovery of degraded forests. Simulations using a simple fire model entirely dependent on environmental controls indicate that the most degraded forests would take much longer to reach biomass typical of old-growth forests, because drier conditions near the ground make subsequent fires more intense and more recurrent. Fires in tropical forests are also closely related to nearby human activities; while results suggest an important feedback between fires and the microenvironment, additional work is needed to improve how the model represents the human impact on current and future fire regimes. Our study highlights that recovery of degraded forests may act as an important carbon sink, but efficient recovery depends on controlling future disturbances.

Population Structure and Historical Demography of the Oriental River Prawn (Macrobrachium nipponense) in Taiwan

PubMed Central

Chu, Ta-Jen; Wang, Daryi; Lee, Ying-Chou; Tzeng, Tzong-Der

2015-01-01

The oriental river prawn (Macrobrachium nipponense) is a non-obligatory amphidromous prawn, and it has a wide distribution covering almost the entire Taiwan. Mitochondrial DNA fragment sequences of the cytochrome oxidase subunit I (COI) and 16S rRNA were combined and used to elucidate the population structure and historical demography of oriental river prawn in Taiwan. A total of 202 individuals from six reservoirs and three estuaries were separately collected. Nucleotide diversity (π) of all populations was 0.01217, with values ranging from 0.00188 (Shihmen Reservoir, SMR, northern Taiwan) to 0.01425 (Mingte Reservoir, MTR, west-central Taiwan). All 76 haplotypes were divided into 2 lineages: lineage A included individuals from all sampling areas except SMR, and lineage B included specimens from all sampling locations except Chengching Lake Reservoir (CLR) and Liyu Lake Reservoir (LLR). All F ST values among nine populations were significantly different except the one between Jhonggang River Estuary (JGE, west-central Taiwan) and Kaoping River Estuary (KPE, southern Taiwan). UPGMA tree of nine populations showed two main groups: the first group included the SMR and Tamsui River Estuary (TSE) (both located northern Taiwan), and the second one included the other seven populations (west-central, southern and eastern Taiwan). Demographic analyses implied a population expansion occurred during the recent history of the species. The dispersal route of this species might be from China to west-central and west-southern Taiwan, and then the part individuals belonging to lineage A and B dispersed southerly and northerly, respectively. And then part individuals in west-central Taiwan fell back to and stay at estuaries as the sea level rose about 18,000 years ago. PMID:26716687

Population Structure and Historical Demography of the Oriental River Prawn (Macrobrachium nipponense) in Taiwan.

PubMed

Chen, Po-Cheng; Shih, Chun-Han; Chu, Ta-Jen; Wang, Daryi; Lee, Ying-Chou; Tzeng, Tzong-Der

2015-01-01

The oriental river prawn (Macrobrachium nipponense) is a non-obligatory amphidromous prawn, and it has a wide distribution covering almost the entire Taiwan. Mitochondrial DNA fragment sequences of the cytochrome oxidase subunit I (COI) and 16S rRNA were combined and used to elucidate the population structure and historical demography of oriental river prawn in Taiwan. A total of 202 individuals from six reservoirs and three estuaries were separately collected. Nucleotide diversity (π) of all populations was 0.01217, with values ranging from 0.00188 (Shihmen Reservoir, SMR, northern Taiwan) to 0.01425 (Mingte Reservoir, MTR, west-central Taiwan). All 76 haplotypes were divided into 2 lineages: lineage A included individuals from all sampling areas except SMR, and lineage B included specimens from all sampling locations except Chengching Lake Reservoir (CLR) and Liyu Lake Reservoir (LLR). All FST values among nine populations were significantly different except the one between Jhonggang River Estuary (JGE, west-central Taiwan) and Kaoping River Estuary (KPE, southern Taiwan). UPGMA tree of nine populations showed two main groups: the first group included the SMR and Tamsui River Estuary (TSE) (both located northern Taiwan), and the second one included the other seven populations (west-central, southern and eastern Taiwan). Demographic analyses implied a population expansion occurred during the recent history of the species. The dispersal route of this species might be from China to west-central and west-southern Taiwan, and then the part individuals belonging to lineage A and B dispersed southerly and northerly, respectively. And then part individuals in west-central Taiwan fell back to and stay at estuaries as the sea level rose about 18,000 years ago.

The demographic consequences of growing older and bigger in oyster populations.

PubMed

Moore, Jacob L; Lipcius, Romuald N; Puckett, Brandon; Schreiber, Sebastian J

2016-10-01

Structured population models, particularly size- or age-structured, have a long history of informing conservation and natural resource management. While size is often easier to measure than age and is the focus of many management strategies, age-structure can have important effects on population dynamics that are not captured in size-only models. However, relatively few studies have included the simultaneous effects of both age- and size-structure. To better understand how population structure, particularly that of age and size, impacts restoration and management decisions, we developed and compared a size-structured integral projection model (IPM) and an age- and size-structured IPM, using a population of Crassostrea gigas oysters in the northeastern Pacific Ocean. We analyzed sensitivity of model results across values of local retention that give populations decreasing in size to populations increasing in size. We found that age- and size-structured models yielded the best fit to the demographic data and provided more reliable results about long-term demography. Elasticity analysis showed that population growth rate was most sensitive to changes in the survival of both large (>175 mm shell length) and small (<75 mm shell length) oysters, indicating that a maximum size limit, in addition to a minimum size limit, could be an effective strategy for maintaining a sustainable population. In contrast, the purely size-structured model did not detect the importance of large individuals. Finally, patterns in stable age and stable size distributions differed between populations decreasing in size due to limited local retention and populations increasing in size due to high local retention. These patterns can be used to determine population status and restoration success. The methodology described here provides general insight into the necessity of including both age- and size-structure into modeling frameworks when using population models to inform restoration and management decisions. © 2016 by the Ecological Society of America.

Projecting the need for hip replacement over the next three decades: influence of changing demography and threshold for surgery

PubMed Central

Birrell, F.; Johnell, O.; Silman, A.

1999-01-01

OBJECTIVES—To estimate the requirement for total hip replacement in the United Kingdom over the next three decades
METHODS—Projection of age and sex specific hip replacements in the UK over 10 year intervals taking account of demographic change and the extrapolation of arthroplasty rates from Sweden; a country with recently introduced guidelines.
RESULTS—Assuming no change in the age and sex specific arthroplasty rates, the estimated number of hip replacements will increase by 40% over the next 30 year period because of demographic change alone. The proportionate change will be substantially higher in men (51%) than women (33%), with a doubling of the number of male hip replacements in those aged over 85. Changes in the threshold for surgery may increase this further—up to double the current number.
CONCLUSION—A sharp rise in hip replacements will be needed to satisfy needs in the UK population over the next 30 years.

 PMID:10460191

What Kids Get from Parents: Packages of Parental Involvement across Complex Family Forms

PubMed Central

Carlson, Marcia J.

2013-01-01

While demographers have continued to document the notable family changes that have occurred in recent decades, the nature of family functioning across diverse family forms is less well understood. In particular, we know little about the level and quality of parental investment that children receive across a range of contemporary family types. In this paper, we use data from a recent U.S. urban birth cohort to examine the ‘package’ of parental involvement that young children receive in two key domains across family types. We aggregate parent-child engagement across three potential parent(-figures)—biological mothers, biological fathers (resident or non-resident), and resident social fathers—and also assess the child’s household income. We examine parental investments at child age 5 and changes in investments between child ages 1 and 5 by family structure categories. Overall, we find that children living with both of their married biological parents are advantaged with respect to both economic resources and parental engagement, while children living with single mothers—or their mother and a cohabiting social father—fare especially poorly in both domains; children in married social-father families receive higher overall levels of parental engagement than those in biological-father families but are much less economically advantaged. Our research sheds light on how changing family demography is related to parental investments in children, which may have implications for public policies designed to support disadvantaged families. PMID:24644373

Toward a gender politics of aging.

PubMed

Carney, Gemma M

2018-01-01

The article proposes a Gender Politics of Aging approach to the study of aging societies. The approach recognizes the feminization of old age, ageism's roots in sexist discourse, and the need to recognize the role of politics in driving demographic debates. Drawing together arguments from feminist gerontology and political demography, the article argues that the intersection of politics and gender must be considered if appropriate responses to an older, feminized demography are to be produced. I conclude that the work of aging feminists provides a rich vein of research and praxis from which a gender politics of aging approach can draw.

Predation risk affects reproductive physiology and demography of elk.

PubMed

Creel, Scott; Christianson, David; Liley, Stewart; Winnie, John A

2007-02-16

Elk (Cervus elaphus) in the Greater Yellowstone Ecosystem alter patterns of aggregation, habitat selection, vigilance, and foraging in the presence of wolves (Canis lupus). Antipredator behaviors like these can reduce predation risk but are also likely to carry costs. Data from five elk populations studied for 16 site years showed that progesterone concentrations (from 1489 fecal samples) declined with the ratio of elk to wolves. In turn, progesterone concentrations were a good predictor of calf recruitment in the subsequent year. Together, these data suggest that wolves indirectly affect the reproductive physiology and the demography of elk through the costs of antipredator behavior.

The Fifteenth International Congress on Hygiene and Demography Held in Washington, D. C. from September 16 to October 5. 1912. I. Some Lessons and Suggestions from the Exhibition; II. Digests of Some of the Papers Presented at the Congress. Bulletin, 1913, No. 18. Whole Number 528

ERIC Educational Resources Information Center

Dresslar, Fletcher B.

1913-01-01

The Fifteenth International Congress on Hygiene and Demography, held in Washington City in the autumn of 1912, was a notable event in the history of sanitation and in the discussion of the conditions of the physical and mental health of the people. The exhibition held in connection with the congress was instructive in many ways, and contained much…

Genetic structuring and recent demographic history of red pandas (Ailurus fulgens) inferred from microsatellite and mitochondrial DNA.

PubMed

Hu, Yibo; Guo, Yu; Qi, Dunwu; Zhan, Xiangjiang; Wu, Hua; Bruford, Michael W; Wei, Fuwen

2011-07-01

Clarification of the genetic structure and population history of a species can shed light on the impacts of landscapes, historical climate change and contemporary human activities and thus enables evidence-based conservation decisions for endangered organisms. The red panda (Ailurus fulgens) is an endangered species distributing at the edge of the Qinghai-Tibetan Plateau and is currently subject to habitat loss, fragmentation and population decline, thus representing a good model to test the influences of the above-mentioned factors on a plateau edge species. We combined nine microsatellite loci and 551 bp of mitochondrial control region (mtDNA CR) to explore the genetic structure and demographic history of this species. A total of 123 individuals were sampled from 23 locations across five populations. High levels of genetic variation were identified for both mtDNA and microsatellites. Phylogeographic analyses indicated little geographic structure, suggesting historically wide gene flow. However, microsatellite-based Bayesian clustering clearly identified three groups (Qionglai-Liangshan, Xiaoxiangling and Gaoligong-Tibet). A significant isolation-by-distance pattern was detected only after removing Xiaoxiangling. For mtDNA data, there was no statistical support for a historical population expansion or contraction for the whole sample or any population except Xiaoxiangling where a signal of contraction was detected. However, Bayesian simulations of population history using microsatellite data did pinpoint population declines for Qionglai, Xiaoxiangling and Gaoligong, demonstrating significant influences of human activity on demography. The unique history of the Xiaoxiangling population plays a critical role in shaping the genetic structure of this species, and large-scale habitat loss and fragmentation is hampering gene flow among populations. The implications of our findings for the biogeography of the Qinghai-Tibetan Plateau, subspecies classification and conservation of red pandas are discussed. © 2011 Blackwell Publishing Ltd.

Population Genetic Structure and Demographic History of Atrina pectinata Based on Mitochondrial DNA and Microsatellite Markers

PubMed Central

Xue, Dong-Xiu; Wang, Hai-Yan; Zhang, Tao; Liu, Jin-Xian

2014-01-01

The pen shell, Atrina pectinata, is one of the commercial bivalves in East Asia and thought to be recently affected by anthropogenic pressure (habitat destruction and/or fishing pressure). Information on its population genetic structure is crucial for the conservation of A. pectinata. Considering its long pelagic larval duration and iteroparity with high fecundity, the genetic structure for A. pectinata could be expected to be weak at a fine scale. However, the unusual oceanography in the coasts of China and Korea suggests potential for restricted dispersal of pelagic larvae and geographical differentiation. In addition, environmental changes associated with Pleistocene sea level fluctuations on the East China Sea continental shelf may also have strongly influenced historical population demography and genetic diversity of marine organisms. Here, partial sequences of the mitochondrial Cytochrome c oxidase subunit I (COI) gene and seven microsatellite loci were used to estimate population genetic structure and demographic history of seven samples from Northern China coast and one sample from North Korea coast. Despite high levels of genetic diversity within samples, there was no genetic differentiation among samples from Northern China coast and low but significant genetic differentiation between some of the Chinese samples and the North Korean sample. A late Pleistocene population expansion, probably after the Last Glacial Maximum, was also demonstrated for A. pectinata samples. No recent genetic bottleneck was detected in any of the eight samples. We concluded that both historical recolonization (through population range expansion and demographic expansion in the late Pleistocene) and current gene flow (through larval dispersal) were responsible for the weak level of genetic structure detected in A. pectinata. PMID:24789175

Chinstrap penguin population genetic structure: one or more populations along the Southern Ocean?

PubMed

Mura-Jornet, Isidora; Pimentel, Carolina; Dantas, Gisele P M; Petry, Maria Virginia; González-Acuña, Daniel; Barbosa, Andrés; Lowther, Andrew D; Kovacs, Kit M; Poulin, Elie; Vianna, Juliana A

2018-06-13

Historical factors, demography, reproduction and dispersal are crucial in determining the genetic structure of seabirds. In the Antarctic marine environment, penguins are a major component of the avian biomass, dominant predators and important bioindicators of ecological change. Populations of chinstrap penguins have decreased in nearly all their breeding sites, and their range is expanding throughout the Antarctic Peninsula. Population genetic structure of this species has been studied in some colonies, but not between breeding colonies in the Antarctic Peninsula or at the species' easternmost breeding colony (Bouvetøya). Connectivity, sex-biased dispersal, diversity, genetic structure and demographic history were studied using 12 microsatellite loci and a mitochondrial DNA region (HVRI) in 12 breeding colonies in the South Shetland Islands (SSI) and the Western Antarctic Peninsula (WAP), and one previously unstudied sub-Antarctic island, 3600 km away from the WAP (Bouvetøya). High genetic diversity, evidence of female bias-dispersal and a sign of population expansion after the last glacial maximum around 10,000 mya were detected. Limited population genetic structure and lack of isolation by distance throughout the region were found, along with no differentiation between the WAP and Bouvetøya (overall microsatellite F ST  = 0.002, p = 0.273; mtDNA F ST  = - 0.004, p = 0.766), indicating long distance dispersal. Therefore, genetic assignment tests could not assign individuals to their population(s) of origin. The most differentiated location was Georges Point, one of the southernmost breeding colonies of this species in the WAP. The subtle differentiation found may be explained by some combination of low natal philopatric behavior, high rates of dispersal and/or generally high mobility among colonies of chinstrap penguins compared to other Pygoscelis species.

The demography of aging in the industrializing portion of the Pacific rim: a case for gender justice.

PubMed

Cowart, M E; Serow, W J

1995-05-01

The authors examine the impact of probable future trends in demographic aging on women's roles in the newly industrializing countries of the Pacific Rim (in Southeastern and east Asia). They also suggest that women will in all probability be expected to cope with additional household and family responsibilities due to demographic aging at a time when they are trying to change gender status and improve gender equity, and that these growing responsibilities could severely handicap women's efforts to play a larger role in the economy and in policy making.

Design for mosquito abundance, diversity, and phenology sampling within the National Ecological Observatory Network

USGS Publications Warehouse

Hoekman, D.; Springer, Yuri P.; Barker, C.M.; Barrera, R.; Blackmore, M.S.; Bradshaw, W.E.; Foley, D. H.; Ginsberg, Howard; Hayden, M. H.; Holzapfel, C. M.; Juliano, S. A.; Kramer, L. D.; LaDeau, S. L.; Livdahl, T. P.; Moore, C. G.; Nasci, R.S.; Reisen, W.K.; Savage, H. M.

2016-01-01

The National Ecological Observatory Network (NEON) intends to monitor mosquito populations across its broad geographical range of sites because of their prevalence in food webs, sensitivity to abiotic factors and relevance for human health. We describe the design of mosquito population sampling in the context of NEON’s long term continental scale monitoring program, emphasizing the sampling design schedule, priorities and collection methods. Freely available NEON data and associated field and laboratory samples, will increase our understanding of how mosquito abundance, demography, diversity and phenology are responding to land use and climate change.

A population-based longitudinal study on the implications of demographics on future blood supply.

PubMed

Greinacher, Andreas; Weitmann, Kerstin; Lebsa, Anne; Alpen, Ulf; Gloger, Doris; Stangenberg, Wolfgang; Kiefel, Volker; Hoffmann, Wolfgang

2016-12-01

Changes in demographics with increases in older age groups and decreases in younger age groups imply an increased demand for blood transfusions paralleled by a decrease in the population eligible for blood donation. However, more restrictive transfusion triggers and the patient blood management initiative also reduce the demand for red blood cells (RBCs). Eastern Germany is a model region for the impact of demographic changes, which manifest in this region approximately 10 years earlier than in other regions due to the 50% birth rate decline after 1989. We report the 2010 longitudinal 5-year follow-up of the study assessing all whole blood donations and RBC transfusions in Mecklenburg-West Pomerania. We compared the projections that were made 5 years ago with: 1) the current age structure of the blood donor and transfusion recipient populations and 2) its impact on blood demand and blood donation numbers in specific age groups. Transfusion rates were lower and blood donation rates were higher than predicted in 2005. Although transfusion rates/1000 decreased in nearly all age groups, the overall annual transfusion rate increased to 66.4 RBC units/1000 (in 2005, 62.2/1000) due to the absolute increase in the elderly population. Despite a 7.4% decline in the population 18 to 65 years of age, whole blood donations increased by 11.7% between 2005 and 2010, but thereafter decreased by 21% (first-time donors by 39.4%), reflecting the effect of the post-1990 birth rate decline on the donor population. Changes in demography and medical practice impact the delicate balance between available blood supply and potential future transfusion needs. In times of pronounced demographic changes, regular monitoring of the blood demand and age structure of blood recipients and donors is required to allow strategic planning to prevent blood shortages or overproduction. © 2016 AABB.

Frequency-dependent population dynamics: effect of sex ratio and mating system on the elasticity of population growth rate.

PubMed

Haridas, C V; Eager, Eric Alan; Rebarber, Richard; Tenhumberg, Brigitte

2014-11-01

When vital rates depend on population structure (e.g., relative frequencies of males or females), an important question is how the long-term population growth rate λ responds to changes in rates. For instance, availability of mates may depend on the sex ratio of the population and hence reproductive rates could be frequency-dependent. In such cases change in any vital rate alters the structure, which in turn, affect frequency-dependent rates. We show that the elasticity of λ to a rate is the sum of (i) the effect of the linear change in the rate and (ii) the effect of nonlinear changes in frequency-dependent rates. The first component is always positive and is the classical elasticity in density-independent models obtained directly from the population projection matrix. The second component can be positive or negative and is absent in density-independent models. We explicitly express each component of the elasticity as a function of vital rates, eigenvalues and eigenvectors of the population projection matrix. We apply this result to a two-sex model, where male and female fertilities depend on adult sex ratio α (ratio of females to males) and the mating system (e.g., polygyny) through a harmonic mating function. We show that the nonlinear component of elasticity to a survival rate is negligible only when the average number of mates (per male) is close to α. In a strictly monogamous species, elasticity to female survival is larger than elasticity to male survival when α<1 (less females). In a polygynous species, elasticity to female survival can be larger than that of male survival even when sex ratio is female biased. Our results show how demography and mating system together determine the response to selection on sex-specific vital rates. Copyright © 2014 Elsevier Inc. All rights reserved.

Changing Amazon biomass and the role of atmospheric CO2 concentration, climate, and land use

NASA Astrophysics Data System (ADS)

Almeida Castanho, Andrea D.; Galbraith, David; Zhang, Ke; Coe, Michael T.; Costa, Marcos H.; Moorcroft, Paul

2016-01-01

The Amazon tropical evergreen forest is an important component of the global carbon budget. Its forest floristic composition, structure, and function are sensitive to changes in climate, atmospheric composition, and land use. In this study biomass and productivity simulated by three dynamic global vegetation models (Integrated Biosphere Simulator, Ecosystem Demography Biosphere Model, and Joint UK Land Environment Simulator) for the period 1970-2008 are compared with observations from forest plots (Rede Amazónica de Inventarios Forestales). The spatial variability in biomass and productivity simulated by the DGVMs is low in comparison to the field observations in part because of poor representation of the heterogeneity of vegetation traits within the models. We find that over the last four decades the CO2 fertilization effect dominates a long-term increase in simulated biomass in undisturbed Amazonian forests, while land use change in the south and southeastern Amazonia dominates a reduction in Amazon aboveground biomass, of similar magnitude to the CO2 biomass gain. Climate extremes exert a strong effect on the observed biomass on short time scales, but the models are incapable of reproducing the observed impacts of extreme drought on forest biomass. We find that future improvements in the accuracy of DGVM predictions will require improved representation of four key elements: (1) spatially variable plant traits, (2) soil and nutrients mediated processes, (3) extreme event mortality, and (4) sensitivity to climatic variability. Finally, continued long-term observations and ecosystem-scale experiments (e.g. Free-Air CO2 Enrichment experiments) are essential for a better understanding of the changing dynamics of tropical forests.

Comorbid post-traumatic stress disorder in alcohol use disorder: relationships to demography, drinking and neuroimmune profile.

PubMed

Neupane, Sudan Prasad; Bramness, Jørgen G; Lien, Lars

2017-08-29

This study examined how alcohol use disorder (AUD) patients with post-traumatic stress disorder (PTSD) differed from those without PTSD in terms of demography, drinking patterns and C-reactive protein, inflammatory cytokines, tryptophan metabolism parameters, and brain-derived neurotrophic factor (BDNF). A consecutive sample (N = 187) of treatment-receiving AUD individuals were recruited from Nepalese facilities. They underwent fully structured psychiatric interviews. Serum levels of inflammatory cytokines [interleukin (IL)-6, IL-1 Receptor antagonist (IL-1Ra), IL-10, tumor necrosis factor-alpha (TNF-α), and interferon-gamma (IFN-γ)] were determined by a multiplex assay, kynurenine and tryptophan levels by high-performance liquid chromatography, and BDNF by enzyme-linked immunosorbent assay (ELISA). The prevalence of exposure to severe trauma and PTSD was 74% and 17%, respectively. PTSD comorbidity was not associated with age, gender, or socioeconomic status, but with co-occurring major depression, history of attempted suicide, earlier peak of drinking problems, higher drinking quantity and withdrawal symptoms, experiencing alcoholic blackouts, and drinking problems among parents. None of the assessed neuroimmune parameters was related to comorbid PTSD. The findings support routine trauma screening in AUD treatment samples and screening for risky drinking in trauma populations to help guide interventions. The expected aberrations in neuroimmune functioning may not be found when examined in a sample with multiple psychiatric morbidities.

Invasion and Persistence of Infectious Agents in Fragmented Host Populations

PubMed Central

Jesse, Marieke; Mazzucco, Rupert; Dieckmann, Ulf; Heesterbeek, Hans; Metz, Johan A. J.

2011-01-01

One of the important questions in understanding infectious diseases and their prevention and control is how infectious agents can invade and become endemic in a host population. A ubiquitous feature of natural populations is that they are spatially fragmented, resulting in relatively homogeneous local populations inhabiting patches connected by the migration of hosts. Such fragmented population structures are studied extensively with metapopulation models. Being able to define and calculate an indicator for the success of invasion and persistence of an infectious agent is essential for obtaining general qualitative insights into infection dynamics, for the comparison of prevention and control scenarios, and for quantitative insights into specific systems. For homogeneous populations, the basic reproduction ratio plays this role. For metapopulations, defining such an ‘invasion indicator’ is not straightforward. Some indicators have been defined for specific situations, e.g., the household reproduction number . However, these existing indicators often fail to account for host demography and especially host migration. Here we show how to calculate a more broadly applicable indicator for the invasion and persistence of infectious agents in a host metapopulation of equally connected patches, for a wide range of possible epidemiological models. A strong feature of our method is that it explicitly accounts for host demography and host migration. Using a simple compartmental system as an example, we illustrate how can be calculated and expressed in terms of the key determinants of epidemiological dynamics. PMID:21980339

Length Distributions of Identity by Descent Reveal Fine-Scale Demographic History

PubMed Central

Palamara, Pier Francesco; Lencz, Todd; Darvasi, Ariel; Pe’er, Itsik

2012-01-01

Data-driven studies of identity by descent (IBD) were recently enabled by high-resolution genomic data from large cohorts and scalable algorithms for IBD detection. Yet, haplotype sharing currently represents an underutilized source of information for population-genetics research. We present analytical results on the relationship between haplotype sharing across purportedly unrelated individuals and a population’s demographic history. We express the distribution of IBD sharing across pairs of individuals for segments of arbitrary length as a function of the population’s demography, and we derive an inference procedure to reconstruct such demographic history. The accuracy of the proposed reconstruction methodology was extensively tested on simulated data. We applied this methodology to two densely typed data sets: 500 Ashkenazi Jewish (AJ) individuals and 56 Kenyan Maasai (MKK) individuals (HapMap 3 data set). Reconstructing the demographic history of the AJ cohort, we recovered two subsequent population expansions, separated by a severe founder event, consistent with previous analysis of lower-throughput genetic data and historical accounts of AJ history. In the MKK cohort, high levels of cryptic relatedness were detected. The spectrum of IBD sharing is consistent with a demographic model in which several small-sized demes intermix through high migration rates and result in enrichment of shared long-range haplotypes. This scenario of historically structured demographies might explain the unexpected abundance of runs of homozygosity within several populations. PMID:23103233

Climatic niche and neutral genetic diversity of the six Iberian pine species: a retrospective and prospective view.

PubMed

Soto, A; Robledo-Arnuncio, J J; González-Martínez, S C; Smouse, P E; Alía, R

2010-04-01

Quaternary climatic fluctuations have left contrasting historical footprints on the neutral genetic diversity patterns of existing populations of different tree species. We should expect the demography, and consequently the neutral genetic structure, of taxa less tolerant to particular climatic extremes to be more sensitive to long-term climate fluctuations. We explore this hypothesis here by sampling all six pine species found in the Iberian Peninsula (2464 individuals, 105 populations), using a common set of chloroplast microsatellite markers, and by looking at the association between neutral genetic diversity and species-specific climatic requirements. We found large variation in neutral genetic diversity and structure among Iberian pines, with cold-enduring mountain species (Pinus uncinata, P. sylvestris and P. nigra) showing substantially greater diversity than thermophilous taxa (P. pinea and P. halepensis). Within species, we observed a significant positive correlation between population genetic diversity and summer precipitation for some of the mountain pines. The observed pattern is consistent with the hypotheses that: (i) more thermophilous species have been subjected to stronger demographic fluctuations in the past, as a consequence of their maladaptation to recurrent glacial cold stages; and (ii) altitudinal migrations have allowed the maintenance of large effective population sizes and genetic variation in cold-tolerant species, especially in more humid regions. In the light of these results and hypotheses, we discuss some potential genetic consequences of impending climate change.

Travelling to the south: Phylogeographic spatial diffusion model in Monttea aphylla (Plantaginaceae), an endemic plant of the Monte Desert

PubMed Central

Cosacov, Andrea; Ferreiro, Gabriela; Johnson, Leigh A.; Sérsic, Alicia N.

2017-01-01

Effects of Pleistocene climatic oscillations on plant phylogeographic patterns are relatively well studied in forest, savanna and grassland biomes, but such impacts remain less explored on desert regions of the world, especially in South America. Here, we performed a phylogeographical study of Monttea aphylla, an endemic species of the Monte Desert, to understand the evolutionary history of vegetation communities inhabiting the South American Arid Diagonal. We obtained sequences of three chloroplast (trnS–trnfM, trnH–psbA and trnQ–rps16) and one nuclear (ITS) intergenic spacers from 272 individuals of 34 localities throughout the range of the species. Population genetic and Bayesian coalescent analyses were performed to infer genealogical relationships among haplotypes, population genetic structure, and demographic history of the study species. Timing of demographic events was inferred using Bayesian Skyline Plot and the spatio-temporal patterns of lineage diversification was reconstructed using Bayesian relaxed diffusion models. Palaeo-distribution models (PDM) were performed through three different timescales to validate phylogeographical patterns. Twenty-five and 22 haplotypes were identified in the cpDNA and nDNA data, respectively. that clustered into two main genealogical lineages following a latitudinal pattern, the northern and the southern Monte (south of 35° S). The northern Monte showed two lineages of high genetic structure, and more relative stable demography than the southern Monte that retrieved three groups with little phylogenetic structure and a strong signal of demographic expansion that would have started during the Last Interglacial period (ca. 120 Ka). The PDM and diffusion models analyses agreed in the southeast direction of the range expansion. Differential effect of climatic oscillations across the Monte phytogeographic province was observed in Monttea aphylla lineages. In northern Monte, greater genetic structure and more relative stable demography resulted from a more stable climate than in the southern Monte. Pleistocene glaciations drastically decreased the species area in the southern Monte, which expanded in a southeastern direction to the new available areas during the interglacial periods. PMID:28582433

Multilocus dataset reveals demographic histories of two peat mosses in Europe

PubMed Central

Szövényi, Péter; Hock, Zsófia; Schneller, Jakob J; Tóth, Zoltán

2007-01-01

Background Revealing the past and present demographic history of populations is of high importance to evaluate the conservation status of species. Demographic data can be obtained by direct monitoring or by analysing data of historical and recent collections. Although these methods provide the most detailed information they are very time consuming. Another alternative way is to make use of the information accumulated in the species' DNA over its history. Recent development of the coalescent theory makes it possible to reconstruct the demographic history of species using nucleotide polymorphism data. To separate the effect of natural selection and demography, multilocus analysis is needed because these two forces can produce similar patterns of polymorphisms. In this study we investigated the amount and pattern of sequence variability of a Europe wide sample set of two peat moss species (Sphagnum fimbriatum and S. squarrosum) with similar distributions and mating systems but presumably contrasting historical demographies using 3 regions of the nuclear genome (appr. 3000 bps). We aimed to draw inferences concerning demographic, and phylogeographic histories of the species. Results All three nuclear regions supported the presence of an Atlantic and Non-Atlantic clade of S. fimbriatum suggesting glacial survival of the species along the Atlantic coast of Europe. Contrarily, S. squarrosum haplotypes showed three clades but no geographic structure at all. Maximum likelihood, mismatch and Bayesian analyses supported a severe historical bottleneck and a relatively recent demographic expansion of the Non-Atlantic clade of S. fimbriatum, whereas size of S. squarrosum populations has probably decreased in the past. Species wide molecular diversity of the two species was nearly the same with an excess of replacement mutations in S. fimbriatum. Similar levels of molecular diversity, contrasting phylogeographic patterns and excess of replacement mutations in S. fimbriatum compared to S. squarrosum mirror unexpected differences in the demography and population history of the species. Conclusion This study represents the first detailed European wide phylodemographic investigation on bryophytes and shows how pattern of nucleotide polymorphism can reveal unexpected differences in the population history of haploid plants with seemingly similar characteristics. PMID:17714592

Demographically-Based Evaluation of Genomic Regions under Selection in Domestic Dogs

PubMed Central

Freedman, Adam H.; Schweizer, Rena M.; Ortega-Del Vecchyo, Diego; Han, Eunjung; Davis, Brian W.; Gronau, Ilan; Silva, Pedro M.; Galaverni, Marco; Fan, Zhenxin; Marx, Peter; Lorente-Galdos, Belen; Ramirez, Oscar; Hormozdiari, Farhad; Alkan, Can; Vilà, Carles; Squire, Kevin; Geffen, Eli; Kusak, Josip; Boyko, Adam R.; Parker, Heidi G.; Lee, Clarence; Tadigotla, Vasisht; Siepel, Adam; Bustamante, Carlos D.; Harkins, Timothy T.; Nelson, Stanley F.; Marques-Bonet, Tomas; Ostrander, Elaine A.; Wayne, Robert K.; Novembre, John

2016-01-01

Controlling for background demographic effects is important for accurately identifying loci that have recently undergone positive selection. To date, the effects of demography have not yet been explicitly considered when identifying loci under selection during dog domestication. To investigate positive selection on the dog lineage early in the domestication, we examined patterns of polymorphism in six canid genomes that were previously used to infer a demographic model of dog domestication. Using an inferred demographic model, we computed false discovery rates (FDR) and identified 349 outlier regions consistent with positive selection at a low FDR. The signals in the top 100 regions were frequently centered on candidate genes related to brain function and behavior, including LHFPL3, CADM2, GRIK3, SH3GL2, MBP, PDE7B, NTAN1, and GLRA1. These regions contained significant enrichments in behavioral ontology categories. The 3rd top hit, CCRN4L, plays a major role in lipid metabolism, that is supported by additional metabolism related candidates revealed in our scan, including SCP2D1 and PDXC1. Comparing our method to an empirical outlier approach that does not directly account for demography, we found only modest overlaps between the two methods, with 60% of empirical outliers having no overlap with our demography-based outlier detection approach. Demography-aware approaches have lower-rates of false discovery. Our top candidates for selection, in addition to expanding the set of neurobehavioral candidate genes, include genes related to lipid metabolism, suggesting a dietary target of selection that was important during the period when proto-dogs hunted and fed alongside hunter-gatherers. PMID:26943675

Sociocultural behavior, sex-biased admixture, and effective population sizes in Central African Pygmies and non-Pygmies.

