Demographic Fluctuations Research Articles

Spatial features of population family structure of Belarus during the period of socio-economic transformations

The article is devoted to the modern tendencies of population family structure transformation in Belarus and their spatial heterogeneity. Spare-time trends of marriages, divorces and population family structure of Belarus during 1989‒2017 were determined. For researching period for population of Belarus marriage decline and divorce rate growth and general increasing of marriage and divorce from northern west to southern east are discovered. Marriage and divorce dynamics is influenced with demographic waves fluctuation. Reduction of number of families, simplification of structure of families, decreasing of family size and general regional degradation of family structure from south to north of Belarus were found out. Economic-geographical typology of administrative districts of Belarus on family structure character was worked through. Dividing approach of economic-geographical typology has double-component character and consider interests of national demographic policy which has pronatalistic aims. On the base of complex of marriage, divorce, family density, family size and family types structure with considering of features of demographic situation characterized with parameters of population natural movement and age structure 3 main economic-geographical types and 9 subtypes of Belarusian districts were distinguished by character of family structure of population. These types are demographic central with progressive family structure, demographic semi-peripheral with family structure of transit type, demographic peripheral with regressive family structure. Demographic central districts with progressive family structure are characterized with relatively preferable parameters of demographic situation and family-matrimonial situation. Demographic semi-peripheral districts with family structure of transit type are the most widespread in Belarus and are characterized with non-stable demographic situation and family structure. Belarusian districts with regressive type of family structure include demographic peripheral territories and are characterized with adverse family structure and demographic situation in general. Economic-geographical researching of population family structure directed on studying and explaining of its modern tendencies must be based on the detailed examination of socio-economic, demographic and spare aspects.

Invasion implies substitution in ecological communities with class-structured populations

Long-term evolution of quantitative traits is classically and usefully described as the directional change in phenotype due to the recurrent fixation of new mutations. A formal justification for such continual evolution ultimately relies on the “invasion implies substitution”-principle. Here, whenever a mutant allele causing a small phenotypic change can successfully invade a population, the ancestral (or wild-type) allele will be replaced, whereby fostering gradual phenotypic change if the process is repeated. It has been argued that this principle holds in a broad range of situations, including spatially and demographically structured populations experiencing frequency- and density-dependent selection under demographic and environmental fluctuations. However, prior studies have not been able to account for all aspects of population structure, leaving unsettled the conditions under which the “invasion implies substitution”-principle really holds. In this paper, we start by laying out a program to explore and clarify the generality of the “invasion implies substitution”-principle. Particular focus is given on finding an explicit and functionally constant representation of the selection gradient on a quantitative trait. Using geometric singular perturbation methods, we then show that the “invasion implies substitution”-principle generalizes to well-mixed and scalar-valued polymorphic multispecies ecological communities that are structured into finitely many demographic (or physiological) classes. The selection gradient is shown to be constant over the evolutionary timescale and that it depends only on the resident phenotype, individual growth-rates, population steady states and reproductive values, all of which are calculated from the resident dynamics. Our work contributes to the theoretical foundations of evolutionary ecology.

A multi-proxy inference of Jōmon population dynamics using bayesian phase models, residential data, and summed probability distribution of 14C dates

We introduce a new workflow for analysing archaeological frequency data associated with relative rather than absolute chronological time-stamps. Our approach takes into account multiple sources of uncertainty by combining Bayesian chronological models and Monte-Carlo simulation to sample possible calendar dates for each archaeological entity. We argue that when applied to settlement data, this combination of methods can bring new life to demographic proxies that are currently under-used due to their lack of chronological accuracy and precision, and provide grounds for further exploring the limits and the potential of the so-called “dates as data” approach based on the temporal frequency of radiocarbon dates. Here we employ this new workflow by re-examining a legacy dataset that has been used to describe a major population rise-and-fall that occurred in central Japan during the Jōmon period (16,000–2,800 cal BP), focusing on the temporal window between 8,000 and 3,000 cal BP. To achieve this goal we: 1) construct the first Bayesian model of forty-two Jōmon ceramic typology based cultural phases using a sample of 2,120 radiocarbon dates; 2) apply the proposed workflow on a dataset of 9,612 Jōmon pit-dwellings; and 3) compare the output to a Summed Probability Distribution (SPD) of 1,550 radiocarbon dates from the same region. Our results provide new estimates on the timing of major demographic fluctuations during the Jōmon period and reveal a generally good correlation between the two proxies, although with some notable discrepancies potentially related to changes in settlement pattern.

