Forest management effects on survival of a long-lived bird

2019 ◽  
Author(s):  
Paul James Haverkamp ◽  
Julian Klein ◽  
Michael Griesser
Keyword(s):  
Life History ◽  
Forest Management ◽  
Reproductive Success ◽  
Boreal Forests ◽  
Late Onset ◽  
Life History Evolution ◽  
Lifetime Reproductive Success ◽  
High Exposure ◽  
Natural Landscapes ◽  
The Impact

1.A high number of reproductive events is a critical fitness correlate for long-lived species. Thus, individuals of these species should be sensitive to factors that increase their mortality. Living in habitats with high exposure to predators can decrease lifespan, but the ecological drivers of longevity within populations remain poorly studied. Forest management in boreal forests can increase the predation risk by creating edges and open forests, which facilitate prey detection for visual hunters.2.We assessed the impact of forest structure on breeding lifespan and lifetime reproductive success on a population of Siberian jays (Perisoreus infaustus) in northern Sweden located in managed and natural landscapes. 3.We used survival analyses to assess the influence of life history and ecological correlates on lifespan after attaining breeder status. The analyses included N=133 individuals within 38 territories in the managed landscape, and N=74 individuals within 25 territories in the natural landscape. The same correlates were used to investigate influences on the number of surviving offspring, as a measure of lifetime reproductive success.4.Breeder lifespan was longest when individuals attained breeder status at an older age, in territories with dense understory, and few linear edges and natural openings, which reduce the risk of detection by primary predators (accipiter hawks). Moreover, a late onset of reproduction was associated with a higher lifetime reproductive success. Remarkably, these effects were only found in the managed landscape. 5.These results suggest that forestry shapes risk gradients in landscapes that particularly affect individuals that begin to breed at an earlier age. Thus, experience may be more critical to survive in managed than natural landscapes, making populations less resilient to disturbance and affecting life history evolution.

scholarly journals Skewed distributions of LRS: beyond mean and variance

2019 ◽  
Author(s):  
Shripad Tuljapurkar ◽  
Wenyun Zuo ◽  
Tim Coulson ◽  
Carol Horvitz ◽  
Jean-Michel Gaillard
Keyword(s):  
Life History ◽  
Reproductive Success ◽  
Population Growth ◽  
Life History Evolution ◽  
Field Studies ◽  
Lifetime Reproductive Success ◽  
Skewed Distributions ◽  
Mean And Variance ◽  
Signatures Of Selection ◽  
Reproductive Rates

AbstractMany field studies find that lifetime reproductive success (LRS) is highly skewed and often multimodal among individuals. Field biologists generate invaluable data on survival and reproductive rates, as a function of age and stage, that are used to parameterise structured models. These models often perform well at predicting population growth and mean LRS, but we do not know whether they accurately predict observed distributions of individual LRS. If the models fail to recreate these distributions, their use may be limited because the LRS is central to understanding life history evolution. We present powerful tools to generate distributions of LRS from age and/or stage structured models. Our methods reveal that structured models do perform well at generating distributions that agree with observations. Our approach also reveals why such skewed distributions arise, and helps resolve a debate about detecting signatures of selection in skewed distributions of LRS.

scholarly journals The impact of self-reported oligo-amenorrhea and hirsutism on fertility and lifetime reproductive success: results from the Northern Finland Birth Cohort 1966

2013 ◽  
Vol 29 (3) ◽  
pp. 628-633 ◽  
Author(s):  
S. West ◽  
M. Vahasarja ◽  
A. Bloigu ◽  
A. Pouta ◽  
S. Franks ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Birth Cohort ◽  
Lifetime Reproductive Success ◽  
The Impact

Haemoproteusinfected birds have increased lifetime reproductive success

Parasitology ◽  
2015 ◽  
Vol 142 (8) ◽  
pp. 1033-1043 ◽  
Author(s):  
M. ZYLBERBERG ◽  
E. P. DERRYBERRY ◽  
C. W. BREUNER ◽  
E. A. MACDOUGALL-SHACKLETON ◽  
J. M. CORNELIUS ◽  
...  
Keyword(s):  
Reproductive Success ◽  
Lifetime Reproductive Success ◽  
Parasitic Infections ◽  
Host Fitness ◽  
Return Rates ◽  
Long Term Study ◽  
In The Wild ◽  
The Impact ◽  
The Relationship

