scholarly journals Quantifying the effect of genetic, environmental and individual demographic stochastic variability for population dynamics in Plantago lanceolata

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ulrich K. Steiner ◽  
Shripad Tuljapurkar ◽  
Deborah A. Roach

AbstractSimple demographic events, the survival and reproduction of individuals, drive population dynamics. These demographic events are influenced by genetic and environmental parameters, and are the focus of many evolutionary and ecological investigations that aim to predict and understand population change. However, such a focus often neglects the stochastic events that individuals experience throughout their lives. These stochastic events also influence survival and reproduction and thereby evolutionary and ecological dynamics. Here, we illustrate the influence of such non-selective demographic variability on population dynamics using population projection models of an experimental population of Plantago lanceolata. Our analysis shows that the variability in survival and reproduction among individuals is largely due to demographic stochastic variation with only modest effects of differences in environment, genes, and their interaction. Common expectations of population growth, based on expected lifetime reproduction and generation time, can be misleading when demographic stochastic variation is large. Large demographic stochastic variation exhibited within genotypes can lower population growth and slow evolutionary adaptive dynamics. Our results accompany recent investigations that call for more focus on stochastic variation in fitness components, such as survival, reproduction, and functional traits, rather than dismissal of this variation as uninformative noise.

2018 ◽  
Author(s):  
Ulrich K. Steiner ◽  
Shripad Tuljapurkar ◽  
Deborah A. Roach

AbstractPredicting ecological and evolutionary population dynamics requires understanding how genetic and environmental parameters influence variation in survival and reproduction among individuals. However such a focus often neglects the stochastic events that individuals experience throughout their lives that also influence survival and reproduction. With an illustrative example, we quantify and illustrate the influence of such non-selective demographic variability on population dynamics using size-structured matrix models of an experimental population ofPlantago lanceolata. Our analysis shows that variation in survival and reproduction among individuals explained by environment, genes, and their interaction was modest compared to the stochastic variation in lifespan and reproduction. We illustrate how expectations on population growth, based on expected lifetime reproduction and generation time, can be misleading when variance in reproduction among individuals of the same genotype (full sibs) was large. Such large within genotype variance can lower population growth, fitness. Our results accompany recent investigations that call for more focus on stochastic variation in survival and reproduction, rather than dismissal of this variation as uninformative noise.


2002 ◽  
Vol 357 (1425) ◽  
pp. 1307-1319 ◽  
Author(s):  
H. Charles J. Godfray ◽  
Mark Rees

Current issues in population dynamics are discussed in the context of The Royal Society Discussion Meeting 'Population growth rate: determining factors and role in population regulation'. In particular, different views on the centrality of population growth rates to the study of population dynamics and the role of experiments and theory are explored. Major themes emerging include the role of modern statistical techniques in bringing together experimental and theoretical studies, the importance of long-term experimentation and the need for ecology to have model systems, and the value of population growth rate as a means of understanding and predicting population change. The last point is illustrated by the application of a recently introduced technique, integral projection modelling, to study the population growth rate of a monocarpic perennial plant, its elasticities to different life-history components and the evolution of an evolutionarily stable strategy size at flowering.


The Condor ◽  
2021 ◽  
Vol 123 (1) ◽  
Author(s):  
Christopher D Pollentier ◽  
Scott D Hull ◽  
David M MacFarland

Abstract Effective management of wildlife requires a full understanding of population dynamics and knowledge of potential drivers that influence population growth. The Ruffed Grouse (Bonasa umbellus) is a popular upland game bird widely distributed across the northern United States and Canada that has experienced population declines within portions of its range in response to forest maturation and habitat loss. Although the species has been extensively studied, few efforts have been made to synthesize demographic data into a sensitivity analysis to guide management actions. We reviewed the literature and compiled Ruffed Grouse vital rates from 14 field studies conducted across four decades (1982−2018) within the Upper Great Lakes region of Michigan, Minnesota, and Wisconsin, USA. We parameterized a deterministic matrix model to evaluate population dynamics and conducted sensitivity analyses to identify vital rates projected to have the greatest influence on the finite rate of population change (λ). Our modeling effort projected a stable but highly variable annual rate of population change (λ = 1.01; 95% CI = 0.88–1.14) for Ruffed Grouse in the Upper Great Lakes region. Stochastic rates of population change derived from spring drumming surveys (λ = 1.01; 95% CI = 0.61–1.45) and Christmas Bird Count surveys (λ = 0.99; 95% CI = 0.62–1.76) of the corresponding regional population provided validation of stable trends over the same time period as our demographic model. Prospective elasticities and variance-scaled sensitivities suggested λ would be greatly influenced by components of reproductive performance: nesting success, chick survival, and post-fledging juvenile survival. Retrospective analysis indicated that much of the overall variability in λ and annual productivity was also attributed to annual variation in nesting success. Management of this species has often focused on fall and overwinter survival, but population projection models provided little evidence that survival was the predominant factor affecting population growth of Ruffed Grouse in this region. A suite of confounding factors and demographic processes that drive population trends can differ significantly across a species’ range. In the Upper Great Lakes region, management efforts aimed at maximizing reproductive success would likely have the greatest potential influence on Ruffed Grouse population growth. Other types of systematic, regional survey data can also be useful for validating population trends derived from demographic modeling studies.