Demographic fluctuations lead to rapid and cyclic shifts in genetic structure among populations of an alpine butterfly, Parnassius smintheus.

Many populations, especially in insects, fluctuate in size, and periods of particularly low population size can have strong effects on genetic variation. Effects of demographic bottlenecks on genetic diversity of single populations are widely documented. Effects of bottlenecks on genetic structure among multiple interconnected populations are less studied, as are genetic changes across multiple cycles of demographic collapse and recovery. We take advantage of a long-term data set comprising demographic, genetic and movement data from a network of populations of the butterfly, Parnassius smintheus, to examine the effects of fluctuating population size on spatial genetic structure. We build on a previous study that documented increased genetic differentiation and loss of spatial genetic patterns (isolation by distance and by intervening forest cover) after a network-wide bottleneck event. Here, we show that genetic differentiation was reduced again and spatial patterns returned to the system extremely rapidly, within three years (i.e. generations). We also show that a second bottleneck had similar effects to the first, increasing differentiation and erasing spatial patterns. Thus, bottlenecks consistently drive random divergence of allele frequencies among populations in this system, but these effects are rapidly countered by gene flow during demographic recovery. Our results reveal a system in which the relative influence of genetic drift and gene flow continually shift as populations fluctuate in size, leading to cyclic changes in genetic structure. Our results also suggest caution in the interpretation of patterns of spatial genetic structure, and its association with landscape variables, when measured at only a single point in time.

Stochastic yield catastrophes and robustness in self-assembly.

A guiding principle in self-assembly is that, for high production yield, nucleation of structures must be significantly slower than their growth. However, details of the mechanism that impedes nucleation are broadly considered irrelevant. Here, we analyze self-assembly into finite-sized target structures employing mathematical modeling. We investigate two key scenarios to delay nucleation: (i) by introducing a slow activation step for the assembling constituents and, (ii) by decreasing the dimerization rate. These scenarios have widely different characteristics. While the dimerization scenario exhibits robust behavior, the activation scenario is highly sensitive to demographic fluctuations. These demographic fluctuations ultimately disfavor growth compared to nucleation and can suppress yield completely. The occurrence of this stochastic yield catastrophe does not depend on model details but is generic as soon as number fluctuations between constituents are taken into account. On a broader perspective, our results reveal that stochasticity is an important limiting factor for self-assembly and that the specific implementation of the nucleation process plays a significant role in determining the yield.

The Impact of COVID-19 Pandemic on Early Childhood Education and Comorbidities in Brazil: Challenges and Perspectives

The COVID-19 pandemic caused numerous changes in the lives of individuals in all geographic regions, not only because of the speed of transmission, but also because the world is experiencing the fourth industrial revolution, which increases the fluxes of data and materials throughout the network society. There is a global picture of changes over time, where pandemics have been gradually replaced by chronic diseases. And, in this context, the most drastic changes in health-disease patterns occur in children and young women and are associated with the demographic and socioeconomic fluctuations that underpin the modernization complex. The current pandemic offers an opportunity for reflection on the concept of health in the current and globalized world. It is up to the human being to definitely learn. In the early childhood education, during this period of the COVID 19 pandemic, it is necessary to deal with some special issues, in a short time: 1) the migration from onsite to remote teaching in the educational system; 2) to consider the current pandemic as a state of exception without forgetting the co-existence of other morbidities that had already been hardly affecting children over the years, such as obesity, high blood pressure and diabetes and 3) the urgent need on how to manage the time for education professionals to re-invent the teaching-learning process through digital tools. Once these challenges are reached, the maintenance of the health-education binomial will have great chances of being successful through joint actions both at the governmental level and by professionals in the area of education and the family of children.