PubMed

Verdu, Paul; Becker, Noémie S A; Froment, Alain; Georges, Myriam; Grugni, Viola; Quintana-Murci, Lluis; Hombert, Jean-Marie; Van der Veen, Lolke; Le Bomin, Sylvie; Bahuchet, Serge; Heyer, Evelyne; Austerlitz, Frédéric

2013-04-01

Sociocultural phenomena, such as exogamy or phylopatry, can largely determine human sex-specific demography. In Central Africa, diverging patterns of sex-specific genetic variation have been observed between mobile hunter-gatherer Pygmies and sedentary agricultural non-Pygmies. However, their sex-specific demography remains largely unknown. Using population genetics and approximate Bayesian computation approaches, we inferred male and female effective population sizes, sex-specific migration, and admixture rates in 23 Central African Pygmy and non-Pygmy populations, genotyped for autosomal, X-linked, Y-linked, and mitochondrial markers. We found much larger effective population sizes and migration rates among non-Pygmy populations than among Pygmies, in agreement with the recent expansions and migrations of non-Pygmies and, conversely, the isolation and stationary demography of Pygmy groups. We found larger effective sizes and migration rates for males than for females for Pygmies, and vice versa for non-Pygmies. Thus, although most Pygmy populations have patrilocal customs, their sex-specific genetic patterns resemble those of matrilocal populations. In fact, our results are consistent with a lower prevalence of polygyny and patrilocality in Pygmies compared with non-Pygmies and a potential female transmission of reproductive success in Pygmies. Finally, Pygmy populations showed variable admixture levels with the non-Pygmies, with often much larger introgression from male than from female lineages. Social discrimination against Pygmies triggering complex movements of spouses in intermarriages can explain these male-biased admixture patterns in a patrilocal context. We show how gender-related sociocultural phenomena can determine highly variable sex-specific demography among populations, and how population genetic approaches contrasting chromosomal types allow inferring detailed human sex-specific demographic history.

Sociocultural Behavior, Sex-Biased Admixture, and Effective Population Sizes in Central African Pygmies and Non-Pygmies

PubMed Central

Verdu, Paul; Becker, Noémie S.A.; Froment, Alain; Georges, Myriam; Grugni, Viola; Quintana-Murci, Lluis; Hombert, Jean-Marie; Van der Veen, Lolke; Le Bomin, Sylvie; Bahuchet, Serge; Heyer, Evelyne; Austerlitz, Frédéric

2013-01-01

Sociocultural phenomena, such as exogamy or phylopatry, can largely determine human sex-specific demography. In Central Africa, diverging patterns of sex-specific genetic variation have been observed between mobile hunter–gatherer Pygmies and sedentary agricultural non-Pygmies. However, their sex-specific demography remains largely unknown. Using population genetics and approximate Bayesian computation approaches, we inferred male and female effective population sizes, sex-specific migration, and admixture rates in 23 Central African Pygmy and non-Pygmy populations, genotyped for autosomal, X-linked, Y-linked, and mitochondrial markers. We found much larger effective population sizes and migration rates among non-Pygmy populations than among Pygmies, in agreement with the recent expansions and migrations of non-Pygmies and, conversely, the isolation and stationary demography of Pygmy groups. We found larger effective sizes and migration rates for males than for females for Pygmies, and vice versa for non-Pygmies. Thus, although most Pygmy populations have patrilocal customs, their sex-specific genetic patterns resemble those of matrilocal populations. In fact, our results are consistent with a lower prevalence of polygyny and patrilocality in Pygmies compared with non-Pygmies and a potential female transmission of reproductive success in Pygmies. Finally, Pygmy populations showed variable admixture levels with the non-Pygmies, with often much larger introgression from male than from female lineages. Social discrimination against Pygmies triggering complex movements of spouses in intermarriages can explain these male-biased admixture patterns in a patrilocal context. We show how gender-related sociocultural phenomena can determine highly variable sex-specific demography among populations, and how population genetic approaches contrasting chromosomal types allow inferring detailed human sex-specific demographic history. PMID:23300254

Susceptibility to disease varies with ontogeny and immunocompetence in a threatened amphibian.

PubMed

Abu Bakar, Amalina; Bower, Deborah S; Stockwell, Michelle P; Clulow, Simon; Clulow, John; Mahony, Michael J

2016-08-01

Ontogenetic changes in disease susceptibility have been demonstrated in many vertebrate taxa, as immature immune systems and limited prior exposure to pathogens can place less developed juveniles at a greater disease risk. By causing the disease chytridiomycosis, Batrachochytrium dendrobatidis (Bd) infection has led to the decline of many amphibian species. Despite increasing knowledge on how Bd varies in its effects among species, little is known on the interaction between susceptibility and development within host species. We compared the ontogenetic susceptibility of post-metamorphic green and golden bell frogs Litoria aurea to chytridiomycosis by simultaneously measuring three host-pathogen responses as indicators of the development of the fungus-infection load, survival rate, and host immunocompetence-following Bd exposure in three life stages (recently metamorphosed juveniles, subadults, adults) over 95 days. Frogs exposed to Bd as recently metamorphosed juveniles acquired higher infection loads and experienced lower immune function and lower survivorship than subadults and adults, indicating an ontogenetic decline in chytridiomycosis susceptibility. By corresponding with an intrinsic developmental maturation in immunocompetence seen in uninfected frogs, we suggest these developmental changes in host susceptibility in L. aurea may be immune mediated. Consequently, the physiological relationship between ontogeny and immunity may affect host population structure and demography through variation in life stage survival, and understanding this can shape management targets for effective amphibian conservation.

Projecting future impacts of hurricanes on the carbon balance of eastern U.S. forests

NASA Astrophysics Data System (ADS)

Fisk, J. P.; Hurtt, G. C.; Chambers, J. Q.; Zeng, H.; Dolan, K.; Flanagan, S.; Rourke, O.; Negron Juarez, R. I.

2011-12-01

In U.S. Atlantic coastal areas, hurricanes are a principal agent of catastrophic wind damage, with dramatic impacts on the structure and functioning of forests. Substantial recent progress has been made to estimate the biomass loss and resulting carbon emissions caused by hurricanes impacting the U.S. Additionally, efforts to evaluate the net effects of hurricanes on the regional carbon balance have demonstrated the importance of viewing large disturbance events in the broader context of recovery from a mosaic of past events. Viewed over sufficiently long time scales and large spatial scales, regrowth from previous storms may largely offset new emissions; however, changes in number, strength or spatial distribution of extreme disturbance events will result in changes to the equilibrium state of the ecosystem and have the potential to result in a lasting carbon source or sink. Many recent studies have linked climate change to changes in the frequency and intensity of hurricanes. In this study, we use a mechanistic ecosystem model, the Ecosystem Demography (ED) model, driven by scenarios of future hurricane activity based on historic activity and future climate projections, to evaluate how changes in hurricane frequency, intensity and spatial distribution could affect regional carbon storage and flux over the coming century. We find a non-linear response where increased storm activity reduces standing biomass stocks reducing the impacts of future events. This effect is highly dependent on the spatial pattern and repeat interval of future hurricane activity. Developing this kind of predictive modeling capability that tracks disturbance events and recovery is key to our understanding and ability to predict the carbon balance of forests.

Developments in the instruction of biostatistics at the Kuwait University Health Science Centre in a decade.

PubMed

Moussa, Mohamed A A

2002-01-01

Kuwait has witnessed many changes that influenced, among other things, the structure of medical education including biostatistics. This article describes the developments in biostatistics instruction and curriculum in the Health Science Centre, University of Kuwait, during the past 10 years. Instead of teaching biostatistics as an independent component, the university has developed an integrated course (35 hr of lectures and 12 hr of tutorial sessions) of biostatistics, epidemiology, and demography that is taught to undergraduate medical and dentistry students to ensure interdisciplinary interaction, to remove redundancies, and to standardize terminology across the three disciplines. The core curriculum of the biostatistics course is compatible with the recommendations of the American Statistical Association. Separate biostatistics courses are also offered to pharmacy and allied health students to address their diverse interests. In addition, new biostatistics and computer applications instruction courses were developed and are taught to the students of the Master of Science (MSc), Master of Public Health (MPH), and PhD programs. For continuing medical education, a workshop on biostatistics and computer applications is organized annually for the medical profession as a collaboration between the Health Science Centre and the Kuwait Institute for Medical Specialization. The instructor and curriculum content of the biostatistics courses are confidentially evaluated and independently analyzed by the office of the Vice Dean for Academic Affairs. Overall, students evaluate the biostatistics instructors highly and are pleased with the content of the biostatistics curriculum. During the last decade, biostatistics instruction in the Kuwait Health Science Centre had many new developments. An integrated course on biostatistics, epidemiology, and demography was developed with emphasis on problem solving and small group learning. Another biostatistics course is offered to the students of the new faculty of pharmacy. Further biostatistics courses became operational for the postgraduate programs: (MSc), (MPH), and PhD. Continuing medical education is supported by workshops, which is a sign of collaboration with the health community, and a consultancy office has been established. Overall, biostatistics instruction is well received by students, and the role of biostatistics is recognized by researchers from the medical profession.

Mechanisms of global diversification in the marine species Madeiran Storm-petrel Oceanodroma castro and Monteiro's Storm-petrel O. monteiroi: Insights from a multi-locus approach.

PubMed

Silva, Mauro F; Smith, Andrea L; Friesen, Vicki L; Bried, Joël; Hasegawa, Osamu; Coelho, M Manuela; Silva, Mónica C

2016-05-01

The evolutionary mechanisms underlying the geographic distribution of gene lineages in the marine environment are not as well understood as those affecting terrestrial groups. The continuous nature of the pelagic marine environment may limit opportunities for divergence to occur and lineages to spatially segregate, particularly in highly mobile species. Here, we studied the phylogeography and historical demography of two tropically distributed, pelagic seabirds, the Madeiran Storm-petrel Oceanodroma castro, sampled in the Azores, Madeira, Galapagos and Japan, and its sister species Monteiro's Storm-petrel O. monteiroi (endemic to the Azores), using a multi-locus dataset consisting of 12 anonymous nuclear loci and the mitochondrial locus control region. Both marker types support the existence of four significantly differentiated genetic clusters, including the sampled O. monteiroi population and three populations within O. castro, although only the mitochondrial locus suggests complete lineage sorting. Multi-locus coalescent analyses suggest that most divergence events occurred within the last 200,000years. The proximity in divergence times precluded robust inferences of the species tree, in particular of the evolutionary relationships of the Pacific populations. Despite the great potential for dispersal, divergence among populations apparently proceeded in the absence of gene flow, emphasizing the effect of non-physical barriers, such as those driven by the paleo-oceanographical environments, philopatry and local adaptation, as important mechanisms of population divergence and speciation in highly mobile marine species. In view of the predicted climate change impacts, future changes in the demography and evolutionary dynamics of marine populations might be expected. Copyright © 2016 Elsevier Inc. All rights reserved.

Estimating future dental services' demand and supply: a model for Northern Germany.

PubMed

Jäger, Ralf; van den Berg, Neeltje; Hoffmann, Wolfgang; Jordan, Rainer A; Schwendicke, Falk

2016-04-01

To plan dental services, a spatial estimation of future demands and supply is required. We aimed at estimating demand and supply in 2030 in Northern Germany based on the expected local socio-demography and oral-health-related morbidity, and the predicted number of dentists and their working time. All analyses were performed on zip-code level. Register data were used to determine the number of retiring dentists and to construct regression models for estimating the number of dentists moving into each zip-code area until 2030. Demand was modelled using projected demography and morbidities. Demand-supply ratios were evaluated and spatial analyses applied. Sensitivity analyses were employed to assess robustness of our findings. Compared with 2011, the population decreased (-7% to -11%) and aged (from mean 46 to 51 years) until 2030. Oral-health-related morbidity changed, leading to more periodontal and fewer prosthetic treatments needs, with the overall demand decreasing in all scenarios (-25% to -33%). In contrast, the overall number of dentists did only limitedly change, resulting in moderate decrease in the supplied service quantities (max. -22%). Thus, the demand-supply ratio increased in all but the worst case scenario, but was unequally distributed between spatial units, with several areas being over- and some being under- or none-serviced in 2030. Within the limitations of the underlying data and the required assumptions, this study expects an increasingly polarized ratio of dental services demand and supply in Northern Germany. Our estimation allows to assess the impact of different influence factors on demand or supply and to specifically identify potential challenges for workforce planning and regulation in different spatial units. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Patterns of Z chromosome divergence among Heliconius species highlight the importance of historical demography.

PubMed

Van Belleghem, Steven M; Baquero, Margarita; Papa, Riccardo; Salazar, Camilo; McMillan, W Owen; Counterman, Brian A; Jiggins, Chris D; Martin, Simon H

2018-03-22

Sex chromosomes are disproportionately involved in reproductive isolation and adaptation. In support of such a "large-X" effect, genome scans between recently diverged populations and species pairs often identify distinct patterns of divergence on the sex chromosome compared to autosomes. When measures of divergence between populations are higher on the sex chromosome compared to autosomes, such patterns could be interpreted as evidence for faster divergence on the sex chromosome, that is "faster-X", barriers to gene flow on the sex chromosome. However, demographic changes can strongly skew divergence estimates and are not always taken into consideration. We used 224 whole-genome sequences representing 36 populations from two Heliconius butterfly clades (H. erato and H. melpomene) to explore patterns of Z chromosome divergence. We show that increased divergence compared to equilibrium expectations can in many cases be explained by demographic change. Among Heliconius erato populations, for instance, population size increase in the ancestral population can explain increased absolute divergence measures on the Z chromosome compared to the autosomes, as a result of increased ancestral Z chromosome genetic diversity. Nonetheless, we do identify increased divergence on the Z chromosome relative to the autosomes in parapatric or sympatric species comparisons that imply postzygotic reproductive barriers. Using simulations, we show that this is consistent with reduced gene flow on the Z chromosome, perhaps due to greater accumulation of incompatibilities. Our work demonstrates the importance of taking demography into account to interpret patterns of divergence on the Z chromosome, but nonetheless provides evidence to support the Z chromosome as a strong barrier to gene flow in incipient Heliconius butterfly species. © 2018 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

Demography and market impacts on dental practices' development in Bulgaria during the period of transition 1990-2010.

PubMed

Katrova, Lydia; Tzokov, Krassimir

2013-11-01

The purpose of this study was to present the impact of demography and market dynamics on the organizational and technological development of dental practices in Bulgaria during the period of socio-economic transition from 1990 to 2010. Relevant data were gathered from the official registers of the Bulgarian Dental Association, National Health Insurance Fund, National Health Information Institute and research studies, published during the period 1990-2010. They were analysed and are discussed in this paper. During the period there was a decrease in population of Bulgaria, from 8,149,468 in 2000 to 7,563,000 in 2010 and a movement from rural areas to cities. There was an aging population with an increase in oral health care needs at a time of decrease in the size of the national labour force and economic growth. Paradoxically, over the last 20 years, the number of dentists in Bulgaria increased by more than 50% from 1997 to 2008. The average age of dentists changed from 39.7 years in 1997 to 41.7 years in 2008. The number of group dental practices increased and the number of individual practices and group practices for specialized dental care and dental centres decreased. The utilization of dental services is currently "about half" that of the mean for all European Union Member States, which is over 80% per year. The growing number of elderly people who have retained their teeth suggests an increase in treatment needs. However, the decline in their purchasing power limits the demand for oral health care services. In order to meet this and other challenges Bulgarian dentists have started changing their traditional solo-practice to group-practice. Copyright © 2013 by Academy of Sciences and Arts of Bosnia and Herzegovina.

Assessing the effects of hybridization and precipitation on invasive weed demography using strength of selection on vital rates.

PubMed

Teitel, Zachary; Klimowski, Agnieszka; Campbell, Lesley G

2016-12-07

As global climate change transforms average temperature and rainfall, species distributions may meet, increasing the potential for hybridization and altering individual fitness and population growth. Altered rainfall specifically may shift the strength and direction of selection, also manipulating population trajectories. Here, we investigated the role of interspecific hybridization and selection imposed by rainfall on the evolution of weedy life-history in non-hybrid (Raphanus raphanistrum) and hybrid (R. raphanistrum x R. sativus) populations using a life table response experiment. In documenting long-term population dynamics, we determined intrinsic (r) and asymptotic (λ) population growth rates and sensitivities, a measure of selection imposed on demographic rates. Hybrid populations experienced 8.7-10.3 times stronger selection than wild populations for increased seedling survival. Whereas crop populations generally exhibit little dormancy and wild populations often exhibit dormancy, non-hybrid populations experienced 10% stronger selection than hybrid populations for exhibiting seed dormancy. Selection on survival-to-flowering in wild, not hybrid, populations declined marginally with increasing soil moisture. Hybrid populations exhibited greater r, but not λ, than wild populations regardless of moisture environment. In general, fecundity contributed most to differences in λ but fecundity only contributed positively to hybrid λ relative to wild λ when precipitation was altered (either higher or lower than control) and not under control watering conditions. Selection on key demographic traits may not change dramatically in response to rainfall, and hybridization may more strongly influence the demography of these weedy species than rainfall. If hybrid populations can respond to selection for increased dormancy, this may make it more difficult to deplete weed seed banks and increase the persistence of crop genes in weed populations.

Effects of temperature and precipitation on grassland bird nesting success as mediated by patch size.

PubMed

Zuckerberg, Benjamin; Ribic, Christine A; McCauley, Lisa A

2018-02-06

Grassland birds are declining faster than any other bird guild across North America. Shrinking ranges and population declines are attributed to widespread habitat loss and increasingly fragmented landscapes of agriculture and other land uses that are misaligned with grassland bird conservation. Concurrent with habitat loss and degradation, temperate grasslands have been disproportionally affected by climate change relative to most other terrestrial biomes. Distributions of grassland birds often correlate with gradients in climate, but few researchers have explored the consequences of weather on the demography of grassland birds inhabiting a range of grassland fragments. To do so, we modeled the effects of temperature and precipitation on nesting success rates of 12 grassland bird species inhabiting a range of grassland patches across North America (21,000 nests from 81 individual studies). Higher amounts of precipitation in the preceding year were associated with higher nesting success, but wetter conditions during the active breeding season reduced nesting success. Extremely cold or hot conditions during the early breeding season were associated with lower rates of nesting success. The direct and indirect influence of temperature and precipitation on nesting success was moderated by grassland patch size. The positive effects of precipitation in the preceding year on nesting success were strongest in relatively small grassland patches and had little effect in large patches. Conversely, warm temperatures reduced nesting success in small grassland patches but increased nesting success in large patches. Mechanisms underlying these differences may be patch-size-induced variation in microclimates and predator activity. Although the exact cause is unclear, large grassland patches, the most common metric of grassland conservation, appears to moderate the effects of weather on grassland-bird demography and could be an effective component of climate-change adaptation. © 2018 Society for Conservation Biology.

Revisiting drought impact on tropical forest photosynthesis: a novel multi-scale integrated approach reveals new insights

NASA Astrophysics Data System (ADS)

Detto, M.; Wu, J.; Xu, X.; Serbin, S.; Rogers, A.

2017-12-01

A fundamental unanswered question for global change ecology is to determine the vulnerability of tropical forests to climate change, particularly with increasing intensity and frequency of drought events. This question, despite its apparent simplicity, remains difficult for earth system models to answer, and is controversial in remote sensing literature. Here, we leverage unique multi-scale remote sensing measurements (from leaf to crown) in conjunction with four-continuous-year (2013-2017) eddy covariance measurements of ecosystem carbon fluxes in a tropical forest in Panama to revisit this question. We hypothesize that drought impacts tropical forest photosynthesis through variation in abiotic drivers (solar radiation, diffuse light fraction, and vapor pressure deficit) that interact with physiological traits that govern photosynthesis, and biotic variation in ecosystem photosynthetic capacity associated with changes in the traits themselves. Our study site, located in a seasonal tropical forest on Barro Colorado Island (BCI), Panama, experienced a significant drought in 2015. Local eddy covariance derived photosynthesis shows an abrupt increase during the drought year. Our specific goal here is to assess the relative impact of abiotic and biotic drivers of such photosynthesis response to interannual drought. To this goal, we derived abiotic drivers from eddy tower-based meteorological measurements. We will derive the biotic drivers using a recently developed leaf demography-ontogeny model, where ecosystem photosynthetic capacity can be described as the product of field measured, age-dependent leaf photosynthetic capacity and local tower-camera derived ecosystem-scale inter-annual variability in leaf age demography of the same time period (2013-2017). Lastly, we will use a process-based model to assess the separate and joint effects of abiotic and biotic drivers on eddy covariance derive photosynthetic interannual variability. Collectively, this novel multi-scale integrated study aims to improve ecophysiological understanding of tropical forest response to interannual climate variability, highlighting the importance to combine state-of-the-art technology and theories to improve future projections of carbon dynamics in the tropics.

Biological processes dominate seasonality of remotely sensed canopy greenness in an Amazon evergreen forest.

PubMed

Wu, Jin; Kobayashi, Hideki; Stark, Scott C; Meng, Ran; Guan, Kaiyu; Tran, Ngoc Nguyen; Gao, Sicong; Yang, Wei; Restrepo-Coupe, Natalia; Miura, Tomoaki; Oliviera, Raimundo Cosme; Rogers, Alistair; Dye, Dennis G; Nelson, Bruce W; Serbin, Shawn P; Huete, Alfredo R; Saleska, Scott R

2018-03-01

Satellite observations of Amazon forests show seasonal and interannual variations, but the underlying biological processes remain debated. Here we combined radiative transfer models (RTMs) with field observations of Amazon forest leaf and canopy characteristics to test three hypotheses for satellite-observed canopy reflectance seasonality: seasonal changes in leaf area index, in canopy-surface leafless crown fraction and/or in leaf demography. Canopy RTMs (PROSAIL and FLiES), driven by these three factors combined, simulated satellite-observed seasonal patterns well, explaining c. 70% of the variability in a key reflectance-based vegetation index (MAIAC EVI, which removes artifacts that would otherwise arise from clouds/aerosols and sun-sensor geometry). Leaf area index, leafless crown fraction and leaf demography independently accounted for 1, 33 and 66% of FLiES-simulated EVI seasonality, respectively. These factors also strongly influenced modeled near-infrared (NIR) reflectance, explaining why both modeled and observed EVI, which is especially sensitive to NIR, captures canopy seasonal dynamics well. Our improved analysis of canopy-scale biophysics rules out satellite artifacts as significant causes of satellite-observed seasonal patterns at this site, implying that aggregated phenology explains the larger scale remotely observed patterns. This work significantly reconciles current controversies about satellite-detected Amazon phenology, and improves our use of satellite observations to study climate-phenology relationships in the tropics. No claim to original US Government works New Phytologist © 2017 New Phytologist Trust.

Estimating Density and Temperature Dependence of Juvenile Vital Rates Using a Hidden Markov Model

PubMed Central

McElderry, Robert M.

2017-01-01

Organisms in the wild have cryptic life stages that are sensitive to changing environmental conditions and can be difficult to survey. In this study, I used mark-recapture methods to repeatedly survey Anaea aidea (Nymphalidae) caterpillars in nature, then modeled caterpillar demography as a hidden Markov process to assess if temporal variability in temperature and density influence the survival and growth of A. aidea over time. Individual encounter histories result from the joint likelihood of being alive and observed in a particular stage, and I have included hidden states by separating demography and observations into parallel and independent processes. I constructed a demographic matrix containing the probabilities of all possible fates for each stage, including hidden states, e.g., eggs and pupae. I observed both dead and live caterpillars with high probability. Peak caterpillar abundance attracted multiple predators, and survival of fifth instars declined as per capita predation rate increased through spring. A time lag between predator and prey abundance was likely the cause of improved fifth instar survival estimated at high density. Growth rates showed an increase with temperature, but the preferred model did not include temperature. This work illustrates how state-space models can include unobservable stages and hidden state processes to evaluate how environmental factors influence vital rates of cryptic life stages in the wild. PMID:28505138

Inferring Recent Demography from Isolation by Distance of Long Shared Sequence Blocks

PubMed Central

Ringbauer, Harald; Coop, Graham

2017-01-01

Recently it has become feasible to detect long blocks of nearly identical sequence shared between pairs of genomes. These identity-by-descent (IBD) blocks are direct traces of recent coalescence events and, as such, contain ample signal to infer recent demography. Here, we examine sharing of such blocks in two-dimensional populations with local migration. Using a diffusion approximation to trace genetic ancestry, we derive analytical formulas for patterns of isolation by distance of IBD blocks, which can also incorporate recent population density changes. We introduce an inference scheme that uses a composite-likelihood approach to fit these formulas. We then extensively evaluate our theory and inference method on a range of scenarios using simulated data. We first validate the diffusion approximation by showing that the theoretical results closely match the simulated block-sharing patterns. We then demonstrate that our inference scheme can accurately and robustly infer dispersal rate and effective density, as well as bounds on recent dynamics of population density. To demonstrate an application, we use our estimation scheme to explore the fit of a diffusion model to Eastern European samples in the Population Reference Sample data set. We show that ancestry diffusing with a rate of σ≈50−−100 km/gen during the last centuries, combined with accelerating population growth, can explain the observed exponential decay of block sharing with increasing pairwise sample distance. PMID:28108588

Holocene fluctuations in human population demonstrate repeated links to food production and climate

PubMed Central

Colledge, Sue; Fuller, Dorian; Fyfe, Ralph; Shennan, Stephen; Stevens, Chris

2017-01-01

We consider the long-term relationship between human demography, food production, and Holocene climate via an archaeological radiocarbon date series of unprecedented sampling density and detail. There is striking consistency in the inferred human population dynamics across different regions of Britain and Ireland during the middle and later Holocene. Major cross-regional population downturns in population coincide with episodes of more abrupt change in North Atlantic climate and witness societal responses in food procurement as visible in directly dated plants and animals, often with moves toward hardier cereals, increased pastoralism, and/or gathered resources. For the Neolithic, this evidence questions existing models of wholly endogenous demographic boom–bust. For the wider Holocene, it demonstrates that climate-related disruptions have been quasi-periodic drivers of societal and subsistence change. PMID:29158411

Count data, detection probabilities, and the demography, dynamics, distribution, and decline of amphibians.

PubMed

Schmidt, Benedikt R

2003-08-01

The evidence for amphibian population declines is based on count data that were not adjusted for detection probabilities. Such data are not reliable even when collected using standard methods. The formula C = Np (where C is a count, N the true parameter value, and p is a detection probability) relates count data to demography, population size, or distributions. With unadjusted count data, one assumes a linear relationship between C and N and that p is constant. These assumptions are unlikely to be met in studies of amphibian populations. Amphibian population data should be based on methods that account for detection probabilities.

[To educate and to inform the population about population].

PubMed

Levy, M L

1993-03-01

Each society has multiple institutions that inform members about themselves and their world. The quality of the information received depends on the balance between the political, religious, intellectual, educational, and media institutions that supply information. Population questions are almost always absent from public education programs, because they deal with themes traditionally reserved for family and religious education. But the contemporary world has changed so much that families and the clerical world are no longer necessarily the best sources of instruction. The ignorance and passivity of many families leave a void that is difficult to fill. The difficulty arises because the need is to assist families in filling their role, and not to substitute for them. Educators, development technicians, psychologists, physicians, and sociologists should not be allowed to monopolize the task of educating children in areas related to population, and morality any more than priests should. The central discipline for questions of population is demography. The use of figures and quantitative categories such as age cohorts gives a "scientific" air to demographic discourse which masks the arbitrariness of many terms. At what age, for example, does one became single, or when does one cease to be an orphan? Explaining the European term "household" to Africans, or the African term "concession" to Europeans, illustrates the semantic problems impeding, understanding and communication. The diffusion of demographic information, like that of all numeric information, assumes that the complexity of data gathering and the conventions of calculation are understood. The risk of error and misunderstanding is greater in population than, for example, for the economy, because of the simple and universal nature of demographic subjects: birth, death, illness. Good understanding of demographic information should lead to a deeper understanding of apparently evident notions such as age, duration of life, households, couples and parenthood. Demography is the statistical study of intimate life. Demography should play the same role in relation to social information that national accounts play in relation to economic information, that of a model requiring careful collection of statistics and mathematical rigor, without discouraging evaluation of sources and questioning of theories by the statistical administrators, the press, or the educational institutions.

From leaf longevity to canopy seasonality: a carbon optimality phenology model for tropical evergreen forests

NASA Astrophysics Data System (ADS)

Xu, X.; Medvigy, D.; Wu, J.; Wright, S. J.; Kitajima, K.; Pacala, S. W.

