Size‐Dependent Interactions Inhibit Coexistence in Intraguild Predation Systems with Life‐History Omnivory

2006 ◽  
Vol 168 (1) ◽  
pp. 62-75 ◽  
Author(s):  
K. E. van de Wolfshaar ◽  
A. M. de Roos ◽  
L. Persson
Keyword(s):  
Life History ◽  
Intraguild Predation ◽  
Size Dependent

Size‐Dependent Mortality Induces Life‐History Changes Mediated through Population Dynamical Feedbacks

2007 ◽  
Vol 170 (2) ◽  
pp. 258-270 ◽  
Author(s):  
Tobias van Kooten ◽  
Lennart Persson ◽  
André M. de Roos
Keyword(s):  
Life History ◽  
Size Dependent ◽  
Dependent Mortality

scholarly journals Match or mismatch: the influence of phenology on size-dependent life history and divergence in population structure

2010 ◽  
Vol 79 (5) ◽  
pp. 1101-1112 ◽  
Author(s):  
Jost Borcherding ◽  
Peter Beeck ◽  
Donald L. DeAngelis ◽  
Werner R. Scharf
Keyword(s):  
Population Structure ◽  
Life History ◽  
Size Dependent

scholarly journals Rapid life-history evolution in a wild Daphnia pulex population in response to novel size-dependent predation

2020 ◽  
Vol 34 (2) ◽  
pp. 257-271
Author(s):  
Ingrid Wathne ◽  
Katja Enberg ◽  
Knut Helge Jensen ◽  
Mikko Heino
Keyword(s):  
Life History ◽  
Daphnia Pulex ◽  
Life History Evolution ◽  
Size Dependent ◽  
History Evolution

scholarly journals A simple length-structured model based on life history ratios and incorporating size-dependent selectivity: application to spawning potential ratios for data-poor stocks

2016 ◽  
Vol 73 (12) ◽  
pp. 1787-1799 ◽  
Author(s):  
Adrian R. Hordyk ◽  
Kotaro Ono ◽  
Jeremy D. Prince ◽  
Carl J. Walters
Keyword(s):  
Life History ◽  
Growth Parameter ◽  
Mortality Rates ◽  
Life History Strategies ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Computationally Efficient ◽  
Size Dependent ◽  
Spawning Potential Ratio ◽  
Recursive Equations

Selectivity in fish is often size-dependent, which results in differential fishing mortality rates across fish of the same age, an effect known as “Lee’s Phenomenon”. We extend previous work on using length composition to estimate the spawning potential ratio (SPR) for data-limited stocks by developing a computationally efficient length-structured per-recruit model that splits the population into a number of subcohorts, or growth-type-groups, to account for size-dependent fishing mortality rates. Two simple recursive equations, using the life history ratio of the natural mortality rate to the von Bertalanffy growth parameter (M/K), were developed to generate length composition data, reducing the complexity of the previous approach. Using simulated and empirical data, we demonstrate that ignoring Lee’s Phenomenon results in overestimates of fishing mortality and negatively biased estimates of SPR. We also explored the behaviour of the model under various scenarios, including alternative life history strategies and the presence of size-dependent natural mortality. The model developed in this paper may be a useful tool to estimate the SPR for data-limited stock where it is not possible to apply more conventional methods.

Comparison of size-dependent reproductive effort in two dandelion (Taraxacum officinale) populations

1998 ◽  
Vol 76 (1) ◽  
pp. 166-173 ◽  
Author(s):  
Clive VJ Welham ◽  
Robert A Setter
Keyword(s):  
Life History ◽  
Reproductive Effort ◽  
Seed Mass ◽  
Taraxacum Officinale ◽  
Reproductive Morphology ◽  
Size Dependent ◽  
Alfalfa Field ◽  
History Approach ◽  
Total Seed ◽  
Lower Ratio

Reproductive effort in dandelions (Taraxacum officinale Weber) from two different habitats was compared. One dandelion population occupied a 5-year-old alfalfa (Medicago spp.) field, an environment subject to regular disturbance but with a relatively low density of neighbours. Individuals from the second population were derived from a number of undisturbed sites where the density of neighbouring grasses was high. Three hypotheses were evaluated with respect to the observed patterns of reproductive effort. One hypothesis, that reproductive effort was a function of differences between habitats in resource availability, did not provide an explanation for our results. A second hypothesis considered patterns of reproductive effort when mortality rates varied with degree of disturbance and neighbour density, which was a consequence of each habitat representing a different successional environment. A third hypothesis used a life-history approach to predict reproductive effort when mortality schedules were size dependent. Both of these hypotheses received support for their predictions. There was more than a sixfold variation in reproductive effort among individuals from the alfalfa field and a fourfold variation on the undisturbed sites. Much of this variation, however, was attributable to a size-dependent relationship between reproductive effort and vegetative mass. Total reproductive effort (total seed plus scape mass) in both populations increased linearly with vegetative mass, but the slope for the population from the alfalfa field was significantly higher. In contrast, proportional reproductive effort (total seed plus scape mass per vegetative mass) showed a curvilinear increase for the alfalfa field population but was linear and negative for the undisturbed population. There were also important differences between the populations in reproductive morphology. Larger plants on the alfalfa field had longer average scape lengths, produced more flower heads (capitula) per plant, had greater seed production, and had a lower ratio of seed mass per pappus area; only mean scape and mean seed mass did not differ significantly. We suggest that dandelions on the alfalfa field have a different reproductive morphology to facilitate colonization of open areas on the field.Key words: Taraxacum, dandelion, reproductive effort, biomass, life history, neighbour density, agriculture, weed.

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