scholarly journals Fire history and weather interact to determine extent and synchrony of mast-seeding in rhizomatous scrub oaks of Florida

2021 ◽  
Vol 376 (1839) ◽  
Author(s):  
Mario B. Pesendorfer ◽  
Reed Bowman ◽  
Georg Gratzer ◽  
Shane Pruett ◽  
Angela Tringali ◽  
...  
Keyword(s):  
Seed Production ◽  
Reproductive Strategies ◽  
Fire History ◽  
Interactive Effects ◽  
Mast Seeding ◽  
Florida Scrub ◽  
Acorn Production ◽  
South Central

In disturbance-prone ecosystems, fitness consequences of plant reproductive strategies are often determined by the relative timing of seed production and disturbance events, but the role of disturbances as proximate drivers of seed production has been overlooked. We use long-term data on seed production in Quercus chapmanii , Q. geminata and Q. inopina , rhizomatous oaks found in south central Florida's oak scrub, to investigate the role of fire history and its interaction with weather in shaping acorn production and its synchrony . Acorn production increased with the time since last fire, combined with additive or interactive effects of spring precipitation (+) or drought (–). Furthermore, multiple matrix regression models revealed that ramet pairs with shared fire history were more synchronous in seed production than ones that burned in different years. Long-term trends suggest that increasingly drier spring weather, in interaction with fire frequency, may drive a decline of seed production. Such declines could affect the community of acorn-reliant vertebrates in the Florida scrub, including endangered Florida scrub-jays ( Aphelocoma coerulescens ). These results illustrate that fire can function as a proximate driver of seed production in mast-seeding species, highlighting the increasingly recognized importance of interactions among reproductive strategies and disturbance regimes in structuring plant populations and communities. This article is part of the theme issue ‘The ecology and evolution of synchronized seed production in plants’.

Social Participation Among Adults Aging With Long-Term Physical Disability: The Role of Socioenvironmental Factors

2019 ◽  
Vol 31 (10_suppl) ◽  
pp. 145S-168S ◽  
Author(s):  
Philippa Clarke ◽  
Erica Twardzik ◽  
Michelle A. Meade ◽  
Mark D. Peterson ◽  
Denise Tate
Keyword(s):  
Built Environment ◽  
Physical Disability ◽  
Functional Limitations ◽  
Interactive Effects ◽  
Environmental Barriers ◽  
Walking Aids ◽  
Poor Access ◽  
Participation Restrictions

Objective: This study examined the environmental barriers and facilitators that hinder or promote participation among adults aging with physical disabilities. Method: Data come from an ongoing study of 1,331 individuals aging with long-term physical disability ( M = 65 years). Linear regression examined the association between individual and socioenvironmental factors and participation restrictions in work, leisure, and social activities. Results: Pain, fatigue, and physical functional limitations were significant barriers to participation for individuals aging with physical disability. Barriers in the built environment also reduced participation, net of health and functioning. Poor access to buildings was especially problematic for participation among individuals not using any mobility aid to get around. But for those using wheel or walking aids, environmental barriers had no adverse effect on participation. Discussion: These findings highlight the importance of disentangling the role of different environmental factors by distinguishing between assistive technology for mobility and the physical built environment, including their interactive effects.

scholarly journals Fire effects on acorn production are consistent with the stored resource hypothesis for masting behavior

2016 ◽  
Vol 46 (1) ◽  
pp. 20-24 ◽  
Author(s):  
Kyle A. Funk ◽  
Walter D. Koenig ◽  
Johannes M.H. Knops
Keyword(s):  
Seed Production ◽  
Fire Effects ◽  
Internal Dynamics ◽  
Acorn Production ◽  
Wild Tree ◽  
Resource Storage ◽  
Controlled Burns ◽  
Baseline Levels ◽  
Resource Hypothesis

Highly variable patterns of seed production (“masting”) have been hypothesized to be driven by internal dynamics of resource storage and depletion. This hypothesis predicts that if seed production is artificially reduced, then the availability of unused stored resources should result in subsequent enhancement of the seed crop. We tested this prediction in two oak species with contrasting patterns of annual seed production (highly variable and relatively constant) by means of controlled burns at various frequencies over a 17-year period. We found that controlled burns reduced acorn production by both species in the year of the burn. In the species with relatively constant productivity, acorn production returned to baseline levels in the year following a burn; however, in the species with highly variable productivity, acorn production significantly increased the year following a burn. These results support a key prediction of the stored resource hypothesis by means of a long-term experimental test in wild tree populations.

scholarly journals Climate change and plant reproduction: trends and drivers of mast seeding change

2021 ◽  
Vol 376 (1839) ◽  
Author(s):  
Andrew Hacket-Pain ◽  
Michał Bogdziewicz
Keyword(s):  
Climate Change ◽  
Seed Production ◽  
Mast Seeding ◽  
Ecosystem Impacts ◽  
Proximate Mechanisms ◽  
Proximate Factors ◽  
Global Vegetation ◽  
Term Response ◽  
Impacts Of Climate Change