2016-12-01

Tropical evergreen forests play a key role in the global carbon, water and energy cycles. Despite apparent evergreenness, this biome shows strong seasonality in leaf litter and photosynthesis. Recent studies have suggested that this seasonality is not directly related to environmental variability but is dominated by seasonal changes of leaf development and senescence. Meanwhile, current terrestrial biosphere models (TBMs) can not capture this pattern because leaf life cycle is highly underrepresented. One challenge to model this leaf life cycle is the remarkable diversity in leaf longevity, ranging from several weeks to multiple years. Ecologists have proposed models where leaf longevity is regarded as a strategy to optimize carbon gain. However previous optimality models can not be readily integrated into TBMs because (i) there are still large biases in predicted leaf longevity and (ii) it is never tested whether the carbon optimality model can capture the observed seasonality in leaf demography and canopy photosynthesis. In this study, we develop a new carbon optimality model for leaf demography. The novelty of our approach is two-fold. First, we incorporate a mechanistic photosynthesis model that can better estimate leaf carbon gain. Second, we consider the interspecific variations in leaf senescence rate, which strongly influence the modelled optimal carbon gain. We test our model with a leaf trait database for Panamanian evergreen forests. Then, we apply the model at seasonal scale and compare simulated seasonality of leaf litter and canopy photosynthesis with in-situ observations from several Amazonian forest sites. We find that (i) compared with original optimality model, the regression slope between observed and predicted leaf longevity increases from 0.15 to 1.04 in our new model and (ii) that our new model can capture the observed seasonal variations of leaf demography and canopy photosynthesis. Our results suggest that the phenology in tropical evergreen forests might result from plant adaptation to optimize canopy carbon gain. Finally, this proposed trait-driven prognostic phenology model could potentially be incorporated into next generation TBMs to improve simulation of carbon and water fluxes in the tropics.

The eastern box turtle at the Patuxent Wildlife Research Center 1940s to the present: another view

USGS Publications Warehouse

Henry, P.F.P.

2003-01-01

Several long-term mark recapture studies have been conducted on box turtles (Terrapene c. carolina) providing valuable information on life span, basic demography, home range, and apparent effects of environmental changes on box turtle survival. One of the longest studied populations was first marked in 1942 on the Patuxent Wildlife Research Center in Maryland, and has been surveyed every 10 years until 1995. The age structure and gender ratio of these turtles in the field may support differential habitat use and survival estimates. A few of the turtles first marked during the 1945 study are still observed throughout the Center. Data collected from turtles marked in the more upland habitats during 1985-2002 indicate a younger age class distribution than that observed in the more protected biota of the bottomland floodplain study area. Extrapolating ages of turtles described in data collected throughout the long-term study, it was estimated that turtles, both males and females, can show reproduction-intent behaviors at ages greater than 54 years old. It is suggested that count data collection be continued on a more frequent cycle, extending over a larger part of the Center.

The Pleistocene history of the sheepshead minnow (Cyprinodon variegatus): Non-equilibrium evolutionary dynamics within a diversifying species complex.

PubMed

Haney, Robert A; Silliman, Brian R; Fry, Adam J; Layman, Craig A; Rand, David M

2007-06-01

The sheepshead minnow, Cyprinodon variegatus, is a widespread fish species that typically inhabits coastal tidal marsh and mangrove swamp environments, ranging from Cape Cod, Massaschusetts to northern Mexico and into the Caribbean. This wide range crosses several biogeographic boundaries which are coincident with genetic structuring within numerous species originating in the Pleistocene. In addition, the more northerly reaches of this species range have been further subject to the evolutionary consequences of Pleistocene glaciation due to local extinction and recolonization of formerly glaciated sites. C. variegatus thus provides an excellent vertebrate model system within which to test the extent of genetic differentiation among populations in a dominant coastal ecosystem and examine patterns of historical demography in populations distributed along a latitudinal gradient. Using mitochondrial control region and ND2 sequence data, we discovered monophyletic clades within C. variegatus with divergence times within the Pleistocene, and very low gene flow between most sites. Intraspecific genetic breaks appear to correspond broadly to biogeographic or oceanic boundaries. Pleistocene climate change appears to have had dramatic impacts on the size and distribution of populations within and near the glacial margins, but has also affected populations far from formerly glaciated regions.

Host age modulates within-host parasite competition

PubMed Central

Izhar, Rony; Routtu, Jarkko; Ben-Ami, Frida

2015-01-01

In many host populations, one of the most striking differences among hosts is their age. While parasite prevalence differences in relation to host age are well known, little is known on how host age impacts ecological and evolutionary dynamics of diseases. Using two clones of the water flea Daphnia magna and two clones of its bacterial parasite Pasteuria ramosa, we examined how host age at exposure influences within-host parasite competition and virulence. We found that multiply-exposed hosts were more susceptible to infection and suffered higher mortality than singly-exposed hosts. Hosts oldest at exposure were least often infected and vice versa. Furthermore, we found that in young multiply-exposed hosts competition was weak, allowing coexistence and transmission of both parasite clones, whereas in older multiply-exposed hosts competitive exclusion was observed. Thus, age-dependent parasite exposure and host demography (age structure) could together play an important role in mediating parasite evolution. At the individual level, our results demonstrate a previously unnoticed interaction of the host's immune system with host age, suggesting that the specificity of immune function changes as hosts mature. Therefore, evolutionary models of parasite virulence might benefit from incorporating age-dependent epidemiological parameters. PMID:25994010

Evolution in Stage-Structured Populations

PubMed Central

Barfield, Michael; Holt, Robert D.; Gomulkiewicz, Richard

2016-01-01

For many organisms, stage is a better predictor of demographic rates than age. Yet no general theoretical framework exists for understanding or predicting evolution in stage-structured populations. Here, we provide a general modeling approach that can be used to predict evolution and demography of stage-structured populations. This advances our ability to understand evolution in stage-structured populations to a level previously available only for populations structured by age. We use this framework to provide the first rigorous proof that Lande’s theorem, which relates adaptive evolution to population growth, applies to stage-classified populations, assuming only normality and that evolution is slow relative to population dynamics. We extend this theorem to allow for different means or variances among stages. Our next major result is the formulation of Price’s theorem, a fundamental law of evolution, for stage-structured populations. In addition, we use data from Trillium grandiflorum to demonstrate how our models can be applied to a real-world population and thereby show their practical potential to generate accurate projections of evolutionary and population dynamics. Finally, we use our framework to compare rates of evolution in age- versus stage-structured populations, which shows how our methods can yield biological insights about evolution in stage-structured populations. PMID:21460563

Parrots as key multilinkers in ecosystem structure and functioning.

PubMed

Blanco, Guillermo; Hiraldo, Fernando; Rojas, Abraham; Dénes, Francisco V; Tella, José L

2015-09-01

Mutually enhancing organisms can become reciprocal determinants of their distribution, abundance, and demography and thus influence ecosystem structure and dynamics. In addition to the prevailing view of parrots (Psittaciformes) as plant antagonists, we assessed whether they can act as plant mutualists in the dry tropical forest of the Bolivian inter-Andean valleys, an ecosystem particularly poor in vertebrate frugivores other than parrots (nine species). We hypothesised that if interactions between parrots and their food plants evolved as primarily or facultatively mutualistic, selection should have acted to maximize the strength of their interactions by increasing the amount and variety of resources and services involved in particular pairwise and community-wide interaction contexts. Food plants showed different growth habits across a wide phylogenetic spectrum, implying that parrots behave as super-generalists exploiting resources differing in phenology, type, biomass, and rewards from a high diversity of plants (113 species from 38 families). Through their feeding activities, parrots provided multiple services acting as genetic linkers, seed facilitators for secondary dispersers, and plant protectors, and therefore can be considered key mutualists with a pervasive impact on plant assemblages. The number of complementary and redundant mutualistic functions provided by parrots to each plant species was positively related to the number of different kinds of food extracted from them. These mutually enhancing interactions were reflected in species-level properties (e.g., biomass or dominance) of both partners, as a likely consequence of the temporal convergence of eco-(co)evolutionary dynamics shaping the ongoing structure and organization of the ecosystem. A full assessment of the, thus far largely overlooked, parrot-plant mutualisms and other ecological linkages could change the current perception of the role of parrots in the structure, organization, and functioning of ecosystems.

Comparative phylogeography of co-distributed Phrygilus species (Aves, Thraupidae) from the Central Andes.

PubMed

Álvarez-Varas, R; González-Acuña, D; Vianna, J A

2015-09-01

The Neotropical ecoregion has been an important place of avian diversification where dispersal and allopatric events coupled with periods of active orogeny and climate change (Late Pliocene-Pleistocene) have shaped the biogeography of the region. In the Neotropics, avian population structure has been sculpted not only by geographical barriers, but also by non-allopatric factors such as natural selection and local adaptation. We analyzed the genetic variation of six co-distributed Phrygilus species from the Central Andes, based on mitochondrial and nuclear markers in conjunction with morphological differentiation. We examined if Phrygilus species share patterns of population structure and historical demography, and reviewed the intraspecific taxonomy in part of their geographic range. Our results showed different phylogeographic patterns between species, even among those belonging to the same phylogenetic clade. P. alaudinus, P. atriceps, and P. unicolor showed genetic differentiation mediated by allopatric mechanisms in response to specific geographic barriers; P. gayi showed sympatric lineages in northern Chile, while P. plebejus and P. fruticeti showed a single genetic group. We found no relationship between geographic range size and genetic structure. Additionally, a signature of expansion was found in three species related to the expansion of paleolakes in the Altiplano region and the drying phase of the Atacama Desert. Morphological analysis showed congruence with molecular data and intraspecific taxonomy in most species. While we detected genetic and phenotypic patterns that could be related to natural selection and local adaptation, our results indicate that allopatric events acted as a major factor in the population differentiation of Phrygilus species. Copyright © 2015 Elsevier Inc. All rights reserved.

Changing crops in response to climate: virtual Nang Rong, Thailand in an agent based simulation

PubMed Central

Malanson, George P.; Verdery, Ashton M.; Walsh, Stephen J.; Sawangdee, Yothin; Heumann, Benjamin W.; McDaniel, Philip M.; Frizzelle, Brian G.; Williams, Nathalie E.; Yao, Xiaozheng; Entwisle, Barbara; Rindfuss, Ronald R.

2014-01-01

The effects of extended climatic variability on agricultural land use were explored for the type of system found in villages of northeastern Thailand. An agent based model developed for the Nang Rong district was used to simulate land allotted to jasmine rice, heavy rice, cassava, and sugar cane. The land use choices in the model depended on likely economic outcomes, but included elements of bounded rationality in dependence on household demography. The socioeconomic dynamics are endogenous in the system, and climate changes were added as exogenous drivers. Villages changed their agricultural effort in many different ways. Most villages reduced the amount of land under cultivation, primarily with reduction in jasmine rice, but others did not. The variation in responses to climate change indicates potential sensitivity to initial conditions and path dependence for this type of system. The differences between our virtual villages and the real villages of the region indicate effects of bounded rationality and limits on model applications. PMID:25061240

Comparative modeling of Bronze Age land use in the Malatya Plain (Turkey)

NASA Astrophysics Data System (ADS)

Arıkan, Bülent; Restelli, Francesca Balossi; Masi, Alessia

2016-03-01

Computational modeling in archeology has proven to be a useful tool in quantifying changes in the paleoenvironment. This especially useful method combines data from diverse disciplines to answer questions focusing on the complex and non-linear aspects of human-environment interactions. The research presented here uses various proxy records to compare the changes in climate during the Bronze Age in the Malatya Plain in eastern Anatolia, which is situated at the northern extremity of northern Mesopotamia. Extensive agropastoral land use modeling was applied to three sites of different size and function in the Malatya Plain during the Early Bronze Age I period to simulate the varying scale and intensity of human impacts in relation to changes in the level of social organization, demography, and temporal length. The results suggest that even in land use types subjected to a light footprint, the scale and intensity of anthropogenic impacts change significantly in relation to the level of social organization.

Hydrology and density feedbacks control the ecology of intermediate hosts of schistosomiasis across habitats in seasonal climates

PubMed Central

Perez-Saez, Javier; Mande, Theophile; Ceperley, Natalie; Bertuzzo, Enrico; Mari, Lorenzo; Rinaldo, Andrea

2016-01-01

We report about field and theoretical studies on the ecology of the aquatic snails (Bulinus spp. and Biomphalaria pfeifferi) that serve as obligate intermediate hosts in the complex life cycle of the parasites causing human schistosomiasis. Snail abundance fosters disease transmission, and thus the dynamics of snail populations are critically important for schistosomiasis modeling and control. Here, we single out hydrological drivers and density dependence (or lack of it) of ecological growth rates of local snail populations by contrasting novel ecological and environmental data with various models of host demography. Specifically, we study various natural and man-made habitats across Burkina Faso’s highly seasonal climatic zones. Demographic models are ranked through formal model comparison and structural risk minimization. The latter allows us to evaluate the suitability of population models while clarifying the relevant covariates that explain empirical observations of snail abundance under the actual climatic forcings experienced by the various field sites. Our results link quantitatively hydrological drivers to distinct population dynamics through specific density feedbacks, and show that statistical methods based on model averaging provide reliable snail abundance projections. The consistency of our ranking results suggests the use of ad hoc models of snail demography depending on habitat type (e.g., natural vs. man-made) and hydrological characteristics (e.g., ephemeral vs. permanent). Implications for risk mapping and space-time allocation of control measures in schistosomiasis-endemic contexts are discussed. PMID:27162339

Hydrology and density feedbacks control the ecology of intermediate hosts of schistosomiasis across habitats in seasonal climates.

PubMed

Perez-Saez, Javier; Mande, Theophile; Ceperley, Natalie; Bertuzzo, Enrico; Mari, Lorenzo; Gatto, Marino; Rinaldo, Andrea

2016-06-07

We report about field and theoretical studies on the ecology of the aquatic snails (Bulinus spp. and Biomphalaria pfeifferi) that serve as obligate intermediate hosts in the complex life cycle of the parasites causing human schistosomiasis. Snail abundance fosters disease transmission, and thus the dynamics of snail populations are critically important for schistosomiasis modeling and control. Here, we single out hydrological drivers and density dependence (or lack of it) of ecological growth rates of local snail populations by contrasting novel ecological and environmental data with various models of host demography. Specifically, we study various natural and man-made habitats across Burkina Faso's highly seasonal climatic zones. Demographic models are ranked through formal model comparison and structural risk minimization. The latter allows us to evaluate the suitability of population models while clarifying the relevant covariates that explain empirical observations of snail abundance under the actual climatic forcings experienced by the various field sites. Our results link quantitatively hydrological drivers to distinct population dynamics through specific density feedbacks, and show that statistical methods based on model averaging provide reliable snail abundance projections. The consistency of our ranking results suggests the use of ad hoc models of snail demography depending on habitat type (e.g., natural vs. man-made) and hydrological characteristics (e.g., ephemeral vs. permanent). Implications for risk mapping and space-time allocation of control measures in schistosomiasis-endemic contexts are discussed.

Optimal time--energy allocation and the evolution of colony demography among eusocial insects. [Polistes fuscatus, Vespa orientalis, ants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Macevicz, S.C.

1979-05-09

This thesis attempts to explain the evolution of certain features of social insect colony population structure by the use of optimization models. Two areas are examined in detail. First, the optimal reproductive strategies of annual eusocial insects are considered. A model is constructed for the growth of workers and reproductives as a function of the resources allocated to each. Next the allocation schedule is computed which yields the maximum number of reproductives by season's end. The results indicate that if there is constant return to scale for allocated resources the optimal strategy is to invest in colony growth until approximatelymore » one generation before season's end, whereupon worker production ceases and reproductive effort is switched entirely to producing queens and males. Furthermore, the results indicate that if there is decreasing return to scale for allocated resources then simultaneous production of workers and reproductives is possible. The model is used to explain the colony demography of two species of wasp, Polistes fuscatus and Vespa orientalis. Colonies of these insects undergo a sudden switch from the production of workers to the production of reproductives. The second area examined concerns optimal forager size distributions for monomorphic ant colonies. A model is constructed that describes the colony's energetic profit as a function which depends on the size distribution of food resources as well as forager efficiency, metabolic costs, and manufacturing costs.« less

Larval settlement rate: a leading determinant of structure in an ecological community of the marine intertidal zone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaines, S.; Roughgarden, J.

Field studies demonstrate that the population structure of the barnacle Balanus glandula differs between locations of high and low larval settlement rate. These observations, together with results from a model for the demography of an open, space-limited population, suggest that the settlement rate may be a more important determinant of rocky intertidal community structure than is presently realized. At the low-settlement location mortality of barnacles is independent of the area occupied by barnacles. At the high-settlement location mortality is cover-dependent due to increased predation by starfish on areas of high barnacle cover. In both locations the cover-independent component of mortalitymore » does not vary with age during the first 60 weeks. Generalizations that the highest species diversity in a rocky intertidal community is found at locations of intermediate disturbance, and that competition causes zonation between species of the barnacle genera Balanus and Chthamalus, seem to apply only to locations with high-settlement rates.« less

Genetic diversity and population structure in contemporary house sparrow populations along an urbanization gradient

PubMed Central

Vangestel, C; Mergeay, J; Dawson, D A; Callens, T; Vandomme, V; Lens, L

2012-01-01

House sparrow (Passer domesticus) populations have suffered major declines in urban as well as rural areas, while remaining relatively stable in suburban ones. Yet, to date no exhaustive attempt has been made to examine how, and to what extent, spatial variation in population demography is reflected in genetic population structuring along contemporary urbanization gradients. Here we use putatively neutral microsatellite loci to study if and how genetic variation can be partitioned in a hierarchical way among different urbanization classes. Principal coordinate analyses did not support the hypothesis that urban/suburban and rural populations comprise two distinct genetic clusters. Comparison of FST values at different hierarchical scales revealed drift as an important force of population differentiation. Redundancy analyses revealed that genetic structure was strongly affected by both spatial variation and level of urbanization. The results shown here can be used as baseline information for future genetic monitoring programmes and provide additional insights into contemporary house sparrow dynamics along urbanization gradients. PMID:22588131

Genetic diversity and population structure in contemporary house sparrow populations along an urbanization gradient.

PubMed

Vangestel, C; Mergeay, J; Dawson, D A; Callens, T; Vandomme, V; Lens, L

2012-09-01

House sparrow (Passer domesticus) populations have suffered major declines in urban as well as rural areas, while remaining relatively stable in suburban ones. Yet, to date no exhaustive attempt has been made to examine how, and to what extent, spatial variation in population demography is reflected in genetic population structuring along contemporary urbanization gradients. Here we use putatively neutral microsatellite loci to study if and how genetic variation can be partitioned in a hierarchical way among different urbanization classes. Principal coordinate analyses did not support the hypothesis that urban/suburban and rural populations comprise two distinct genetic clusters. Comparison of FST values at different hierarchical scales revealed drift as an important force of population differentiation. Redundancy analyses revealed that genetic structure was strongly affected by both spatial variation and level of urbanization. The results shown here can be used as baseline information for future genetic monitoring programmes and provide additional insights into contemporary house sparrow dynamics along urbanization gradients.

The impact of seed extraction on the population dynamics of Pinus maximartinezii

NASA Astrophysics Data System (ADS)

López-Mata, Lauro

2013-05-01

Pinus maximartinezii is a rare, endemic, threatened species known from a single small population in the state of Zacatecas, Mexico. Among the pine species that produce edible nuts, it produces one of the largest and most nutritious seeds. The seeds of P. maximartinezii have historically been used for human consumption. The cones are harvested directly from the trees, and the seeds are sold illegally in local, national and international markets. However, the effects of seed extraction must be thoroughly evaluated to determine the potential impacts on population stability. To assess the impact of different rates of seed harvesting on the demography of this species, a 2-yr study of population dynamics was conducted in three 0.1-ha plots. A 9 × 9 size-structured matrix model was used to simulate changes in population growth over time in conjunction with increasing stepwise reductions in fecundity. The population growth rate (λ) of P. maximartinezii was 1.1175, with a 95% confidence interval (CI) from 1.1008 to 1.1321, and it was relatively insensitive to changes in fecundity and growth. Under a seed extraction intensity of 99%, λ decreased to 1.0241, with a CI from 1.0177 to 1.0361. Elasticity analysis was then performed to identify the combined effects of proportional changes in fecundities and the largest stasis elements on λ. The results suggest that a sound conservation strategy should focus on improving the survival of juveniles and adults during their first reproductive events and on the largest adults, as well as on protecting the habitat of this threatened endemic species.

Health Data Publications No. 27. Mozambique.

DTIC Science & Technology

PUBLIC HEALTH, *MOZAMBIQUE, EDUCATION , ECONOMICS, DEMOGRAPHY, MAPS, ANIMALS, WASTE DISPOSAL, MEDICAL SERVICES, MEDICAL RESEARCH, SOCIOLOGY, EPIDEMIOLOGY, WATER SUPPLIES, PLANTS(BOTANY), VETERINARY MEDICINE.

Hanford Environmental Dose Reconstruction Project monthly report, November 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cannon, S.D.; Finch, S.M.

1992-12-31

The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The TSP consists of experts in environmental pathways, epidemiology, surface-water transport, ground-water transport, statistics, demography, agriculture, meteorology, nuclear engineering, radiation dosimetry, and cultural anthropology. Included are appointed members representing the states of Oregon, Washington. and Idaho, a representative of Native American tribes, and an individual representing the public. The project is divided into the following technical tasks: Source terms; environmental transport; environmental monitoring data; demography, food consumption and agriculture; environmentalmore » pathways and dose estimates.« less

Hanford Environmental Dose Reconstruction Project monthly report, November 1992

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cannon, S.D.; Finch, S.M.

1992-01-01

The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The TSP consists of experts in environmental pathways, epidemiology, surface-water transport, ground-water transport, statistics, demography, agriculture, meteorology, nuclear engineering, radiation dosimetry, and cultural anthropology. Included are appointed members representing the states of Oregon, Washington. and Idaho, a representative of Native American tribes, and an individual representing the public. The project is divided into the following technical tasks: Source terms; environmental transport; environmental monitoring data; demography, food consumption and agriculture; environmentalmore » pathways and dose estimates.« less

Mosquito population dynamics from cellular automata-based simulation

NASA Astrophysics Data System (ADS)

Syafarina, Inna; Sadikin, Rifki; Nuraini, Nuning

2016-02-01

In this paper we present an innovative model for simulating mosquito-vector population dynamics. The simulation consist of two stages: demography and dispersal dynamics. For demography simulation, we follow the existing model for modeling a mosquito life cycles. Moreover, we use cellular automata-based model for simulating dispersal of the vector. In simulation, each individual vector is able to move to other grid based on a random walk. Our model is also capable to represent immunity factor for each grid. We simulate the model to evaluate its correctness. Based on the simulations, we can conclude that our model is correct. However, our model need to be improved to find a realistic parameters to match real data.

Focus on environmental risks and migration: causes and consequences

NASA Astrophysics Data System (ADS)

Adger, W. Neil; Arnell, Nigel W.; Black, Richard; Dercon, Stefan; Geddes, Andrew; Thomas, David S. G.

2015-06-01

Environmental change poses risks to societies, including disrupting social and economic systems such as migration. At the same time, migration is an effective adaptation to environmental and other risks. We review novel science on interactions between migration, environmental risks and climate change. We highlight emergent findings, including how dominant flows of rural to urban migration mean that populations are exposed to new risks within destination areas and the requirement for urban sustainability. We highlight the issue of lack of mobility as a major issue limiting the effectiveness of migration as an adaptation strategy and leading to potentially trapped populations. The paper presents scenarios of future migration that show both displacement and trapped populations over the incoming decades. Papers in the special issue bring new insights from demography, human geography, political science and environmental science to this emerging field.

Is the caesarean section rate a performance indicator of an obstetric unit?

PubMed

Singh, Ruchi; Nath Trivedi, Amarendra

2011-02-01

The indications of caesarean section are increasing. The need to respect maternal desire in the decision making has been supported by law and ethics. Some of the other contributors to the increasing caesarean section rate are breech with failed external cephalic version, decreasing rate of trial of scar, increasing induction rate and electronic fetal heart rate monitoring and changing demography. Despite the adverse effects of caesarean section, the incidence of severe morbidity and mortality is low. The strategies put forward to reduce the caesarean section rate (CSR) have not been effective and in no country or province, the CSR has come down. CSR should not be looked at in isolation or as high or low. It is the product of changing obstetric practice and societal norms and demographics. CSR not reflect the performance of a maternity unit.

Holocene fluctuations in human population demonstrate repeated links to food production and climate.

PubMed

Bevan, Andrew; Colledge, Sue; Fuller, Dorian; Fyfe, Ralph; Shennan, Stephen; Stevens, Chris

2017-12-05

We consider the long-term relationship between human demography, food production, and Holocene climate via an archaeological radiocarbon date series of unprecedented sampling density and detail. There is striking consistency in the inferred human population dynamics across different regions of Britain and Ireland during the middle and later Holocene. Major cross-regional population downturns in population coincide with episodes of more abrupt change in North Atlantic climate and witness societal responses in food procurement as visible in directly dated plants and animals, often with moves toward hardier cereals, increased pastoralism, and/or gathered resources. For the Neolithic, this evidence questions existing models of wholly endogenous demographic boom-bust. For the wider Holocene, it demonstrates that climate-related disruptions have been quasi-periodic drivers of societal and subsistence change. Copyright © 2017 the Author(s). Published by PNAS.

Improving predictions of tropical forest response to climate change through integration of field studies and ecosystem modeling.

PubMed

Feng, Xiaohui; Uriarte, María; González, Grizelle; Reed, Sasha; Thompson, Jill; Zimmerman, Jess K; Murphy, Lora

2018-01-01

Tropical forests play a critical role in carbon and water cycles at a global scale. Rapid climate change is anticipated in tropical regions over the coming decades and, under a warmer and drier climate, tropical forests are likely to be net sources of carbon rather than sinks. However, our understanding of tropical forest response and feedback to climate change is very limited. Efforts to model climate change impacts on carbon fluxes in tropical forests have not reached a consensus. Here, we use the Ecosystem Demography model (ED2) to predict carbon fluxes of a Puerto Rican tropical forest under realistic climate change scenarios. We parameterized ED2 with species-specific tree physiological data using the Predictive Ecosystem Analyzer workflow and projected the fate of this ecosystem under five future climate scenarios. The model successfully captured interannual variability in the dynamics of this tropical forest. Model predictions closely followed observed values across a wide range of metrics including aboveground biomass, tree diameter growth, tree size class distributions, and leaf area index. Under a future warming and drying climate scenario, the model predicted reductions in carbon storage and tree growth, together with large shifts in forest community composition and structure. Such rapid changes in climate led the forest to transition from a sink to a source of carbon. Growth respiration and root allocation parameters were responsible for the highest fraction of predictive uncertainty in modeled biomass, highlighting the need to target these processes in future data collection. Our study is the first effort to rely on Bayesian model calibration and synthesis to elucidate the key physiological parameters that drive uncertainty in tropical forests responses to climatic change. We propose a new path forward for model-data synthesis that can substantially reduce uncertainty in our ability to model tropical forest responses to future climate. © 2017 John Wiley & Sons Ltd.

Improving predictions of tropical forest response to climate change through integration of field studies and ecosystem modeling

USGS Publications Warehouse

Feng, Xiaohui; Uriarte, María; González, Grizelle; Reed, Sasha C.; Thompson, Jill; Zimmerman, Jess K.; Murphy, Lora

2018-01-01

Tropical forests play a critical role in carbon and water cycles at a global scale. Rapid climate change is anticipated in tropical regions over the coming decades and, under a warmer and drier climate, tropical forests are likely to be net sources of carbon rather than sinks. However, our understanding of tropical forest response and feedback to climate change is very limited. Efforts to model climate change impacts on carbon fluxes in tropical forests have not reached a consensus. Here we use the Ecosystem Demography model (ED2) to predict carbon fluxes of a Puerto Rican tropical forest under realistic climate change scenarios. We parameterized ED2 with species-specific tree physiological data using the Predictive Ecosystem Analyzer workflow and projected the fate of this ecosystem under five future climate scenarios. The model successfully captured inter-annual variability in the dynamics of this tropical forest. Model predictions closely followed observed values across a wide range of metrics including above-ground biomass, tree diameter growth, tree size class distributions, and leaf area index. Under a future warming and drying climate scenario, the model predicted reductions in carbon storage and tree growth, together with large shifts in forest community composition and structure. Such rapid changes in climate led the forest to transition from a sink to a source of carbon. Growth respiration and root allocation parameters were responsible for the highest fraction of predictive uncertainty in modeled biomass, highlighting the need to target these processes in future data collection. Our study is the first effort to rely on Bayesian model calibration and synthesis to elucidate the key physiological parameters that drive uncertainty in tropical forests responses to climatic change. We propose a new path forward for model-data synthesis that can substantially reduce uncertainty in our ability to model tropical forest responses to future climate.

Travelling waves and spatial hierarchies in measles epidemics

NASA Astrophysics Data System (ADS)

Grenfell, B. T.; Bjørnstad, O. N.; Kappey, J.

2001-12-01

Spatio-temporal travelling waves are striking manifestations of predator-prey and host-parasite dynamics. However, few systems are well enough documented both to detect repeated waves and to explain their interaction with spatio-temporal variations in population structure and demography. Here, we demonstrate recurrent epidemic travelling waves in an exhaustive spatio-temporal data set for measles in England and Wales. We use wavelet phase analysis, which allows for dynamical non-stationarity-a complication in interpreting spatio-temporal patterns in these and many other ecological time series. In the pre-vaccination era, conspicuous hierarchical waves of infection moved regionally from large cities to small towns; the introduction of measles vaccination restricted but did not eliminate this hierarchical contagion. A mechanistic stochastic model suggests a dynamical explanation for the waves-spread via infective `sparks' from large `core' cities to smaller `satellite' towns. Thus, the spatial hierarchy of host population structure is a prerequisite for these infection waves.

Clustering of 770,000 genomes reveals post-colonial population structure of North America

NASA Astrophysics Data System (ADS)

Han, Eunjung; Carbonetto, Peter; Curtis, Ross E.; Wang, Yong; Granka, Julie M.; Byrnes, Jake; Noto, Keith; Kermany, Amir R.; Myres, Natalie M.; Barber, Mathew J.; Rand, Kristin A.; Song, Shiya; Roman, Theodore; Battat, Erin; Elyashiv, Eyal; Guturu, Harendra; Hong, Eurie L.; Chahine, Kenneth G.; Ball, Catherine A.

2017-02-01

Despite strides in characterizing human history from genetic polymorphism data, progress in identifying genetic signatures of recent demography has been limited. Here we identify very recent fine-scale population structure in North America from a network of over 500 million genetic (identity-by-descent, IBD) connections among 770,000 genotyped individuals of US origin. We detect densely connected clusters within the network and annotate these clusters using a database of over 20 million genealogical records. Recent population patterns captured by IBD clustering include immigrants such as Scandinavians and French Canadians; groups with continental admixture such as Puerto Ricans; settlers such as the Amish and Appalachians who experienced geographic or cultural isolation; and broad historical trends, including reduced north-south gene flow. Our results yield a detailed historical portrait of North America after European settlement and support substantial genetic heterogeneity in the United States beyond that uncovered by previous studies.

