Low Population Growth Research Articles

Research on the Factors Contributing to Low Fertility in South Korea

In 2023, South Korea had a fertility rate of 0.8831, the lowest in the world. Compared to most other east Asian countries, Korea recovered from the Second World War relatively earlier and is home to some of the most influential companies in the world today. Therefore, while other east Asian countries are in the industrial stage characterized by moderate to high rates of population growth, Korea is already a post-industrial society, marked by low population growth. This paper aims to identify the contributing factors to South Koreas low fertility rate by examining previous surveys completed by Koreans, interviews done with Koreans, and statistics about the Korean economy and society. These surveys, interviews, and statistics show the current economic, social, and cultural characteristics of the country and the flaws in them that lead to low fertility rate. The first significant factor related to the low fertility rate in South Korea is the high economic uncertainty due to rising living costs. Many Koreans struggle to achieve financial independence and move out of their parents homes, which is a barrier to starting a family. The second factor is the rising number of women obtaining higher levels of education and subsequently entering the workforce. The last factor is the practice of neo-Confucianism beliefs that are patriarchal in nature. Therefore, the proposed solution is that the Korean government should focus on changing current social and cultural beliefs to minimize the conflict between family and work for Korean women.

Research on the Fiscal and Tax Subsidy System of Family Birth in China under the Background of Three Children

With the rapid development of China's socialist market economy, the trend of population aging is obvious, the "three children policy" is timely introduced, and the problem of resident fertility has risen to the level of national strategy. In 2021, the state actively implemented the "three-child" policy, which provided institutional guidance for solving the problem of population aging. In this context, how China should give full play to the economic leverage effect of fiscal and tax law, and guide and encourage the masses to respond to the national call to give birth to three children by economic means, is a very meaningful realistic topic. To study the optimization of the "fertility friendly" fiscal and tax subsidy policy, explore the optimization of the population structure, timely solve the practical problems for the stable development of the population, the fiscal and tax subsidy policy provides corresponding positive supporting measures to encourage fertility. It establishes the policy, delay and reverse the trend of low population growth of China, and facilitate the implementation of the "comprehensive three child" policy. Current our country to encourage fertility fiscal subsidy policy lack of stable source of income, encourage family fertility fiscal subsidy policy function object is not extensive, encourage family fertility fiscal subsidy policy each link imbalance, encourage family fertility tax single, personal income tax lack of family declaration unit, can through to encourage birth to provide adequate subsidies support, in the family for the tax collection, the implementation of differentiated tax incentive rules to change the current situation. Therefore, from the perspective of fiscal and tax law, it is of certain practical significance to improve the fertility incentive mechanism to stimulate the recovery of fertility rate.

The Impact of Population Growth on Land Covers in Tegal Regency, Indonesia in 2015 and 2023

Abstract The purpose of study was to examine how Tegal Regency’s population expansion has affected the land cover for eight years and identify the land cover changes in Tegal Regency that resulted from population growth between 2015 and 2023. This research used descriptive quantitative because of the population growth rate calculation and spatial analysis to compare the highest and lowest population growth and determine the amount of land cover change in 2015-2023 in Tegal Regency. The results of this study showed that the Bojong Sub-district had the highest population growth rate of 2.46%, with a growth of 13,327 people, while the Talang Sub-district had the lowest growth rate of 0.90%, with a growth of 7,492 people. The higher the population, the more land is needed to build settlements, so there is a change in built-up land cover, which in 2015 was 13,900.47 ha to 15,417.70 ha in 2023. The most built-up land cover has increased in area in Margasari Sub-district because of the high population change of 15,900 people. In this case, population growth significantly impacted the amount of land cover in Tegal Regency in 2015-2023.

