scholarly journals Density dependence can obscure nonlethal effects of disturbance on life history of medium-sized cetaceans

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0252677
Author(s):  
Vincent Hin ◽  
John Harwood ◽  
André M. de Roos
Keyword(s):  
Density Dependence ◽  
Prey Availability ◽  
Population Level ◽  
Vital Rates ◽  
Negative Effects ◽  
Pilot Whale ◽  
Individual Health ◽  
Individual Health Status ◽  
History Of ◽  
Nonlethal Effects

Nonlethal disturbance of animals can cause behavioral and physiological changes that affect individual health status and vital rates, with potential consequences at the population level. Predicting these population effects remains a major challenge in ecology and conservation. Monitoring fitness-related traits may improve detection of upcoming population changes, but the extent to which individual traits are reliable indicators of disturbance exposure is not well understood, especially for populations regulated by density dependence. Here we study how density dependence affects a population’s response to disturbance and modifies the disturbance effects on individual health and vital rates. We extend an energy budget model for a medium-sized cetacean (the long-finned pilot whale Globicephala melas) to an individual-based population model in which whales feed on a self-replenishing prey base and disturbance leads to cessation of feeding. In this coupled predator-prey system, the whale population is regulated through prey depletion and the onset of yearly repeating disturbances on the whale population at carrying capacity decreased population density and increased prey availability due to reduced top-down control. In populations faced with multiple days of continuous disturbance each year, female whales that were lactating their first calf experienced increased mortality due to depletion of energy stores. However, increased prey availability led to compensatory effects and resulted in a subsequent improvement of mean female body condition, mean age at first reproduction and higher age-specific reproductive output. These results indicate that prey-mediated density dependence can mask negative effects of disturbance on fitness-related traits and vital rates, a result with implications for the monitoring and management of marine mammal populations.

Burning creates contrasting demographic patterns in Polygala lewtonii (Polygalaceae): a cradle-to-grave analysis of multiple cohorts in a perennial herb

2012 ◽  
Vol 60 (4) ◽  
pp. 347 ◽  
Author(s):  
Carl W. Weekley ◽  
Eric S. Menges
Keyword(s):  
Seedling Recruitment ◽  
Fire Regime ◽  
Seedling Survival ◽  
Fire Effects ◽  
Perennial Herb ◽  
Vital Rates ◽  
Negative Effects ◽  
History Of ◽  
Demographic Trajectories ◽  
Demographic Patterns

Fire drives the population dynamics of many plants. By following successive cohorts of Polygala lewtonii Small (Polygalaceae), a short-lived herb endemic to fire-maintained Florida sandhills, in both burned and unburned microsites, we investigated how fire affected vital rates throughout cohort lifetimes. We followed cohorts from before to 6 years after a prescribed fire in 220 25-cm-radius quadrats, recording survival and seedling recruitment quarterly, and growth and fecundity annually. Fire effects were most pronounced in the first 2 post-burn quarterly censuses, when cohorts in burned (v. unburned) quadrats had seven-fold higher seedling recruitment, significantly higher seedling survival, and a 16.7% gain (v. 1.2% loss) in quadrat occupancy. Plants in burned (v. unburned) quadrats also flowered earlier, were more likely to survive to reproduce and had longer lifespans. The negative effects of density on survival were relaxed in burned quadrats for the first 2 censuses. Burning creates contrasting demographic trajectories for burned v. unburned cohorts. In burned microsites, higher seedling recruitment and survival, earlier flowering and longer lifespans combine to produce a greater contribution to the seedbank and, thus, to population viability. The present study documents the pyro-demographic mechanisms linking the life history of a perennial herb with a frequent fire regime.

scholarly journals Inter-specific Variability in Demographic Processes Affects Abundance-Occupancy Relationships

2020 ◽  
Author(s):  
Bilgecan Şen ◽  
H. Reşit Akçakaya
Keyword(s):  
Density Dependence ◽  
Bird Species ◽  
Population Level ◽  
Mathematical Structure ◽  
Demographic Parameters ◽  
Vital Rates ◽  
Analysis Method ◽  
Demographic Processes ◽  
Dependence Assumption ◽  
Population Demographic