Clustering of 770,000 genomes reveals post-colonial population structure of North America

PubMed Central

Han, Eunjung; Carbonetto, Peter; Curtis, Ross E.; Wang, Yong; Granka, Julie M.; Byrnes, Jake; Noto, Keith; Kermany, Amir R.; Myres, Natalie M.; Barber, Mathew J.; Rand, Kristin A.; Song, Shiya; Roman, Theodore; Battat, Erin; Elyashiv, Eyal; Guturu, Harendra; Hong, Eurie L.; Chahine, Kenneth G.; Ball, Catherine A.

2017-01-01

Despite strides in characterizing human history from genetic polymorphism data, progress in identifying genetic signatures of recent demography has been limited. Here we identify very recent fine-scale population structure in North America from a network of over 500 million genetic (identity-by-descent, IBD) connections among 770,000 genotyped individuals of US origin. We detect densely connected clusters within the network and annotate these clusters using a database of over 20 million genealogical records. Recent population patterns captured by IBD clustering include immigrants such as Scandinavians and French Canadians; groups with continental admixture such as Puerto Ricans; settlers such as the Amish and Appalachians who experienced geographic or cultural isolation; and broad historical trends, including reduced north-south gene flow. Our results yield a detailed historical portrait of North America after European settlement and support substantial genetic heterogeneity in the United States beyond that uncovered by previous studies. PMID:28169989

Clustering of 770,000 genomes reveals post-colonial population structure of North America.

PubMed

Han, Eunjung; Carbonetto, Peter; Curtis, Ross E; Wang, Yong; Granka, Julie M; Byrnes, Jake; Noto, Keith; Kermany, Amir R; Myres, Natalie M; Barber, Mathew J; Rand, Kristin A; Song, Shiya; Roman, Theodore; Battat, Erin; Elyashiv, Eyal; Guturu, Harendra; Hong, Eurie L; Chahine, Kenneth G; Ball, Catherine A

2017-02-07

Despite strides in characterizing human history from genetic polymorphism data, progress in identifying genetic signatures of recent demography has been limited. Here we identify very recent fine-scale population structure in North America from a network of over 500 million genetic (identity-by-descent, IBD) connections among 770,000 genotyped individuals of US origin. We detect densely connected clusters within the network and annotate these clusters using a database of over 20 million genealogical records. Recent population patterns captured by IBD clustering include immigrants such as Scandinavians and French Canadians; groups with continental admixture such as Puerto Ricans; settlers such as the Amish and Appalachians who experienced geographic or cultural isolation; and broad historical trends, including reduced north-south gene flow. Our results yield a detailed historical portrait of North America after European settlement and support substantial genetic heterogeneity in the United States beyond that uncovered by previous studies.

DIM SUM: demography and individual migration simulated using a Markov chain.

PubMed

Brown, Jeremy M; Savidge, Kevin; McTavish, Emily Jane B

2011-03-01

An increasing number of studies seek to infer demographic history, often jointly with genetic relationships. Despite numerous analytical methods for such data, few simulations have investigated the methods' power and robustness, especially when underlying assumptions have been violated. DIM SUM (Demography and Individual Migration Simulated Using a Markov chain) is a stand-alone Java program for the simulation of population demography and individual migration while recording ancestor-descendant relationships. It does not employ coalescent assumptions or discrete population boundaries. It is extremely flexible, allowing the user to specify border positions, reactions of organisms to borders, local and global carrying capacities, individual dispersal kernels, rates of reproduction and strategies for sampling individuals. Spatial variables may be specified using image files (e.g., as exported from gis software) and may vary through time. In combination with software for genetic marker simulation, DIM SUM will be useful for testing phylogeographic (e.g., nested clade phylogeographic analysis, coalescent-based tests and continuous-landscape frameworks) and landscape-genetic methods, specifically regarding violations of coalescent assumptions. It can also be used to explore the qualitative features of proposed demographic scenarios (e.g. regarding biological invasions) and as a pedagogical tool. DIM SUM (with user's manual) can be downloaded from http://code.google.com/p/bio-dimsum. © 2010 Blackwell Publishing Ltd.

The porcupine caribou herd

USGS Publications Warehouse

Griffith, Brad; Douglas, David C.; Walsh, Noreen E.; Young, Donald D.; McCabe, Thomas R.; Russell, Donald E.; White, Robert G.; Cameron, Raymond D.; Whitten, Kenneth R.; Douglas, David C.; Reynolds, Patricia E.; Rhode, E.B.

2002-01-01

Documentation of the natural range of variation in ecological, life history, and physiological characteristics of caribou (Rangifer tarandus) of the Porcupine caribou herd is a necessary base for detecting or predicting any potential effects of industrial development on the performance (e.g., distribution, demography, weight-gain of individuals) of the herd. To demonstrate an effect of development, post-development performance must differ from pre-development performance while accounting for any natural environmental trends.We had 2 working hypotheses for our investigations: 1) performance of the Porcupine caribou herd was associated with environmental patterns and habitat quality, and 2) access to important habitats was a key influence on demography.We sought to document the range of natural variation in habitat conditions, herd size, demography (defined here as survival and reproduction), sources and magnitude of mortality, distribution, habitat use, and weight gain and loss, and to develop an understanding of the interactions among these characteristics of the herd.In addition, we investigated ways that we could use this background information, combined with auxiliary information from the adjacent Central Arctic caribou herd, to predict the direction and magnitude of any potential effects of industrial oil development in the 1002 Area of the Arctic National Wildlife Refuge on Porcupine caribou herd calf survival on the herd's calving grounds during June.

A kinetic theory for age-structured stochastic birth-death processes

NASA Astrophysics Data System (ADS)

Chou, Tom; Greenman, Chris

Classical age-structured mass-action models such as the McKendrick-von Foerster equation have been extensively studied but they are structurally unable to describe stochastic fluctuations or population-size-dependent birth and death rates. Conversely, current theories that include size-dependent population dynamics (e.g., carrying capacity) cannot be easily extended to take into account age-dependent birth and death rates. In this paper, we present a systematic derivation of a new fully stochastic kinetic theory for interacting age-structured populations. By defining multiparticle probability density functions, we derive a hierarchy of kinetic equations for the stochastic evolution of an aging population undergoing birth and death. We show that the fully stochastic age-dependent birth-death process precludes factorization of the corresponding probability densities, which then must be solved by using a BBGKY-like hierarchy. Our results generalize both deterministic models and existing master equation approaches by providing an intuitive and efficient way to simultaneously model age- and population-dependent stochastic dynamics applicable to the study of demography, stem cell dynamics, and disease evolution. NSF.

78 FR 19446 - Census Scientific Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-01

... disciplines: Statistical sciences, demography, economics, geography, psychology, survey methodology, social and behavioral sciences, information technology, and other fields of expertise, as appropriate. Last...

Genetic demographic networks: Mathematical model and applications.

PubMed

Kimmel, Marek; Wojdyła, Tomasz

2016-10-01

Recent improvement in the quality of genetic data obtained from extinct human populations and their ancestors encourages searching for answers to basic questions regarding human population history. The most common and successful are model-based approaches, in which genetic data are compared to the data obtained from the assumed demography model. Using such approach, it is possible to either validate or adjust assumed demography. Model fit to data can be obtained based on reverse-time coalescent simulations or forward-time simulations. In this paper we introduce a computational method based on mathematical equation that allows obtaining joint distributions of pairs of individuals under a specified demography model, each of them characterized by a genetic variant at a chosen locus. The two individuals are randomly sampled from either the same or two different populations. The model assumes three types of demographic events (split, merge and migration). Populations evolve according to the time-continuous Moran model with drift and Markov-process mutation. This latter process is described by the Lyapunov-type equation introduced by O'Brien and generalized in our previous works. Application of this equation constitutes an original contribution. In the result section of the paper we present sample applications of our model to both simulated and literature-based demographies. Among other we include a study of the Slavs-Balts-Finns genetic relationship, in which we model split and migrations between the Balts and Slavs. We also include another example that involves the migration rates between farmers and hunters-gatherers, based on modern and ancient DNA samples. This latter process was previously studied using coalescent simulations. Our results are in general agreement with the previous method, which provides validation of our approach. Although our model is not an alternative to simulation methods in the practical sense, it provides an algorithm to compute pairwise distributions of alleles, in the case of haploid non-recombining loci such as mitochondrial and Y-chromosome loci in humans. Copyright © 2016 Elsevier Inc. All rights reserved.

Proposal of a short-form version of the Brazilian Food Insecurity Scale

PubMed Central

dos Santos, Leonardo Pozza; Lindemann, Ivana Loraine; Motta, Janaína Vieira dos Santos; Mintem, Gicele; Bender, Eliana; Gigante, Denise Petrucci

2014-01-01

OBJECTIVE To propose a short version of the Brazilian Food Insecurity Scale. METHODS Two samples were used to test the results obtained in the analyses in two distinct scenarios. One of the studies was composed of 230 low income families from Pelotas, RS, Southern Brazil, and the other was composed of 15,575 women, whose data were obtained from the 2006 National Survey on Demography and Health. Two models were tested, the first containing seven questions, and the second, the five questions that were considered the most relevant ones in the concordance analysis. The models were compared to the Brazilian Food Insecurity Scale, and the sensitivity, specificity and accuracy parameters were calculated, as well as the kappa agreement test. RESULTS Comparing the prevalence of food insecurity between the Brazilian Food Insecurity Scale and the two models, the differences were around 2 percentage points. In the sensitivity analysis, the short version of seven questions obtained 97.8% and 99.5% in the Pelotas sample and in the National Survey on Demography and Health sample, respectively, while specificity was 100% in both studies. The five-question model showed similar results (sensitivity of 95.7% and 99.5% in the Pelotas sample and in the National Survey on Demography and Health sample, respectively). In the Pelotas sample, the kappa test of the seven-question version totaled 97.0% and that of the five-question version, 95.0%. In the National Survey on Demography and Health sample, the two models presented a 99.0% kappa. CONCLUSIONS We suggest that the model with five questions should be used as the short version of the Brazilian Food Insecurity Scale, as its results were similar to the original scale with a lower number of questions. This version needs to be administered to other populations in Brazil in order to allow for the adequate assessment of the validity parameters. PMID:25372169

Demography and ecology of mangrove diamondback terrapins in a wilderness area of Everglades National Park, Florida, USA

USGS Publications Warehouse

Hart, K.M.; McIvor, C.C.

2008-01-01

Diamondback Terrapins (Malaclemys terrapin) are distributed in brackish water habitats along the U.S. east coast from Massachusetts to Texas, but many populations may be in decline. Whereas ample morphological, behavioral, and reproductive information has been collected for terrapins living in temperate salt marsh habitats, comparatively little is known about mangrove terrapins. To understand population structure of mangrove M. terrapin living in a wilderness area, we conducted a capture-recapture study in the remote, protected Big Sable Creek complex of Everglades National Park, Florida. The goals of the study were to collect baseline demographic data and to compare population structure and growth rates of mangrove terrapins with what is known for more well studied salt marsh terrapins in locations that experience human-imposed threats. We marked 300 terrapins; the sex ratio was 1 female:1.2 males. Considerable sexual size dimorphism was apparent, with reproductively mature females three times larger (by mass) than mature males. Eighty percent of females and 94% of males were classified as mature, based on straight plastron length (SPL). For a subset of terrapins not yet at maximum size (n = 39), we measured growth as a change in straight carapace length over time of 0.3-26.4 mm/yr for females (n = 26) and 0.9-14.5 mm/yr for males (n = 13). Our study presents the first demographic data on mangrove M. terrapin in the coastal Everglades. ?? 2008 by the American Society of Ichthyologists and Herpetologists.

Identification of metapopulation dynamics among Northern Goshawks of the Alexander Archipelago, Alaska, and Coastal British Columbia

USGS Publications Warehouse

Sonsthagen, Sarah A.; McClaren, Erica L.; Doyle, Frank I.; Titus, K.; Sage, George K.; Wilson, Robert E.; Gust, Judy R.; Talbot, Sandra L.

2012-01-01

Northern Goshawks occupying the Alexander Archipelago, Alaska, and coastal British Columbia nest primarily in old-growth and mature forest, which results in spatial heterogeneity in the distribution of individuals across the landscape. We used microsatellite and mitochondrial data to infer genetic structure, gene flow, and fluctuations in population demography through evolutionary time. Patterns in the genetic signatures were used to assess predictions associated with the three population models: panmixia, metapopulation, and isolated populations. Population genetic structure was observed along with asymmetry in gene flow estimates that changed directionality at different temporal scales, consistent with metapopulation model predictions. Therefore, Northern Goshawk assemblages located in the Alexander Archipelago and coastal British Columbia interact through a metapopulation framework, though they may not fit the classic model of a metapopulation. Long-term population sources (coastal mainland British Columbia) and sinks (Revillagigedo and Vancouver islands) were identified. However, there was no trend through evolutionary time in the directionality of dispersal among the remaining assemblages, suggestive of a rescue-effect dynamic. Admiralty, Douglas, and Chichagof island complex appears to be an evolutionarily recent source population in the Alexander Archipelago. In addition, Kupreanof island complex and Kispiox Forest District populations have high dispersal rates to populations in close geographic proximity and potentially serve as local source populations. Metapopulation dynamics occurring in the Alexander Archipelago and coastal British Columbia by Northern Goshawks highlight the importance of both occupied and unoccupied habitats to long-term population persistence of goshawks in this region.

Positive correlation between genetic diversity and fitness in a large, well-connected metapopulation.

PubMed

Vandewoestijne, Sofie; Schtickzelle, Nicolas; Baguette, Michel

2008-11-05

Theory predicts that lower dispersal, and associated gene flow, leads to decreased genetic diversity in small isolated populations, which generates adverse consequences for fitness, and subsequently for demography. Here we report for the first time this effect in a well-connected natural butterfly metapopulation with high population densities at the edge of its distribution range. We demonstrate that: (1) lower genetic diversity was coupled to a sharp decrease in adult lifetime expectancy, a key component of individual fitness; (2) genetic diversity was positively correlated to the number of dispersing individuals (indicative of landscape functional connectivity) and adult population size; (3) parameters inferred from capture-recapture procedures (population size and dispersal events between patches) correlated much better with genetic diversity than estimates usually used as surrogates for population size (patch area and descriptors of habitat quality) and dispersal (structural connectivity index). Our results suggest that dispersal is a very important factor maintaining genetic diversity. Even at a very local spatial scale in a metapopulation consisting of large high-density populations interconnected by considerable dispersal rates, genetic diversity can be decreased and directly affect the fitness of individuals. From a biodiversity conservation perspective, this study clearly shows the benefits of both in-depth demographic and genetic analyses. Accordingly, to ensure the long-term survival of populations, conservation actions should not be blindly based on patch area and structural isolation. This result may be especially pertinent for species at their range margins, particularly in this era of rapid environmental change.

Owned dog ecology and demography in Villa de Tezontepec, Hidalgo, Mexico.

PubMed

Kisiel, Luz Maria; Jones-Bitton, Andria; Sargeant, Jan M; Coe, Jason B; Flockhart, D T Tyler; Reynoso Palomar, Alejandro; Canales Vargas, Erick J; Greer, Amy L

2016-12-01

Dog overpopulation in developing countries has negative implications for the health and safety of people, including the transmission of zoonotic diseases, physical attacks and intimidation to humans and animals, as well as impacts on canine welfare. Understanding the ecology and demographic characteristics of a dog population can help in the planning and monitoring of canine population control programs. Little data exist regarding demography and dynamics of domestic dog populations in semi-urban areas in Mexico. A cross-sectional study was carried out between October 21 and November 7, 2015, to characterize the dog ecology and demography in Villa de Tezontepec, Hidalgo, Mexico. A face-to-face survey was used to collect data from randomly selected households in four contiguous communities using stratified two-stage cluster sampling. Within each household, adults answered questions related to their dogs and their experiences with dog bites and aggression. A total of 328 households were interviewed, representing a participation rate of 90.9% (328/361) and 1,450 people. Approximately 65.2% of the households owned one or more dogs, with a mean of 1.3 (SD=1.5) and 2.0 (SD=1.5) owned dogs in all participant households and dog-owning households, respectively. The human: owned dog ratio for all participant households was 3.4:1 (1450/428), and for the dog-owning households was 2.3:1 (984/428). The owned dog male: female ratio was 1.4:1 (249/179). Approximately 74.4% (95.0% CI=69.8% - 78.7%) of the owned dogs were older than one year (mean age: 2.9 years; SD=2.5). The mean age of owned female dogs at first litter was 1.9 years (SD=1.2) and the mean litter size was 4.2 puppies (SD=2.1). Approximately 36.9% (95.0% CI=31.8% - 46.4%) of the females were spayed, and 14.1% (95.0% CI=10.7% - 19.7%) of the males were neutered. Only 44.9% (95.0% CI=40.1% - 49.7%) were always confined when unsupervised. Approximately 84.4% (95.0% CI=80.6% - 87.7%) were reported to have been vaccinated against rabies in 2015. The knowledge of owned dog demography and ecology provided by this study can inform local government planning of dog population control interventions, and could serve as a baseline for the development of agent-based models to evaluate the effects of different dog population control strategies on dog demography. Copyright © 2016 Elsevier B.V. All rights reserved.

Long-Term Effects of Tetanus Toxoid Inoculation on the Demography and Life Expectancy of the Cayo Santiago Rhesus Macaques

PubMed Central

KESSLER, MATTHEW J.; PACHECO, RAISA HERNÁNDEZ; RAWLINS, RICHARD G.; RUIZ-LAMBRIDES, ANGELINA; DELGADO, DIANA L.; SABAT, ALBERTO M.

2014-01-01

Tetanus was a major cause of mortality in the free-ranging population of rhesus monkeys on Cayo Santiago prior to 1985 when the entire colony was given its first dose of tetanus toxoid. The immediate reduction in mortality that followed tetanus toxoid inoculation (TTI) has been documented, but the long-term demographic effects of eliminating tetanus infections have not. This study uses the Cayo Santiago demographic database to construct comparative life tables 12 years before, and 12 years after, TTI. Life tables and matrix projection models are used to test for differences in: (i) survival among all individuals as well as among social groups, (ii) long-term fitness of the population, (iii) age distribution, (iv) reproductive value, and (v) life expectancy. A retrospective life table response experiment (LTRE) was performed to determine which life cycle transition contributed most to observed changes in long-term fitness of the population post-TTI. Elimination of clinical tetanus infections through mass inoculation improved the health and well-being of the monkeys. It also profoundly affected the population by increasing survivorship and long-term fitness, decreasing the differences in survival rates among social groups, shifting the population’s age distribution towards older individuals, and increasing reproductive value and life expectancy. These findings are significant because they demonstrate the long-term effects of eradicating a major cause of mortality at a single point in time on survival, reproduction, and overall demography of a naturalistic population of primates. PMID:25230585

An Approximate Markov Model for the Wright-Fisher Diffusion and Its Application to Time Series Data.

PubMed

Ferrer-Admetlla, Anna; Leuenberger, Christoph; Jensen, Jeffrey D; Wegmann, Daniel

2016-06-01

The joint and accurate inference of selection and demography from genetic data is considered a particularly challenging question in population genetics, since both process may lead to very similar patterns of genetic diversity. However, additional information for disentangling these effects may be obtained by observing changes in allele frequencies over multiple time points. Such data are common in experimental evolution studies, as well as in the comparison of ancient and contemporary samples. Leveraging this information, however, has been computationally challenging, particularly when considering multilocus data sets. To overcome these issues, we introduce a novel, discrete approximation for diffusion processes, termed mean transition time approximation, which preserves the long-term behavior of the underlying continuous diffusion process. We then derive this approximation for the particular case of inferring selection and demography from time series data under the classic Wright-Fisher model and demonstrate that our approximation is well suited to describe allele trajectories through time, even when only a few states are used. We then develop a Bayesian inference approach to jointly infer the population size and locus-specific selection coefficients with high accuracy and further extend this model to also infer the rates of sequencing errors and mutations. We finally apply our approach to recent experimental data on the evolution of drug resistance in influenza virus, identifying likely targets of selection and finding evidence for much larger viral population sizes than previously reported. Copyright © 2016 by the Genetics Society of America.

[Generation Y : recruitment, retention and development].

PubMed

Schmidt, C E; Möller, J; Schmidt, K; Gerbershagen, M U; Wappler, F; Limmroth, V; Padosch, S A; Bauer, M

2011-06-01

There is a significant shortage of highly qualified personnel in medicine, especially skilled doctors and nurses. This shortage of qualified labor has led to competition between hospitals. Analyzing the circumstances of the competition, nurses and doctors of the so-called generation Y are of importance. Recruitment and retention of these staff members will become a critical success factor for hospitals in the future. An internet search was conducted using the key words "generation Y and medicine, demography, personnel and hospitals". A search in Medline/pubmed for scientific studies on the topics of labor shortage was performed using the key words "personnel, shortage doctors, generation X, baby boomer, personnel and demographic changes, staff". Finally, sources from public institutions and academic medical societies were analyzed. The data were sorted by main categories and relevance for hospitals. Statistical analysis was done using descriptive measures. The analysis confirmed the heterogeneous and complex flood of information on the topic demography and generation. A comparison of the generations showed that they can be separated into baby boomers (born 1946-1964 live to work), generation X (born 1965-1980 work to live) and generation Y (born 1981 and after, live while working). Members of generation Y "live while working" are oriented to competence and less with hierarchies. They exchange information using modern communication methods and within networks. Internet and computers are part of their daily routine. Employees of generation Y challenge leadership in hospitals by increasing the demands. However, generation Y can significantly increase professionalization and competitiveness for hospitals.

Patterns of Nucleotide Diversity at the Regions Encompassing the Drosophila Insulin-Like Peptide (dilp) Genes: Demography vs. Positive Selection in Drosophila melanogaster

PubMed Central

Guirao-Rico, Sara; Aguadé, Montserrat

2013-01-01

In Drosophila, the insulin-signaling pathway controls some life history traits, such as fertility and lifespan, and it is considered to be the main metabolic pathway involved in establishing adult body size. Several observations concerning variation in body size in the Drosophila genus are suggestive of its adaptive character. Genes encoding proteins in this pathway are, therefore, good candidates to have experienced adaptive changes and to reveal the footprint of positive selection. The Drosophila insulin-like peptides (DILPs) are the ligands that trigger the insulin-signaling cascade. In Drosophila melanogaster, there are several peptides that are structurally similar to the single mammalian insulin peptide. The footprint of recent adaptive changes on nucleotide variation can be unveiled through the analysis of polymorphism and divergence. With this aim, we have surveyed nucleotide sequence variation at the dilp1-7 genes in a natural population of D. melanogaster. The comparison of polymorphism in D. melanogaster and divergence from D. simulans at different functional classes of the dilp genes provided no evidence of adaptive protein evolution after the split of the D. melanogaster and D. simulans lineages. However, our survey of polymorphism at the dilp gene regions of D. melanogaster has provided some evidence for the action of positive selection at or near these genes. The regions encompassing the dilp1-4 genes and the dilp6 gene stand out as likely affected by recent adaptive events. PMID:23308258

Factors for Preterm Births in Germany - An Analysis of Representative German Data (KiGGS).

PubMed

Weichert, A; Weichert, T M; Bergmann, R L; Henrich, W; Kalache, K D; Richter, R; Neymeyer, J; Bergmann, K E

2015-08-01

Introduction: Preterm birth is a global scourge, the leading cause of perinatal mortality and morbidity. This study set out to identify the principal risk factors for preterm birth, based on the German Health Interview and Examination Survey for Children and Adolescents (KiGGS). A range of possible factors influencing preterm birth were selected for inclusion in the questionnaire, covering factors such as gender, national origin, immigrant background, demography, living standard, family structure, parental education and vocational training. Methods: All data were taken from the aforementioned KiGGS survey conducted between 2003 and 2006. A total of 17 641 children and adolescents (8656 girls and 8985 boys) drawn from 167 German towns and municipalities deemed to be representative of the Federal Republic of Germany were included in the study. Gestational age at birth was available for 14 234 datasets. The questionnaire included questions from the following areas as possible factors influencing preterm birth: gender, national origins, immigrant background, demography, living standard, family structure, parental education and vocational training. Results: The preterm birth rate was 11.6 %, higher than that of other national statistical evaluations. Around 57.4 % of multiple pregnancies and 10 % of singleton pregnancies resulted in preterm delivery. Multiple pregnancy was found to be the most important risk factor (OR 13.116). With regard to national origins and immigration background, mothers from Turkey, the Middle East, and North Africa had a higher incidence of preterm birth. Preterm birth was more prevalent in cities and large towns than in small towns and villages. Conclusion: Risk factors associated with preterm birth were identified. These should help with the early identification of pregnant women at risk. The preterm birth rate in our survey was higher than that found in other national statistical evaluations based on process data. More than half of all multiple pregnancies ended in preterm birth.

Hanford Environmental Dose Reconstruction Project monthly report

DOE Office of Scientific and Technical Information (OSTI.GOV)

McMakin, A.H., Cannon, S.D.; Finch, S.M.

1992-09-01

The objective of the Hanford Environmental Dose Reconstruction MDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The TSP consists of experts in envirorunental pathways. epidemiology, surface-water transport, ground-water transport, statistics, demography, agriculture, meteorology, nuclear engineering. radiation dosimetry. and cultural anthropology. Included are appointed members representing the states of Oregon, Washington, and Idaho, a representative of Native American tribes, and an individual representing the public. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impact onmore » humans (dose estimates): Source Terms; Environmental Transport; Environmental Monitoring Data Demography, Food Consumption, and Agriculture; and Environmental Pathways and Dose Estimates.« less

A non-marine source of variability in Adélie Penguin demography

USGS Publications Warehouse

Fraser, William R.; Patterson-Fraser, Donna L.; Ribic, Christine; Schofield, Oscar; Ducklow, Hugh

2013-01-01

A primary research objective of the Palmer Long Term Ecological Research (LTER) program has been to identify and understand the factors that regulate the demography of Adélie penguins (Pygoscelis adeliae). In this context, our work has been focused on variability in the marine environment on which this species depends for virtually all aspects of its life history (Ainley, 2002). As we show here, however, there are patterns evident in the population dynamics of Adélie penguins that are better explained by variability in breeding habitat quality rather than by variability in the marine system. Interactions between the geomorphology of the terrestrial environment that, in turn, affect patterns of snow deposition, drive breeding habitat quality.

[Demography and training of residents in gynaecology and obstetrics: results of a national survey].

PubMed

Bendifallah, S; Hudry, D; Niangoh Timoh, K; Yaribakht, S; Boyon, C; Wafo, E

2012-01-01

To survey French trainees in obstetrics and gynaecology on the general demographic evolution and the quality of training. A questionnaire was sent to the 919 trainees in obstetrics and gynaecology during the academic year 2010-2011. Answer rate was 38.5%. Almost all trainees (99.4%) wish to have a two-year hospital position before applying for consultant or beginning a private practice; 60.4% of these trainees declare this option realistic. Trainees demography is marked by an increasing number of young doctors to train and a feminization. The need of a debate is crucial to assure quality of training after the recent increase in the number of residents and trainees reforms. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

The big challenges in modeling human and environmental well-being.

PubMed

Tuljapurkar, Shripad

2016-01-01

This article is a selective review of quantitative research, historical and prospective, that is needed to inform sustainable development policy. I start with a simple framework to highlight how demography and productivity shape human well-being. I use that to discuss three sets of issues and corresponding challenges to modeling: first, population prehistory and early human development and their implications for the future; second, the multiple distinct dimensions of human and environmental well-being and the meaning of sustainability; and, third, inequality as a phenomenon triggered by development and models to examine changing inequality and its consequences. I conclude with a few words about other important factors: political, institutional, and cultural.

Mentoring: leadership, learning, legacy.

PubMed

Friedman, Paula K

2006-01-01

As the dental profession develops over the next few decades, there will be identifiable changes in the demography of the profession. Enrollment trends reflect a growing number of women in dental schools and in the dental profession. There is an increasing number of dentists--men and women--from countries and cultures outside of the United States. The profession must be prepared to address the question of how to engage women--as well as minorities--in more active and visible roles in organized dentistry. The challenge is clear, and the outcome will provide an indicator to the strength of our professional associations in the future. Mentoring of women dentists is one effective way of creating a pathway to participation.

Cascading effects of thermally-induced anemone bleaching on associated anemonefish hormonal stress response and reproduction.

PubMed

Beldade, Ricardo; Blandin, Agathe; O'Donnell, Rory; Mills, Suzanne C

2017-10-10

Organisms can behaviorally, physiologically, and morphologically adjust to environmental variation via integrative hormonal mechanisms, ultimately allowing animals to cope with environmental change. The stress response to environmental and social changes commonly promotes survival at the expense of reproduction. However, despite climate change impacts on population declines and diversity loss, few studies have attributed hormonal stress responses, or their regulatory effects, to climate change in the wild. Here, we report hormonal and fitness responses of individual wild fish to a recent large-scale sea warming event that caused widespread bleaching on coral reefs. This 14-month monitoring study shows a strong correlation between anemone bleaching (zooxanthellae loss), anemonefish stress response, and reproductive hormones that decreased fecundity by 73%. These findings suggest that hormone stress responses play a crucial role in changes to population demography following climate change and plasticity in hormonal responsiveness may be a key mechanism enabling individual acclimation to climate change.Elevated temperatures can cause anemones to bleach, with unknown effects on their associated symbiotic fish. Here, Beldade and colleagues show that climate-induced bleaching alters anemonefish hormonal stress response, resulting in decreased reproductive hormones and severely impacted reproduction.

Effects of climate change and variability on population dynamics in a long-lived shorebird.

PubMed

van de Pol, Martijn; Vindenes, Yngvild; Saether, Bernt-Erik; Engen, Steinar; Ens, Bruno J; Oosterbeek, Kees; Tinbergen, Joost M

2010-04-01

Climate change affects both the mean and variability of climatic variables, but their relative impact on the dynamics of populations is still largely unexplored. Based on a long-term study of the demography of a declining Eurasian Oystercatcher (Haematopus ostralegus) population, we quantify the effect of changes in mean and variance of winter temperature on different vital rates across the life cycle. Subsequently, we quantify, using stochastic stage-structured models, how changes in the mean and variance of this environmental variable affect important characteristics of the future population dynamics, such as the time to extinction. Local mean winter temperature is predicted to strongly increase, and we show that this is likely to increase the population's persistence time via its positive effects on adult survival that outweigh the negative effects that higher temperatures have on fecundity. Interannual variation in winter temperature is predicted to decrease, which is also likely to increase persistence time via its positive effects on adult survival that outweigh the negative effects that lower temperature variability has on fecundity. Overall, a 0.1 degrees C change in mean temperature is predicted to alter median time to extinction by 1.5 times as many years as would a 0.1 degrees C change in the standard deviation in temperature, suggesting that the dynamics of oystercatchers are more sensitive to changes in the mean than in the interannual variability of this climatic variable. Moreover, as climate models predict larger changes in the mean than in the standard deviation of local winter temperature, the effects of future climatic variability on this population's time to extinction are expected to be overwhelmed by the effects of changes in climatic means. We discuss the mechanisms by which climatic variability can either increase or decrease population viability and how this might depend both on species' life histories and on the vital rates affected. This study illustrates that, for making reliable inferences about population consequences in species in which life history changes with age or stage, it is crucial to investigate the impact of climate change on vital rates across the entire life cycle. Disturbingly, such data are unavailable for most species of conservation concern.