Mate choice, reproductive success and inbreeding in white rhinoceros: New insights for conservation management.

Improving our sparse knowledge of the mating and reproductive behaviour of white rhinoceros (Ceratotherium simum Burchell, 1817) is essential for the effective conservation of this iconic species. By combining morphological, physiological and habitat data with paternity assignments of 104 known mother–offspring pairs collected over a period of 13 years, we provide the most comprehensive analysis of the mating system in this species. We show that while the overall mating system was promiscuous, and both males and females produced more offspring when mating with several partners, half of all females with multiple offspring were monogamous. Additionally, we find that mating and reproductive success varied significantly among territorial males in two independent sets of males. In females, however, variation in the mating and the reproductive success was not larger than expected by random demographic fluctuations. Horn size, testosterone metabolite concentration, territory size, habitat openness and the volume of preferred food within the territory did not seem to influence male mating or reproductive success. Moreover, there was no sign of inbreeding avoidance: females tended to mate more frequently with closely related males, and one daughter produced a progeny with her father. The lack of inbreeding avoidance, in combination with the skew in male reproductive success, the partial monogamy in females and the territorial‐based mating system, jeopardizes the already low genetic variation in the species. Considering that the majority of populations are restricted to fenced reserves and private farms, we recommend taking preventive measures that aim to reduce inbreeding in white rhinoceros. A video abstract can be viewed here.

Space and time predictions of schistosomiasis snail host population dynamics across hydrologic regimes in Burkina Faso.

The ecology of the aquatic snails that serve as obligatory intermediate hosts of human schistosomiasis is driven by climatic and hydrological factors which result in specific spatial patterns of occurrence and abundance. These patterns in turn affect, jointly with other determinants, the geography of the disease and the timing of transmission windows, with direct implications for the success of control and elimination programmes in the endemic countries. We address the spatial distribution of the intermediate hosts and their seasonal population dynamics within a predictive ecohydrological framework developed at the national scale for Burkina Faso, West Africa. The approach blends river network-wide information on hydrological ephemerality which conditions snail habitat suitability together with ensembles of discrete time ecological models forced by remotely sensed estimates of temperature and precipitation. The models were validated against up to four years of monthly snail abundance data. Simulations of model ensembles accounting for the uncertainty in remotely sensed products adequately reproduce observed snail demographic fluctuations observed in the field across habitat types, and produce national scale predictions by accounting for spatial patterns of hydrological conditions in the country. Geospatial estimates of seasonal snail abundance underpin large-scale, spatially explicit predictions of schistosomiasis incidence. This work can therefore contribute to the development of disease control and elimination programmes.

Novel method for detection probability and estimating population size of mountain frog, Rana macrocnemis (Boulenger, 1885) at the end of its distribution range

Local amphibian populations at the edge of a species range are possibly of greater conservation concern than any other amphibians group. They experience greater demographic fluctuation than populations at the core of the range. We detected the most suitable distribution range of R. macrocnemis by maximum entropy (MaxEnt) method at the end of the southeastern edge of natural distribution range to find out which environmental variables have a significant role in determining the distribution pattern of this species in marginal populations. According to the map constructed, three important variables had a high contribution to species presence as land cover (63.4%), annual precipitation (27%), and precipitation of coldest quarter of the year (5.4%) variables. Then, we described new methods for estimating detection probability for terrestrial frogs, specifically R. macrocnemis. Finally, we estimated the population size of mountain frogs by calculated detection probability. Our repeated capture–re-capture (RCR) results suggest that the estimated detection probability for R. macrocnemis is: $$\widehat{p} = 0.052$$. Thus, the total average number of R. macrocnemis obtained from the 17 habitat sites is 982.5 adults (range: 708–1211 adults). In conclusion, the population estimates by detection probability index are generally much higher than densities reported for the Mountain frog populations than visual encounter estimation about 50.5 adults (range: 37–63 adults).

