scholarly journals Responses of European anchovy vital rates and population growth to environmental fluctuations: An individual-based modeling approach

2013 ◽  
Vol 250 ◽  
pp. 370-383 ◽  
Author(s):  
H. Pethybridge ◽  
D. Roos ◽  
V. Loizeau ◽  
L. Pecquerie ◽  
C. Bacher
Keyword(s):  
Population Growth ◽  
Vital Rates ◽  
European Anchovy ◽  
Modeling Approach ◽  
Environmental Fluctuations ◽  
Individual Based Modeling

An individual-based modeling approach for evaluation of endpoint sensitivity in harpacticoid copepod life-cycle tests and optimization of test design

2011 ◽  
Vol 30 (10) ◽  
pp. 2353-2362 ◽  
Author(s):  
Thomas G. Preuss ◽  
Markus Brinkmann ◽  
Elin Lundström ◽  
Bengt-Erik Bengtsson ◽  
Magnus Breitholtz
Keyword(s):  
Life Cycle ◽  
Harpacticoid Copepod ◽  
Test Design ◽  
Modeling Approach ◽  
Individual Based Modeling

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.

Characterization of elasticity patterns of North American freshwater fishes

2006 ◽  
Vol 63 (9) ◽  
pp. 2050-2066 ◽  
Author(s):  
Luis A Vélez-Espino ◽  
Michael G Fox ◽  
Robert L McLaughlin
Keyword(s):  
Population Growth ◽  
North American ◽  
Growth Rates ◽  
Freshwater Fishes ◽  
Adult Survival ◽  
Juvenile Survival ◽  
Vital Rates ◽  
Population Growth Rates ◽  
North American Freshwater ◽  
Trade Offs

We applied elasticity analysis to 88 North American freshwater fishes to assess the relative impacts of changes in the vital rates on asymptotic population growth. Variance in vital rates was summarized for four distinct functional groups: (i) species with population growth rates strongly sensitive to perturbations in adult survival; (ii) species with population growth rates sensitive to perturbations in overall survival; (iii) species with population growth rates most sensitive to perturbations in juvenile survival; and (iv) species with population growth rates sensitive to perturbations in juvenile survival and fecundity. The results of the present study also showed that (a) elasticity patterns cannot be inferred in a straightforward manner from trade-offs between life-history traits, (b) the sensitivity of a population's growth rate to changes in adult survival and fecundity can be predicted empirically from life span and age at maturity, respectively, (c) elasticities are highly conserved among genera within the same taxonomic family, and (d) there are key divergences between elasticity patterns of freshwater fish and other vertebrate taxa.

scholarly journals Translating Effects of Inbreeding Depression on Component Vital Rates to Overall Population Growth in Endangered Bighorn Sheep

2011 ◽  
Vol 25 (6) ◽  
pp. 1240-1249 ◽  
Author(s):  
HEATHER E. JOHNSON ◽  
L. SCOTT MILLS ◽  
JOHN D. WEHAUSEN ◽  
THOMAS R. STEPHENSON ◽  
GORDON LUIKART
Keyword(s):  
Population Growth ◽  
Inbreeding Depression ◽  
Bighorn Sheep ◽  
Vital Rates

scholarly journals Managing multiple vital rates to maximize greater sage-grouse population growth

2011 ◽  
Vol 76 (2) ◽  
pp. 336-347 ◽  
Author(s):  
Rebecca L. Taylor ◽  
Brett L. Walker ◽  
David E. Naugle ◽  
L. Scott Mills
Keyword(s):  
Population Growth ◽  
Vital Rates ◽  
Sage Grouse

scholarly journals Understanding contributions of cohort effects to growth rates of fluctuating populations

2020 ◽  
Author(s):  
Heiko Wittmer ◽  
R Powell ◽  
C King
Keyword(s):  
New Zealand ◽  
Population Growth ◽  
Matrix Models ◽  
Growth Rates ◽  
Management Strategies ◽  
Cohort Effects ◽  
Vital Rates ◽  
Beech Forests ◽  
Rate Of Increase ◽  
Fluctuating Populations

1. Understanding contributions of cohort effects to variation in population growth of fluctuating populations is of great interest in evolutionary biology and may be critical in contributing towards wildlife and conservation management. Cohort-specific contributions to population growth can be evaluated using age-specific matrix models and associated elasticity analyses. 2. We developed age-specific matrix models for naturally fluctuating populations of stoats Mustela erminea in New Zealand beech forests. Dynamics and productivity of stoat populations in this environment are related to the 3-5 year masting cycle of beech trees and consequent effects on the abundance of rodents. 3. The finite rate of increase (λ) of stoat populations in New Zealand beech forests varied substantially, from 1.98 during seedfall years to 0.58 during post-seedfall years. Predicted mean growth rates for stoat populations in continuous 3-, 4- or 5-year cycles are 0.85, 1.00 and 1.13. The variation in population growth was a consequence of high reproductive success of females during seedfall years combined with low survival and fertility of females of the post-seedfall cohort. 4. Variation in population growth was consistently more sensitive to changes in survival rates both when each matrix was evaluated in isolation and when matrices were linked into cycles. Relative contributions to variation in population growth from survival and fertility, especially in 0-1-year-old stoats, also depend on the year of the cycle and the number of transitional years before a new cycle is initiated. 5. Consequently, management strategies aimed at reducing stoat populations that may be best during one phase of the beech seedfall cycle may not be the most efficient during other phases of the cycle. We suggest that management strategies based on elasticities of vital rates need to consider how population growth rates vary so as to meet appropriate economic and conservation targets. © 2007 The Authors.

scholarly journals Warming, soil moisture, and loss of snow increase Bromus tectorum’s population growth rate

Elem Sci Anth ◽  
2014 ◽  
Vol 2 ◽  
Author(s):  
Aldo Compagnoni ◽  
Peter B. Adler
Keyword(s):  
Growth Rate ◽  
Population Growth ◽  
Snow Cover ◽  
Population Growth Rate ◽  
Experimental Manipulation ◽  
Direct Effects ◽  
Vital Rates ◽  
Positive Effects ◽  
The North ◽  
Increasing Temperature

Abstract Climate change threatens to exacerbate the impacts of invasive species. In temperate ecosystems, direct effects of warming may be compounded by dramatic reductions in winter snow cover. Cheatgrass (Bromus tectorum) is arguably the most destructive biological invader in basins of the North American Intermountain West, and warming could increase its performance through direct effects on demographic rates or through indirect effects mediated by loss of snow. We conducted a two-year experimental manipulation of temperature and snow pack to test whether 1) warming increases cheatgrass population growth rate and 2) reduced snow cover contributes to cheatgrass’ positive response to warming. We used infrared heaters operating continuously to create the warming treatment, but turned heaters on only during snowfalls for the snowmelt treatment. We monitored cheatgrass population growth rate and the vital rates that determine it: emergence, survival and fecundity. Growth rate increased in both warming and snowmelt treatments. The largest increases occurred in warming plots during the wettest year, indicating that the magnitude of response to warming depends on moisture availability. Warming increased both fecundity and survival, especially in the wet year, while snowmelt contributed to the positive effects of warming by increasing survival. Our results indicate that increasing temperature will exacerbate cheatgrass impacts, especially where warming causes large reductions in the depth and duration of snow cover.

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