The Manchester Uveitis Clinic: the first 3000 patients--epidemiology and casemix.

PubMed

Jones, Nicholas P

2015-04-01

To demonstrate the demography, anatomical, and diagnostic classification of patients with uveitis attending the Manchester Uveitis Clinic (MUC), a specialist uveitis clinic in the northwest of England, UK. Retrospective retrieval of data on a computerized database incorporating all new referrals to MUC from 1991 to 2013. A total of 3000 new patients with uveitis were seen during a 22-year period. The anatomical types seen were anterior 46%; intermediate 11.1%; posterior 21.8%; and panuveitis 21.1%. The most common diagnoses were Fuchs heterochromic uveitis (11.5% of total), sarcoidosis-related uveitis (9.7%), idiopathic intermediate uveitis (7.9%), idiopathic acute anterior uveitis (7.0%), and toxoplasmosis (6.9%). Syphilis and tuberculosis-associated uveitis increased markedly in frequency during the study period. The uveitis casemix in this region reflects a predominantly white Caucasian population in a temperate country, but with changing characteristics owing to increasing immigration, enhanced diagnostic techniques, changes in referral pattern, and some real changes in disease incidence.

Rapid climate change and the rate of adaptation: insight from experimental quantitative genetics.

PubMed

Shaw, Ruth G; Etterson, Julie R

2012-09-01

Evolution proceeds unceasingly in all biological populations. It is clear that climate-driven evolution has molded plants in deep time and within extant populations. However, it is less certain whether adaptive evolution can proceed sufficiently rapidly to maintain the fitness and demographic stability of populations subjected to exceptionally rapid contemporary climate change. Here, we consider this question, drawing on current evidence on the rate of plant range shifts and the potential for an adaptive evolutionary response. We emphasize advances in understanding based on theoretical studies that model interacting evolutionary processes, and we provide an overview of quantitative genetic approaches that can parameterize these models to provide more meaningful predictions of the dynamic interplay between genetics, demography and evolution. We outline further research that can clarify both the adaptive potential of plant populations as climate continues to change and the role played by ongoing adaptation in their persistence. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

Evolutionary rescue in vertebrates: evidence, applications and uncertainty

PubMed Central

Vander Wal, E.; Garant, D.; Festa-Bianchet, M.; Pelletier, F.

2013-01-01

The current rapid rate of human-driven environmental change presents wild populations with novel conditions and stresses. Theory and experimental evidence for evolutionary rescue present a promising case for species facing environmental change persisting via adaptation. Here, we assess the potential for evolutionary rescue in wild vertebrates. Available information on evolutionary rescue was rare and restricted to abundant and highly fecund species that faced severe intentional anthropogenic selective pressures. However, examples from adaptive tracking in common species and genetic rescues in species of conservation concern provide convincing evidence in favour of the mechanisms of evolutionary rescue. We conclude that low population size, long generation times and limited genetic variability will result in evolutionary rescue occurring rarely for endangered species without intervention. Owing to the risks presented by current environmental change and the possibility of evolutionary rescue in nature, we suggest means to study evolutionary rescue by mapping genotype → phenotype → demography → fitness relationships, and priorities for applying evolutionary rescue to wild populations. PMID:23209171

Promoting physical activity and improving dietary quality of Singaporean adolescents: effectiveness of a school-based fitness and wellness program.

PubMed

Loong, Claudine; Leo, Latasha; Goh, Danielle; Lim, Pei Sin; Loke, Wai Mun

2018-01-13

Limited data are available on the effectiveness of the school-based structured fitness and wellness program to influence dietary quality and physical activity levels in Singaporean adolescents. The study examined if a 20-h (over 10 weeks) school-based structured fitness and wellness module affects the diet quality indices, energy intakes, physical activity levels and the associated energy expenditures in a group of healthy, male adolescents with low diet quality and physical activity levels. Participant demography, anthropometry, dietary intake and daily physical activity were obtained at the beginning, mid-point and end of the 10-week program. Physical activity levels were assessed accelerometrically over a 1-weekday period. Dietary intake were taken using a structured 7-day food diary, and diet quality assessed using the Diet Quality Index-International (DQI-I). The 31 enrolled participants (age 19.8 ± 0.6 years) with body mass index (BMI) (19.8 ± 0.6 kg/m2) followed diets of low diet quality scores (48.3 ± 9.6 out of 100) and engaged in 3.87 ± 2.00 h of physical activity daily before the start of the intervention. Their dietary quality and physical activity levels did not change significantly throughout the intervention period. They scored poorly in the moderation and overall balance components of the diet quality assessment. The physical activity duration correlated inversely to the diet quality scores. Our results suggest that the prescribed school-based fitness and wellness module was ineffective in influencing the diet quality and physical activity levels of Singaporean male adolescents with low diet quality and physical activity levels.

Regional Eco-hydrologic Sensitivity to Projected Amazonian Land Use Scenarios

NASA Astrophysics Data System (ADS)

Knox, R. G.; Longo, M.; Zhang, K.; Levine, N. M.; Moorcroft, P. R.; Bras, R. L.

2011-12-01

Given business as usual land-use practices, it is estimated that by 2050 roughly half of the Amazon's pre-anthropogenic closed-canopy forest stands would remain. Of this, eight of the Amazon's twelve major hydrologic basins would lose more than half of their forest cover to deforestation. With the availability of these land-use projections, we may start to question the associated response of the region's hydrologic climate to significant land-cover change. Here the Ecosystem-Demography Model 2 (EDM2, a dynamic and spatially distributed terrestrial model of plant structure and composition, succession, disturbance and thermodynamic transfer) is coupled with the Brazilian Regional Atmospheric Model (BRAMS, a three-dimensional limited area model of the atmospheric fluid momentum equations and physics parameterizations for closing the system of equations at the lower boundary, convection, radiative transfer, microphysics, etc). This experiment conducts decadal simulations, framed with high-reliability lateral boundary conditions of reanalysis atmospheric data (ERA-40 interim) and variable impact of land-use scenarios (SimAmazonia). This is done by initializing the regional ecosystem structure with both aggressive and conservationist deforestation scenarios, and also by differentially allowing and not-allowing dynamic vegetation processes. While the lateral boundaries of the simulation will not reflect the future climate in the region, reanalysis data has provided improved realism as compared to results derived from GCM boundary data. Therefore, the ecosystem response (forest composition and structure) and the time-space patterns of hydrologic information (soil moisture, rainfall, evapotranspiration) are objectively compared in the context of a sensitivity experiment, as opposed to a forecast. The following questions are addressed. How do aggressive and conservative scenarios of Amazonian deforestation effect the regional patterning of hydrologic information in the Amazon and South American Convergence Zone, and does forest response in these regions influence that patterning of hydrologic information?

Land Use and Land Cover Change in Forest Frontiers: The Role of Household Life Cycles

NASA Technical Reports Server (NTRS)

Walker, Robert

2002-01-01

Tropical deforestation remains a critical issue given its present rate and a widespread consensus regarding its implications for the global carbon cycle and biodiversity. Nowhere is the problem more pronounced than in the Amazon basin, home to the world's largest intact, tropical forest. This article addresses land cover change processes at household level in the Amazon basin, and to this end adapts a concept of domestic life cycle to the current institutional environment of tropical frontiers. In particular, it poses a risk minimization model that integrates demography with market-based factors such as transportation costs and accessibility. In essence, the article merges the theory of Chayanov with the household economy framework, in which markets exist for inputs (including labor), outputs, and capital. The risk model is specified and estimated, using survey data for 261 small producers along the Transamazon Highway in the eastern sector of the Brazilian Amazon.

Dispersal

USGS Publications Warehouse

Clobert, J.; Danchin, E.; Dhondt, A.A.; Nichols, J.D.

2001-01-01

The ability of species to migrate and disperse is a trait that has interested ecologists for many years. Now that so many species and ecosystems face major environmental threats from habitat fragmentation and global climate change, the ability of species to adapt to these changes by dispersing, migrating, or moving between patches of habitat can be crucial to ensuring their survival. This book provides a timely and wide-ranging overview of the study of dispersal and incorporates much of the latest research. The causes, mechanisms, and consequences of dispersal at the individual, population, species and community levels are considered. The potential of new techniques and models for studying dispersal, drawn from molecular biology and demography, is also explored. Perspectives and insights are offered from the fields of evolution, conservation biology and genetics. Throughout the book, theoretical approaches are combined with empirical data, and care has been taken to include examples from as wide a range of species as possible.

Nurses' perceptions of ethical issues in the care of older people.

PubMed

Rees, Jenny; King, Lindy; Schmitz, Karl

2009-07-01

The aim of this thematic literature review is to explore nurses' perceptions of ethical issues in the care of older people. Electronic databases were searched from September 1997 to September 2007 using specific key words with tight inclusion criteria, which revealed 17 primary research reports. The data analysis involved repeated reading of the findings and sorting of those findings into four themes. These themes are: sources of ethical issues for nurses; differences in perceptions between nurses and patients/relatives; nurses' personal responses to ethical issues; and the patient-nurse relationship. The findings reveal that ageism is one of the major sources of the ethical issues that arise for nurses caring for older people. Education and organizational change can combat ageist attitudes. Wider training is required in the care of older people, workplace skills, palliative care and pain management for older people. The demands of a changing global demography will necessitate further research in this field.

A Spatial Dashboard for Alzheimer's Disease in New South Wales.

PubMed

Robertson, Hamish; Nicholas, Nick; Dhagat, Amit; Travaglia, Joanne

2017-01-01

This paper illustrates a proof of concept scenario for the application of comprehensive data visualisation methods in the rapidly changing aged care sector. The scenario we explored is population ageing and the dementias with an emphasis on the spatial effects of change over time at the Statistical Area 2 (SA2) level for the state of New South Wales. We did this using a combination of methods, culminating in the use of the Tableau software environment to explore the intersections of demography, epidemiology and their formal cost of care implications. In addition, we briefly illustrate how key infrastructure data can be included in the same data management context by showing how service providers can be integrated and mapped in conjunction with other analyses. This is an innovative and practical approach to some of the complex issues already faced in the health and aged care sectors which can only become more pronounced as population ageing progresses.

Full circumpolar migration ensures evolutionary unity in the Emperor penguin.

PubMed

Cristofari, Robin; Bertorelle, Giorgio; Ancel, André; Benazzo, Andrea; Le Maho, Yvon; Ponganis, Paul J; Stenseth, Nils Chr; Trathan, Phil N; Whittington, Jason D; Zanetti, Enrico; Zitterbart, Daniel P; Le Bohec, Céline; Trucchi, Emiliano

2016-06-14

Defining reliable demographic models is essential to understand the threats of ongoing environmental change. Yet, in the most remote and threatened areas, models are often based on the survey of a single population, assuming stationarity and independence in population responses. This is the case for the Emperor penguin Aptenodytes forsteri, a flagship Antarctic species that may be at high risk continent-wide before 2100. Here, using genome-wide data from the whole Antarctic continent, we reveal that this top-predator is organized as one single global population with a shared demography since the late Quaternary. We refute the view of the local population as a relevant demographic unit, and highlight that (i) robust extinction risk estimations are only possible by including dispersal rates and (ii) colony-scaled population size is rather indicative of local stochastic events, whereas the species' response to global environmental change is likely to follow a shared evolutionary trajectory.

Full circumpolar migration ensures evolutionary unity in the Emperor penguin

PubMed Central

Cristofari, Robin; Bertorelle, Giorgio; Ancel, André; Benazzo, Andrea; Le Maho, Yvon; Ponganis, Paul J.; Stenseth, Nils Chr; Trathan, Phil N.; Whittington, Jason D.; Zanetti, Enrico; Zitterbart, Daniel P.; Le Bohec, Céline; Trucchi, Emiliano

2016-01-01

Defining reliable demographic models is essential to understand the threats of ongoing environmental change. Yet, in the most remote and threatened areas, models are often based on the survey of a single population, assuming stationarity and independence in population responses. This is the case for the Emperor penguin Aptenodytes forsteri, a flagship Antarctic species that may be at high risk continent-wide before 2100. Here, using genome-wide data from the whole Antarctic continent, we reveal that this top-predator is organized as one single global population with a shared demography since the late Quaternary. We refute the view of the local population as a relevant demographic unit, and highlight that (i) robust extinction risk estimations are only possible by including dispersal rates and (ii) colony-scaled population size is rather indicative of local stochastic events, whereas the species' response to global environmental change is likely to follow a shared evolutionary trajectory. PMID:27296726

Sexual behavior, risk perception, and HIV transmission can respond to HIV antiviral drugs and vaccines through multiple pathways.

PubMed

Tully, Stephen; Cojocaru, Monica; Bauch, Chris T

2015-10-28

There has been growing use of highly active antiretroviral treatment (HAART) for HIV and significant progress in developing prophylactic HIV vaccines. The simplest theories of counterproductive behavioral responses to such interventions tend to focus on single feedback mechanisms: for instance, HAART optimism makes infection less scary and thus promotes risky sexual behavior. Here, we develop an agent based, age-structured model of HIV transmission, risk perception, and partner selection in a core group to explore behavioral responses to interventions. We find that interventions can activate not one, but several feedback mechanisms that could potentially influence decision-making and HIV prevalence. In the model, HAART increases the attractiveness of unprotected sex, but it also increases perceived risk of infection and, on longer timescales, causes demographic impacts that partially counteract HAART optimism. Both HAART and vaccination usually lead to lower rates of unprotected sex on the whole, but intervention effectiveness depends strongly on whether individuals over- or under-estimate intervention coverage. Age-specific effects cause sexual behavior and HIV prevalence to change in opposite ways in old and young age groups. For complex infections like HIV-where interventions influence transmission, demography, sexual behavior and risk perception-we conclude that evaluations of behavioral responses should consider multiple feedback mechanisms.

Cross-national comparability of burden of disease estimates: the European Disability Weights Project.

PubMed Central

Essink-Bot, Marie-Louise; Pereira, Joaquin; Packer, Claire; Schwarzinger, Michael; Burstrom, Kristina

2002-01-01

OBJECTIVE: To investigate the sources of cross-national variation in disability-adjusted life-years (DALYs) in the European Disability Weights Project. METHODS: Disability weights for 15 disease stages were derived empirically in five countries by means of a standardized procedure and the cross-national differences in visual analogue scale (VAS) scores were analysed. For each country the burden of dementia in women, used as an illustrative example, was estimated in DALYs. An analysis was performed of the relative effects of cross-national variations in demography, epidemiology and disability weights on DALY estimates. FINDINGS: Cross-national comparison of VAS scores showed almost identical ranking orders. After standardization for population size and age structure of the populations, the DALY rates per 100000 women ranged from 1050 in France to 1404 in the Netherlands. Because of uncertainties in the epidemiological data, the extent to which these differences reflected true variation between countries was difficult to estimate. The use of European rather than country-specific disability weights did not lead to a significant change in the burden of disease estimates for dementia. CONCLUSIONS: Sound epidemiological data are the first requirement for burden of disease estimation and relevant between-countries comparisons. DALY estimates for dementia were relatively insensitive to differences in disability weights between European countries. PMID:12219156

Host age modulates within-host parasite competition.

PubMed

Izhar, Rony; Routtu, Jarkko; Ben-Ami, Frida

2015-05-01

In many host populations, one of the most striking differences among hosts is their age. While parasite prevalence differences in relation to host age are well known, little is known on how host age impacts ecological and evolutionary dynamics of diseases. Using two clones of the water flea Daphnia magna and two clones of its bacterial parasite Pasteuria ramosa, we examined how host age at exposure influences within-host parasite competition and virulence. We found that multiply-exposed hosts were more susceptible to infection and suffered higher mortality than singly-exposed hosts. Hosts oldest at exposure were least often infected and vice versa. Furthermore, we found that in young multiply-exposed hosts competition was weak, allowing coexistence and transmission of both parasite clones, whereas in older multiply-exposed hosts competitive exclusion was observed. Thus, age-dependent parasite exposure and host demography (age structure) could together play an important role in mediating parasite evolution. At the individual level, our results demonstrate a previously unnoticed interaction of the host's immune system with host age, suggesting that the specificity of immune function changes as hosts mature. Therefore, evolutionary models of parasite virulence might benefit from incorporating age-dependent epidemiological parameters. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Fear affects parental care, which predicts juvenile survival and exacerbates the total cost of fear on demography.

PubMed

Dudeck, Blair P; Clinchy, Michael; Allen, Marek C; Zanette, Liana Y

2018-01-01

Fear itself (perceived predation risk) can affect wildlife demography, but the cumulative impact of fear on population dynamics is not well understood. Parental care is arguably what most distinguishes birds and mammals from other taxa, yet only one experiment on wildlife has tested fear effects on parental food provisioning and the repercussions this has for the survival of dependent offspring, and only during early-stage care. We tested the effect of fear on late-stage parental care of mobile dependent offspring, by locating radio-tagged Song Sparrow fledglings and broadcasting predator or non-predator playbacks in their vicinity, measuring their parent's behavior and their own, and tracking the offspring's survival to independence. Fear significantly reduced late-stage parental care, and parental fearfulness (as indexed by their reduction in provisioning when hearing predators) significantly predicted their offspring's condition and survival. Combining results from this experiment with that on early-stage care, we project that fear itself is powerful enough to reduce late-stage survival by 24%, and cumulatively reduce the number of young reaching independence by more than half, 53%. Experiments in invertebrate and aquatic systems demonstrate that fear is commonly as important as direct killing in affecting prey demography, and we suggest focusing more on fear effects and on offspring survival will reveal the same for wildlife. © 2017 by the Ecological Society of America.

Retrospective analysis of attitudes to ageing in the Economist: apocalyptic demography for opinion formers.

PubMed

Martin, Ruth; Williams, Caroline; O'Neill, Desmond

2009-12-08

To investigate the description of older people and ageing in a major weekly newspaper, influential in political and financial circles, to see whether it reflected ageing in a balanced manner, and to what extent it indulged in apocalyptic demography-the portrayal of population ageing as a financial burden rather than a scientific advance. Electronic search of the digital archive of the Economist of articles published between January 1997 and April 2008. Main outcomes measures Categorisation of articles as portraying population ageing as a burden or a benefit or with a balanced view. Of 6306 identified articles, 262 were relevant. Most featured pensions, demography, and politics. Of these 262, 64% portrayed population ageing as a burden and 12% as a benefit; 24% had a balanced view. Most articles therefore showed a predominantly ageist view of older people as a burden on society, often portraying them as frail non-contributors. Recurrent themes included pension and demographic "time bombs" and future unsustainable costs of health care for older people. This negative view of older people might be influential in shaping the attitudes of readers, who include opinion formers in political and economic circles. Gerontologists (including geriatricians) need to engage with influential media, as well as helping to promote a professional development of journalists that is informed and knowledgeable about the negative impact of ageism on the wellbeing of older people.

Dialectics of a medical provision policy in priority areas in Brazil.

PubMed

Weber, César Augusto Trinta

2017-03-01

The people living in vulnerable areas that are difficult to access in Brazil represent a portion of the population that has proven very sensitive to lack of medical and health services. The government, seeking to solve the situation urgently, implemented the More Doctors Program [Programa Mais Médicos, in the Portuguese original] in 2013. To discuss the More Doctors Program, with the purpose of contributing to the debate on the provision of medical policies in Brazil. Study based on the review of official documents: Programa Mais Médicos - dois anos: mais saúde para os brasileiros, 2015 [More Doctors Program - two years: more health for Brazilians, 2015]; Operational Audit Report, TC Nº 005391/2014-8, the Court of Auditors of Brazil; and Medical Demography in Brazil 2015. The import of exchange physicians without diploma revalidation has cast a shadow on the technical quality of services offered to the population. In terms of infrastructure, the reduction of resources paralyzed works and made the care network maintenance projects impossible. The creation of new medical schools has created uncertainty about the possibility of quality education being offered, with minimum and sufficient structure including laboratories, clinics and teaching hospitals indispensable to medical training. The regional inequalities of concentration and dispersion of physicians, showed by studies on medical demography in Brazil, stem from several factors, including the lack of a career path and working conditions. There is no point in having physicians if they do not have safe and ethical conditions to establish the diagnosis and a treatment plan, as well as to monitor the rehabilitation of the patient.

Yangtze River, an insignificant genetic boundary in tufted deer (Elaphodus cephalophus): the evidence from a first population genetics study.

PubMed

Sun, Zhonglou; Pan, Tao; Wang, Hui; Pang, Mujia; Zhang, Baowei

2016-01-01

Great rivers were generally looked at as the geographical barrier to gene flow for many taxonomic groups. The Yangtze River is the third largest river in the world, and flows across South China and into the East China Sea. Up until now, few studies have been carried out to evaluate its effect as a geographical barrier. In this study, we attempted to determine the barrier effect of the Yangtze River on the tufted deer ( Elaphodus cephalophus ) using the molecular ecology approach. Using mitochondrial DNA control region (CR) sequences and 13 nuclear microsatellite loci, we explored the genetic structure and gene flow in two adjacent tufted deer populations (Dabashan and Wulingshan populations), which are separated by the Yangtze River. Results indicated that there are high genetic diversity levels in the two populations, but no distinguishable haplotype group or potential genetic cluster was detected which corresponded to specific geographical population. At the same time, high gene flow was observed between Wulingshan and Dabashan populations. The tufted deer populations experienced population decrease from 0.3 to 0.09 Ma BP, then followed by a distinct population increase. A strong signal of recent population decline ( T = 4,396 years) was detected in the Wulingshan population by a Markov-Switching Vector Autoregressions(MSVAR) process population demography analysis. The results indicated that the Yangtze River may not act as an effective barrier to gene flow in the tufted deer. Finally, we surmised that the population demography of the tufted deer was likely affected by Pleistocene climate fluctuations and ancient human activities.

Signatures of large-scale and local climates on the demography of white-tailed ptarmigan in Rocky Mountain National Park, Colorado, USA.

PubMed

Wang, Guiming; Hobbs, N Thompson; Galbraith, Hector; Giesen, Kenneth M

2002-09-01

Global climate change may impact wildlife populations by affecting local weather patterns, which, in turn, can impact a variety of ecological processes. However, it is not clear that local variations in ecological processes can be explained by large-scale patterns of climate. The North Atlantic oscillation (NAO) is a large-scale climate phenomenon that has been shown to influence the population dynamics of some animals. Although effects of the NAO on vertebrate population dynamics have been studied, it remains uncertain whether it broadly predicts the impact of weather on species. We examined the ability of local weather data and the NAO to explain the annual variation in population dynamics of white-tailed ptarmigan ( Lagopus leucurus) in Rocky Mountain National Park, USA. We performed canonical correlation analysis on the demographic subspace of ptarmigan and local-climate subspace defined by the empirical orthogonal function (EOF) using data from 1975 to 1999. We found that two subspaces were significantly correlated on the first canonical variable. The Pearson correlation coefficient of the first EOF values of the demographic and local-climate subspaces was significant. The population density and the first EOF of local-climate subspace influenced the ptarmigan population with 1-year lags in the Gompertz model. However, the NAO index was neither related to the first two EOF of local-climate subspace nor to the first EOF of the demographic subspace of ptarmigan. Moreover, the NAO index was not a significant term in the Gompertz model for the ptarmigan population. Therefore, local climate had stronger signature on the demography of ptarmigan than did a large-scale index, i.e., the NAO index. We conclude that local responses of wildlife populations to changing climate may not be adequately explained by models that project large-scale climatic patterns.

Snowscape Ecology: Linking Snow Properties to Wildlife Movements and Demography

NASA Astrophysics Data System (ADS)

Prugh, L.; Verbyla, D.; van de Kerk, M.; Mahoney, P.; Sivy, K. J.; Liston, G. E.; Nolin, A. W.

2017-12-01

Snow enshrouds up to one third of the global land mass annually and exerts a major influence on animals that reside in these "snowscapes," (landscapes covered in snow). Dynamic snowscapes may have especially strong effects in arctic and boreal regions where dry snow persists for much of the year. Changes in temperature and hydrology are transforming northern regions, with profound implications for wildlife that are not well understood. We report initial findings from a NASA ABoVE project examining effects of snow properties on Dall sheep (Ovis dalli dalli). We used the MODSCAG snow fraction product to map spring snowline elevations and snow-off dates from 2000-2015 throughout the global range of Dall sheep in Alaska and northwestern Canada. We found a negative effect of spring snow cover on Dall sheep recruitment that increased with latitude. Using meteorological data and a daily freeze/thaw status product derived from passive microwave remote sensing from 1983-2012, we found that sheep survival rates increased in years with higher temperatures, less winter precipitation, fewer spring freeze-thaw events, and more winter freeze-thaw events. To examine the effects of snow depth and density on sheep movements, we used location data from GPS-collared sheep and a snowpack evolution model (SnowModel). We found that sheep selected for shallow, fluffy snow at high elevations, but they selected for denser snow as depth increased. Our field measurements identified a critical snow density threshold of 329 (± 18 SE) kg/m3 to support the weight of Dall sheep. Thus, sheep may require areas of shallow, fluffy snow for foraging, while relying on hard-packed snow for winter travel. These findings highlight the importance of multiple snowscape properties on wildlife movements and demography. The integrated study of snow properties and ecological processes, which we call snowscape ecology, will greatly improve global change forecasting.

Gender matters in medical education.

PubMed

Bleakley, Alan

2013-01-01

Women are in the majority in terms of entry to medical schools worldwide and will soon represent the majority of working doctors. This has been termed the 'feminising' of medicine. In medical education, such gender issues tend to be restricted to discussions of demographic changes and structural inequalities based on a biological reading of gender. However, in contemporary social sciences, gender theory has moved beyond both biology and demography to include cultural issues of gendered ways of thinking. Can contemporary feminist thought drawn from the social sciences help medical educators to widen their appreciation and understanding of the feminising of medicine? Post-structuralist feminist critique, drawn from the social sciences, focuses on cultural practices, such as language use, that support a dominant patriarchy. Such a critique is not exclusive to women, but may be described as supporting a tender-minded approach to practice that is shared by both women and men. The demographic feminising of medicine may have limited effect in terms of changing both medical culture and medical education practices without causing radical change to entrenched cultural habits that are best described as patriarchal. Medical education currently suffers from male biases, such as those imposed by 'andragogy', or adult learning theory, and these can be positively challenged through post-structuralist feminist critique. Women doctors entering the medical workforce can resist and reformulate the current dominant patriarchy rather than reproducing it, supported by male feminists. Such a feminising of medicine can extend to medical education, but will require an appropriate theoretical framework to make sense of the new territory. The feminising of medical education informed by post-structuralist frameworks may provide a platform for the democratisation of medical culture and practices, further informing authentic patient-centred practices of care. © Blackwell Publishing Ltd 2013.

Profound Climatic Effects on Two East Asian Black-Throated Tits (Ave: Aegithalidae), Revealed by Ecological Niche Models and Phylogeographic Analysis

PubMed Central

Wang, Wenjuan; Lin, Congtian; Gao, Bin; Yang, Xiaojun; Zhang, Zhengwang; Lei, Fumin

2011-01-01

Although a number of studies have assessed the effects of geological and climatic changes on species distributions in East Asian, we still have limited knowledge of how these changes have impacted avian species in south-western and southern China. Here, we aim to study paleo-climatic effects on an East Asian bird, two subspecies of black-throated tit (A. c. talifuensis–concinnus) with the combined analysis of phylogeography and Ecological Niche Models (ENMs). We sequenced three mitochondrial DNA markers from 32 populations (203 individuals) and used phylogenetic inferences to reconstruct the intra-specific relationships among haplotypes. Population genetic analyses were undertaken to gain insight into the demographic history of these populations. We used ENMs to predict the distribution of target species during three periods; last inter-glacial (LIG), last glacial maximum (LGM) and present. We found three highly supported, monophyletic MtDNA lineages and different historical demography among lineages in A. c. talifuensis–concinnus. These lineages formed a narrowly circumscribed intra-specific contact zone. The estimated times of lineage divergences were about 2.4 Ma and 0.32 Ma respectively. ENMs predictions were similar between present and LGM but substantially reduced during LIG. ENMs reconstructions and molecular dating suggest that Pleistocene climate changes had triggered and shaped the genetic structure of black-throated tit. Interestingly, in contrast to profound impacts of other glacial cycles, ENMs and phylogeographic analysis suggest that LGM had limited effect on these two subspecies. ENMs also suggest that Pleistocene climatic oscillations enabled the formation of the contact zone and thus support the refuge theory. PMID:22195047

Hanford Environmental Dose Reconstruction Project

DOE Office of Scientific and Technical Information (OSTI.GOV)

McMakin, A.H.; Cannon, S.D.; Finch, S.M.

1992-07-01

The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The TSP consists of experts in environmental pathways, epidemiology, surface-water transport, ground-water transport, statistics, demography, agriculture, meteorology, nuclear engineering, radiation dosimetry, and cultural anthropology. Included are appointed technical members representing the states of Oregon, Washington, and Idaho, a representative of Native American tribes, and an individual representing the public. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impactmore » on humans (dose estimates): Source terms, environmental transport, environmental monitoring data, demography, food consumption, and agriculture, and environmental pathways and dose estimates. Progress is discussed.« less

Hanford Environmental Dose Reconstruction Project. Monthly report

DOE Office of Scientific and Technical Information (OSTI.GOV)

McMakin, A.H.; Cannon, S.D.; Finch, S.M.

1992-07-01

The objective of the Hanford Environmental Dose Reconstruction (HEDR) Project is to estimate the radiation doses that individuals and populations could have received from nuclear operations at Hanford since 1944. The TSP consists of experts in environmental pathways, epidemiology, surface-water transport, ground-water transport, statistics, demography, agriculture, meteorology, nuclear engineering, radiation dosimetry, and cultural anthropology. Included are appointed technical members representing the states of Oregon, Washington, and Idaho, a representative of Native American tribes, and an individual representing the public. The project is divided into the following technical tasks. These tasks correspond to the path radionuclides followed from release to impactmore » on humans (dose estimates): Source terms, environmental transport, environmental monitoring data, demography, food consumption, and agriculture, and environmental pathways and dose estimates. Progress is discussed.« less

Macroscale patterns in body size of intertidal crustaceans provide insights on climate change effects.

PubMed

Jaramillo, Eduardo; Dugan, Jenifer E; Hubbard, David M; Contreras, Heraldo; Duarte, Cristian; Acuña, Emilio; Schoeman, David S

2017-01-01

Predicting responses of coastal ecosystems to altered sea surface temperatures (SST) associated with global climate change, requires knowledge of demographic responses of individual species. Body size is an excellent metric because it scales strongly with growth and fecundity for many ectotherms. These attributes can underpin demographic as well as community and ecosystem level processes, providing valuable insights for responses of vulnerable coastal ecosystems to changing climate. We investigated contemporary macroscale patterns in body size among widely distributed crustaceans that comprise the majority of intertidal abundance and biomass of sandy beach ecosystems of the eastern Pacific coasts of Chile and California, USA. We focused on ecologically important species representing different tidal zones, trophic guilds and developmental modes, including a high-shore macroalga-consuming talitrid amphipod (Orchestoidea tuberculata), two mid-shore scavenging cirolanid isopods (Excirolana braziliensis and E. hirsuticauda), and a low-shore suspension-feeding hippid crab (Emerita analoga) with an amphitropical distribution. Significant latitudinal patterns in body sizes were observed for all species in Chile (21° - 42°S), with similar but steeper patterns in Emerita analoga, in California (32°- 41°N). Sea surface temperature was a strong predictor of body size (-4% to -35% °C-1) in all species. Beach characteristics were subsidiary predictors of body size. Alterations in ocean temperatures of even a few degrees associated with global climate change are likely to affect body sizes of important intertidal ectotherms, with consequences for population demography, life history, community structure, trophic interactions, food-webs, and indirect effects such as ecosystem function. The consistency of results for body size and temperature across species with different life histories, feeding modes, ecological roles, and microhabitats inhabiting a single widespread coastal ecosystem, and for one species, across hemispheres in this space-for-time substitution, suggests predictions of ecosystem responses to thermal effects of climate change may potentially be generalised, with important implications for coastal conservation.

