Population Dynamics of Evolutionary Change: Demographic Parameters as Indicators of Fitness

1997 ◽  
Vol 51 (3) ◽  
pp. 180-184 ◽  
Author(s):  
Bertram G. Murray
1981 ◽  
Vol 59 (11) ◽  
pp. 2115-2122 ◽  
Author(s):  
Gordon R. Burns

Populations of Clethrionomys rutilus were studied on two islands (Island 2 and Green Island) in the Mackenzie River during the summers of 1976 to 1978. This was done to examine the demographic parameters related to confinement of northern red-backed vole populations on islands.The number of voles on Island 2 in 1977 increased until late June and then remained nearly constant until trapping ceased in late August. On Green Island in 1977 and 1978 and Island 2 in 1978, populations grew all summer and even in August had not reached the densities found during the 1977 high on Island 2. Island 2 in 1977 had an unusually low number of maturing young voles. Higher wounding rates and shorter adjusted range lengths were associated with higher population densities.Although high densities of voles were reached early in the summer of 1977 on Island 2, numbers stopped increasing before the end of the breeding season. Restraint of growth potential was seen in poor maturation of the young and in declining juvenile survival and recruitment of young through summer.


2016 ◽  
Author(s):  
Olivier Gimenez ◽  
Christophe Barbraud

SummaryCapture-recapture models for estimating demographic parameters allow covariates to be incorporated to better understand population dynamics. However, high-dimensionality and multicollinearity can hamper estimation and inference. Principal component analysis is incorporated within capture-recapture models and used to reduce the number of predictors into uncorrelated synthetic new variables. Principal components are selected by sequentially assessing their statistical significance. We provide an example on seabird survival to illustrate our approach. Our method requires standard statistical tools, which permits an efficient and easy implementation using standard software.


Author(s):  
Г.П. Неверова ◽  
G.P. Neverova

The paper investigates the model of population dynamics with age structure and density dependence of birth rate. We consider two situations: 1) the population develops freely and 2) the population is exploited. It was shown that harvesting leads to the stabilization of the dynamics. There is multiregimism, i.e. different dynamic regimes are possible with the same values of demographic parameters. It is shown that even a single harvesting in the current population size could lead to a change of the observed dynamic regime.


Oecologia ◽  
1998 ◽  
Vol 117 (3) ◽  
pp. 381-390 ◽  
Author(s):  
Manuel Soler ◽  
Juan J. Soler ◽  
Juan G. Martinez ◽  
Tomás Pérez-Contreras ◽  
Anders P. Møller

2021 ◽  
Author(s):  
Stefano Palmero ◽  
Elisa Belotti ◽  
Luděk Bufka ◽  
Martin Gahbauer ◽  
Christoph Heibl ◽  
...  

Abstract Large carnivores are crucial for ecosystems but are increasingly threatened by human persecution and habitat destruction. Successful conservation of this guild requires information on long-term population dynamics through the demographic surveys. We camera trapped Eurasian lynx between 2009 and 2018 in two strictly protected areas in the Bohemian Forest Ecosystem, estimating sex-specific demographic parameters using spatial capture-recapture (SCR) models as well as the relative abundance index of its prey species and a mesopredator seeking potential drivers of lynx population dynamics. Over 48 677 trap nights, we detected 65 lynx individuals. Density increased to 1.31 and 2.39 individuals/100 km2 for open and closed population SCR models, respectively, with positive population growth rates. Survival rates were high (females 83%, males 88%) and per capita recruitment was low (females 13%, males 9%), indicating a low yearly population turnover. Reproductive parameters showed successful reproduction. Our results reveal the importance of the study area as host to a saturated population and key source for the potential lynx metapopulation. The observed increasing lynx number is most likely represented by dispersing individuals due to reduced mortality outside the protected areas as the number of reproducing females inside remained constant. In what is the first open population SCR study on lynx, we provide demographic parameters contributing to the development of model-based population viability forecasting and inform lynx management in the study area as well as in similar contexts.


2019 ◽  
Vol 14 (6) ◽  
pp. 542-560
Author(s):  
Selene VARGAS‐GARCÍA ◽  
Víctor ARGAEZ ◽  
Israel SOLANO‐ZAVALETA ◽  
J. Jaime ZÚÑIGA‐VEGA

2015 ◽  
Vol 66 (1) ◽  
pp. 78 ◽  
Author(s):  
E. García-Seoane ◽  
M. Fabeiro ◽  
A. Silva ◽  
I. Meneses

It is important to understand the population dynamics of myctophids for a better understanding of the functioning of the ecosystem. In this work, age-based demography parameters of glacier lanternfish (Benthosema glaciale (Reinhardt, 1837)) were calculated. This study was based on 1213 individuals collected in the Flemish Cap during June–July 2008 and 2010. Ages were estimated from counts of annuli in the whole otolith. A strong relationship was found between both diameters of the otolith and fish length, and between otolith weight and increment number. Males predominated in 2008 (37.6% were females) whereas no differences from the expected sex ratio of 1:1 were observed in 2010. The somatic growth of B. glaciale is quite fast for the first three years and decreasing thereafter. The von Bertalanffy growth curves revealed interannual differences and no sexual dimorphism in growth. The instantaneous natural mortality coefficient, M, was 0.65 year–1 for the overall population. The maximum age recorded was 7. Our results were compared with age-based demographic parameters from previous studies in the Flemish Cap and in other regions. Because myctophids are considered opportunistic strategists, changes in their demographic features may reflect shifts in the ecosystem.


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