Multigenerational effects of glyphosate-based herbicide and emamectin benzoate insecticide on the reproduction and gene expression of the copepod Pseudodiaptomus annandalei (Sewell, 1919)

This study investigates the effects of glyphosate-based herbicide (GLY) and pure emamectin benzoate (EB) insecticide on the brackish copepod Pseudodiaptomus annandalei. The 96h median lethal concentration (96 h LC50) was higher in the GLY exposure (male: 3420.96 ± 394.67 μg/L; female: 3093.46 ± 240.67 μg/L) than in the EB (male: 79.10 ± 7.30 μg/L; female: 6.38 ± 0.72 μg/L). Based on the result of 96h LC50, we further examined the effects of GLY and EB exposures at sub-lethal concentrations on the naupliar production of P. annandalei. Subsequently, a multigenerational experiment was conducted to assess the long-term impact of GLY and EB at concentrations 375 μg/L, and 0.025 μg/L respectively determined by sub-lethal exposure testing. During four consecutive generations, population growth, clutch size, prosome length and width, and sex ratio were measured. The copepods exposed to GLY and EB showed lower population growth but higher clutch size than the control group in most generations. Gene expression analysis indicated that GLY and EB exposures resulted in the downregulation of reproduction-related (vitellogenin) and growth-related (myosin heavy chain) genes, whereas a stress-related gene (heat shock protein 70) was upregulated after multigenerational exposure. The results of the toxicity test after post-multigenerational exposure indicated that the long-term GLY-exposed P. annandalei displayed greater vulnerability towards GLY toxicity compared to newly-exposed individuals. Whereas, the tolerance of EB was significantly higher in the long-term exposed copepod than in newly-exposed individuals. This suggests that P. annandalei might have greater adaptability towards EB toxicity than towards GLY toxicity. This study reports for the first time the impacts of common pesticides on the copepod P. annandalei, which have implications for environmental risk assessment and contributes to a better understanding of copepod physiological responses towards pesticide contaminations.

Where we stand on chronic wasting disease: A systematic literature review of its prevalence patterns, impacts, and management interventions

With high fatality and no cure, chronic wasting disease (CWD) has infected cervids in multiple regions, including the United States, Canada, Europe, and South Korea. Despite the rapid growth of literature on CWD, the full scope of its ecological, social, and economic impacts and the most effective and socially acceptable management strategies to mitigate the disease is unclear. Of 3008 initially identified published peer-reviewed papers, 134 were included in a final systematic literature review to synthesize the current knowledge on CWD transmission patterns, impacts, and the effectiveness of management interventions. The number of publications on CWD has increased steadily since 2000 with an average of six papers per year. Most papers were related to CWD prevalence (39 %), human behavior (33 %), CWD impacts (31 %), and management interventions (16 %). Environmental factors such as soil, water, and plants were identified as the most common transmission medium, with a higher prevalence rate among adult male cervids than females. Hunters showed a higher risk perception and were more likely to change hunting behavior due to CWD detection than non-hunters. Ecological impacts included the decreased survival rate accompanied by lower population growth, eventually leading to the decline of cervid populations. Culling was found to be an effective and widely implemented management strategy across countries, although it often was associated with public resistance. Despite potentially high negative economic impacts anticipated due to CWD, studies on this subject were limited. Sustained surveillance, ongoing research, and engagement of affected stakeholders will be essential for future disease control and management.

What drives wild boar density and population growth in Mediterranean environments?

Accurate prediction of fluctuations of wildlife local number of individuals is crucial for effective population management to minimise human-wildlife conflicts. Climate, habitat, food availability, and density dependence are among the main factors influencing mammalian population dynamics. In southern Europe, precipitation and temperature, particularly during summer have been suggested as key factors affecting wild boar (Sus scrofa L.). However, there is uncertainty regarding the role of these factors and the mechanisms driving population fluctuations. This study utilized long-term data of wild boar populations from 14 study sites collected for 23 years in Catalonia, Spain, to analyse the factors that drive population density and growth rate. Generalized Additive Mixed Models (GAMM) explained respectively, 94 % and 65 % of the density and growth rate variability. Spring precipitation in both current and previous year, female weight, and forest cover (particularly above 60 %) were directly associated with higher wild boar densities and population growth rates. The interaction between crop cover and total annual precipitation also played a significant role in determining population density. Higher densities were linked to lower population growth in the following year, likely due to a density-dependent process. These results suggest that the expected decrease in rainfall linked with global warming may limit the availability of natural resources and potentially slow wild boar population growth. Nevertheless, wild boar can exploit alternative anthropogenic food sources, potentially leading to an increase of human-wildlife conflicts. Therefore, incorporating management policies aimed at restricting wild boar access to human food sources is key for controlling their reproductive output. Additionally, landscape management strategies targeted at diminishing refuge and resource availability in regions experiencing high wild boar impact are essential for contributing to sustainable coexistence between wild boars and human populations.