Stock vs. Bond yields and demographic fluctuations

Abstract This paper analyzes the strong comovement between real stock and nominal bond yields at generational frequencies. Using a stochastic overlapping generations model with cash-in-advance constraints, we show that the simulated life-cycle patterns in savings behavior make both real stock and nominal bond yields comove with the changing population age structure. These persistent comovements account for the equilibrium relation between stock and bond markets. A stochastic Fisher decomposition of nominal bond yields reveals that, while having a moderate effect on both the inflation risk premium and expected inflation, demographic changes affect nominal yields mainly through real bond yields. Using both U.S. data and a cross-country panel, we find empirical support for these theoretical predictions. Finally, we show that the strength of the demographic effect on real yields explains cross-country differences in the comovement between stock and bond markets, while alternative demographic channels fail to explain such cross-country heterogeneity.

Demographic fluctuations and the emergence of arctic maritime adaptations

Our goal is to study the role of demographic change in the development and spread of maritime adaptations in the North American Arctic over the last 6000 years. We compile and analyze a regional radiocarbon database (n = 935) for northern Alaska, using Oxcal to analyze demographic patterns in summed probability distributions. We find that northern Alaskan populations grew significantly over the last 4500 years, although growth was punctuated by three periods of decline from approximately 3700 to 3125 cal BP, 1000 cal BP, and 600 cal BP. We assess possible alternative explanations for the observed demographic patterns (e.g. calibration and taphonomic effects, investigator bias). Region-wide erosion and calibration effects likely contribute to the dearth of radiocarbon dates around 1000 cal BP, and sampling bias may contribute to the post-600 cal BP decline. However, we conclude that the overall pattern reflects regional population growth, decline, and recovery. Population growth predates intensification of marine resource procurement by at least 1200 years; we hypothesize that population growth was a possible driver for late Holocene marine intensification in the Arctic. These findings have further implications for understanding the process of intensification and the development of complexity in coastal hunter-gatherer societies.

Modeling the Factors Affecting the First Birth in the Family's' Fertility in Hamedan Province

Background: The role of fertility as the most important determinant of demographic fluctuations has given more importance to its studies compared with other demographic phenomena. In this context, different indexes are used to measure fertility patterns where the index of the first birth after marriage has received much attention.
 Materials and Methods: This was a cross-sectional (descriptive-analytic) study in which the fertility data of women are converted into a fictitious cohort and investigated. In this study, married woman in the age group of 15 to 49 years in 500 families in Hamedan were selected. In this study, a researcher-made questionnaire was used that included information related to the number of live births (fertility) and factors related to it (i.e. date of marriage, age, the first pregnancy, number of unwanted pregnancies, average interval between children, and the use of contraceptives). Univariate and multivariate survival analysis was carried out for the interval between marriage and the first birth. In the univariate section, using Kaplan-Meir method and log-rank test, survival functions of the interval between the first births after marriage in different predictive variables were compared.
 Result: Mean age of mothers at the first birth was 22.04±4.357 years and mean number of live births was 2.18±0.904. The first marriage age of women, parental education, women’s employment, the use of contraceptives, and the number of live births were at a significance level of 5%.
 Conclusion: It can be concluded that parental education, women’s employment, and use of contraceptives play important roles in population growth.

Cultural change and population dynamics during the Bronze Age: Integrating archaeological and palaeoenvironmental evidence for Schleswig-Holstein, Northern Germany

In archaeology, change in material culture is viewed as indicating social or cultural transformation and is the basis of our typo-chronological classification of phases and periods. The material culture from northern Germany reveals both quantitative and qualitative changes during the Bronze Age. At the same time, there is also evidence for ‘boom and bust’ cycles in population density/size, as indicated by changing human impact on the environment in several Bronze Age palaeoenvironmental records. These demographic fluctuations may relate to the observed changes in social phenomena in aspects of ideology, technology, food production and habitation. For example, innovations in food production, such as the adoption of new crops and agricultural techniques, could have led to population growth. While usually viewed by archaeologists as a ‘negative’ development, population stress or collapse may have favoured the emergence of new cultural phenomena. In order to test the cause-and-effect relationship between population dynamics and sociocultural change, we synthesise the archaeological evidence – qualitative and quantitative information from settlements, deposition finds (hoards), burials, material culture and architectural remains – for the Bronze Age in northern Germany, mainly Schleswig-Holstein, and compare it with the boom and bust pattern seen in the palaeoenvironmental record. The synchronicity of changes at ca. 1500 BC and ca. 1100 BC reflects the relationship between phases of major sociocultural transformation in the archaeological datasets and booms and busts in the palaeoenvironmental record of the region seen as a proxies for palaeo-demography. This sets the stage for a better understanding of the transformation of practices and relationships in the Bronze Age communities of the region.