SUMMARYThe impact of haematozoan infection on host fitness has received substantial attention since Hamilton and Zuk posited that parasites are important drivers of sexual selection. However, short-term studies testing the assumption that these parasites consistently reduce host fitness in the wild have produced contradictory results. To address this complex issue, we conducted a long-term study examining the relationship between naturally occurring infection withHaemoproteusandPlasmodium, and lifetime reproductive success and survival of Mountain White-crowned Sparrows. Specifically, we tested the hypothesis that birds infected with haematozoan parasites have reduced survival (as determined by overwinter return rates) and reproductive success. Contrary to expectation, there was no relationship betweenHaemoproteusandPlasmodiuminfection and reproduction or survival in males, nor was there a relationship betweenPlasmodiuminfection and reproduction in females. Interestingly,Haemoproteus-infected females had significantly higher overwinter return rates and these females fledged more than twice as many chicks during their lifetimes as did uninfected females. We discuss the impact of parasitic infections on host fitness in light of these findings and suggest that, in the case of less virulent pathogens, investment in excessive immune defence may decrease lifetime reproduction.

scholarly journals Impacts of forest management on soil properties: a fundamental research topic for Mexico

2020 ◽  
Vol 27 (1) ◽  
pp. 33-52 ◽  
Author(s):  
Karla Valladares-Samperio ◽  
◽  
Leopoldo Galicia-Sarmiento ◽  
Keyword(s):  
Forest Management ◽  
Boreal Forests ◽  
Negative Influence ◽  
Biological Properties ◽  
Ecosystem Functions ◽  
Functional Changes ◽  
Wood Harvesting ◽  
Intensive Forest Management ◽  
The Impact

Introduction: The increase in the intensity of wood harvesting has a negative influence on ecosystem functions of soils in temperate and boreal forests. Objective: To understand the impacts of intensive and extensive forest management methods on the physical, chemical and biological properties of soils, and consequences on nutrient availability and stabilization processes in temperate and boreal forests. Results and discussion: Intensive forest management methods can generate greater imbalance in the processes of availability and stabilization of nutrients, compared to selective methods. The impact is reflected in the deterioration of soil structure and the decrease of nutrient reserves and microbial communities. These damages affect fertility and functionality of soil, decreasing long-term productivity. Affectations depend on the intensity of biomass extracted, environmental conditions and site preparation. This makes evident the need to monitor forest management and its impact on soil ecology in temperate forests, which maintains long-term productivity and ensures the availability of wood volumes. Conclusion: In Mexico, the impact of forest management has been scarcely analyzed and it is indispensable to understand the functional changes in the processes that determine soil fertility and forest productivity.

scholarly journals The impact of parental investment on lifetime reproductive success in Iceland

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2904 ◽  
Author(s):  
Robert F. Lynch ◽  
Emily C. Lynch
Keyword(s):  
Reproductive Success ◽  
Parental Investment ◽  
Genetic Data ◽  
Lifetime Reproductive Success ◽  
Narrow Sense ◽  
Narrow Sense Heritability ◽  
Full Sibling ◽  
Close Relatives ◽  
The Impact ◽  
The Relationship

BackgroundDemonstrating the impact that parents have on the fitness of their children is a crucial step towards understanding how parental investment has affected human evolution. Parents not only transfer genes to their children, they also influence their environments. By analyzing reproductive patterns within and between different categories of close relatives, this study provides insight into the genetic and environmental effects that parents have on the fitness of their offspring.MethodsWe use data spanning over two centuries from an exceptionally accurate Icelandic genealogy, Íslendingabók, to analyze the relationship between the fertility rates of close relatives. Also, using genetic data, we determine narrow sense heritability estimates (h2) to further explore the genetic impact on lifetime reproductive success. Finally, we construct four simulations to model the expected contribution of genes and resources on reproductive success.ResultsThe relationship between the reproduction of all full sibling pairs was significant and positive across all birth decades (r = 0.19) while the reproductive relationship between parents and offspring was often negative across many decades and undetectable overall (r = 0.00) (Fig. 1 and Table 1). Meanwhile, genetic data among 8,456 pairs of full siblings revealed a narrow sense heritability estimate (h2) of 0.00 for lifetime reproductive success. A resources model (following the rule that resources are transmitted from parents to children, distributed equally among siblings, and are the only factor affecting reproductive success) revealed a similar trend: a negative relationship between parent and offspring reproduction (r =  − 0.35) but a positive relationship among full siblings (r = 0.28). The relationship between parent and offspring lifetime reproductive success (LRS) and full sibling LRS was strongly and positively correlated across time (r = 0.799,p < 0.001). Similarly, the LRS among full siblings was positively correlated with both the LRS among half siblings (r = 0.532,p = 0.011) and the relationship between the LRS of aunts and uncles with their nieces and nephews (r = 0.438,p = 0.042).DiscussionWe show that an individual’s lifetime reproductive success is best predicted by the reproduction of their full and half siblings, but not their parents, grandparents or aunts and uncles. Because all siblings share at least one parent, we believe parental investment has had an important impact on fitness. Overall, these results indicate that direct parental investment, but not genes, is likely to have had an important and persistent impact on lifetime reproductive success across more than two centuries of Icelandic history.