Macroscale patterns in body size of intertidal crustaceans provide insights on climate change effects

PubMed Central

Dugan, Jenifer E.; Hubbard, David M.; Contreras, Heraldo; Duarte, Cristian; Acuña, Emilio; Schoeman, David S.

2017-01-01

Predicting responses of coastal ecosystems to altered sea surface temperatures (SST) associated with global climate change, requires knowledge of demographic responses of individual species. Body size is an excellent metric because it scales strongly with growth and fecundity for many ectotherms. These attributes can underpin demographic as well as community and ecosystem level processes, providing valuable insights for responses of vulnerable coastal ecosystems to changing climate. We investigated contemporary macroscale patterns in body size among widely distributed crustaceans that comprise the majority of intertidal abundance and biomass of sandy beach ecosystems of the eastern Pacific coasts of Chile and California, USA. We focused on ecologically important species representing different tidal zones, trophic guilds and developmental modes, including a high-shore macroalga-consuming talitrid amphipod (Orchestoidea tuberculata), two mid-shore scavenging cirolanid isopods (Excirolana braziliensis and E. hirsuticauda), and a low-shore suspension-feeding hippid crab (Emerita analoga) with an amphitropical distribution. Significant latitudinal patterns in body sizes were observed for all species in Chile (21° - 42°S), with similar but steeper patterns in Emerita analoga, in California (32°- 41°N). Sea surface temperature was a strong predictor of body size (-4% to -35% °C-1) in all species. Beach characteristics were subsidiary predictors of body size. Alterations in ocean temperatures of even a few degrees associated with global climate change are likely to affect body sizes of important intertidal ectotherms, with consequences for population demography, life history, community structure, trophic interactions, food-webs, and indirect effects such as ecosystem function. The consistency of results for body size and temperature across species with different life histories, feeding modes, ecological roles, and microhabitats inhabiting a single widespread coastal ecosystem, and for one species, across hemispheres in this space-for-time substitution, suggests predictions of ecosystem responses to thermal effects of climate change may potentially be generalised, with important implications for coastal conservation. PMID:28481897

Family life course transitions and rural household economy during China's market reform.

PubMed

Chen, Feinian; Korinek, Kim

2010-11-01

This article investigates the effect of family life course transitions on labor allocation strategies in rural Chinese households. We highlight three types of economic activity that involve reallocation of household labor oriented toward a more diversified, nonfarm rural economy: involvement in wage employment, household entrepreneurship, and/or multiple activities that span economic sectors. With the use of data from the China Health and Nutrition Survey (CHNS 1997, 2000, and 2004), our longitudinal analyses of rural household economic activity point to the significance of household demography, life course transitions, and local economic structures as factors facilitating household labor reallocation. First, as expected, a relatively youthful household structure is conducive to innovative economic behavior. Second, household entrances and exits are significant, but their impacts are not equal. Life events such as births, deaths, marriage, or leaving home for school or employment affect household economy in distinctive ways. Finally, the reallocations of household labor undertaken by households are shaped by local economic structures: in particular, the extent of village-level entrepreneurial activity, off-farm employment, and out-migration.

Family Life Course Transitions and Rural Household Economy During China’s Market Reform

PubMed Central

CHEN, FEINIAN; KORINEK, KIM

2010-01-01

This article investigates the effect of family life course transitions on labor allocation strategies in rural Chinese households. We highlight three types of economic activity that involve reallocation of household labor oriented toward a more diversified, nonfarm rural economy: involvement in wage employment, household entrepreneurship, and/or multiple activities that span economic sectors. With the use of data from the China Health and Nutrition Survey (CHNS 1997, 2000, and 2004), our longitudinal analyses of rural household economic activity point to the significance of household demography, life course transitions, and local economic structures as factors facilitating household labor reallocation. First, as expected, a relatively youthful household structure is conducive to innovative economic behavior. Second, household entrances and exits are significant, but their impacts are not equal. Life events such as births, deaths, marriage, or leaving home for school or employment affect household economy in distinctive ways. Finally, the reallocations of household labor undertaken by households are shaped by local economic structures: in particular, the extent of village-level entrepreneurial activity, off-farm employment, and out-migration. PMID:21308566

Do occupation and work conditions really matter? A longitudinal analysis of psychological distress experiences among Canadian workers.

PubMed

Marchand, Alain; Demers, Andrée; Durand, Pierre

2005-07-01

This study analyses the relationship between occupation, work conditions and the experience of psychological distress within a model encompassing the stress promoted by constraints-resources embedded in macrosocial structures (occupational structure), structures of daily life (workplace, family, social networks outside the workplace) and agent personality (demography, physical health, psychological traits, life habits, stressful childhood events). Longitudinal data were derived from Statistics Canada's National Population Health Survey and comprised 6,359 workers nested in 471 occupations, followed four times between 1994-1995 and 2000-2001. Discrete time survival multilevel regressions were conducted on first and repeated episodes of psychological distress. Results showed that 42.9 per cent of workers had reported one episode of psychological distress and 18.7 per cent had done so more than once. Data supported the model and challenged the results of previous studies. The individual's position in the occupational structure plays a limited role when the structures of daily life and agent personality are accounted for. In the workplace, job insecurity and social support are important determinants, but greater decision authority increases the risk of psychological distress. Workplace constraints-resources are not moderated either by the other structures of daily life or by agent personality.

Genetic Structure of Bluefin Tuna in the Mediterranean Sea Correlates with Environmental Variables

PubMed Central

Riccioni, Giulia; Stagioni, Marco; Landi, Monica; Ferrara, Giorgia; Barbujani, Guido; Tinti, Fausto

2013-01-01

Background Atlantic Bluefin Tuna (ABFT) shows complex demography and ecological variation in the Mediterranean Sea. Genetic surveys have detected significant, although weak, signals of population structuring; catch series analyses and tagging programs identified complex ABFT spatial dynamics and migration patterns. Here, we tested the hypothesis that the genetic structure of the ABFT in the Mediterranean is correlated with mean surface temperature and salinity. Methodology We used six samples collected from Western and Central Mediterranean integrated with a new sample collected from the recently identified easternmost reproductive area of Levantine Sea. To assess population structure in the Mediterranean we used a multidisciplinary framework combining classical population genetics, spatial and Bayesian clustering methods and a multivariate approach based on factor analysis. Conclusions FST analysis and Bayesian clustering methods detected several subpopulations in the Mediterranean, a result also supported by multivariate analyses. In addition, we identified significant correlations of genetic diversity with mean salinity and surface temperature values revealing that ABFT is genetically structured along two environmental gradients. These results suggest that a preference for some spawning habitat conditions could contribute to shape ABFT genetic structuring in the Mediterranean. However, further studies should be performed to assess to what extent ABFT spawning behaviour in the Mediterranean Sea can be affected by environmental variation. PMID:24260341

Demographic variation across successional stages and their effects on the population dynamics of the neotropical palm Euterpe precatoria.

PubMed

Otárola, Mauricio Fernández; Avalos, Gerardo

2014-06-01

• Premise of the study: Environmental heterogeneity is a strong selective force shaping adaptation and population dynamics across temporal and spatial scales. Natural and anthropogenic gradients influence the variation of environmental and biotic factors, which determine population demography and dynamics. Successional gradients are expected to influence demographic parameters, but the relationship between these gradients and the species life history, habitat requirements, and degree of variation in demographic traits remains elusive.• Methods: We used the palm Euterpe precatoria to test the effect of successional stage on plant demography within a continuous population. We calculated demographic parameters for size stages and performed matrix analyses to investigate the demographic variation within primary and secondary forests of La Selva, Costa Rica.• Key results: We observed differences in mortality and recruitment of small juveniles between primary and secondary forests. Matrix models described satisfactorily the chronosequence of population changes, which were characterized by high population growth rate in disturbed areas, and decreased growth rate in old successional forests until reaching stability.• Conclusions: Different demographic parameters can be expressed in contiguous subpopulations along a gradient of successional stages with important consequences for population dynamics. Demographic variation superimposed on these gradients contributes to generate subpopulations with different demographic composition, density, and ecological properties. Therefore, the effects of spatial variation must be reconsidered in the design of demographic analyses of tropical palms, which are prime examples of subtle local adaptation. These considerations are crucial in the implementation of management plans for palm species within spatially complex and heterogeneous tropical landscapes. © 2014 Botanical Society of America, Inc.

Long-term effects of tetanus toxoid inoculation on the demography and life expectancy of the Cayo Santiago rhesus macaques.

PubMed

Kessler, Matthew J; Hernández Pacheco, Raisa; Rawlins, Richard G; Ruiz-Lambrides, Angelina; Delgado, Diana L; Sabat, Alberto M

2015-02-01

Tetanus was a major cause of mortality in the free-ranging population of rhesus monkeys on Cayo Santiago prior to 1985 when the entire colony was given its first dose of tetanus toxoid. The immediate reduction in mortality that followed tetanus toxoid inoculation (TTI) has been documented, but the long-term demographic effects of eliminating tetanus infections have not. This study uses the Cayo Santiago demographic database to construct comparative life tables 12 years before, and 12 years after, TTI. Life tables and matrix projection models are used to test for differences in: (i) survival among all individuals as well as among social groups, (ii) long-term fitness of the population, (iii) age distribution, (iv) reproductive value, and (v) life expectancy. A retrospective life table response experiment (LTRE) was performed to determine which life cycle transition contributed most to observed changes in long-term fitness of the population post-TTI. Elimination of clinical tetanus infections through mass inoculation improved the health and well-being of the monkeys. It also profoundly affected the population by increasing survivorship and long-term fitness, decreasing the differences in survival rates among social groups, shifting the population's age distribution towards older individuals, and increasing reproductive value and life expectancy. These findings are significant because they demonstrate the long-term effects of eradicating a major cause of mortality at a single point in time on survival, reproduction, and overall demography of a naturalistic population of primates. © 2014 Wiley Periodicals, Inc.

Density, Demography, and Influential Environmental Factors on Overwintering Populations of Sogatella furcifera (Hemiptera: Delphacidae) in Southern Yunnan, China

PubMed Central

Hu, Shao-Ji; Fu, Da-Ying; Han, Zhong-Liang; Ye, Hui

2015-01-01

Sogatella furcifera (Horváth) (Hemiptera: Delphacidae) is the most serious pest on rice in southwestern China. Yunnan province is within this region and is a major overwintering area for S. furcifera in China. This field study was carried out over 4 yr (2010–2013) and focused on S. furcifera distribution, population density, and demography, as well as the relationship between various environmental factors and the distribution and density of overwintering S. furcifera in Yunnan. Our study demonstrated that overwintering populations of S. furcifera mainly occurred in valleys and lowlands below 25.02°N and 1,680 m above sea level (a.s.l.), where ratooning rice was present. The overwintering range of S. furcifera has expanded in Yunnan compared with 20 yr ago, and regional climate change is believed to be the main contributing cause for this expansion. Environmental factor analysis showed that the mean air temperature of the coldest quarter and precipitation of the coldest quarter were two key factors that were strongly linked to the overwintering distribution and density of S. furcifera in Yunnan. Wintertime temperature was the principal influencing factor to determine the distribution and density of S. furcifera, while the effect of precipitation was indirect in that it influenced the insect’s distribution via its host. This study documented the major overwintering areas of S. furcifera in Yunnan, which can be used to predict outbreak potential in the following spring. Hence, key climatic factors, overwintering distribution, and density of S. furcifera should be used when forecasting outbreaks in spring. PMID:25978998

Impacts of water and nitrogen supplies on the physiology, leaf demography and nitrogen dynamics of Betula pendula.

PubMed

Wendler, Renate; Millard, Peter

1996-01-01

We determined the response of Betula pendula Roth. trees to a restricted water supply, and quantified the interactions between tree N and water status on leaf demography and internal N cycling. In April 1993, 3-year-old trees were planted in sand culture and four treatments applied: high-N supply (56 mg tree(-1) week(-1)) with either 2 dm(3) water week(-1) (HN+) or 0.9 dm(3) water week(-1) (HN-), or low-N supply (14 mg tree(-1) week(-1)) with 2 dm(3) (LN+) or 0.9 dm(3) (LN-) water week(-1). Until 1994, the N supplied to trees was enriched with (15)N to 5.4 atom %. During 1993, there were few differences in the growth or leaf demography of trees in the LN+ and LN- treatments, but the high-N treatment increased tree growth. Leaf mass and area were initially similar in trees in the HN+ and HN- treatments, but the trees in the HN- treatment had a smaller root system. Net assimilation rate under saturating light was higher in trees in the HN+ treatment than in trees in the LN+ treatment. There was an N x water supply interaction as a result of trees in the HN- treatment closing their stomata by the beginning of August. However, there was no difference in gas exchange characteristics of leaves in the LN+ and LN- treatments. Although leaf senescence and abscission started in the HN- treatment by mid-August and continued for about 90 days, whereas leaf abscission in the other treatments did not start until the beginning of October and only lasted 25-30 days, the trees in the HN+ and HN- treatments remobilized similar amounts of (15)N for leaf growth in the spring of 1994. There were no differences in predawn water potential among treatments and no evidence of osmotic adjustment. We conclude that B. pendula trees avoid rather than tolerate drought. The interaction between the effects of nitrogen and water supplies on leaf demography and internal cycling of N are discussed.

Population structure of resident, immigrant, and swimming Corophium volutator (Amphipoda) on an intertidal mudflat in the Bay of Fundy, Canada

NASA Astrophysics Data System (ADS)

Drolet, David; Barbeau, Myriam A.

2012-05-01

Spatial variation in biotic and abiotic conditions, and differences in dispersive behavior of different life history stages can result in the formation of zones with different demography for infaunal and epifaunal species within vast intertidal flats. In this study, we evaluated within-mudflat homogeneity of the infaunal amphipod Corophium volutator found in the mud (residents), colonizing artificially disturbed areas (immigrants), and caught in the water column (swimmers) on a large mudflat in the upper Bay of Fundy, Canada. Densities of residents, immigrants, and swimmers were well structured in space (both along and across shore). Occasionally, significant differences in size structure, sex ratio, and proportion of ovigerous females were found at different intertidal levels, but these were short-lived. Comparisons of size and sex structure of residents, immigrants, and swimmers revealed occasional marked differences, with small juveniles and large adult males moving most. However, this size-bias in movement did not translate into zones with different population dynamics, suggesting that ample dispersal, through swimming and drifting in the water column, homogenized the population and masked potential effects of variation in environmental conditions. We therefore conclude that the mudflat represents one homogeneous population.

Demographics: people and markets.

PubMed

Merrick, T W; Tordella, S J

1988-02-01

The basics of demography are now basic to us business as well. Demographics combine demographic data with socioeconomic and geographic factors to help business and other managers know the market for their goods and services. This pamphlet explains market, product, and site analyses, discusses data sources and resources, and includes case studies involving major corporations. Post-war population trends have had an enormous impact on consumer and labor markets, bringing home to business the importance of taking advantage of demographic shifts. Advances in computerized access to data describing changes and increased consciousness of their economic significance has spurred the application of demographic knowledge by managers and the growth of the demographics information industry. The pamphlet describes the resources and methods of demographics including the creation and use of demographic data products.

Relationships between population density, fine-scale genetic structure, mating system and pollen dispersal in a timber tree from African rainforests.

PubMed

Duminil, J; Daïnou, K; Kaviriri, D K; Gillet, P; Loo, J; Doucet, J-L; Hardy, O J

2016-03-01

Owing to the reduction of population density and/or the environmental changes it induces, selective logging could affect the demography, reproductive biology and evolutionary potential of forest trees. This is particularly relevant in tropical forests where natural population densities can be low and isolated trees may be subject to outcross pollen limitation and/or produce low-quality selfed seeds that exhibit inbreeding depression. Comparing reproductive biology processes and genetic diversity of populations at different densities can provide indirect evidence of the potential impacts of logging. Here, we analysed patterns of genetic diversity, mating system and gene flow in three Central African populations of the self-compatible legume timber species Erythrophleum suaveolens with contrasting densities (0.11, 0.68 and 1.72 adults per ha). The comparison of inbreeding levels among cohorts suggests that selfing is detrimental as inbred individuals are eliminated between seedling and adult stages. Levels of genetic diversity, selfing rates (∼16%) and patterns of spatial genetic structure (Sp ∼0.006) were similar in all three populations. However, the extent of gene dispersal differed markedly among populations: the average distance of pollen dispersal increased with decreasing density (from 200 m in the high-density population to 1000 m in the low-density one). Overall, our results suggest that the reproductive biology and genetic diversity of the species are not affected by current logging practices. However, further investigations need to be conducted in low-density populations to evaluate (1) whether pollen limitation may reduce seed production and (2) the regeneration potential of the species.

Positive correlation between genetic diversity and fitness in a large, well-connected metapopulation

PubMed Central

Vandewoestijne, Sofie; Schtickzelle, Nicolas; Baguette, Michel

2008-01-01

Background Theory predicts that lower dispersal, and associated gene flow, leads to decreased genetic diversity in small isolated populations, which generates adverse consequences for fitness, and subsequently for demography. Here we report for the first time this effect in a well-connected natural butterfly metapopulation with high population densities at the edge of its distribution range. Results We demonstrate that: (1) lower genetic diversity was coupled to a sharp decrease in adult lifetime expectancy, a key component of individual fitness; (2) genetic diversity was positively correlated to the number of dispersing individuals (indicative of landscape functional connectivity) and adult population size; (3) parameters inferred from capture-recapture procedures (population size and dispersal events between patches) correlated much better with genetic diversity than estimates usually used as surrogates for population size (patch area and descriptors of habitat quality) and dispersal (structural connectivity index). Conclusion Our results suggest that dispersal is a very important factor maintaining genetic diversity. Even at a very local spatial scale in a metapopulation consisting of large high-density populations interconnected by considerable dispersal rates, genetic diversity can be decreased and directly affect the fitness of individuals. From a biodiversity conservation perspective, this study clearly shows the benefits of both in-depth demographic and genetic analyses. Accordingly, to ensure the long-term survival of populations, conservation actions should not be blindly based on patch area and structural isolation. This result may be especially pertinent for species at their range margins, particularly in this era of rapid environmental change. PMID:18986515

Trapped within the city: integrating demography, time since isolation and population-specific traits to assess the genetic effects of urbanization.

PubMed

Lourenço, André; Álvarez, David; Wang, Ian J; Velo-Antón, Guillermo

2017-03-01

Urbanization is a severe form of habitat fragmentation that can cause many species to be locally extirpated and many others to become trapped and isolated within an urban matrix. The role of drift in reducing genetic diversity and increasing genetic differentiation is well recognized in urban populations. However, explicit incorporation and analysis of the demographic and temporal factors promoting drift in urban environments are poorly studied. Here, we genotyped 15 microsatellites in 320 fire salamanders from the historical city of Oviedo (Est. 8th century) to assess the effects of time since isolation, demographic history (historical effective population size; N e ) and patch size on genetic diversity, population structure and contemporary N e . Our results indicate that urban populations of fire salamanders are highly differentiated, most likely due to the recent N e declines, as calculated in coalescence analyses, concomitant with the urban development of Oviedo. However, urbanization only caused a small loss of genetic diversity. Regression modelling showed that patch size was positively associated with contemporary N e , while we found only moderate support for the effects of demographic history when excluding populations with unresolved history. This highlights the interplay between different factors in determining current genetic diversity and structure. Overall, the results of our study on urban populations of fire salamanders provide some of the very first insights into the mechanisms affecting changes in genetic diversity and population differentiation via drift in urban environments, a crucial subject in a world where increasing urbanization is forecasted. © 2017 John Wiley & Sons Ltd.

Population models for passerine birds: structure, parameterization, and analysis

USGS Publications Warehouse

Noon, B.R.; Sauer, J.R.; McCullough, D.R.; Barrett, R.H.

1992-01-01

Population models have great potential as management tools, as they use infonnation about the life history of a species to summarize estimates of fecundity and survival into a description of population change. Models provide a framework for projecting future populations, determining the effects of management decisions on future population dynamics, evaluating extinction probabilities, and addressing a variety of questions of ecological and evolutionary interest. Even when insufficient information exists to allow complete identification of the model, the modelling procedure is useful because it forces the investigator to consider the life history of the species when determining what parameters should be estimated from field studies and provides a context for evaluating the relative importance of demographic parameters. Models have been little used in the study of the population dynamics of passerine birds because of: (1) widespread misunderstandings of the model structures and parameterizations, (2) a lack of knowledge of life histories of many species, (3) difficulties in obtaining statistically reliable estimates of demographic parameters for most passerine species, and (4) confusion about functional relationships among demographic parameters. As a result, studies of passerine demography are often designed inappropriately and fail to provide essential data. We review appropriate models for passerine bird populations and illustrate their possible uses in evaluating the effects of management or other environmental influences on population dynamics. We identify environmental influences on population dynamics. We identify parameters that must be estimated from field data, briefly review existing statistical methods for obtaining valid estimates, and evaluate the present status of knowledge of these parameters.

Landscape change and sediment yield of rivers in the northeastern US during 19th century

NASA Astrophysics Data System (ADS)

Urbanova, T.; Wreschnig, A. J.; Ruffing, C. M.; McCormack, S. M.; Bain, D. J.; Hermans, C. M.

2009-12-01

During the 19th century, population growth, dam construction, and large scale forest clearing, particularly for agriculture, was followed by a massive migration to urban and industrialized centers. This led to the high degree of rural land abandonment in many parts of northeastern US. Such significant changes in land use and demography impacted sediment loading and delivery to receiving waters. The objective of this study is to assess the historical changes in sediment loading to waters as a result of land use change and related change in soil erosion, dam dynamics and sediment trapping. Various methods for assessing soil erosion, sediment yield and dam influence will be used and compared (RUSLE, BQART model, dam trapping efficiency). We expect to see 1) an accelerated erosion rates and sediment yield following forest clearing and intensification of agriculture and 2) decreased sediment delivery to estuaries with an increasing number of dams. While sediment management often focuses on fluvial corridors, our understanding of historic upland dynamics remains rudimentary. This study aims to highlight and explain the interconnectedness of the landscape-hydro system; with a particular emphasis on anthropogenic forcing and influences.

Social Relations and Technology: Continuity, Context, and Change

PubMed Central

Antonucci, Toni C; Ajrouch, Kristine J; Manalel, Jasmine A

2017-01-01

Abstract Social relations, although basic to human nature, health and well-being, have become increasingly complicated as a result of changing population demography and technology. In this essay, we provide a historical overview of social relations, especially as they affect older people. We briefly review the evolution of theory and measurement surrounding social relations as well as early empirical evidence. We consider how social relations have changed over time as well as continuity and change regarding basic characteristics of social relations. Of special interest is the emerging influence of technology on how people maintain contact, especially the changing ways people can use technology to increase, decrease, maintain, or avoid social relations. We consider both negative and positive aspects of these new technologies and their influence on health and well-being. Finally, we conclude that new and emerging technologies hold great promise for the future by overcoming traditional barriers to maintaining social contact, support exchange, and information acquisition. Nevertheless, we caution that these new technologies can have the dehumanizing effect of distance thus creating the potential for insensitivity and increased negativity. In sum, we are cautiously optimistic about the promise of technology to expand, but not replace, traditional forms of social contact. PMID:29795794

Social Relations and Technology: Continuity, Context, and Change.

PubMed

Antonucci, Toni C; Ajrouch, Kristine J; Manalel, Jasmine A

2017-11-01

Social relations, although basic to human nature, health and well-being, have become increasingly complicated as a result of changing population demography and technology. In this essay, we provide a historical overview of social relations, especially as they affect older people. We briefly review the evolution of theory and measurement surrounding social relations as well as early empirical evidence. We consider how social relations have changed over time as well as continuity and change regarding basic characteristics of social relations. Of special interest is the emerging influence of technology on how people maintain contact, especially the changing ways people can use technology to increase, decrease, maintain, or avoid social relations. We consider both negative and positive aspects of these new technologies and their influence on health and well-being. Finally, we conclude that new and emerging technologies hold great promise for the future by overcoming traditional barriers to maintaining social contact, support exchange, and information acquisition. Nevertheless, we caution that these new technologies can have the dehumanizing effect of distance thus creating the potential for insensitivity and increased negativity. In sum, we are cautiously optimistic about the promise of technology to expand, but not replace, traditional forms of social contact.

Ecotoxicology and spatial modeling in population dynamics: an illustration with brown trout.

PubMed

Chaumot, Arnaud; Charles, Sandrine; Flammarion, Patrick; Auger, Pierre

2003-05-01

We developed a multiregion matrix population model to explore how the demography of a hypothetical brown trout population living in a river network varies in response to different spatial scenarios of cadmium contamination. Age structure, spatial distribution, and demographic and migration processes are taken into account in the model. Chronic or acute cadmium concentrations affect the demographic parameters at the scale of the river range. The outputs of the model constitute population-level end points (the asymptotic population growth rate, the stable age structure, and the asymptotic spatial distribution) that allow comparing the different spatial scenarios of contamination regarding the demographic response at the scale of the whole river network. An analysis of the sensitivity of these end points to lower order parameters enables us to link the local effects of cadmium to the global demographic behavior of the brown trout population. Such a link is of broad interest in the point of view of ecotoxicological management.

Too many swipes for today: The development of the Problematic Tinder Use Scale (PTUS)

PubMed Central

Orosz, Gábor; Tóth-Király, István; Bőthe, Beáta; Melher, Dóra

2016-01-01

Background and aims Tinder is a very popular smartphone-based geolocated dating application. The goal of the present study was creating a short Problematic Tinder Use Scale (PTUS). Methods Griffiths’ (2005) six-component model was implemented for covering all components of problematic Tinder use. Confirmatory factor analyses were carried out on a Tinder user sample (N = 430). Results Both the 12- and the 6-item versions were tested. The 6-item unidimensional structure has appropriate reliability and factor structure. No salient demography-related differences were found. Users irrespectively to their relationship status have similar scores on PTUS. Discussion Tinder users deserve the attention of scientific examination considering their large proportion among smartphone users. It is especially true considering the emerging trend of geolocated online dating applications. Conclusions Before PTUS, no prior scale has been created to measure problematic Tinder use. The PTUS is a suitable and reliable measure to assess problematic Tinder use. PMID:27415602

Too many swipes for today: The development of the Problematic Tinder Use Scale (PTUS).

PubMed

Orosz, Gábor; Tóth-Király, István; Bőthe, Beáta; Melher, Dóra

2016-09-01

Background and aims Tinder is a very popular smartphone-based geolocated dating application. The goal of the present study was creating a short Problematic Tinder Use Scale (PTUS). Methods Griffiths' ( 2005 ) six-component model was implemented for covering all components of problematic Tinder use. Confirmatory factor analyses were carried out on a Tinder user sample (N = 430). Results Both the 12- and the 6-item versions were tested. The 6-item unidimensional structure has appropriate reliability and factor structure. No salient demography-related differences were found. Users irrespectively to their relationship status have similar scores on PTUS. Discussion Tinder users deserve the attention of scientific examination considering their large proportion among smartphone users. It is especially true considering the emerging trend of geolocated online dating applications. Conclusions Before PTUS, no prior scale has been created to measure problematic Tinder use. The PTUS is a suitable and reliable measure to assess problematic Tinder use.

Less Is More--A Lesson in Global Arithmetic.

ERIC Educational Resources Information Center

Pomar, Ana L.

1995-01-01

Describes classroom activities that integrate math concepts with environmental science, demography, and language arts. The lesson helps students understand the competition between natural resources and the law of supply and demand. (HTH)

California travel trends and demographics study

DOT National Transportation Integrated Search

2002-12-01

In collaboration with its regional and citizen planning partners, the California Department of Transportation is currently developing a long-term, multimodal transportation plan for the state of California. The California Travel Trends and Demographi...

The role of historical and contemporary processes on phylogeographic structure and genetic diversity in the Northern Cardinal, Cardinalis cardinalis

PubMed Central

2011-01-01

Background Earth history events such as climate change are believed to have played a major role in shaping patterns of genetic structure and diversity in species. However, there is a lag between the time of historical events and the collection of present-day samples that are used to infer contemporary population structure. During this lag phase contemporary processes such as dispersal or non-random mating can erase or reinforce population differences generated by historical events. In this study we evaluate the role of both historical and contemporary processes on the phylogeography of a widespread North American songbird, the Northern Cardinal, Cardinalis cardinalis. Results Phylogenetic analysis revealed deep mtDNA structure with six lineages across the species' range. Ecological niche models supported the same geographic breaks revealed by the mtDNA. A paleoecological niche model for the Last Glacial Maximum indicated that cardinals underwent a dramatic range reduction in eastern North America, whereas their ranges were more stable in México. In eastern North America cardinals expanded out of glacial refugia, but we found no signature of decreased genetic diversity in areas colonized after the Last Glacial Maximum. Present-day demographic data suggested that population growth across the expansion cline is positively correlated with latitude. We propose that there was no loss of genetic diversity in areas colonized after the Last Glacial Maximum because recent high-levels of gene flow across the region have homogenized genetic diversity in eastern North America. Conclusion We show that both deep historical events as well as demographic processes that occurred following these events are critical in shaping genetic pattern and diversity in C. cardinalis. The general implication of our results is that patterns of genetic diversity are best understood when information on species history, ecology, and demography are considered simultaneously. PMID:21599972

Evolutionary demography and the population history of the European early Neolithic.

PubMed

Shennan, Stephen

2009-04-01

In this paper I propose that evolutionary demography and associated theory from human behavioral ecology provide a strong basis for explaining the available evidence for the patterns observed in the first agricultural settlement of Europe in the 7th-5th millennium cal. BC, linking together a variety of what have previously been disconnected observations and casting doubt on some long-standing existing models. An outline of relevant aspects of life history theory, which provides the foundation for understanding demography, is followed by a review of large-scale demographic patterns in the early Neolithic, which point to rapid population increase and a process of demic diffusion. More localized socioeconomic and demographic patterns suggesting rapid expansion to local carrying capacities and an associated growth of inequality in the earliest farming communities of central Europe (the Linear Pottery Culture, or LBK) are then outlined and shown to correspond to predictions of spatial population ecology and reproductive skew theory. Existing models of why it took so long for farming to spread to northern and northwest Europe, which explain the spread in terms of the gradual disruption of hunter-gatherer ways of life, are then questioned in light of evidence for population collapse at the end of the LBK. Finally, some broader implications of the study are presented, including the suggestion that the pattern of an initial agricultural boom followed by a bust may be relevant in other parts of the world.

Incorporating non-equilibrium dynamics into demographic history inferences of a migratory marine species.