Financial development and population growth: Evidence from bank concentration in China

Using 288 cities in China from 2000 to 2018, we show that a one-standard-deviation increase in bank concentration is associated with 7.9% lower population growth relative to the mean. This effect holds robust after controlling for city characteristics. Cities with higher bank concentration have less entrepreneurship and labor income. We use China's 2009 bank deregulation as a quasi-natural experiment, and find that the shock leads to significant increases in population growth for cities with new entry of joint-stock banks and city commercial banks. We argue the deregulation increases credit supply, which relieves local households' financial constraints and improves population growth.

Assessment of Future Water Demand Utilizing the Weap Model in Bhavnagar City, Gujarat, India

Abstract: Water resources management and analysis is very critical in today’s ever increasing and demanding world. Different types of schemes and software for management are available to meet these requirements. WEAP (Water Evaluation and Planning) software is an integrated approach towards evaluating and planning of water demand and supply that can be very helpful in analysing and understanding water requirements of a particular city, area or region based on various inputs and further trying to understand and predict the future requirements. In this study, a WEAP model for future water demand of Bhavnagar city in Gujarat, is developed, that can predict the water demand requirement upto year 2041. Evaluation of WEAP is done based on census data for 2011 (as census data for 2021 for 10 year period was discontinued due to Covid-19 pandemic), considering 1.67% of growth rate. The final results include three scenarios, namely, Low population growth rate 1.5%, Moderated population growth rate 2%, High population growth rate 2.5%.

Multi-trait diversification in marine diatoms in constant and warmed environments.

Phytoplankton are photosynthetic marine microbes that affect food webs, nutrient cycles and climate regulation. Their roles are determined by correlated phytoplankton functional traits including cell size, chlorophyll content and cellular composition. Here, we explore patterns of evolution in interrelated trait values and correlations. Because both chance events and natural selection contribute to phytoplankton trait evolution, we used population bottlenecks to diversify six genotypes of Thalassiosirid diatoms. We then evolved them as large populations in two environments. Interspecific variation and within-species evolution were visualized for nine traits and their correlations using reduced axes (a trait-scape). Our main findings are that shifts in trait values resulted in movement of evolving populations within the trait-scape in both environments, but were more frequent when large populations evolved in a novel environment. Which trait relationships evolved was population-specific, but greater departures from ancestral trait correlations were associated with lower population growth rates. There was no single master trait that could be used to understand multi-trait evolution. Instead, repeatable multi-trait evolution occurred along a major axis of variation defined by several diatom traits and trait relationships. Because trait-scapes capture changes in trait relationships and values together, they offer an insightful way to study multi-trait variation.

Net benefit of smaller human populations to environmental integrity and individual health and wellbeing.

The global human population is still growing such that our collective enterprise is driving environmental catastrophe. Despite a decline in average population growth rate, we are still experiencing the highest annual increase of global human population size in the history of our species-averaging an additional 84 million people per year since 1990. No review to date has accumulated the available evidence describing the associations between increasing population and environmental decline, nor solutions for mitigating the problems arising. We summarize the available evidence of the relationships between human population size and growth and environmental integrity, human prosperity and wellbeing, and climate change. We used PubMed, Google Scholar, and Web of Science to identify all relevant peer-reviewed and gray-literature sources examining the consequences of human population size and growth on the biosphere. We reviewed papers describing and quantifying the risks associated with population growth, especially relating to climate change. These risks are global in scale, such as greenhouse-gas emissions, climate disruption, pollution, loss of biodiversity, and spread of disease-all potentially catastrophic for human standards of living, health, and general wellbeing. The trends increasing the risks of global population growth are country development, demographics, maternal education, access to family planning, and child and maternal health. Support for nations still going through a demographic transition is required to ensure progress occurs within planetary boundaries and promotes equity and human rights. Ensuring the wellbeing for all under this aim itself will lower population growth and further promote environmental sustainability.

