Stochastic stable population growth

1981 ◽  
Vol 18 (02) ◽  
pp. 325-334 ◽  
Author(s):  
Kenneth Lange ◽  
William Holmes
Keyword(s):  
Stochastic Process ◽  
Population Growth ◽  
Age Structure ◽  
Random Matrix ◽  
Vital Rates ◽  
Limit Theory ◽  
Matrix Products ◽  
Considerable Simplification ◽  
Projective Metric ◽  
Demographic Theory

In classical demographic theory, the age structure of a population eventually stabilizes, and the population as a whole grows at a geometric rate. It is possible to prove stochastic analogues of these results if vital rates fluctuate according to a stationary stochastic process. The approach taken here is to study the action of random matrix products on random vectors. This permits the application of Hilbert's projective metric and leads to considerable simplification of the ergodic and central limit theory of population growth.

Stochastic stable population growth

1981 ◽  
Vol 18 (2) ◽  
pp. 325-334 ◽  
Author(s):  
Kenneth Lange ◽  
William Holmes
Keyword(s):  
Stochastic Process ◽  
Population Growth ◽  
Age Structure ◽  
Random Matrix ◽  
Vital Rates ◽  
Limit Theory ◽  
Matrix Products ◽  
Considerable Simplification ◽  
Projective Metric ◽  
Demographic Theory

In classical demographic theory, the age structure of a population eventually stabilizes, and the population as a whole grows at a geometric rate. It is possible to prove stochastic analogues of these results if vital rates fluctuate according to a stationary stochastic process. The approach taken here is to study the action of random matrix products on random vectors. This permits the application of Hilbert's projective metric and leads to considerable simplification of the ergodic and central limit theory of population growth.

Convergence of the age structure: Applications of the projective metric

1975 ◽  
Vol 7 (1) ◽  
pp. 84-93 ◽  
Author(s):  
Martin Golubitsky ◽  
Emmett B. Keeler ◽  
Michael Rothschild
Keyword(s):  
Age Structure ◽  
Projective Metric

scholarly journals Fertility decline and social change: new trends and challenges

2003 ◽  
Vol 30 (2) ◽  
pp. 297
Author(s):  
Bali Ram
Keyword(s):  
Social Change ◽  
Population Growth ◽  
Family Structure ◽  
Age Structure ◽  
Fertility Decline ◽  
Intergenerational Support ◽  
Population Stability ◽  
Future Prospects ◽  
Age Patterns

This article presents an overview of recent fertility declines and their effects on social change in both industrialized and industrializing countries. The focus is primarily on the levels and age patterns of fertility, which influence social change through three major mechanisms, reductions in population growth, modifications in age structure, and changes in family structure. Some future prospects are also discussed, especially in the view of the viability of immigration as a solution to population stability, graying of the industrialized world, intergenerational support, and loneliness.

scholarly journals Beyond demographic buffering: Context dependence in demographic strategies across animals

2021 ◽  
Author(s):  
Omar Lenzi ◽  
Arpat Ozgul ◽  
Roberto Salguero-Gomez ◽  
Maria Paniw
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Temporal Variation ◽  
Population Growth Rate ◽  
Natural Populations ◽  
Environmental Context ◽  
Context Dependence ◽  
Vital Rate ◽  
Rate Variation ◽  
Vital Rates

Temporal variation in vital rates (e.g., survival, reproduction) can decrease the long-term mean performance of a population. Species are therefore expected to evolve demographic strategies that counteract the negative effects of vital rate variation on the population growth rate. One key strategy, demographic buffering, is reflected in a low temporal variation in vital rates critical to population dynamics. However, comparative studies in plants have found little evidence for demographic buffering, and little is known about the prevalence of buffering in animal populations. Here, we used vital rate estimates from 31 natural populations of 29 animal species to assess the prevalence of demographic buffering. We modeled the degree of demographic buffering using a standard measure of correlation between the standard deviation of vital rates and the sensitivity of the population growth rate to changes in such vital rates across populations. We also accounted for the effects of life-history traits, i.e., age at first reproduction and spread of reproduction across the life cycle, on these correlation measures. We found no strong or consistent evidence of demographic buffering across the study populations. Instead, key vital rates could vary substantially depending on the specific environmental context populations experience. We suggest that it is time to look beyond concepts of demographic buffering when studying natural populations towards a stronger focus on the environmental context-dependence of vital-rate variation.

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

scholarly journals Projected Population Size and Age Structure for Canada and Provinces: With and Without International Migration

2007 ◽  
Vol 34 (2) ◽  
pp. 103 ◽  
Author(s):  
Shirley Loh ◽  
M. V. George
Keyword(s):  
Population Growth ◽  
International Migration ◽  
Age Structure ◽  
Current Level ◽  
The Other ◽  
Population Projections ◽  
Limited Effect ◽  
Continuous Increase ◽  
Size And Age Structure ◽  
The Impact

This paper examines the effect of net international migration on prospective population growth and age structure in Canada for the next 50 years. It also examines the impact of international migration on provincial growth and distribution. The procedure used in this study is by comparing two projected population scenarios, one with international migration and the other without international migration, based on the latest 2005-based population projections. The analysis of the scenarios shows that the assumed level of international migration which is higher than the current level contributes to a continuous increase in population over the next 50 years, but has limited effect to prevent or offset the overall aging trend.

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