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Climate variation and regional gradients in population dynamics of two hole-nesting passerines.

https://arctichealth.org/en/permalink/ahliterature95879
Source
Proc Biol Sci. 2003 Nov 22;270(1531):2397-404
Publication Type
Article
Date
Nov-22-2003
Author
Saether Bernt-Erik
Engen Steinar
Møller Anders Pape
Matthysen Erik
Adriaensen Frank
Fiedler Wolfgang
Leivits Agu
Lambrechts Marcel M
Visser Marcel E
Anker-Nilssen Tycho
Both Christiaan
Dhondt André A
McCleery Robin H
McMeeking John
Potti Jamie
Røstad Ole Wiggo
Thomson David
Author Affiliation
Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway. bernt-erik.sather@bio.ntnu.no
Source
Proc Biol Sci. 2003 Nov 22;270(1531):2397-404
Date
Nov-22-2003
Language
English
Publication Type
Article
Keywords
Animals
Climate
Environment
Europe
Geography
Models, Biological
Population Dynamics
Songbirds - physiology
Abstract
Latitudinal gradients in population dynamics can arise through regional variation in the deterministic components of the population dynamics and the stochastic factors. Here, we demonstrate an increase with latitude in the contribution of a large-scale climate pattern, the North Atlantic Oscillation (NAO), to the fluctuations in size of populations of two European hole-nesting passerine species. However, this influence of climate induced different latitudinal gradients in the population dynamics of the two species. In the great tit the proportion of the variability in the population fluctuations explained by the NAO increased with latitude, showing a larger impact of climate on the population fluctuations of this species at higher latitudes. In contrast, no latitudinal gradient was found in the relative contribution of climate to the variability of the pied flycatcher populations because the total environmental stochasticity increased with latitude. This shows that the population ecological consequences of an expected climate change will depend on how climate affects the environmental stochasticity in the population process. In both species, the effects will be larger in those parts of Europe where large changes in climate are expected.
PubMed ID
14667357 View in PubMed
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Demographic characteristics of extinction in a small, insular population of house sparrows in northern Norway.

https://arctichealth.org/en/permalink/ahliterature79355
Source
Conserv Biol. 2006 Dec;20(6):1761-7
Publication Type
Article
Date
Dec-2006
Author
Ringsby Thor Harald
Saether Bernt-Erik
Jensen Henrik
Engen Steinar
Author Affiliation
Department of Biology, Norwegian University of Science and Technology, N-7491, Trondheim, Norway. thor.harald.ringsby@bio.ntnu.no
Source
Conserv Biol. 2006 Dec;20(6):1761-7
Date
Dec-2006
Language
English
Publication Type
Article
Keywords
Animals
Conservation of Natural Resources
Demography
Extinction, Biological
Female
Humans
Male
Models, Biological
Norway
Population Density
Population Dynamics
Predictive value of tests
Sparrows - growth & development
Stochastic Processes
Time Factors
Abstract
In conservation ecology there is an urgent need for indicators that can be used to predict the risk of extinction of populations. Identifying extinction-prone populations has been difficult because few data sets on the demographic characteristics of the final stage to extinction are available and because of problems in separating out stochastic effects from changes in the expected dynamics. We documented the demographic changes that occurred during the period prior to extinction of a small island population of House Sparrows (Passer domesticus) after the end of permanent human settlement. A mark-recapture analysis revealed that this decline to extinction was mainly due to increased mortality after closure of the last farm that resulted in a negative long-term-specific growth rate. No change occurred in either the structural composition (breeding sex ratio and age distribution) of the population or in female recruitment. No male, however, recruits were produced on the island after the farm closure. Based on a simple, stochastic, density-dependent model we constructed a population prediction interval (PPI) to estimate the time to extinction. The 95% PPI slightly overestimated the time to extinction with large uncertainty in predictions, especially due to the influence of demographic stochasticity and parameter drift. Our results strongly emphasize the importance of access to data on temporal variation that can be used to parameterize simple population models that allow estimation of critical parameters for credible prediction of time to extinction.
Notes
Erratum In: Conserv Biol. 2007 Apr;21(2):566
PubMed ID
17181811 View in PubMed
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Effective size of fluctuating populations with two sexes and overlapping generations.