An approach to the pollution haven and pollution halo hypotheses in MINT countries.

This study examines the nonlinear relationship between foreign direct investment (FDI) and the ecological footprint (EF), trying to confirm the pollution haven hypothesis (PHH). We use a panel data model for MINT (Mexico, Indonesia, Nigeria, and Turkey) countries in the period 1990-2013 and an empirical framework based on the pollution haven hypothesis (PHH). Using the fully modified least squares (FMOLS) and dynamic ordinary least squares (DOLS) econometric methodologies, the empirical results confirm an inverted-U relationship between FDI and the ecological footprint. To reinforce our analysis, we check the connection between economic growth and the ecological footprint, validating the environmental Kuznets curve (EKC) hypothesis for MINT countries. Finally, we also confirm a negative connection between renewable energy use, the urbanization process, and the changes in the ecological footprint. These findings offer a series of useful recommendations for policymakers, where the promotion of clean industries and energy-efficiency actions are essential for reducing environmental damage in MINT countries. We highlight the viability of the ecological footprint as a first-order environmental indicator whose evolution is determined by demographic fluctuations.

Anthropology of changing paradigms of urban water systems

The dynamic interaction between society and nature is influenced by the prevailing normative, cognitive, and regulative societal systems, which guide the relationships between society and nature or ecology. Therefore, mature cities with increasingly complex urban interactions must shift from the simple agenda of demand–supply to multi-criterion models that takes into account factors like impacts of climate change, variation in settlement patterns, human vulnerability, and resource optimization to balance the society–ecology relationship. However, rapidly growing megacities have failed to balance their development and associated societal goals. This paper presents an assessment of the paradigm shift in the relationship between people and water as a resource, or the hydro-social construct, along a temporal gradient from about ad 1206 to the present for an ancient Asian city, namely Delhi. The city struggles at present with many challenges, including demographic fluctuations, increasing geographic spread, economic restructuring, changes in land use and settlement patterns, and, most relevant here, the transition from a water-sensitive city to a water-scarce city. The study identifies the causes of shifts in the water–society relationships and areas of interventions, that takes into account the physical, economic, and social characteristics of the city’s water resource to ensure that water, a basic human need, must be accessible to all inhabitants of the city.

Biogeography and adaptation in the Kuril Islands, Northeast Asia

ABSTRACTThe Circumpolar North is generally recognized as a challenging environment to inhabit and yet, we know relatively little about how people managed their welfare in these places. Here, we add to the understanding of maritime hunter-gatherers in the subarctic North Pacific through a comparative approach that synthesizes biogeographic and archaeological data from the Kuril Islands. We conclude that our faunal, ceramic and lithic evidence support expectations from biogeography as assemblages from low biodiversity and insular regions show limited diet breadth, more locally produced pottery and a conservation of lithic resources. However, we highlight that these ecological factors did not strictly determine the occupation history of the archipelago as radiocarbon data suggests all regions experienced similar demographic fluctuations regardless of their biogeography. These results imply additional pressures influenced the strategic use and settlement of the Kuril Islands and the need for increased chronological resolution to disentangle these complex historical factors.

Pinned, locked, pushed, and pulled traveling waves in structured environments

Traveling fronts describe the transition between two alternative states in a great number of physical and biological systems. Examples include the spread of beneficial mutations, chemical reactions, and the invasions by foreign species. In homogeneous environments, the alternative states are separated by a smooth front moving at a constant velocity. This simple picture can break down in structured environments such as tissues, patchy landscapes, and microfluidic devices. Habitat fragmentation can pin the front at a particular location or lock invasion velocities into specific values. Locked velocities are not sensitive to moderate changes in dispersal or growth and are determined by the spatial and temporal periodicity of the environment. The synchronization with the environment results in discontinuous fronts that propagate as periodic pulses. We characterize the transition from continuous to locked invasions and show that it is controlled by positive density-dependence in dispersal or growth. We also demonstrate that velocity locking is robust to demographic and environmental fluctuations and examine stochastic dynamics and evolution in locked invasions.