PubMed

Carroll, E L; Alderman, R; Bannister, J L; Bérubé, M; Best, P B; Boren, L; Baker, C S; Constantine, R; Findlay, K; Harcourt, R; Lemaire, L; Palsbøll, P J; Patenaude, N J; Rowntree, V J; Seger, J; Steel, D; Valenzuela, L O; Watson, M; Gaggiotti, O E

2018-05-03

Understanding how dispersal and gene flow link geographically separated the populations over evolutionary history is challenging, particularly in migratory marine species. In southern right whales (SRWs, Eubalaena australis), patterns of genetic diversity are likely influenced by the glacial climate cycle and recent history of whaling. Here we use a dataset of mitochondrial DNA (mtDNA) sequences (n = 1327) and nuclear markers (17 microsatellite loci, n = 222) from major wintering grounds to investigate circumpolar population structure, historical demography and effective population size. Analyses of nuclear genetic variation identify two population clusters that correspond to the South Atlantic and Indo-Pacific ocean basins that have similar effective breeder estimates. In contrast, all wintering grounds show significant differentiation for mtDNA, but no sex-biased dispersal was detected using the microsatellite genotypes. An approximate Bayesian computation (ABC) approach with microsatellite markers compared the scenarios with gene flow through time, or isolation and secondary contact between ocean basins, while modelling declines in abundance linked to whaling. Secondary-contact scenarios yield the highest posterior probabilities, implying that populations in different ocean basins were largely isolated and came into secondary contact within the last 25,000 years, but the role of whaling in changes in genetic diversity and gene flow over recent generations could not be resolved. We hypothesise that these findings are driven by factors that promote isolation, such as female philopatry, and factors that could promote dispersal, such as oceanographic changes. These findings highlight the application of ABC approaches to infer the connectivity in mobile species with complex population histories and, currently, low levels of differentiation.

Evaluation of Geomorphic Changes, Using Landsat Data and its Impact on Coastal Community

NASA Astrophysics Data System (ADS)

Mahar, G. A.

2017-12-01

temporal study with the help of landsat satellite image has been carried out to assess the degree of the geomorphic degradation of different deltaic features and its consequent impact on the demography and socioeconomics of the people. Interactive correlation of the present analyses of the Indus water-flow in relation to the manmade water divergent structures reveals that the massive water divergence to upstream areas by depleting water availability into the downstream areas have caused severe imbalance in the equilibrium between the fluvial and marine hydrodynamics. The dominance of the marine hydrodynamic conditions have caused irreversible damage to the physical environment due to the rapid landward sea invasion. Based on the results of the present study it has been identified that i) the coastline is rapidly retreating; ii) individual creeks and the creeks' network are enlarging by the erosional phenomenon laterally as well as longitudinally; iii) tidally influenced areas are rapidly expanding; iv) overall area of the deltaic lakes is reducing but the frequency of the lakes occurrences is increasing; v) the course and the thalweg of the Indus river is widening seaward and narrowing landward; vi) populated areas along the coastline have been evacuated due to the massive seawater intrusions; vii) agricultural and fishing activities are tremendously declining and viii) food productivity per acre is decreasing. Moreover, it is also revealed that i) the shelf slope is steeping and retreating faster and ii) geometry of the Indus canyon is also rapidly changing. This phenomenon has affected the socio-economic of the coastal community and from many place force them to move from their native places.

Comments on "Complementarity and Conflict among Population and Other Policies: Specifying an Economic-Demographic Model for a Developing Country".

PubMed

Khan, A H

1993-01-01

The critique of Mariano's economic-demographic model of population and other policies for developing countries cites the value of such a detailed model for developing a family planning policy within the context of macroeconomic government policies. The model points out the impact on fertility of effective family planning policies and increased educational expenditures. Work force participation and reduced fertility is also affected by increased female educational levels, which in combination with increasing health expenditures for children reduces infant mortality as a means of further reducing fertility. Savings and investment increase with reduced fertility and reduce population growth. Per capital income increases with higher investment and lower population growth; the effect is to increase resource availability for improvements in health and education. Rural-urban migration must be balanced by policies in urban areas supporting industrial investment and policies in rural areas for increased educational and health expenditures. Changes in the structure of demand affect the structure of the economy, which in turn affects exports. The paper contributes to a model of simultaneous equations for estimating the linkages between demography and economics factors already known. The model combines the Chicago-Columbia model and the Pennsylvania model but ignores biological variables such as those identified by Behrman and Wolfe as women's health status, breast feeding, and nutritional level. International migration may be important for some countries such as the Philippines and Thailand. Extended families may be an important variable excluded from the model. Criticism is directed to the measure of rural-urban migration which does not separate out by age those migrating between countries. The assumption is that international migrants only come from urban areas. In Bangladesh the man-land ratio was found to be important. Changing definitions of literacy may impact on the model outcomes. Cost of schooling should be considered. Regardless of the deficits in the factors included, the model is still commended.

Understanding the demographic drivers of realized population growth rates.

PubMed

Koons, David N; Arnold, Todd W; Schaub, Michael

2017-10-01

Identifying the demographic parameters (e.g., reproduction, survival, dispersal) that most influence population dynamics can increase conservation effectiveness and enhance ecological understanding. Life table response experiments (LTRE) aim to decompose the effects of change in parameters on past demographic outcomes (e.g., population growth rates). But the vast majority of LTREs and other retrospective population analyses have focused on decomposing asymptotic population growth rates, which do not account for the dynamic interplay between population structure and vital rates that shape realized population growth rates (λt=Nt+1/Nt) in time-varying environments. We provide an empirical means to overcome these shortcomings by merging recently developed "transient life-table response experiments" with integrated population models (IPMs). IPMs allow for the estimation of latent population structure and other demographic parameters that are required for transient LTRE analysis, and Bayesian versions additionally allow for complete error propagation from the estimation of demographic parameters to derivations of realized population growth rates and perturbation analyses of growth rates. By integrating available monitoring data for Lesser Scaup over 60 yr, and conducting transient LTREs on IPM estimates, we found that the contribution of juvenile female survival to long-term variation in realized population growth rates was 1.6 and 3.7 times larger than that of adult female survival and fecundity, respectively. But a persistent long-term decline in fecundity explained 92% of the decline in abundance between 1983 and 2006. In contrast, an improvement in adult female survival drove the modest recovery in Lesser Scaup abundance since 2006, indicating that the most important demographic drivers of Lesser Scaup population dynamics are temporally dynamic. In addition to resolving uncertainty about Lesser Scaup population dynamics, the merger of IPMs with transient LTREs will strengthen our understanding of demography for many species as we aim to conserve biodiversity during an era of non-stationary global change. © 2017 by the Ecological Society of America.

US GeoData

USGS Publications Warehouse

,

1992-01-01

US GeoData tapes are computer tapes which contain cartographic data in digital form. The 1:2,000,000-scale data are available in two forms. The graphic form can be used to generate computer-plotted maps. The content and scale of the maps can be varied to meet your needs. The topologically-structured form of US GeoData is suitable for input to geographic information systems for use in spatial analysis and geographic studies. Both forms must be used in conjunction with appropriate software. US GeoData tapes offer convenience, accuracy, flexibility, and cost effectiveness to many map users. Business, industry, and government users who are involved in network planning and analysis, transportation, demography, land use, or any activity where data can be related to, or plotted on a map will find US GeoData a valuable resource.

Battling Against Interfaith Relations in Israel: Religion, Therapy, and Social Services.

PubMed

Hakak, Yohai

2016-01-01

One of the less studied aspects of the Israeli-Palestinian conflict is its demography. On the Jewish side, active steps are taken by the state to encourage Jewish immigration and Jewish births and discourage Jewish assimilation. As part of these efforts, the "problematic relationships" between Arab men and Jewish women from low socioeconomic background have become a high agenda item in public discussions in Israel during the last decade. I will examine here how the diagnostic category "girls at risk" and a therapeutic intervention employed by social services dealing with these couples helps maintaining the delicate balance between Jewish and democratic values. I will analyze these practices as a solution to a structural problem of the Jewish enclave in Israel. © 2015 American Association for Marriage and Family Therapy.

Simulating fire-induced ecological succession with the dynamically coupled fire-vegetation model, ED-SPIFTIRE

NASA Astrophysics Data System (ADS)

Spessa, A.; Fisher, R.

2009-04-01

The simulation of fire-vegetation feedbacks is crucial for determining fire-induced changes to ecosystem structure and function, and emissions of trace gases and aerosols under future climate change. A new global fire model SPITFIRE (SPread and InTensity of FIRE) has been designed to overcome many of the limitations in existing fire models set within DGVM frameworks (Thonicke et al. 2008). SPITFIRE has been applied in coupled mode globally (Thonicke et al. 2008) and northern Australia (Spessa et al. unpubl.) as part of the LPJ DGVM. It has also been driven with MODIS burnt area data applied to sub-Saharan Africa (Lehsten et al. 2008) as part of the LPJ-GUESS vegetation model (Smith et al. 2001). Recently, Spessa & Fisher (unpubl.) completed the coupling of SPIFTIRE to the Ecosystem Demography (ED) model (Moorecroft et al. 2001), which has been globalised by Dr R. Fisher as part of the development of the new land surface scheme JULES (Joint UK Environment Simulator) within the QUEST Earth System Model (http://www.quest-esm.ac.uk/). In contrast to the LPJ DGVM, ED is a ‘size and age structured' approximation of an individual based gap model. The major innovation of the ED-SPITFIRE model compared with LPJ-SPITFIRE is the categorisation of each climatic grid cell into a series of non-spatially contiguous patches which are defined by a common ‘age since last disturbance'. In theory, the age-class structure of ED facilitates ecologically realistic processes of succession and re-growth to be represented. By contrast, LPJ DGVM adopts an ‘area-based approach' that implicitly averages individual and patch differences across a wider area and across ‘populations' of PFTs. This presentation provides an overview of SPITFIRE, and provides preliminary results from ED-SPITFIRE applied to northern Australian savanna ecosystems which, due to spatio-temporal variation in fire disturbance, comprise a patchwork of grasses and trees at different stages of post-fire succession. Comparisons with similar simulations undertaken with LPJ-SPITFIRE are also presented.

Genotyping by sequencing resolves shallow population structure to inform conservation of Chinook salmon (Oncorhynchus tshawytscha)

PubMed Central

Larson, Wesley A; Seeb, Lisa W; Everett, Meredith V; Waples, Ryan K; Templin, William D; Seeb, James E

2014-01-01

Recent advances in population genomics have made it possible to detect previously unidentified structure, obtain more accurate estimates of demographic parameters, and explore adaptive divergence, potentially revolutionizing the way genetic data are used to manage wild populations. Here, we identified 10 944 single-nucleotide polymorphisms using restriction-site-associated DNA (RAD) sequencing to explore population structure, demography, and adaptive divergence in five populations of Chinook salmon (Oncorhynchus tshawytscha) from western Alaska. Patterns of population structure were similar to those of past studies, but our ability to assign individuals back to their region of origin was greatly improved (>90% accuracy for all populations). We also calculated effective size with and without removing physically linked loci identified from a linkage map, a novel method for nonmodel organisms. Estimates of effective size were generally above 1000 and were biased downward when physically linked loci were not removed. Outlier tests based on genetic differentiation identified 733 loci and three genomic regions under putative selection. These markers and genomic regions are excellent candidates for future research and can be used to create high-resolution panels for genetic monitoring and population assignment. This work demonstrates the utility of genomic data to inform conservation in highly exploited species with shallow population structure. PMID:24665338

Assessing the drivers shaping global patterns of urban vegetation landscape structure.

PubMed

Dobbs, C; Nitschke, C; Kendal, D

2017-08-15

Vegetation is one of the main resources involve in ecosystem functioning and providing ecosystem services in urban areas. Little is known on the landscape structure patterns of vegetation existing in urban areas at the global scale and the drivers of these patterns. We studied the landscape structure of one hundred cities around the globe, and their relation to demography (population), socioeconomic factors (GDP, Gini Index), climate factors (temperature and rain) and topographic characteristics (altitude, variation in altitude). The data revealed that the best descriptors of landscape structure were amount, fragmentation and spatial distribution of vegetation. Populated cities tend to have less, more fragmented, less connected vegetation with a centre of the city with low vegetation cover. Results also provided insights on the influence of socioeconomics at a global scale, as landscape structure was more fragmented in areas that are economically unequal and coming from emergent economies. This study shows the effects of the social system and climate on urban landscape patterns that gives useful insights for the distribution in the provision of ecosystem services in urban areas and therefore the maintenance of human well-being. This information can support local and global policy and planning which is committing our cities to provide accessible and inclusive green space for all urban inhabitants. Copyright © 2017 Elsevier B.V. All rights reserved.

The Lagrangian Ensemble metamodel for simulating plankton ecosystems

NASA Astrophysics Data System (ADS)

Woods, J. D.

2005-10-01

This paper presents a detailed account of the Lagrangian Ensemble (LE) metamodel for simulating plankton ecosystems. It uses agent-based modelling to describe the life histories of many thousands of individual plankters. The demography of each plankton population is computed from those life histories. So too is bio-optical and biochemical feedback to the environment. The resulting “virtual ecosystem” is a comprehensive simulation of the plankton ecosystem. It is based on phenotypic equations for individual micro-organisms. LE modelling differs significantly from population-based modelling. The latter uses prognostic equations to compute demography and biofeedback directly. LE modelling diagnoses them from the properties of individual micro-organisms, whose behaviour is computed from prognostic equations. That indirect approach permits the ecosystem to adjust gracefully to changes in exogenous forcing. The paper starts with theory: it defines the Lagrangian Ensemble metamodel and explains how LE code performs a number of computations “behind the curtain”. They include budgeting chemicals, and deriving biofeedback and demography from individuals. The next section describes the practice of LE modelling. It starts with designing a model that complies with the LE metamodel. Then it describes the scenario for exogenous properties that provide the computation with initial and boundary conditions. These procedures differ significantly from those used in population-based modelling. The next section shows how LE modelling is used in research, teaching and planning. The practice depends largely on hindcasting to overcome the limits to predictability of weather forecasting. The scientific method explains observable ecosystem phenomena in terms of finer-grained processes that cannot be observed, but which are controlled by the basic laws of physics, chemistry and biology. What-If? Prediction ( WIP), used for planning, extends hindcasting by adding events that describe natural or man-made hazards and remedial actions. Verification is based on the Ecological Turing Test, which takes account of uncertainties in the observed and simulated versions of a target ecological phenomenon. The rest of the paper is devoted to a case study designed to show what LE modelling offers the biological oceanographer. The case study is presented in two parts. The first documents the WB model (Woods & Barkmann, 1994) and scenario used to simulate the ecosystem in a mesocosm moored in deep water off the Azores. The second part illustrates the emergent properties of that virtual ecosystem. The behaviour and development of an individual plankton lineage are revealed by an audit trail of the agent used in the computation. The fields of environmental properties reveal the impact of biofeedback. The fields of demographic properties show how changes in individuals cumulatively affect the birth and death rates of their population. This case study documents the virtual ecosystem used by Woods, Perilli and Barkmann (2005; hereafter WPB); to investigate the stability of simulations created by the Lagrangian Ensemble metamodel. The Azores virtual ecosystem was created and analysed on the Virtual Ecology Workbench (VEW) which is described briefly in the Appendix.

Making do with less: Must sparse data preclude informed harvest strategies for European waterbirds?

USGS Publications Warehouse

Johnson, Fred A.; Alhainen, Mikko; Fox, Anthony D.; Madsen, Jesper; Guillemain, Matthieu

2018-01-01

The demography of many European waterbirds is not well understood because most countries have conducted little monitoring and assessment, and coordination among countries on waterbird management has little precedent. Yet intergovernmental treaties now mandate the use of sustainable, adaptive harvest strategies, whose development is challenged by a paucity of demographic information. In this study, we explore how a combination of allometric relationships, fragmentary monitoring and research information, and expert judgment can be used to estimate the parameters of a theta-logistic population model, which in turn can be used in a Markov decision process to derive optimal harvesting strategies. We show how to account for considerable parametric uncertainty, as well as for different management objectives. We illustrate our methodology with a poorly understood population of taiga bean geese (Anser fabalis fabalis), which is a popular game bird in Fennoscandia. Our results for taiga bean geese suggest that they may have demographic rates similar to other, well-studied species of geese, and our model-based predictions of population size are consistent with the limited monitoring information available. Importantly, we found that by using a Markov decision process, a simple scalar population model may be sufficient to guide harvest management of this species, even if its demography is age-structured. Finally, we demonstrated how two different management objectives can lead to very different optimal harvesting strategies, and how conflicting objectives may be traded off with each other. This approach will have broad application for European waterbirds by providing preliminary estimates of key demographic parameters, by providing insights into the monitoring and research activities needed to corroborate those estimates, and by producing harvest management strategies that are optimal with respect to the managers’ objectives, options, and available demographic information.

Effects of attitudes and demography on public support for endangered species conservation.

PubMed

Liordos, Vasilios; Kontsiotis, Vasileios J; Anastasiadou, Magdalini; Karavasias, Efstathios

2017-10-01

It is critical for managers to understand how attitudes and demography affect public's preferences for species protection for designing successful conservation projects. 1080 adults in Greece were asked to rate pictures of 12 endangered species on aesthetic and negativistic attitudes, and intention to support their conservation. Factor analysis identified a group of animals for which respondents indicated high levels of support for their conservation (red deer, loggerhead sea turtle, brown bear, common pheasant, European ground squirrel, glossy ibis) and a group of animals for which respondents indicated low levels of support (black vulture, great white shark, fire-bellied toad, western barbastelle, Cretan tube web spider, Milos viper). The species that received the highest support were also rated as the most attractive and safest, excluding the fearsome brown bear. Structural models revealed that aesthetic, moralistic and negativistic attitudes were the stronger predictors of support. Aesthetic and moralistic attitudes were positively, and negativistic attitudes negatively, correlated with support for conservation in both groups. Consumptive users scored lower in aesthetics and were less supportive of protection in the high support group, while nonconsumptive users showed the opposite trend. Respondents residing in urban areas deemed animals of high support more attractive and less fearsome and were more supportive of conservation than rural residents in both groups. Females of higher education viewed animals of low support as fearsome, however they supported their conservation. Our study identified popular species that can be used as flagship species to facilitate the implementation of conservation projects. The results of this study could also be used to design a communication and outreach campaign to raise awareness about the ecosystem value of less attractive species. Copyright © 2017 Elsevier B.V. All rights reserved.

Modelling the growth of Populus species using Ecosystem Demography (ED) model

NASA Astrophysics Data System (ADS)

Wang, D.; Lebauer, D. S.; Feng, X.; Dietze, M. C.

2010-12-01

Hybrid poplar plantations are an important source being evaluated for biomass production. Effective management of such plantations requires adequate growth and yield models. The Ecosystem Demography model (ED) makes predictions about the large scales of interest in above- and belowground ecosystem structure and the fluxes of carbon and water from a description of the fine-scale physiological processes. In this study, we used a workflow management tool, the Predictive Ecophysiological Carbon flux Analyzer (PECAn), to integrate literature data, field measurement and the ED model to provide predictions of ecosystem functioning. Parameters for the ED ensemble runs were sampled from the posterior distribution of ecophysiological traits of Populus species compiled from the literature using a Bayesian meta-analysis approach. Sensitivity analysis was performed to identify the parameters which contribute the most to the uncertainties of the ED model output. Model emulation techniques were used to update parameter posterior distributions using field-observed data in northern Wisconsin hybrid poplar plantations. Model results were evaluated with 5-year field-observed data in a hybrid poplar plantation at New Franklin, MO. ED was then used to predict the spatial variability of poplar yield in the coterminous United States (United States minus Alaska and Hawaii). Sensitivity analysis showed that root respiration, dark respiration, growth respiration, stomatal slope and specific leaf area contribute the most to the uncertainty, which suggests that our field measurements and data collection should focus on these parameters. The ED model successfully captured the inter-annual and spatial variability of the yield of poplar. Analyses in progress with the ED model focus on evaluating the ecosystem services of short-rotation woody plantations, such as impacts on soil carbon storage, water use, and nutrient retention.

The Norwegian Institute of Public Health Twin Study of Mental Health: Examining Recruitment and Attrition Bias

PubMed Central

Tambs, Kristian; Rønning, Torbjørn; Prescott, C. A.; Kendler, Kenneth S.; Reichborn-Kjennerud, Ted; Torgersen, Svenn; Harris, Jennifer R.

2009-01-01

All Norwegian twin pairs born 1967–1974 and still living in Norway in 1992 were invited to a health questionnaire study (Q1). 2,570 pairs (65%) participated. These cohorts and the twin cohorts born 1967–1979 were invited to a new questionnaire study (Q2) in 1998. This time 3,334 pairs (53%) participated. Almost all pairs having participated in the 1998 study were invited to an interview study of mental health (MHS), taking place 1999–2004. 1,391 complete pairs (44%) participated. The questionnaire studies included extensive data on somatic health with fewer items on mental health and demography. Health-related and demographic information available from the Medical Birth Registry on all invited twins was applied to predict participation to the first study. A few registry variables indicating poor health predicted nonparticipation in Q1. Health information and demography from Q1 were tested as predictors of participation in the follow-up study (Q2). Monozygosity, female sex, being unmarried, having no children, and high education predicted participation, whereas few indicators of poor mental and somatic health and unhealthy lifestyle moderately predicted nonparticipation in Q2. No health indicators reported in Q2 predicted further participation. Standard genetic twin analyses of indicators of various mental disorders from Q2, validated by diagnostic data from the MHS, did not indicate differences in genetic/environmental covariance structures between participants and nonparticipants in MHS. In general the results show a moderate selection towards good mental and somatic health. Attrition from Q2 to the MHS does not appear to affect twin analyses of mental health related variables. PMID:19335186

Prospects for European labour demand.

PubMed

Lindley, R M

1988-07-01

The impact of economic and technological trends upon the level and structure of labor demand is examined, exploring the methods used to model the labor market and making special reference to demography and technology. Evidence on recent and prospective changes in labor demand is reviewed for France, Germany, Italy, the Netherlands, and the UK. The models used to explore future employment scenarios usually fail to incorporate the linkages required to fully analyze the various demographic-economic interactions. Further, this is not generally viewed as a limitation, given the time frame of most employment projections and their preoccupation with changes in the structure of labor demand. Medium-term multisectoral models tend to pay more attention to both demographic and technical change, but the treatment of both aspects is limited. The projections provide a framework for considering how both socioeconomic behavior and policy might change to achieve different outcomes. The greater a model's behavioral content, as expressed in its relationships between different variables, the greater the insight obtainable from simulation exercises. The 1st half of the 1970s was characterized by a reduction in German employment, representing the severest of European reactions to the oil crisis. The 2nd half of the decade recorded rapid growth in Italy and the Netherlands. The 1980s started with marked declines in Germany and the UK. Overall, the net gains of the 1970s were lost in the recession following the 2nd oil crisis. In none of the 5 countries studied does any realistic prospect emerge of achieving full employment before 2000. The most optimistic outcome is that unemployment will decline only slowly, it at all. The growth of both new forms and areas of employment will not compensate sufficiently for the loss of jobs elsewhere and the growth of labor supply. The industrial sector will continue to experience change in favor of the service sector but at a slower rate than during the 1975-85 decade. After the adjustment of the recession, European manufacturing industry is relatively more competitive and overall will experience a slower employment decline. Further, the growth of services will be limited by the effects of restrictive budgetary policies upon the development of public services. In all 5 countries, the main projected areas of employment growth are business and related services, tourism and leisure activities, and health care. Those occupations most likely to expand are the more highly qualified groups associated with the growth sectors. The main changes in the location of functions within the economic structure are likely to be the continuing contracting out of service functions within production industries to the service sector; and the growth of small relative to large enterprises.

Timescales and the management of ecological systems.

PubMed

Hastings, Alan

2016-12-20

Human management of ecological systems, including issues like fisheries, invasive species, and restoration, as well as others, often must be undertaken with limited information. This means that developing general principles and heuristic approaches is important. Here, I focus on one aspect, the importance of an explicit consideration of time, which arises because of the inherent limitations in the response of ecological systems. I focus mainly on simple systems and models, beginning with systems without density dependence, which are therefore linear. Even for these systems, it is important to recognize the necessary delays in the response of the ecological system to management. Here, I also provide details for optimization that show how general results emerge and emphasize how delays due to demography and life histories can change the optimal management approach. A brief discussion of systems with density dependence and tipping points shows that the same themes emerge, namely, that when considering issues of restoration or management to change the state of an ecological system, that timescales need explicit consideration and may change the optimal approach in important ways.

Linking extreme interannual changes in prey availability to foraging behaviour and breeding investment in a marine predator, the macaroni penguin.

PubMed

Horswill, Cat; Trathan, Philip N; Ratcliffe, Norman

2017-01-01

Understanding the mechanisms that link prey availability to predator behaviour and population change is central to projecting how a species may respond to future environmental pressures. We documented the behavioural responses and breeding investment of macaroni penguins Eudyptes chrysolophus across five breeding seasons where local prey density changed by five-fold; from very low to highly abundant. When prey availability was low, foraging trips were significantly longer and extended overnight. Birds also foraged farther from the colony, potentially in order to reach more distant foraging grounds and allow for increased search times. These extended foraging trips were also linked to a marked decrease in fledgling weights, most likely associated with reduced rates of provisioning. Furthermore, by comparing our results with previous work on this population, it appears that lowered first-year survival rates associated, at least partially, with fledging masses were also evident for this cohort. This study integrates a unique set of prey density, predator behaviour and predator breeding investment data to highlight a possible behavioural mechanism linking perturbations in prey availability to population demography.

Population dynamics of American horseshoe crabs-historic climatic events and recent anthropogenic pressures

USGS Publications Warehouse

Faurby, S.; King, T.L.; Obst, M.; Hallerman, E.M.; Pertoldi, C.; Funch, P.

2010-01-01

Populations of the American horseshoe crab, Limulus polyphemus, have declined, but neither the causes nor the magnitude are fully understood. In order to evaluate historic demography, variation at 12 microsatellite DNA loci surveyed in 1218 L. polyphemus sampled from 28 localities was analysed with Bayesian coalescent-based methods. The analysis showed strong declines in population sizes throughout the species' distribution except in the geographically isolated southern-most population in Mexico, where a strong increase in population size was inferred. Analyses suggested that demographic changes in the core of the distribution occurred in association with the recolonization after the Ice Age and also by anthropogenic effects, such as the past overharvest of the species for fertilizer or the current use of the animals as bait for American eel (Anguilla rostrata) and whelk (Busycon spp.) fisheries. This study highlights the importance of considering both climatic changes and anthropogenic effects in efforts to understand population dynamics-a topic which is highly relevant in the ongoing assessments of the effects of climate change and overharvest. ?? 2010 Blackwell Publishing Ltd.

Population dynamics of American horseshoe crabs--historic climatic events and recent anthropogenic pressures.

PubMed

Faurby, Søren; King, Tim L; Obst, Matthias; Hallerman, Eric M; Pertoldi, Cino; Funch, Peter

2010-08-01

Populations of the American horseshoe crab, Limulus polyphemus, have declined, but neither the causes nor the magnitude are fully understood. In order to evaluate historic demography, variation at 12 microsatellite DNA loci surveyed in 1218 L. polyphemus sampled from 28 localities was analysed with Bayesian coalescent-based methods. The analysis showed strong declines in population sizes throughout the species' distribution except in the geographically isolated southern-most population in Mexico, where a strong increase in population size was inferred. Analyses suggested that demographic changes in the core of the distribution occurred in association with the recolonization after the Ice Age and also by anthropogenic effects, such as the past overharvest of the species for fertilizer or the current use of the animals as bait for American eel (Anguilla rostrata) and whelk (Busycon spp.) fisheries. This study highlights the importance of considering both climatic changes and anthropogenic effects in efforts to understand population dynamics--a topic which is highly relevant in the ongoing assessments of the effects of climate change and overharvest.

Climate change in the oceans: evolutionary versus phenotypically plastic responses of marine animals and plants

PubMed Central

Reusch, Thorsten B H

2014-01-01

I summarize marine studies on plastic versus adaptive responses to global change. Due to the lack of time series, this review focuses largely on the potential for adaptive evolution in marine animals and plants. The approaches were mainly synchronic comparisons of phenotypically divergent populations, substituting spatial contrasts in temperature or CO2 environments for temporal changes, or in assessments of adaptive genetic diversity within populations for traits important under global change. The available literature is biased towards gastropods, crustaceans, cnidarians and macroalgae. Focal traits were mostly environmental tolerances, which correspond to phenotypic buffering, a plasticity type that maintains a functional phenotype despite external disturbance. Almost all studies address coastal species that are already today exposed to fluctuations in temperature, pH and oxygen levels. Recommendations for future research include (i) initiation and analyses of observational and experimental temporal studies encompassing diverse phenotypic traits (including diapausing cues, dispersal traits, reproductive timing, morphology) (ii) quantification of nongenetic trans-generational effects along with components of additive genetic variance (iii) adaptive changes in microbe–host associations under the holobiont model in response to global change (iv) evolution of plasticity patterns under increasingly fluctuating environments and extreme conditions and (v) joint consideration of demography and evolutionary adaptation in evolutionary rescue approaches. PMID:24454551

The Parana paradox: can a model explain the decadal impacts of climate variability and land-cover change?

NASA Astrophysics Data System (ADS)

Lee, E.; Moorcroft, P. R.; Livino, A.; Briscoe, J.

2013-12-01

Since the 1970s, despite a decrease in rainfall, flow in the Parana river has increased. This paradox is explored using the Ecosystem Demography (ED) model. If there were no change in land cover, the modeled runoff decreased from the 1970s to the 2000s by 11.8% (with 1970 land cover) or 18.8% (with 2008 land cover). When the model is run holding climate constant, the decadal average of the modeled runoff increased by 24.4% (with the 1970s climate) or by 33.6% (with 2000s climate). When the model is run allowing both the actual climate and land-cover changes, the model gives an increase in the decadal average of runoff by 8.5%. This agrees well with 10.5% increase in the actual stream flow as measured at Itaipu. There are three main conclusions from this work. First, the ED model is able to explain a major, paradoxical, reality in the Parana basin. Second, it is necessary to take into account both climate and land use changes when exploring past or future changes in river flows. Third, the ED model, now coupled with a regional climate model (i.e., EDBRAMS), is a sound basis for exploring likely changes in river flows in major South American rivers.

The economic demography of passenger intermodal transportation : opportunities and challenges.

DOT National Transportation Integrated Search

2015-12-01

The research on intermodal transportation is vast. However, most efforts have focused on freight transportation. There is much less research on intermodal passenger transportationlargely due to lack of a comprehensive dataset for effectively study...

Life tables as "predictors" of average longevity.

PubMed Central

Irwin, A. C.

1976-01-01

Selected figures from Canadian life tables have been analysed to illustrate one potential use of routinely collected and published data. A plea is made for the inclusion of the fundamentals of demography in undergraduate medical education. PMID:1083283

Evolutionary contributions to the study of human fertility.