C4 photosynthesis provided an immediate demographic advantage to populations of the grass Alloteropsis semialata.

C4 photosynthesis is a key innovation in land plant evolution, but its immediate effects on population demography are unclear. We explore the early impact of the C4 trait on the trajectories of C4 and non-C4 populations of the grass Alloteropsis semialata. We combine niche models projected into paleoclimate layers for the last 5 million years with demographic models based on genomic data. The initial split between C4 and non-C4 populations was followed by a larger expansion of the ancestral C4 population, and further diversification led to the unparalleled expansion of descendant C4 populations. Overall, C4 populations spread over three continents and achieved the highest population growth, in agreement with a broader climatic niche that rendered a large potential range over time. The C4 populations that remained in the region of origin, however, experienced lower population growth, rather consistent with local geographic constraints. Moreover, the posterior transfer of some C4-related characters to non-C4 counterparts might have facilitated the recent expansion of non-C4 populations in the region of origin. Altogether, our findings support that C4 photosynthesis provided an immediate demographic advantage to A. semialata populations, but its effect might be masked by geographic contingencies.

Markov equilibrium of social security: An analytic solution under CRRA utility and the future of social security

The politico-economic sustainability of pay-as-you-go social security has been studied with the help of two-period overlapping generation models under Markovian equilibrium concepts. The literature has mostly used logarithmic utility for tractability, whereas versions under the more general isoelastic CRRA utility have only been analyzed computationally. This paper demonstrates that a prototypical social security model under CRRA utility has a closed-form solution; it revisits previously obtained computational conclusions and presents new findings and extensions. Quantitatively, the model can explain the observed path of payroll tax rates in the USA and predicts increased tax rates as the equilibrium response to lower future population growth rates. The model predicts a gradual increase in tax rates, from the current 12.4% to about 15% or so in 2060, and then staying at that level. Benefits are expected to decrease slowly, by about 2% (or less) per decade, starting in 2030.

EFFECT OF UREA CONCENTRATION ON THE GROWTH OF CELLS OF Nannochloropsis sp. LABORATORY SCALE

This research was conducted from October 2021 to January 2022 in the Natural Feed Laboratory of the Brackish Water Cultivation Fisheries Center (BPBAP) Ujung Batee, Aceh. This study aimed to determine whether urea has an effect and the best urea concentration on the growth of Nannochloropsis sp. This study used an experimental method with one-factor RAL (Completely Randomised Design), consisting of 4 levels of treatment and control with three replications so that 15 experimental units were obtained. The treatments tested were the uses of urea 40 ppm (treatment A), urea 60 ppm (treatment B), urea 80 ppm (treatment C), urea 100 ppm (treatment D), and Walne 1 ml (control). The population density of Nannochlropsis sp. was found in treatment D on day 4 (2414 x 104 cells/mL), and the lowest population growth was shown in treatment A (1177 x 104 cells/mL). The highest absolute growth rate occurred in treatment D (2229x 104 cells/mL), while the highest relative growth rate occurred in treatment D (1205%), and the highest specific growth rate occurred in treatment B (79% per day).

