Population, Public Health and the Environment in China

1998 ◽  
Vol 156 ◽  
pp. 986-1015 ◽  
Author(s):  
Judith Banister
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Age Structure ◽  
Population Growth Rate ◽  
Large Population ◽  
Age Groups ◽  
Population Increase ◽  
Structure Changes ◽  
Working Age ◽  
A Minor

To the extent that China's population size or population growth rate causes environmental destruction, such damage has already been done over the last several centuries, especially in the most recent 50 years. The impacts of China's large population and continuing population increase are basically irreversible in the medium-term. But in the coming decades, the relatively low PRC population growth rate will be a minor continuing environmental problem. Other environmental effects associated with population will be twofold. First, China's current age structure is strongly skewed toward the working age groups, and the population aged between 15 and 64 will increase dramatically in the coming decade. This contributes to huge unmet current and future demand for employment. Because the legitimacy of the PRC government depends in part on its success in generating jobs, it will continue to endeavour to meet the challenge of employment generation. This imperative, aggravated by the age structure changes, can be expected to take precedence over environmental considerations where these goals conflict. Secondly, the rising living standards of China's population will contribute to further environmental deterioration. When an enormous population rapidly multiplies its per capita income, the impacts can be massive and ecologically destabilizing.

scholarly journals Changes in age‐structure over four decades were a key determinant of population growth rate in a long‐lived mammal

2020 ◽  
Vol 89 (10) ◽  
pp. 2268-2278
Author(s):  
John Jackson ◽  
Khyne U. Mar ◽  
Win Htut ◽  
Dylan Z. Childs ◽  
Virpi Lummaa
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Age Structure ◽  
Population Growth Rate

Limitations of the Single-Age Sample for Research on Birth Order

1980 ◽  
Vol 51 (3) ◽  
pp. 831-837 ◽  
Author(s):  
John N. McCall
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Normal Distribution ◽  
Birth Order ◽  
Random Sample ◽  
Population Model ◽  
Population Growth Rate ◽  
Age Groups ◽  
Family Unit ◽  
Large Families

A simulated completed family population model was used to illustrate bias in single-age samples which results from changes in population growth rate. The model comprised 100 families or 238 individuals who ranged from 2 to 22 yr. in age. IQ-codes from a normal distribution were assigned to these individuals so that IQ correlated –.25 with family size and –.39 with occupational level. This produced a correlation of –.27 between birth order and IQ. A random sample, stratified random sample, and a random family unit sample estimated this last correlation quite closely. But estimates of this same correlation were spuriously high for 6 of the 11 single-age groups. These results were linked to an excess of early-borns in small families and an excess of later-borns in large families.

scholarly journals Fall supplemental feeding increases population growth rate of an endangered caribou herd

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e10708
Author(s):  
Douglas C. Heard ◽  
Kathryn L. Zimmerman
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Population Increase ◽  
Adult Survival ◽  
Management Approach ◽  
Annual Growth Rate ◽  
Supplemental Feeding ◽  
Management Actions ◽  
The Impact

Most woodland caribou (Rangifer tarandus caribou) populations are declining primarily because of unsustainable predation resulting from habitat-mediated apparent competition. Wolf (Canis lupus) reduction is an effective recovery option because it addresses the direct effect of predation. We considered the possibility that the indirect effects of predation might also affect caribou population dynamics by adversely affecting summer foraging behaviour. If spring and/or summer nutrition was inadequate, then supplemental feeding in fall might compensate for that limitation and contribute to population growth. Improved nutrition and therefore body condition going into winter could increase adult survival and lead to improved reproductive success the next spring. To test that hypothesis, we fed high-quality food pellets to free-ranging caribou in the Kennedy Siding caribou herd each fall for six years, starting in 2014, to see if population growth rate increased. Beginning in winter 2015–16, the Province of British Columbia began a concurrent annual program to promote caribou population increase by attempting to remove most wolves within the Kennedy Siding and the adjacent caribou herds’ ranges. To evaluate the impact of feeding, we compared lambdas before and after feeding began, and to the population trend in the adjacent Quintette herd over the subsequent four years. Supplemental feeding appeared to have an incremental effect on population growth. Population growth of the Kennedy Siding herd was higher in the year after feeding began (λ = 1.06) compared to previous years (λ = 0.91) and to the untreated Quintette herd (λ = 0.95). Average annual growth rate of the Kennedy Siding herd over the subsequent four years, where both feeding and wolf reduction occurred concurrently, was higher than in the Quintette herd where the only management action in those years was wolf reduction (λ = 1.16 vs. λ = 1.08). The higher growth rate of the Kennedy Siding herd was due to higher female survival (96.2%/yr vs. 88.9%/yr). Many caribou were in relatively poor condition in the fall. Consumption of supplemental food probably improved their nutritional status which ultimately led to population growth. Further feeding experiments on other caribou herds using an adaptive management approach would verify the effect of feeding as a population recovery tool. Our results support the recommendation that multiple management actions should be implemented to improve recovery prospects for caribou.