Climate change is reshaping global vegetation through its impacts on plant mortality, but recruitment creates the next generation of plants and will determine the structure and composition of future communities. Recruitment depends on mean seed production, but also on the interannual variability and among-plant synchrony in seed production, the phenomenon known as mast seeding. Thus, predicting the long-term response of global vegetation dynamics to climate change requires understanding the response of masting to changing climate. Recently, data and methods have become available allowing the first assessments of long-term changes in masting. Reviewing the literature, we evaluate evidence for a fingerprint of climate change on mast seeding and discuss the drivers and impacts of these changes. We divide our discussion into the main characteristics of mast seeding: interannual variation, synchrony, temporal autocorrelation and mast frequency. Data indicate that masting patterns are changing but the direction of that change varies, likely reflecting the diversity of proximate factors underlying masting across taxa. Experiments to understand the proximate mechanisms underlying masting, in combination with the analysis of long-term datasets, will enable us to understand this observed variability in the response of masting. This will allow us to predict future shifts in masting patterns, and consequently ecosystem impacts of climate change via its impacts on masting. This article is part of the theme issue ‘The ecology and evolution of synchronized seed production in plants’.

scholarly journals Studying the genetic basis of masting

2021 ◽  
Vol 376 (1839) ◽  
Author(s):  
Akiko Satake ◽  
Dave Kelly
Keyword(s):  
Genetic Basis ◽  
Molecular Mechanisms ◽  
Mast Seeding ◽  
Ecological Genomics ◽  
Theme Issue ◽  
Natural Conditions ◽  
Genetic Level ◽  
Seed Crops

The mechanisms underlying mast seeding have traditionally been studied by collecting long-term observational data on seed crops and correlating seedfall with environmental variables. Significant progress in ecological genomics will improve our understanding of the evolution of masting by clarifying the genetic basis of masting traits and the role of natural selection in shaping those traits. Here, we summarize three important aspects in studying the evolution of masting at the genetic level: which traits govern masting, whether those traits are genetically regulated, and which taxa show wide variation in these traits. We then introduce recent studies on the molecular mechanisms of masting. Those studies measure seasonal changes in gene expression in natural conditions to quantify how multiple environmental factors combine to regulate floral initiation, which in many masting plant species is the single largest contributor to among-year variation in seed crops. We show that Fagaceae offers exceptional opportunities for evolutionary investigations because of its diversity at both the phenotypic and genetic levels and existing documented genome sequences. This article is part of the theme issue ‘The ecology and evolution of synchronized seed production in plants’.

Reproductive Behavior in the Human Male

2019 ◽  
pp. 123-141
Author(s):  
Stefan M. M. Goetz ◽  
Glenn Weisfeld ◽  
Samuele Zilioli
Keyword(s):  
Reproductive Strategies ◽  
Life History Theory ◽  
Parental Effort ◽  
Evolutionary Time ◽  
Short Term ◽  
Physical Conditions ◽  
Human Male ◽  
Evolutionary Success

Given the pivotal role of differential reproduction to the evolutionary success of ancestral men, evolution has produced a plethora of reproductive strategies aimed at solving the complexities of intramale competition and satisfying and/or thwarting the reproductive desires of women. Life history theory recognizes that an organism has limited resources and must invest energy appropriately. Broadly, reproductive strategies can be dichotomized into short-term (emphasizing mating over parental effort) versus long-term (emphasizing parenting over mating effort) strategies. Increasingly, the neuroendocrine system—especially testosterone—has been recognized as the proximate mechanism orchestrating adoption of one strategy over the other. This chapter reviews behaviors geared toward solving problems associated with both long-term and short-term reproductive strategies and discusses the neuroendocrine correlates. The adoption of one strategy over another is conceptualized as conditional or facultative adaptations in which strategic switching points are tuned over evolutionary time to produce optimal fitness responses to men’s social and physical conditions.

scholarly journals Climate change and plant reproduction: trends and drivers of mast seeding change

2021 ◽  
Author(s):  
Andrew Hacket-Pain ◽  
Michał Bogdziewicz
Keyword(s):  
Climate Change ◽  
Seed Production ◽  
Mast Seeding ◽  
Ecosystem Impacts ◽  
Proximate Mechanisms ◽  
Proximate Factors ◽  
Global Vegetation ◽  
Term Response ◽  
Impacts Of Climate Change

Climate change is reshaping global vegetation through its impacts on plant mortality, but recruitment creates the next generation of plants and will determine the structure and composition of future communities. Recruitment depends on mean seed production, but also on the interannual variability and among-plant synchrony in seed production, the phenomenon known as mast seeding. Thus, predicting the long-term response of global vegetation dynamics to climate change requires understanding the response of masting to changing climate. Recently, data and methods have become available allowing the first assessments of long-term changes in masting. Reviewing the literature, we evaluate evidence for a fingerprint of climate change on mast seeding and discuss the drivers and impacts of these changes. We divide our discussion into the main characteristics of mast seeding: interannual variation, synchrony, temporal autocorrelation, and mast frequency. Data indicate that masting patterns, are changing, but the direction of that change varies, likely reflecting the diversity of proximate factors underlying masting across taxa. Experiments to understand the proximate mechanisms underlying masting, in combination with the analysis of long-term datasets, will enable us to understand this observed variability in the response of masting. This will allow us to predict future shifts in masting patterns, and consequently ecosystem impacts of climate change via its impacts on masting.