2019 ◽  
Vol 6 (1) ◽  
pp. 37-72
Author(s):  
Ulaş Sunata ◽  
Dila Ergül

39 ilçesiyle Türkiye’nin en büyük nüfusuna sahip ili İstanbul aynı zamanda Türkiye’nin en çok iç göç alan şehridir. Özellikle kırdan kente göç bağlamında sosyo-ekonomik ve demografik özellikleriyle birçok araştırmaya konu olmuştur. Fakat İstanbul yerleşik nüfusunun Türkiye’nin diğer şehirlerine kayıtlı olma yoğunluğu da önemlidir. Bu çalışmanın amacı 2012 ve 2017 yıllarındaki nüfus değişimini göz önünde bulundurarak İstanbul ilçelerinin ayrıntılı nüfus yoğunluğu ve büyüme analizini yapmak, ilgili faktörleri değerlendirmek, hemşehri ağlarını okumak adına yerleşik nüfus kütük bilgileri bakımından inceleyerek elde edilen örüntüler doğrultusunda ilçe tipolojileri oluşturmaktır. Çalışmanın birinci bölümünde ilgili beş yıllık nüfus değişimlerine göre İstanbul ilçe nüfusları analiz edilmiştir. Ardından her bir ilçe için nüfusa kayıtlı olunan kente göre nüfus büyüme hızlarına bakılarak ilçelerin ağırlıklı olarak barındırdığı hemşehri ağları belirlenmiştir. İkinci bölümde ise ilçeler nüfus değişim özelliklerine göre belirli kategorilere ayrılmış ve bu kategoriler doğrultusunda ilçe tipolojileri oluşturulmuştur..ABSTRACT IN ENGLISHA District Level Analysis of Istanbul’s Population Change (2012-2017)Istanbul having the largest population of Turkey with its 39 districts is the most internal-migrant-receiving city in Turkey. Particularly in the context of rural-to-urban migration, Istanbul has been became a subject of various researches with its socio-economic and demographic features. However, the density of Istanbul’s settled population who registered other cities of Turkey is important. The main aim of this study is to analyse population growth of all districts considering the population change between 2012 and 2017, to evaluate the related factors and to develop a district typology by using the data of settled population according to their family registration in the name of reading the current countryman networks. In the first section of the study, district populations of Istanbul are examined regarding the related five-year change. Afterwards, most repeated countryman networks of all Istanbul’s districts are specified regarding the population growth rate of the registered cities. In the latter section of the study, districts were divided into categories regarding the specific population change features which help to create district typology.


1977 ◽  
Vol 16 (2) ◽  
pp. 220-222
Author(s):  
Zeba A. Sathar

The book covers a wide field, touching on almost all aspects of popula¬tion change on a world-wide scale. It discusses, using world and country data, the relationships between demographic and socio-economic variables, and elaborates on" their relative importance in the determination of population problems which confront the world as a whole and nations individually. Policies designed to alleviate these problems are discussed with an emphasis on those related to population control. The first chapter is entitled "Population Growth: Past and Prospective" and reviews the various parameters associated with population change in the past and in the future. It touches upon the concept of a stable population in order to show the elements which cause a population to change (i.e. remove it from its stable condition). The main elements of change, population growth, migration, mortality and natality are discussed individually. The chapter is concluded by a description of the main differences in these elements and other socio-economic conditions as they exist in the less-developed and developed countries.


2015 ◽  
Vol 282 (1806) ◽  
pp. 20150173 ◽  
Author(s):  
Ayco J. M. Tack ◽  
Tommi Mononen ◽  
Ilkka Hanski

Climate change is known to shift species' geographical ranges, phenologies and abundances, but less is known about other population dynamic consequences. Here, we analyse spatio-temporal dynamics of the Glanville fritillary butterfly ( Melitaea cinxia ) in a network of 4000 dry meadows during 21 years. The results demonstrate two strong, related patterns: the amplitude of year-to-year fluctuations in the size of the metapopulation as a whole has increased, though there is no long-term trend in average abundance; and there is a highly significant increase in the level of spatial synchrony in population dynamics. The increased synchrony cannot be explained by increasing within-year spatial correlation in precipitation, the key environmental driver of population change, or in per capita growth rate. On the other hand, the frequency of drought during a critical life-history stage (early larval instars) has increased over the years, which is sufficient to explain the increasing amplitude and the expanding spatial synchrony in metapopulation dynamics. Increased spatial synchrony has the general effect of reducing long-term metapopulation viability even if there is no change in average metapopulation size. This study demonstrates how temporal changes in weather conditions can lead to striking changes in spatio-temporal population dynamics.


Radiocarbon ◽  
2017 ◽  
Vol 59 (6) ◽  
pp. 1761-1770 ◽  
Author(s):  
Yongje Oh ◽  
Matthew Conte ◽  
Seungho Kang ◽  
Jangsuk Kim ◽  
Jaehoon Hwang

AbstractPopulation growth has been evoked both as a causal factor and consequence of the transition to agriculture. The use of radiocarbon (14C) dates as proxies for population allows for reevaluations of population as a variable in the transition to agriculture. In Korea, numerous rescue excavations during recent decades have offered a wealth of14C data for this application. A summed probability distribution (SPD) of14C dates is investigated to reconstruct population trends preceding and following adoptions of food production in prehistoric Korea. Important cultivars were introduced to Korea in two episodes: millets during the Chulmun Period (ca. 6000–1500 BCE) and rice during the Mumun Period (ca. 1500–300 BCE). The SPD suggests that while millet production had little impact on Chulmun populations, a prominent surge in population appears to have followed the introduction of rice. The case in prehistoric Korea demonstrates that the adoption of food production does not lead inevitably towards sustained population growth. Furthermore, the data suggest that the transition towards intensive agriculture need not occur under conditions of population pressure resulting from population growth. Rather, intensive rice farming in prehistoric Korea began during a period of population stagnation.


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