https://arctichealth.org/en/permalink/ahliterature83760
Source
Evolution Int J Org Evolution. 2007 Aug;61(8):1873-85
Publication Type
Article
Date
Aug-2007
Author
Engen Steinar
Ringsby Thor Harald
Saether Bernt-Erik
Lande Russell
Jensen Henrik
Lillegård Magnar
Ellegren Hans
Author Affiliation
Population Biology Center, Department of Mathematical Sciences, Norwegian University of Science and Technology, N-7491 Trondheim, Norway. steinaen@math.ntnu.no
Source
Evolution Int J Org Evolution. 2007 Aug;61(8):1873-85
Date
Aug-2007
Language
English
Publication Type
Article
Abstract
We derive formulas that can be applied to estimate the effective population size N(e) for organisms with two sexes reproducing once a year and having constant adult mean vital rates independent of age. Temporal fluctuations in population size are generated by demographic and environmental stochasticity. For populations with even sex ratio at birth, no deterministic population growth and identical mean vital rates for both sexes, the key parameter determining N(e) is simply the mean value of the demographic variance for males and females considered separately. In this case Crow and Kimura's generalization of Wright's formula for N(e) with two sexes, in terms of the effective population sizes for each sex, is applicable even for fluctuating populations with different stochasticity in vital rates for males and females. If the mean vital rates are different for the sexes then a simple linear combination of the demographic variances determines N(e), further extending Wright's formula. For long-lived species an expression is derived for N(e) involving the generation times for both sexes. In the general case with nonzero population growth and uneven sex ratio of newborns, we use the model to investigate numerically the effects of different population parameters on N(e). We also estimate the ratio of effective to actual population size in six populations of house sparrows on islands off the coast of northern Norway. This ratio showed large interisland variation because of demographic differences among the populations. Finally, we calculate how N(e) in a growing house sparrow population will change over time.
PubMed ID
17683430 View in PubMed
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Spatial and temporal variation in the relative contribution of density dependence, climate variation and migration to fluctuations in the size of great tit populations.

https://arctichealth.org/en/permalink/ahliterature95428
Source
J Anim Ecol. 2009 Mar;78(2):447-59
Publication Type
Article
Date
Mar-2009
Author
Grøtan Vidar
Saether Bernt-Erik
Engen Steinar
van Balen Johan H
Perdeck Albert C
Visser Marcel E
Author Affiliation
Department of Biology, Centre for Conservation Biology, Norwegian University of Science and Technology, Trondheim, Norway. vidar.grotan@bio.ntnu.no
Source
J Anim Ecol. 2009 Mar;78(2):447-59
Date
Mar-2009
Language
English
Publication Type
Article
Keywords
Animal Migration - physiology
Animals
Climate
Female
Male
Models, Biological
Population Dynamics
Sparrows - physiology
Time Factors
Abstract
1. The aim of the present study is to model the stochastic variation in the size of five populations of great tit Parus major in the Netherlands, using a combination of individual-based demographic data and time series of population fluctuations. We will examine relative contribution of density-dependent effects, and variation in climate and winter food on local dynamics as well as on number of immigrants. 2. Annual changes in population size were strongly affected by temporal variation in number of recruits produced locally as well as by the number of immigrants. The number of individuals recruited from one breeding season to the next was mainly determined by the population size in year t, the beech crop index (BCI) in year t and the temperature during March-April in year t. The number of immigrating females in year t + 1 was also explained by the number of females present in the population in year t, the BCI in autumn year t and the temperature during April-May in year t. 3. By comparing predictions of the population model with the recorded number of females, the simultaneous modelling of local recruitment and immigration explained a large proportion of the annual variation in recorded population growth rates. 4. Environmental stochasticity especially caused by spring temperature and BCI did in general contribute more to annual fluctuations in population size than density-dependent effects. Similar effects of climate on local recruitment and immigration also caused covariation in temporal fluctuations of immigration and local production of recruits. 5. The effects of various variables in explaining fluctuations in population size were not independent, and the combined effect of the variables were generally non-additive. Thus, the effects of variables causing fluctuations in population size should not be considered separately because the total effect will be influenced by covariances among the explanatory variables. 6. Our results show that fluctuations in the environment affect local recruitment as well as annual fluctuations in the number of immigrants. This effect of environment on the interchange of individuals among populations is important for predicting effects of global climate change on the pattern of population fluctuations.
PubMed ID
19302127 View in PubMed
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