Assessing long-term risks of prairie seed harvest: what is the role of life-history?

Botany ◽  
2017 ◽  
Vol 95 (11) ◽  
pp. 1081-1092 ◽  
Author(s):  
Justin C. Meissen ◽  
Susan M. Galatowitsch ◽  
Meredith W. Cornett
Keyword(s):  
Tallgrass Prairie ◽  
High Intensity ◽  
Reproductive Strategies ◽  
Extinction Risk ◽  
Native Plant ◽  
Seed Harvest ◽  
Prairie Restorations ◽  
Clonal Species

To meet the demand for more and larger tallgrass prairie restorations, seed is frequently collected en-masse from remnant native plant populations. Overharvesting of seed may lead to population extinctions, but these risks are not well studied. Species’ reproductive strategies may provide a basis for risk assessment. We assessed extinction risks associated with seed harvest for grassland plant species with different reproductive strategies (clonal vs. non-clonal). Using stage-based matrix models, we projected the extinction risk for two clonal and four non-clonal prairie species subjected to five harvest scenarios: (i) no harvest, (ii and iii) annual harvest at low/high intensity (50% and 75% seeds removed), and (iv and v) triennial harvest at low/high intensity. We compared the magnitude of growth or decline (λ) and mean extinction risk among populations during a 25-year modeling period. Non-clonal species were robust to triennial and low-intensity harvest, but susceptible to decreases in population growth (λ) up to 0.5 and elevated extinction risks up to 95% with high intensity annual harvest. Clonal species were unaffected by seed harvest, owing to a compensatory effect of vegetative propagation on growth rates. To maintain populations of non-clonal species in remnant grasslands, high intensity annual harvest should be avoided.

Water quality changes in south-central Ontario lakes and the role of local factors in regulating lake response to regional stressors

2011 ◽  
Vol 68 (6) ◽  
pp. 1038-1050 ◽  
Author(s):  
Michelle E. Palmer ◽  
Norman D. Yan ◽  
Andrew M. Paterson ◽  
Robert E. Girard
Keyword(s):  
Water Quality ◽  
Acidic Deposition ◽  
Quality Parameters ◽  
Quality Changes ◽  
South Central ◽  
Chloride Water ◽  
Long Term Monitoring ◽  
Term Monitoring

The long-term monitoring of eight lakes near Dorset, Ontario, indicates that the water quality has changed significantly over the last 30 years. However, trends in the Dorset lakes may not be representative of changes in other south-central Ontario lakes, as the Dorset lakes are within a small area and span a limited gradient of lake and watershed characteristics. To determine the regional extent of water quality changes, we assessed the chemical changes in 36 diverse lakes that were first sampled between 1981 and 1990 and were resampled in 2004–2005. Similar to trends in the Dorset lakes, changes in the regional lakes included decreasing acidity, calcium, conductivity, metals, and phosphorus, and increasing dissolved organic carbon, nitrogen, sodium, and chloride. Water quality changes were driven by regional stressors, including acidic deposition, climate, and lakeshore residential development. However, stressor-induced responses differed among lakes. Increases in sodium and chloride were greater in developed lakes that were close to winter-maintained roads. Site-specific characteristics, such as lake and watershed morphometry, could not explain heterogeneous changes in the remaining water quality parameters. These results indicate that other factors play an important role in regulating individual lake response to regional stressors.

The direct and interactive effects of job insecurity and job embeddedness on unethical pro-organizational behavior

2017 ◽  
Vol 46 (6) ◽  
pp. 1182-1198 ◽  
Author(s):  
Sumit Kumar Ghosh
Keyword(s):  
Organizational Behavior ◽  
Job Insecurity ◽  
Job Embeddedness ◽  
Interactive Effects ◽  
Stepwise Multiple Regression ◽  
Empirical Examination ◽  
Content Type ◽  
Multiple Regression Technique

Purpose The purpose of this paper is to empirically examine both the direct effects and the interactive effects of job insecurity and job embeddedness on unethical pro-organizational behavior. Design/methodology/approach Data were collected, using established scales, from employees of different Indian organizations. In all, 346 responses were collected. The data were analyzed using a stepwise multiple regression technique. Findings The results of the analysis reveal that both job insecurity and job embeddedness are positively linked to unethical pro-organizational behavior. Further, the relationship between job insecurity and unethical pro-organizational behavior is moderated by job embeddedness. Research limitations/implications The study’s results indicate that managers should be aware that employees who run the risk of losing their jobs might be inclined to perform pro-organizational behavior that could be unethical. Intrinsically, such acts could be detrimental to the organization’s long-term health and therefore managers should be vigilant and timely in discouraging this behavior. Originality/value Unethical pro-organizational behavior as a means used by employees to combat job insecurity has not previously been addressed by researchers. Thus, this study contributes to the literature through its empirical examination of the role of job insecurity and job embeddedness as factors influencing unethical pro-organizational behavior.

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