Population Trends in the World and the Asia Pacific Region

This presentation explores the population trends in both the global and Asia-Pacific regions, examining the underlying factors that influence population growth and population age structure. The presentation highlights the importance of understanding fertility rates and their implications to population ageing, particularly in the context of the Asia-Pacific region. Fertility rates have declined in all regions of the world, however there is still substantial diversity across the globe. In high- and middle-income countries, fertility is now at low levels, some at extremely low levels. In low-income countries, the levels of fertility are more variable, with some countries seeing substantial decline, while others have declined, but at a slower rate. Because of low fertility, some countries have seen substantial population ageing in recent decades, and in the absence of migration, are experiencing depopulation. Other countries, buoyed by their migration policies, are ageing at a slower rate, and do not face the implications of a declining population. In the Asia-Pacific region there are substantial demographic shifts underway. The population has been declining in Japan for over 10 years, and is also declining in South Korea and most recently, China. All populations have very low fertility rates, with South Korea the lowest in the world, at 0.8 in 2021. Japan and South Korea also have very low immigration rates. In 2023, India overtook China as the world’s most populous country. While most regions of the world now have low population growth, populations in Africa are still growing rapidly, fuelled by a young population structure. This provides the region with a potential ‘demographic dividend’ which can contribute to economic opportunities. By outlining the drivers of population change, their implications, policy responses, and future challenges, this presentation will provide insights into the complexities of demographic shifts in today’s world.

Euro area economic growth between 2010 and 2019 in the light of secular stagnation theory

Achieving economic growth remains an important issue for economic policy today. Growth in developed economies has slowed considerably in recent decades. In our study, we examine economic growth in the euro area between 2010 and 2019 in the light of secular stagnation theory. The concept of secular stagnation was developed by Hansen after the Great Depression of 1929-33. According to this theory, the cauSes of secular stagnation are low population growth and weak technological development. The concept was brought back into the economic discourse after 2010 by Summers.

Where Are the Demographic Dividends in Sub-Saharan Africa?

This paper reviews the concept of the demographic dividend and the empirical evidence therefor. The demographic dividend is mainly the result of fertility decline (lower number of births, lower population growth) which translates into a population age structure with a larger work force (age 15–64) and a smaller proportion of children (age 0–14), together with initially few elderly persons (age 65+). In turn, this favors economic growth, but it also has many consequences for households and for state budgets, as well as long-term consequences for population size and the environment. The first part of this paper shows the small correlations at the national macro-economic level between dependency ratios and economic growth. The second part shows the strong correlations at the household level between levels of fertility, child mortality and modern education. The third part discusses the many other correlates of the demographic dividend. The often-cited and controversial focus of the demographic dividend on economic growth hides many other positive effects of fertility control on households, on state budgets, and, in the long-run, on societies and the environment.

Spawner weight and ocean temperature drive Allee effect dynamics in Atlantic cod, Gadus morhua: inherent and emergent density regulation

Abstract. Stocks of Atlantic cod, Gadus morhua, show diverse recovery responses when fishing pressure is relieved. The expected outcome of reduced fishing pressure is that the population regains its size. However, there are also cod stocks that seem to be locked in a state of low abundance from which population growth does not occur (or only slowly occurs). A plausible explanation for this phenomenon can be provided by the Allee effect, which takes place when recruitment per capita is positively related to population density or abundance. However, because of methodological limitations and data constraints, such a phenomenon is often perceived as being rare or non-existent in marine fish. In this study, we used time series of 17 Atlantic cod stocks to fit a family of population equations that consider the abundance of spawners, their body weight and sea water temperature as independent components of recruitment. The developed stock-recruitment function disentangles the effects of spawner abundance, spawner weight and temperature on recruitment dynamics and captures the diversity of density dependencies (compensation, Allee effect) of the recruitment production in Atlantic cod. The results show for 13 cod stocks an inherent spawner-abundance-related Allee effect. Allee effect strength, i.e., the relative change between maximum and minimum recruitment per capita at low abundance, was increased when recruitment production was suppressed by unfavorable changes in water temperature and/or in spawner weight. The latter can be a concomitant of heavy fishing or a result of temperature-related altered body growth. Allee effect strength was decreased when spawner weight and/or temperature elevated recruitment production. We show how anthropogenic stress can increase the risk of Allee effects in stocks where ocean temperature and/or spawner weight had been beneficial in the past but are likely to unmask and strengthen an inherent Allee effect under future conditions.

Extended stage duration and diminished fecundity in deltamethrin-resistant Triatoma infestans (Klug, 1834) of the Argentinean Chaco.