Holocene demographic fluctuations, climate and erosion in the Mediterranean: A meta data-analysis

As part of the Changing the Face of the Mediterranean Project, we consider how human pressure and concomitant erosion has affected a range of Mediterranean landscapes between the Neolithic and, in some cases, the post-medieval period. Part of this assessment comprises an investigation of relationships among palaeodemographic data, evidence for vegetation change and some consideration of rapid climate change events. The erosion data include recent or hitherto unpublished work from the authors. Where possible, we consider summed probabilities of 14C dates as well as the first published synthesis of all known optically stimulated luminescence dated sequences. The results suggest that while there were some periods when erosion took place contemporaneously across a number of regions, possibly induced by climate changes, more often than not, we see a complex and heterogeneous interplay of demographic and environmental changes that result in a mixed pattern of erosional activity across the Mediterranean.

Historical demography of four gecko species specializing in boulder cave habitat: Implications in the evolutionary dead end hypothesis and conservation.

Specialization in narrow ecological niches may not only help species to survive in competitive or unique environments but also contribute to their extermination over evolutionary time. Although the "evolutionary dead end" hypothesis has long been debated, empirical evidence from species with detailed information on niche specialization and evolutionary history remains rare. Here we use a group of four closely related Cnemaspis gecko species that depend highly on granite boulder caves in the Mekong Delta to investigate the potential impact of ecological specialization on their evolution and population dynamics. Isolated by unsuitable floodplain habitats, these boulder-dwelling geckos are among the most narrowly distributed Squamata in the world. We applied several coalescence-based approaches combined with the RAD-seq technique to estimate their divergence times, gene flow and demographic fluctuations during the speciation and population differentiation processes. Our results reveal long-term population shrinkage in the four geckos and limited gene flow during their divergence. The results suggest that the erosion and fragmentation of the granite boulder hills have greatly impacted population divergence and declines. The habitat specialization of these geckos has led to fine-scaled speciation in these granite rocky hills; in contrast, specialization might also have pushed these species toward the edge of extinction. Our study also emphasizes the conservation urgency of these vulnerable, cave-dependent geckos.

Conservation and historical distribution of two bumblebee species from the Atlantic Forest

In this study, we analysed the processes resulting in the origin of two endemic sister species of bumblebees in the Brazilian Atlantic Forest. We studied the historical distribution pattern of Bombus bahiensis, which is restricted to small fragments in eastern Brazil and the phylogeographic pattern and historical demography of B. brasiliensis, which is widely distributed in southern and south-eastern Brazil and neighbouring regions of Uruguay, Paraguay, and Argentina. We used ecological niche models, niche analyses, and genetic and distribution data (i) to test the role of niche differentiation on the divergence between the two species, (ii) to find potential distribution areas for the most restricted B. bahiensis, and (iii) to evaluate the conservation status of both species. Our results showed that B. brasiliensis populations are able to disperse across mosaics of anthropogenic and preserved areas and exhibit low levels of spatial genetic structure. Otherwise, B. bahiensis presented a restricted distribution range and likely a lower diversity, where it is suffering with an increasing habitat loss. The climatic oscillations of the Pleistocene influenced the population structure of both species in different ways, probably due to differences in their effective population sizes, physiology and past demographic fluctuations. Specifically, while B. brasiliensis expanded its distribution range in the last 500, 000 years throughout most of the Atlantic Forest, B. bahiensis remained restricted to a small rainforest area between southern Bahia and northern Espírito Santo states in Brazil. In its southern distribution, in the state of Espírito Santo, B. bahiensis is currently very rare or extinct. Currently, the adjacent ranges of Bombus brasiliensis and B. bahiensis do not overlap and our results indicate that these species may have further diversified through a reinforcement process associated to niche specialization and differentiation.