PubMed

Sear, Rebecca

2015-01-01

Demography, lacking an overarching theoretical framework of its own, has drawn on theories in many other social sciences to inform its analyses. The aim of this paper is to bring to the demographic community's attention research in the evolutionary sciences on fertility, and to demonstrate that evolutionary theory can be another useful tool in the demographer's toolkit. I first dispel some myths which impede the incorporation of evolutionary theory into demography: I make it clear that evolutionary explanations do not assume that all human behaviour is hardwired and functions to maximize genetic fitness; that they are able to explain variation in human behaviour; and that they are not necessarily alternatives to social science explanations. I then describe the diversity of work on fertility by evolutionary researchers, particularly human evolutionary ecologists and cultural evolutionists, and illustrate the usefulness of the evolutionary approach with examples of its application to age at first birth and the fertility transition.

Economic demography in fuzzy spatial dilemmas and power laws

NASA Astrophysics Data System (ADS)

Fort, H.; Pérez, N.

2005-03-01

Adaptive agents, playing the iterated Prisoner's Dilemma (IPD) in a two-dimensional spatial setting and governed by Pavlovian strategies ("higher success-higher chance to stay"), are used to approach the problem of cooperation between self-interested individuals from a novel angle: We investigate the effect of different possible measures of success (MS) used by players to asses their performance in the game. These MS involve quantities such as: the player's utilities U, his cumulative score (or "capital") W, his neighborhood "welfare", etc. To handle an imprecise concept like "success" the agents use fuzzy logic. The degree of cooperation, the "economic demography" and the "efficiency" attained by the system depend dramatically on the MS. Specifically, patterns of "segregation" or "exploitation" are observed for some MS. On the other hand, power laws, that may be interpreted as signatures of critical self-organization (SOC), constitute a common feature for all the MS.

Diversity of ageing across the tree of life.

PubMed

Jones, Owen R; Scheuerlein, Alexander; Salguero-Gómez, Roberto; Camarda, Carlo Giovanni; Schaible, Ralf; Casper, Brenda B; Dahlgren, Johan P; Ehrlén, Johan; García, María B; Menges, Eric S; Quintana-Ascencio, Pedro F; Caswell, Hal; Baudisch, Annette; Vaupel, James W

2014-01-09

Evolution drives, and is driven by, demography. A genotype moulds its phenotype's age patterns of mortality and fertility in an environment; these two patterns in turn determine the genotype's fitness in that environment. Hence, to understand the evolution of ageing, age patterns of mortality and reproduction need to be compared for species across the tree of life. However, few studies have done so and only for a limited range of taxa. Here we contrast standardized patterns over age for 11 mammals, 12 other vertebrates, 10 invertebrates, 12 vascular plants and a green alga. Although it has been predicted that evolution should inevitably lead to increasing mortality and declining fertility with age after maturity, there is great variation among these species, including increasing, constant, decreasing, humped and bowed trajectories for both long- and short-lived species. This diversity challenges theoreticians to develop broader perspectives on the evolution of ageing and empiricists to study the demography of more species.

Demography, vulnerabilities and right to health to Brazilian prison population.

PubMed

Soares, Marden Marques; Bueno, Paula Michele Martins Gomes

2016-06-01

This study investigates the latest research on the profile of the Brazilian prison population, its demography and current laws and regulations. It aims in the direction of ensuring the human right to health. Brazilian prison system is a complex universe in which state and federal criminal contexts keep more than 607,000 people in custody. This population is composed of 75% of young and black people, 67% poorly educated and 41% are pre-trial detainees, living in overcrowded prisons and architecturally vandalized, with population growth of around 575% in 24 years, making this environment a major focus of production of diseases. The prison becomes the object of differentiated intervention by public bodies linked to the executive and the judiciary - it is worth remarking that the data show the high level of inequalities and health vulnerabilities among the prison population, whose needs involve a set of cross-sector of transverse public policies actions towards penal execution.

Determinants of cariogenic snacking in adolescents in Belfast and Helsinki.

PubMed

Freeman, R; Heimonen, H; Speedy, P; Tuutti, H

2000-12-01

The aim of the study was to investigate the determinants of reported snack consumption in adolescents residing in Belfast, Northern Ireland and Helsinki, Finland. Ten % random samples of 14-15 yr old Belfast (n = 628) and Helsinki (n = 600) adolescents were obtained. A questionnaire assessed their demography, oral health knowledge, attitudes and the consumption of cariogenic snacks containing non-milk extrinsic sugars (NMES). Five hundred and eighty-nine (94%) questionnaires were returned in Belfast and 441 (74%) questionnaires in Helsinki. Belfast adolescents had significantly higher levels of oral health knowledge and higher consumption rates for snacks containing NMES. The Helsinki adolescents had more positive attitudes towards their oral health. Multivariant analysis showed that demography was the most direct determinant of cariogenic snacking. The acquisition of oral health knowledge played a minor role. There is a need to develop tailored and focused programmes to promote healthier snacking regimes in adolescents.

Predictors of early survival in Soay sheep: cohort-, maternal- and individual-level variation

PubMed Central

Jones, Owen R; Crawley, Michael J; Pilkington, Jill G; Pemberton, Josephine M

2005-01-01

A demographic understanding of population dynamics requires an appreciation of the processes influencing survival—a demographic rate influenced by parameters varying at the individual, maternal and cohort level. There have been few attempts to partition the variance in demography contributed by each of these parameter types. Here, we use data from a feral population of Soay sheep (Ovis aries), from the island of St Kilda, to explore the relative importance of these parameter types on early survival. We demonstrate that the importance of variation occurring at the level of the individual, and maternally, far outweighs that occurring at the cohort level. The most important variables within the individual and maternal levels were birth weight and maternal age class, respectively. This work underlines the importance of using individual based models in ecological demography and we, therefore, caution against studies that focus solely on population processes. PMID:16321784

Nocturnal Awakening & Sleep Duration in Veterans with PTSD: An Actigraphic Study

PubMed Central

S. Khawaja, Imran; M. Hashmi, Ali; Westermeyer, Joseph; Thuras, Paul; Hurwitz, Thomas

2013-01-01

Objective: To assess whether awakenings from sleep and sleep duration in Post Traumatic Stress Disorder (PTSD) were related to demography, posttraumatic or depressive symptoms, subjective sleep quality, and daytime sleepiness. Methods: Sample consisted of 23 veterans with lifetime PTSD and current sleep disturbance not due to apnea or other diagnosable conditions. Data collection included demography, two weeks of actigraphy, Beck Depression Inventory, Posttraumatic Checklist, Clinical Assessment of Posttraumatic Symptoms, Pittsburgh Sleep Quality Index, and Epworth Sleepiness Scale. Results: The study revealed that awakenings increased with younger age. Variability in awakenings also increased with younger age (p = 0.002). More awakenings were associated with shorter sleep duration. Conclusions: These paradoxical observations regarding younger age and more awakening may be related to increased sleep symptoms early in the course and then gradual waning of posttraumatic symptoms over time, since awakenings tend to increase with age in normals (rather than decrease, as we observed). PMID:24353674

Nocturnal Awakening & Sleep Duration in Veterans with PTSD: An Actigraphic Study.

PubMed

Khawaja, Imran S; M Hashmi, Ali; Westermeyer, Joseph; Thuras, Paul; Hurwitz, Thomas

2013-07-01

To assess whether awakenings from sleep and sleep duration in Post Traumatic Stress Disorder (PTSD) were related to demography, posttraumatic or depressive symptoms, subjective sleep quality, and daytime sleepiness. Sample consisted of 23 veterans with lifetime PTSD and current sleep disturbance not due to apnea or other diagnosable conditions. Data collection included demography, two weeks of actigraphy, Beck Depression Inventory, Posttraumatic Checklist, Clinical Assessment of Posttraumatic Symptoms, Pittsburgh Sleep Quality Index, and Epworth Sleepiness Scale. The study revealed that awakenings increased with younger age. Variability in awakenings also increased with younger age (p = 0.002). More awakenings were associated with shorter sleep duration. These paradoxical observations regarding younger age and more awakening may be related to increased sleep symptoms early in the course and then gradual waning of posttraumatic symptoms over time, since awakenings tend to increase with age in normals (rather than decrease, as we observed).

Sexual development and reproductive demography of the green humphead parrotfish ( Bolbometopon muricatum) in the Solomon Islands

NASA Astrophysics Data System (ADS)

Hamilton, R. J.; Adams, S.; Choat, J. H.

2008-03-01

An investigation of the reproductive biology of the green humphead parrotfish ( Bolbometopon muricatum) from three areas in the Western Province of the Solomon Islands revealed that B. muricatum exhibits several features that differ from the pattern of reproductive development observed in most parrotfishes. Unlike most parrotfishes, histological evidence suggests that the sexual pattern of B. muricatum is essentially gonochoristic with high incidences of anatomical but non-functional hermaphroditism. B. muricatum also differs from other parrotfishes in that all males pass through an immature female (or bisexual) phase as demonstrated by all adult testis retaining the ex-ovarian lumen and peripheral sperm sinuses in the gonad wall. However, a protogynous diandric reproductive strategy cannot be excluded given that sampling may have missed transitional individuals. Marked variation in the demography of male B. muricatum between the three locations examined is considered to reflect variation in historical fishing effort.

A population-based longitudinal study on the implication of demographic changes on blood donation and transfusion demand.

PubMed

Greinacher, Andreas; Weitmann, Kerstin; Schönborn, Linda; Alpen, Ulf; Gloger, Doris; Stangenberg, Wolfgang; Stüpmann, Kerstin; Greger, Nico; Kiefel, Volker; Hoffmann, Wolfgang

2017-06-13

Transfusion safety includes the risk of transmission of pathogens, appropriate transfusion thresholds, and sufficient blood supply. All industrialized countries experience major ongoing demographic changes resulting from low birth rates and aging of the baby boom generation. Little evidence exists about whether future blood supply and demand correlate with these demographic changes. The ≥50% decline in birth rate in the eastern part of Germany after 1990 facilitates systematic study of the effects of pronounced demographic changes on blood donation and demand. In this prospective, 10-year longitudinal study, we enrolled all whole blood donors and all patients receiving red blood cell transfusions in the state of Mecklenburg-West Pomerania. We compared projections made in 2005 based on the projected demographic changes with: (1) number and age distribution of blood donors and transfusion recipients in 2015 and (2) blood demand within specific age and patient groups. Blood donation rates closely followed the demographic changes, showing a decrease of -18% (vs projected -23%). In contrast, 2015 transfusion rates were -21.3% lower than projected. We conclude that although changes in demography are highly predictive for the blood supply, transfusion demand is strongly influenced by changes in medical practice. Given ongoing pronounced demographic change, regular monitoring of the donor/recipient age distributions and associated impact on blood demand/supply relationships is required to allow strategic planning to prevent blood shortages or overproduction.

Genome Sequencing of Museum Specimens Reveals Rapid Changes in the Genetic Composition of Honey Bees in California

PubMed Central

Ramirez, Santiago R; Dean, Cheryl A; Sciligo, Amber; Tsutsui, Neil D

2018-01-01

Abstract The western honey bee, Apis mellifera, is an enormously influential pollinator in both natural and managed ecosystems. In North America, this species has been introduced numerous times from a variety of different source populations in Europe and Africa. Since then, feral populations have expanded into many different environments across their broad introduced range. Here, we used whole genome sequencing of historical museum specimens and newly collected modern populations from California (USA) to analyze the impact of demography and selection on introduced populations during the past 105 years. We find that populations from both northern and southern California exhibit pronounced genetic changes, but have changed in different ways. In northern populations, honey bees underwent a substantial shift from western European to eastern European ancestry since the 1960s, whereas southern populations are dominated by the introgression of Africanized genomes during the past two decades. Additionally, we identify an isolated island population that has experienced comparatively little change over a large time span. Fine-scale comparison of different populations and time points also revealed SNPs that differ in frequency, highlighting a number of genes that may be important for recent adaptations in these introduced populations. PMID:29346588

Health Impacts of Climate Change in Vanuatu: An Assessment and Adaptation Action Plan

PubMed Central

Spickett, Jeffery T; Katscherian, Dianne; McIver, Lachlan

2013-01-01

Climate change is one of the greatest global challenges and Pacific island countries are particularly vulnerable due to, among other factors, their geography, demography and level of economic development. A Health Impact Assessment (HIA) framework was used as a basis for the consideration of the potential health impacts of changes in the climate on the population of Vanuatu, to assess the risks and propose a range of potential adaptive responses appropriate for Vanuatu. The HIA process involved the participation of a broad range of stakeholders including expert sector representatives in the areas of bio-physical, socio-economic, infrastructure, environmental diseases and food, who provided informed comment and input into the understanding of the potential health impacts and development of adaptation strategies. The risk associated with each of these impacts was assessed with the application of a qualitative process that considered both the consequences and the likelihood of each of the potential health impacts occurring. Potential adaptation strategies and actions were developed which could be used to mitigate the identified health impacts and provide responses which could be used by the various sectors in Vanuatu to contribute to future decision making processes associated with the health impacts of climate change. PMID:23618474

Defaunation leads to microevolutionary changes in a tropical palm

PubMed Central

Carvalho, Carolina S.; Galetti, Mauro; Colevatti, Rosane G.; Jordano, Pedro

2016-01-01

Many large species have declined worldwide due to habitat fragmentation and poaching. The defaunation of large frugivores and the consequent reductions of seed dispersal services may have immediate effects on plant demography. Yet, the lasting effects of frugivore defaunation on microevolutionary processes of the plants they disperse remain understudied. We tested if the loss of large seed dispersers can lead to microevolutionary changes of a tropical palm. We show that frugivore defaunation is the main driver of changes in allelic frequency among populations. Turnover of alleles accounted for 100% of dissimilarity in allelic frequencies of individuals between defaunated and non-defaunated forests; and individuals from defaunated sites are 1.5 times more similar genetically than those found in pristine sites. Given that sizeable fractions of the palm fruit crops remain undispersed in defaunated sites due to lack of large-bodied frugivores, this distinct pattern of gene pool composition of early recruits may reveal strong dispersal limitation for specific genotypes, or collapses of gene flow between fragmented areas, or both. Because most of tropical tree species rely on seed dispersal by vertebrates, our results show that defaunation has a lasting effect on microevolutionary processes, with potential consequences for persistence under scenarios of environmental change. PMID:27535709

Sensitivity of burned area in Europe to climate change, atmospheric CO2 levels, and demography: A comparison of two fire-vegetation models

NASA Astrophysics Data System (ADS)

Wu, Minchao; Knorr, Wolfgang; Thonicke, Kirsten; Schurgers, Guy; Camia, Andrea; Arneth, Almut

2015-11-01

Global environmental changes and human activity influence wildland fires worldwide, but the relative importance of the individual factors varies regionally and their interplay can be difficult to disentangle. Here we evaluate projected future changes in burned area at the European and sub-European scale, and we investigate uncertainties in the relative importance of the determining factors. We simulated future burned area with LPJ-GUESS-SIMFIRE, a patch-dynamic global vegetation model with a semiempirical fire model, and LPJmL-SPITFIRE, a dynamic global vegetation model with a process-based fire model. Applying a range of future projections that combine different scenarios for climate changes, enhanced CO2 concentrations, and population growth, we investigated the individual and combined effects of these drivers on the total area and regions affected by fire in the 21st century. The two models differed notably with respect to the dominating drivers and underlying processes. Fire-vegetation interactions and socioeconomic effects emerged as important uncertainties for future burned area in some European regions. Burned area of eastern Europe increased in both models, pointing at an emerging new fire-prone region that should gain further attention for future fire management.

Gender relations, demographic change and the prospects for sustainable development in Africa.

PubMed

Ahonsi, B A

1995-01-01

The author explores the interrelationships between gender relations, demographic change, and Africa's prospects for sustainable development in the larger context of the ecological, economic, and sociopolitical forces which shape living conditions in the region. To make the analysis manageable, the author adopts the concept of sustainable development as the organizing and selecting principle in the exploration of issues central to the development of his argument. Rapid and uneven population growth is just one of many factors implicated in Africa's econo-environmental crisis. However, its strong synergism with gender relations and the limited scope for overcoming the externally derived problems suggests that a transition to lower fertility and higher women's status may be Africa's most realistic road to sustainable development. Discussion is presented under the following headings: concept of sustainable development as an analytical framework, salient aspects of Africa's demography, environmental degradation in Africa, economic stagnation and decline, gender considerations common to the key aspects of Africa's development crisis, and movement toward an enhanced prospect for sustainable development in Africa.

Some economics of global warming

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schelling, T.C.

1992-03-01

The greenhouse effect itself is simple enough to understand and is not in any real dispute. What is in dispute is its magnitude over the coming century, its translation into changes in climates around the globe, and the impacts of those climate changes on human welfare and the natural environment. These are beyond the professional understanding of any single person. The sciences involved are too numerous and diverse. Demography, economics, biology, and the technology sciences are needed to project emissions; atmospheric chemistry, oceanography, biology, and meteorology are needed to translate emissions into climates; biology, agronomy, health sciences, economics, sociology, andmore » glaciology are needed to identify and assess impacts on human societies and natural ecosystems. And those are not all. There are expert judgments on large pieces of the subject, but no single person clothed in this panoply of disciplines has shown up or is likely to. This article makes an attempt to forecast the economic and social consequences of global warming due to anthropogenic greenhouse gases, and attempting to prevent it.« less

Whole-genome sequencing of giant pandas provides insights into demographic history and local adaptation.

PubMed

Zhao, Shancen; Zheng, Pingping; Dong, Shanshan; Zhan, Xiangjiang; Wu, Qi; Guo, Xiaosen; Hu, Yibo; He, Weiming; Zhang, Shanning; Fan, Wei; Zhu, Lifeng; Li, Dong; Zhang, Xuemei; Chen, Quan; Zhang, Hemin; Zhang, Zhihe; Jin, Xuelin; Zhang, Jinguo; Yang, Huanming; Wang, Jian; Wang, Jun; Wei, Fuwen

2013-01-01

The panda lineage dates back to the late Miocene and ultimately leads to only one extant species, the giant panda (Ailuropoda melanoleuca). Although global climate change and anthropogenic disturbances are recognized to shape animal population demography their contribution to panda population dynamics remains largely unknown. We sequenced the whole genomes of 34 pandas at an average 4.7-fold coverage and used this data set together with the previously deep-sequenced panda genome to reconstruct a continuous demographic history of pandas from their origin to the present. We identify two population expansions, two bottlenecks and two divergences. Evidence indicated that, whereas global changes in climate were the primary drivers of population fluctuation for millions of years, human activities likely underlie recent population divergence and serious decline. We identified three distinct panda populations that show genetic adaptation to their environments. However, in all three populations, anthropogenic activities have negatively affected pandas for 3,000 years.

Transforming management of tropical coastal seas to cope with challenges of the 21st century.

PubMed

Sale, Peter F; Agardy, Tundi; Ainsworth, Cameron H; Feist, Blake E; Bell, Johann D; Christie, Patrick; Hoegh-Guldberg, Ove; Mumby, Peter J; Feary, David A; Saunders, Megan I; Daw, Tim M; Foale, Simon J; Levin, Phillip S; Lindeman, Kenyon C; Lorenzen, Kai; Pomeroy, Robert S; Allison, Edward H; Bradbury, R H; Corrin, Jennifer; Edwards, Alasdair J; Obura, David O; Sadovy de Mitcheson, Yvonne J; Samoilys, Melita A; Sheppard, Charles R C

2014-08-15

Over 1.3 billion people live on tropical coasts, primarily in developing countries. Many depend on adjacent coastal seas for food, and livelihoods. We show how trends in demography and in several local and global anthropogenic stressors are progressively degrading capacity of coastal waters to sustain these people. Far more effective approaches to environmental management are needed if the loss in provision of ecosystem goods and services is to be stemmed. We propose expanded use of marine spatial planning as a framework for more effective, pragmatic management based on ocean zones to accommodate conflicting uses. This would force the holistic, regional-scale reconciliation of food security, livelihoods, and conservation that is needed. Transforming how countries manage coastal resources will require major change in policy and politics, implemented with sufficient flexibility to accommodate societal variations. Achieving this change is a major challenge - one that affects the lives of one fifth of humanity. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Cytonuclear genetics of experimental fish hybrid zones inside Biosphere 2

USGS Publications Warehouse

Scribner, K.T.; Avise, John C.

1994-01-01

Two species of mosquitofish (family Poeciliidae) known to hybridize in nature were introduced into freshwater habitats inside Biosphere 2, and their population genetics were monitored after 2 years. Within four to six generations, nuclear and cytoplasmic markers characteristic of Gambusia holbrooki had risen greatly in frequency, although some Gambusia affinis alleles and haplotypes were retained primarily in recombinant genotypes, indicative of introgressive hybridization. The temporal cytonuclear dynamics proved similar to population genetic changes observed in replicated experimental hybrid populations outside of Biosphere 2, thus indicating strong directional selection favoring G. holbrooki genotypes across the range of environments monitored. When interpreted in the context of species-specific population demographies observed previously, results suggest that the extremely rapid evolution in these zones of secondary contact is attributable primarily to species differences in life-history traits.

Mobile Health Applications to Promote Active and Healthy Ageing

PubMed Central

Helbostad, Jorunn L.; Vereijken, Beatrix; Becker, Clemens; Todd, Chris; Taraldsen, Kristin; Pijnappels, Mirjam; Aminian, Kamiar; Mellone, Sabato

2017-01-01

The European population is ageing, and there is a need for health solutions that keep older adults independent longer. With increasing access to mobile technology, such as smartphones and smartwatches, the development and use of mobile health applications is rapidly growing. To meet the societal challenge of changing demography, mobile health solutions are warranted that support older adults to stay healthy and active and that can prevent or delay functional decline. This paper reviews the literature on mobile technology, in particular wearable technology, such as smartphones, smartwatches, and wristbands, presenting new ideas on how this technology can be used to encourage an active lifestyle, and discusses the way forward in order further to advance development and practice in the field of mobile technology for active, healthy ageing. PMID:28335475

Mobile Health Applications to Promote Active and Healthy Ageing.

PubMed

Helbostad, Jorunn L; Vereijken, Beatrix; Becker, Clemens; Todd, Chris; Taraldsen, Kristin; Pijnappels, Mirjam; Aminian, Kamiar; Mellone, Sabato

2017-03-18

The European population is ageing, and there is a need for health solutions that keep older adults independent longer. With increasing access to mobile technology, such as smartphones and smartwatches, the development and use of mobile health applications is rapidly growing. To meet the societal challenge of changing demography, mobile health solutions are warranted that support older adults to stay healthy and active and that can prevent or delay functional decline. This paper reviews the literature on mobile technology, in particular wearable technology, such as smartphones, smartwatches, and wristbands, presenting new ideas on how this technology can be used to encourage an active lifestyle, and discusses the way forward in order further to advance development and practice in the field of mobile technology for active, healthy ageing.

Interactions between demography and environmental effects are important determinants of population dynamics

PubMed Central

Gamelon, Marlène; Grøtan, Vidar; Nilsson, Anna L. K.; Engen, Steinar; Hurrell, James W.; Jerstad, Kurt; Phillips, Adam S.; Røstad, Ole W.; Slagsvold, Tore; Walseng, Bjørn; Stenseth, Nils C.; Sæther, Bernt-Erik

2017-01-01

Climate change will affect the population dynamics of many species, yet the consequences for the long-term persistence of populations are poorly understood. A major reason for this is that density-dependent feedback effects caused by fluctuations in population size are considered independent of stochastic variation in the environment. We show that an interplay between winter temperature and population density can influence the persistence of a small passerine population under global warming. Although warmer winters favor an increased mean population size, density-dependent feedback can cause the local population to be less buffered against occasional poor environmental conditions (cold winters). This shows that it is essential to go beyond the population size and explore climate effects on the full dynamics to elaborate targeted management actions. PMID:28164157

Climate, demography and lek stability in an Amazonian bird

PubMed Central

Ryder, Thomas B.; Sillett, T. Scott

2016-01-01

Lekking is a rare, but iconic mating system where polygynous males aggregate and perform group displays to attract females. Existing theory postulates that demographic and environmental stability are required for lekking to be an evolutionarily viable reproductive strategy. However, we lack empirical tests for the hypotheses that lek stability is facilitated by age-specific variation in demographic rates, and by predictable, abundant resources. To address this knowledge gap, we use multistate models to examine how two demographic elements of lek stability—male survival and recruitment—vary with age, social status and phase of the El Niño Southern Oscillation (ENSO) in a Neotropical frugivorous bird, the wire-tailed manakin (Pipra filicauda). Our results show that demographic and environmental conditions were related to lek stability in the Ecuadorean Amazon. Apparent annual survival probability of territorial males was higher than that of non-territorial floaters, and recruitment probability increased as males progressed in an age-graded queue. Moreover, annual survival of territorial males and body condition of both floaters and territory holders were higher following years with El Niño conditions, associated with reduced rainfall and probably higher fruit production in the northern Neotropics, and lower after years with wet, La Niña conditions that predominated our study. Recruitment probabilities varied annually, independent of ENSO phase, and increased over our study period, but the annual mean number of territorial males per lek declined. Our results provide empirical support for hypothesized demographic and environmental drivers of lek dynamics. This study also suggests that climate-mediated changes in resource availability can affect demography and subsequent lek stability in a relatively buffered, lowland rainforest. PMID:26791615

Climate, demography and lek stability in an Amazonian bird.

PubMed

Ryder, Thomas B; Sillett, T Scott

2016-01-27

Lekking is a rare, but iconic mating system where polygynous males aggregate and perform group displays to attract females. Existing theory postulates that demographic and environmental stability are required for lekking to be an evolutionarily viable reproductive strategy. However, we lack empirical tests for the hypotheses that lek stability is facilitated by age-specific variation in demographic rates, and by predictable, abundant resources. To address this knowledge gap, we use multistate models to examine how two demographic elements of lek stability-male survival and recruitment-vary with age, social status and phase of the El Niño Southern Oscillation (ENSO) in a Neotropical frugivorous bird, the wire-tailed manakin (Pipra filicauda). Our results show that demographic and environmental conditions were related to lek stability in the Ecuadorean Amazon. Apparent annual survival probability of territorial males was higher than that of non-territorial floaters, and recruitment probability increased as males progressed in an age-graded queue. Moreover, annual survival of territorial males and body condition of both floaters and territory holders were higher following years with El Niño conditions, associated with reduced rainfall and probably higher fruit production in the northern Neotropics, and lower after years with wet, La Niña conditions that predominated our study. Recruitment probabilities varied annually, independent of ENSO phase, and increased over our study period, but the annual mean number of territorial males per lek declined. Our results provide empirical support for hypothesized demographic and environmental drivers of lek dynamics. This study also suggests that climate-mediated changes in resource availability can affect demography and subsequent lek stability in a relatively buffered, lowland rainforest. © 2016 The Author(s).

The Effects of Habitat Type and Volcanic Eruptions on the Breeding Demography of Icelandic Whimbrels Numenius phaeopus.

PubMed

Katrínardóttir, Borgný; Alves, José A; Sigurjónsdóttir, Hrefna; Hersteinsson, Páll; Gunnarsson, Tómas G

2015-01-01

Distinct preference of species for habitats is most often driven by long term differences in demographic rates between habitats. Estimating variation in those rates is key for developing successful conservation strategies. Stochastic events can interact with underlying variation in habitat quality in regulating demography but the opportunities to explore such interactions are rare. Whimbrels in Iceland show a strong preference for sparsely vegetated riverplains. Such habitats in Iceland face various threats, e.g., climate change, river regulation and spread of alien plant species. In this study we compared demographic parameters of breeding Whimbrels between riverplains and other habitats before, during and after volcanic eruption events to estimate the importance of the habitats for the species and the effect of ash deposit on breeding success. We found that an estimated minimum of 23% of the Icelandic population of Whimbrels and c. 10% of the world population of the species breed in riverplain habitats in Iceland. Whimbrels bred consistently at much higher densities in riverplain habitats than in other habitats and riverplains also had higher densities of pairs with fledglings although the proportion of successful breeders was similar between habitats. Predation by livestock may have had a considerable negative effect on breeding success on our study sites. Breeding was negatively affected by the volcanic activity, probably through the effects of ash on the invertebrate food supply, with breeding success being gradually worse closer to the eruption. Breeding success was equally affected by volcanism across habitats which differed in underlying habitat quality. This study gives an example of how populations can be regulated by factors which operate at different spatial scales, such as local variation in habitat quality and stochastic events which impact larger areas.

Density, Demography, and Influential Environmental Factors on Overwintering Populations of Sogatella furcifera (Hemiptera: Delphacidae) in Southern Yunnan, China.

PubMed

Hu, Shao-Ji; Fu, Da-Ying; Han, Zhong-Liang; Ye, Hui

2015-01-01

Sogatella furcifera (Horváth) (Hemiptera: Delphacidae) is the most serious pest on rice in southwestern China. Yunnan province is within this region and is a major overwintering area for S. furcifera in China. This field study was carried out over 4 yr (2010-2013) and focused on S. furcifera distribution, population density, and demography, as well as the relationship between various environmental factors and the distribution and density of overwintering S. furcifera in Yunnan. Our study demonstrated that overwintering populations of S. furcifera mainly occurred in valleys and lowlands below 25.02°N and 1,608 m above sea level (a.s.l.), where ratooning rice was present [corrected]. The overwintering range of S. furcifera has expanded in Yunnan compared with 20 yr ago, and regional climate change is believed to be the main contributing cause for this expansion. Environmental factor analysis showed that the mean air temperature of the coldest quarter and precipitation of the coldest quarter were two key factors that were strongly linked to the overwintering distribution and density of S. furcifera in Yunnan. Wintertime temperature was the principal influencing factor to determine the distribution and density of S. furcifera, while the effect of precipitation was indirect in that it influenced the insect's distribution via its host. This study documented the major overwintering areas of S. furcifera in Yunnan, which can be used to predict outbreak potential in the following spring. Hence, key climatic factors, overwintering distribution, and density of S. furcifera should be used when forecasting outbreaks in spring. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

Age, stage and senescence in plants

PubMed Central

Caswell, Hal; Salguero-Gómez, Roberto

2013-01-01

1. Senescence (an increase in the mortality rate or force of mortality, or a decrease in fertility, with increasing age) is a widespread phenomenon. Theories about the evolution of senescence have long focused on the age trajectories of the selection gradients on mortality and fertility. In purely age-classified models, these selection gradients are non-increasing with age, implying that traits expressed early in life have a greater impact on fitness than traits expressed later in life. This pattern leads inevitably to the evolution of senescence if there are trade-offs between early and late performance. 2. It has long been suspected that the stage- or size-dependent demography typical of plants might change these conclusions. In this paper, we develop a model that includes both stage- and age-dependence and derive the age-dependent, stage-dependent and age×stage-dependent selection gradients on mortality and fertility. 3. We applied this model to stage-classified population projection matrices for 36 species of plants, from a wide variety of growth forms (from mosses to trees) and habitats. 4. We found that the age-specific selection gradients within a life cycle stage can exhibit increases with age (we call these contra-senescent selection gradients). In later stages, often large size classes in plant demography, the duration of these contra-senescent gradients can exceed the life expectancy by several fold. 5. Synthesis. The interaction of age- and stage-dependence in plants leads to selection pressures on senescence fundamentally different from those found in previous, age-classified theories. This result may explain the observation that large plants seem less subject to senescence than most kinds of animals. The methods presented here can lead to improved analysis of both age-dependent and stage-dependent demographic properties of plant populations. PMID:23741075