AbstractSpecies with large local abundances tend to occupy more sites. One of the mechanisms proposed to explain this widely reported inter-specific relationship is a cross-scale hypothesis based on dynamics at the population level. Called the vital rates mechanism, it uses within-population demographic processes of population growth and density dependence to explain how positive inter-specific abundance-occupancy relationships can arise. Even though the vital rates mechanism is mathematically simple, it has never been tested directly because of the difficulty in estimating the demographic parameters involved. Here, using a recently introduced mark-recapture analysis method on 17 bird species, we show that inter-specific variability in density dependence strength can weaken both abundance-occupancy relationships and the expected corollaries of the vital rates mechanism. We demonstrate that one of the key assumptions of vital rates mechanism, that density dependence strength should be similar among species, is not met for these 17 species. Additionally, the mathematical structure of vital rates mechanism that relate population-level abundance and intrinsic growth rate is only weakly observed in our data. We argue that this mismatch of mathematical structure and data together with the violation of density dependence assumption weakens the expected positive abundance-occupancy association. Vital rates mechanism also predicts conditions under which positive abundance-occupancy association is weakened or even reversed; our results are consistent with these predictions. More generally, our findings support a cross-scale mechanism of macroecological abundance-occupancy relationship emerging from density-dependent dynamics at the population level.

Attachment Theory

2018 ◽  
Author(s):  
Marilyn Watson
Keyword(s):  
Longitudinal Study ◽  
Attachment Theory ◽  
Interpersonal Relationships ◽  
Insecure Attachment ◽  
Parent Attachment ◽  
Negative Effects ◽  
Attachment Relationships ◽  
John Bowlby ◽  
History Of ◽  
Mary Ainsworth

The origins of attachment theory and the work of John Bowlby and Mary Ainsworth are described. Four types of child–parent attachment relationships—secure, insecure/anxious, insecure/ambivalent, and insecure/disorganized—are outlined along with the ways each type might manifest itself in the classroom. A longitudinal study, conducted by Alan Sroufe and his colleagues, of the development and effects on learning and interpersonal relationships of different child–parent attachment relationships is described. Teachers too have a history of attachment relationships that can affect how they relate to their students. The chapter describes adult attachment and how one’s attachment history might, positively or negatively, affect one’s ability to build positive, nurturing relationships with students. Specific examples of ways teachers can offset the negative effects of a student’s or their own history of insecure attachment are described.

scholarly journals Patterns of Weight Change in Aging and Dying

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 491-491
Author(s):  
Stephen Thielke
Keyword(s):  
Older Adults ◽  
Weight Loss ◽  
Risk Factor ◽  
Weight Change ◽  
Population Level ◽  
Chronological Age ◽  
Average Weight ◽  
Remaining Life ◽  
Entire Cohort ◽  
History Of

Abstract Little research has characterized the natural history of weight change in older adults. Different changes may occur during aging and dying. We analyzed 18 years of weight measures from a cohort of 736,361 Veterans, all of whom had died at age 70 or older. We produced summary measures that accounted for both chronological age and number of years before death. Several clear population-level trends appeared. (1) The average weight of the sample declined across all ages at a rate of about 0.18 BMI points per year. (2) Starting about seven years before death, the amount of loss began to accelerate, reaching a decline of 0.75 BMI points in the year before death. (3) Changes in weight relative to years of remaining life were independent of chronologic age. People who died at age 70 experienced, on average, the same type and duration of terminal decline as did those who died at age 95. (4) The dying process involved a cumulative loss of about 1.3 BMI points. (5) The distribution of weights during advancing age both declined and narrowed. (6) Disproportionate deaths occurred at the lower BMI ranges (below a BMI of 24), and especially below 18, regardless of age. (7) The finding in #5 is explained by the entire cohort losing weight, with death of the thinnest members. These findings argue for examining survival time in studies of weight change. They indicate that weight loss may be a natural part of dying, rather than a risk factor for it.

Do researchers impact their study populations? Assessing the effect of field procedures in a long term population monitoring of sea kraits

2012 ◽  
Vol 33 (3-4) ◽  
pp. 365-372 ◽  
Author(s):  
Thomas Fauvel ◽  
François Brischoux ◽  
Marine Jeanne Briand ◽  
Xavier Bonnet
Keyword(s):  
Body Condition ◽  
New Caledonia ◽  
Stress Hormones ◽  
Population Level ◽  
Population Monitoring ◽  
Long Term Effects ◽  
Negative Effects ◽  
Short Term ◽  
Head Morphology