Reproductive Effort and Costs

2021 ◽  
pp. 59-74
Author(s):  
Jeffrey A. Hutchings
Keyword(s):  
Life History ◽  
Reproductive Success ◽  
Total Energy ◽  
Reproductive Effort ◽  
Life History Evolution ◽  
Reproductive Costs ◽  
Positive Outcomes ◽  
Differential Allocation ◽  
Trade Offs ◽  
Potential Benefits

Predictions about life-history evolution are intellectually bereft without a consideration of trade-offs. Benefits derived from making one life-history ‘decision’ are made at a cost of not realizing potential benefits associated with alternative decisions. These trade-offs are the inevitable product of constraints, often driven by an individual’s differential allocation of fixed resources to reproduction versus survival or growth. These allocations prevent multiple positive outcomes from being simultaneously realized. Reproductive effort is the proportion of total energy or resources allocated to all elements of reproduction. Reproductive effort generates reproductive costs. Increases in current reproductive effort reduce future reproductive success by affecting survival, growth, and/or fecundity. The causal mechanisms of these costs can be energetic, ecological, behavioural, or genetic. Evidence for reproductive costs is widespread. Instances where the evidence of costs is equivocal are usually caused by using among-individual correlations to study what is a within-individual phenomenon.

scholarly journals Life history variation is maintained by fitness trade-offs and negative frequency-dependent selection

2018 ◽  
Vol 115 (17) ◽  
pp. 4441-4446 ◽  
Author(s):  
Mark R. Christie ◽  
Gordon G. McNickle ◽  
Rod A. French ◽  
Michael S. Blouin
Keyword(s):  
Life History ◽  
Reproductive Success ◽  
Life History Strategies ◽  
Lifetime Reproductive Success ◽  
Life History Variation ◽  
Additional Energy ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Trade Offs ◽  
Negative Frequency Dependent Selection

The maintenance of diverse life history strategies within and among species remains a fundamental question in ecology and evolutionary biology. By using a near-complete 16-year pedigree of 12,579 winter-run steelhead (Oncorhynchus mykiss) from the Hood River, Oregon, we examined the continued maintenance of two life history traits: the number of lifetime spawning events (semelparous vs. iteroparous) and age at first spawning (2–5 years). We found that repeat-spawning fish had more than 2.5 times the lifetime reproductive success of single-spawning fish. However, first-time repeat-spawning fish had significantly lower reproductive success than single-spawning fish of the same age, suggesting that repeat-spawning fish forego early reproduction to devote additional energy to continued survival. For single-spawning fish, we also found evidence for a fitness trade-off for age at spawning: older, larger males had higher reproductive success than younger, smaller males. For females, in contrast, we found that 3-year-old fish had the highest mean lifetime reproductive success despite the observation that 4- and 5-year-old fish were both longer and heavier. This phenomenon was explained by negative frequency-dependent selection: as 4- and 5-year-old fish decreased in frequency on the spawning grounds, their lifetime reproductive success became greater than that of the 3-year-old fish. Using a combination of mathematical and individual-based models parameterized with our empirical estimates, we demonstrate that both fitness trade-offs and negative frequency-dependent selection observed in the empirical data can theoretically maintain the diverse life history strategies found in this population.

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