Pyrethroid-resistance is an emergent trait in populations of various insect species. For Triatoma infestans (Klug, 1834) (Heteroptera: Reduviidae), the major vector of Chagas disease in the southern part of South America, hotspot areas of pyrethroid-resistance have recently been found in the Chaco Province of Argentina. Resistant condition can reduce fitness of individuals in the absence of insecticide exposure, that is, fitness costs. We evaluated the existence of developmental and/or reproductive costs in T. infestans collected from two areas of pyrethroid-resistance in Chaco Province, Argentina. Three toxicological groups were defined from field-collected insects: susceptible (survival <20%), moderately resistant (survival between 20% and 80%) and highly resistant (survival >80%). Cohorts of the three toxicological groups were followed-up to study life cycle and reproductive parameters. Additionally, we parameterized matrix population growth models. First and IV nymphal stages of the resistant groups exhibited a longer stage duration than susceptible ones. The reproductive days and hatching success showed significant lower values revealing reproductive costs for the resistant groups. Matrix analysis showed lower population growth rates for the resistant groups. Our results support developmental and reproductive costs for pyrethroid-resistant individuals. This trait could be interpreted as lower population recovery ability for pyrethroid-resistant individuals compared to susceptible insects after alternative vector control actions.

Spatial Agglomeration and Coupling Coordination of Population, Economics, and Construction Land in Chinese Prefecture-Level Cities from 2010 to 2020

Exploring the spatial pattern and development strategies of urbanization from the perspective of the multi-dimensional coordination of population, economy, and land is the key to solving the problems of the urban–rural gap and human–land contradiction. This paper analyzed the spatial agglomeration of population, economy, and construction land area growth rates and explored their coordinated development in Chinese prefecture-level cities from 2010 to 2020 by using the spatial autocorrelation model, elasticity coefficient model, and coupling coordination model. The results are as follows: (1) China’s population, economy, and construction land area were all growing, with the highest economic growth and the lowest population growth, and most prefecture-level cities in central and northeastern China had negative population growth. (2) The growth rates of the population, economy, and construction land in Chinese prefecture-level cities had significant positive spatial clustering characteristics; the spatial agglomeration of the economy was the most prominent and the high-value areas were mainly concentrated in western China. (3) The elasticity coefficients between the population, economy, and construction land in most Chinese prefecture-level cities indicate uneven development of urbanization, manifested as population growth lagging behind construction land expansion and further lagging behind economic development. (4) More than 56% of Chinese prefecture-level cities have uncoordinated development among the population, economy, and construction land mainly distributed in northeast China and central China. The results can provide references and decision-making support for promoting the sustainable development of China’s new urbanization.

Effects of litter quality on foraging behaviour and demographic parameters in Folsomia candida (Collembola).

Litter quality has long been associated with demographic parameters of Collembola populations. However, little is known about the capacity of Collembola to perceive and seek better litter quality. To address this gap, three complementary laboratory experiments were carried out with the Collembola Folsomia candida. First, populations were fed on three different types of leaf litters (Quercus pubescens, Acer opalus and Prunus avium) and a control (agar-agar-brewer's yeast mixture) for 6 weeks to assess their impacts on demography (reproduction rate and population size). Second, the body length of individuals differentially fed with the same four types of resources was measured to assess a functional trait that can potentially affect movement parameters such as prospected area or foraging speed. Third, F. candida single individuals were exposed to the same litter quality gradient and placed at an increasing distance from the litter (from 1 to 5 cm). For 10 min, their foraging behaviour was recorded which included prospected area, foraging speed, perception distance and success in reaching the litter (foraging success). As expected, low-quality litter (i.e. Q. pubescens) contributed to low population growth compared to the control treatment and the high-quality litters (P. avium and A. opalus). In the third experiment, the probability of finding the resource was negatively correlated to the distance, but was unrelated to the litter quality and the Collembola body length. When resource was perceived, F. candida was able to switch from non-directional to directional movements, with a large variability in the perception distance from a few millimetres to several centimetres. Taken together, our results indicate that litter quality plays a relevant role in Collembola demographic parameters once the population settles on litter patch, but not on foraging behaviour to select high-quality resources.