Structured Population Models

2021 ◽  
pp. 47-60
Author(s):  
Timothy E. Essington
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Matrix Model ◽  
Age Structure ◽  
Population Growth Rate ◽  
Population Models ◽  
State Variables ◽  
Elasticity Analysis ◽  
Structured Population Models ◽  
Structured Population

The chapter “Structured Population Models” illustrates how one adds more detail to a model, first through density-independent models, then by showing common matrix-model formulations and how those are used to reveal properties of structured models (e.g. population growth rate, stage/age structure). Structured population models have more detail than their nonstructured counterparts. They account for the differences among individuals within a population, usually by explicitly modeling them as distinct state variables. Elasticity analysis is introduced as a way to identify life stages that have a disproportionately large influence on population growth rate. Structured density-dependent models are briefly introduced as extensions on these models.

scholarly journals Concerning demographic limitations on the population growth rate of West Australian (Breeding Stock D) humpback whales

2020 ◽  
pp. 201-208
Author(s):  
A. Brandão ◽  
D.S. Butterworth
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Age Structure ◽  
Population Growth Rate ◽  
Extreme Values ◽  
Humpback Whales ◽  
Demographic Parameters ◽  
Natural Mortality ◽  
Transient Effects ◽  
Rate Of Increase

The upper bound of 0.126 on the maximum demographically possible annual growth rate for humpback whales that has standardly been imposedon recent applications of age-aggregated assessment models for this species in the IWC Scientific Committee, is based on an analysis that assumessteady age structure. It is conceivable that transient age-structure effects could admit greater population growth rates for short periods than suggestedby such a bound. This possibility is addressed by developing an age-structured population model in which possible density dependent changes inpregnancy rate, age at first parturition and natural mortality are modelled explicitly, and allowance is made for the possibility of natural mortalityincreasing at older ages. The model is applied to the case of the west Australian humpback whale population (Breeding Stock D), for which breedingground surveys over the 1982–1994 period provide a point estimate of 0.10 for the annual population growth rate. Results based upon the breedingpopulation survey estimate of abundance of 10,032 in 1999 suggest that 0.12 is the maximum demographically feasible annual rate of increase forthis stock over 1982–1994 if it is a closed population. This result is based on essentially the same parameter choices as led to the earlier r = 0.126bound, i.e. that in the limit of low population size the age at first parturition approaches five years from above, the annual pregnancy rate 0.5 frombelow, and the annual natural mortality rate 0.01 from above. Transient effects do not appear able to reconcile the observed rate of increase withless extreme values of demographic parameters than led to the previously imposed upper bound of 0.126 on the maximum possible annual growthrate. Although use of extreme values reported for demographic parameters for Northern Hemisphere humpback whale populations, rather than thoseconsidered here, would reduce this suggested maximum rate of 0.12, the conclusion that transient effects have a very limited impact on observedpopulation growth rates would be unlikely to change.

scholarly journals Population and Development vs Quality of Life: A Sociological Appraisal

2021 ◽  
Vol 7 (5) ◽  
pp. 45-51
Author(s):  
Mohammad Taghi Sheykhi
Keyword(s):  
Quality Of Life ◽  
Growth Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Population Increase ◽  
High Population ◽  
Population Growth Rates ◽  
High Population Growth ◽  
Very High

The two variables of population and development affect each other in an indirect manner in which when population increase happens, development is reduced. The two effectively impact quality of life. It is strongly recommended to control population in order to achieve development. Sociologists are widely responsible to create the balance of population and development. As resources are limited in each country, an organized and planned population is needed towards any development. The phenomenon development being multi-lateral, needs an appropriate population size. It is worth mentioning that population naturally grows, but resources for development do not. Overall, Asia, Africa, and Latin America had very high population growth rate of 2.1% between 1955 and 1975. Fortunately, increase of literacy and education has caused population growth rates to decline in the past two decades in many parts of the developing countries. The only part of the developing world with high population growth rate is Africa in which the population will increase to over 4.2 billion by the year 2100; threatening other parts of the world. Such a situation will widely endanger quality of life.

scholarly journals Biological scaling in green algae: the role of cell size and geometry

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Helena Bestová ◽  
Jules Segrestin ◽  
Klaus von Schwartzenberg ◽  
Pavel Škaloud ◽  
Thomas Lenormand ◽  
...  
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Population Growth Rate ◽  
Internal Diffusion ◽  
Scaling Exponent ◽  
Power Scaling ◽  
Nutrient Distribution ◽  
Metabolic Scaling ◽  
Key Factor ◽  
Size And Morphology

AbstractThe Metabolic Scaling Theory (MST), hypothesizes limitations of resource-transport networks in organisms and predicts their optimization into fractal-like structures. As a result, the relationship between population growth rate and body size should follow a cross-species universal quarter-power scaling. However, the universality of metabolic scaling has been challenged, particularly across transitions from bacteria to protists to multicellulars. The population growth rate of unicellulars should be constrained by external diffusion, ruling nutrient uptake, and internal diffusion, operating nutrient distribution. Both constraints intensify with increasing size possibly leading to shifting in the scaling exponent. We focused on unicellular algae Micrasterias. Large size and fractal-like morphology make this species a transitional group between unicellular and multicellular organisms in the evolution of allometry. We tested MST predictions using measurements of growth rate, size, and morphology-related traits. We showed that growth scaling of Micrasterias follows MST predictions, reflecting constraints by internal diffusion transport. Cell fractality and density decrease led to a proportional increase in surface area with body mass relaxing external constraints. Complex allometric optimization enables to maintain quarter-power scaling of population growth rate even with a large unicellular plan. Overall, our findings support fractality as a key factor in the evolution of biological scaling.

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