Long term population monitoring is essential to ecological studies; however, field procedures may disturb individuals. Assessing this topic is important in worldwide declining taxa such as reptiles. Previous studies focussed on animal welfare issues and examined short-term effects (e.g. increase of stress hormones due to handling). Long-term effects with possible consequences at the population level remain poorly investigated. In the present study, we evaluated the effects of widely used field procedures (e.g. handling, marking, forced regurgitation) both on short-term (hormonal stress response) and on long-term (changes in body condition, survival) scales in two intensively monitored populations of sea kraits (Laticauda spp.) in New Caledonia. Focusing on the most intensively monitored sites, from 2002 to 2012, we gathered approximately 11 200 captures/recaptures on 4500 individuals. Each snake was individually marked (scale clipping + branding) and subjected to various measurements (e.g. body size, head morphology, palpation). In addition, a subsample of more than 500 snakes was forced to regurgitate their prey for dietary analyses. Handling caused a significant stress hormonal response, however we found no detrimental long-term effect on body condition. Forced regurgitation did not cause any significant effect on both body condition one year later and survival. These results suggest that the strong short-term stress provoked by field procedures did not translate into negative effects on the population. Although similar analyses are required to test the validity of our conclusions in other species, our results suggest distinguishing welfare and population issues to evaluate the potential impact of population surveys.

scholarly journals Predictors of invertebrate biomass and rate of advancement of invertebrate phenology across eight sites in the North American Arctic

Polar Biology ◽  
2021 ◽  
Vol 44 (2) ◽  
pp. 237-257
Author(s):  
Rebecca Shaftel ◽  
Daniel J. Rinella ◽  
Eunbi Kwon ◽  
Stephen C. Brown ◽  
H. River Gates ◽  
...  
Keyword(s):  
Prey Availability ◽  
Population Level ◽  
The Arctic ◽  
Environmental Drivers ◽  
Chick Survival ◽  
The North ◽  
Phenological Mismatch ◽  
Nesting Sites ◽  
North American Arctic

AbstractAverage annual temperatures in the Arctic increased by 2–3 °C during the second half of the twentieth century. Because shorebirds initiate northward migration to Arctic nesting sites based on cues at distant wintering grounds, climate-driven changes in the phenology of Arctic invertebrates may lead to a mismatch between the nutritional demands of shorebirds and the invertebrate prey essential for egg formation and subsequent chick survival. To explore the environmental drivers affecting invertebrate availability, we modeled the biomass of invertebrates captured in modified Malaise-pitfall traps over three summers at eight Arctic Shorebird Demographics Network sites as a function of accumulated degree-days and other weather variables. To assess climate-driven changes in invertebrate phenology, we used data from the nearest long-term weather stations to hindcast invertebrate availability over 63 summers, 1950–2012. Our results confirmed the importance of both accumulated and daily temperatures as predictors of invertebrate availability while also showing that wind speed negatively affected invertebrate availability at the majority of sites. Additionally, our results suggest that seasonal prey availability for Arctic shorebirds is occurring earlier and that the potential for trophic mismatch is greatest at the northernmost sites, where hindcast invertebrate phenology advanced by approximately 1–2.5 days per decade. Phenological mismatch could have long-term population-level effects on shorebird species that are unable to adjust their breeding schedules to the increasingly earlier invertebrate phenologies.

scholarly journals Role of the periodic table in discovery of new elements

2011 ◽  
Vol 1 (1) ◽  
pp. 1-5 ◽  
Author(s):  
D.C. Hoffman
Keyword(s):  
Periodic Table ◽  
Predictive Power ◽  
Chemical Elements ◽  
Chemical Properties ◽  
Negative Effects ◽  
Current Form ◽  
Future Role ◽  
History Of ◽  
Chemical Techniques

AbstractThis year (2009) marks the 140th Anniversary of Mendeleev's original 1869 periodic table of the elements based on atomic weights. It also marks the 175th anniversary of his birth in Tolbosk, Siberia. The history of the development of periodic tables of the chemical elements is briefly reviewed beginning with the presentation by Dmitri Mendeleev and his associate Nikolai Menshutkin of their original 1869 table based on atomic weights. The value, as well as the sometimes negative effects, of periodic tables in guiding the discovery of new elements based on their predicted chemical properties is assessed. It is noteworthy that the element with Z=101 (mendelevium) was identified in 1955 using chemical techniques. The discoverers proposed the name mendelevium to honor the predictive power of the Mendeleev Periodic Table. Mendelevium still remains the heaviest element to have been identified first by chemical rather than nuclear or physical techniques. The question concerning whether there will be a future role for the current form of the periodic table in predicting chemical properties and aid in the identification of elements beyond those currently known is considered.

scholarly journals Terror and Insecurity: The Impact of Boko Haram Crisis on Nigeria’s External Image

2014 ◽  
Vol 43 ◽  
pp. 27-34 ◽  
Author(s):  
Adebowale Adeyemi-Suenu
Keyword(s):  
Political History ◽  
The Political ◽  
Negative Effects ◽  
Boko Haram ◽  
Central Thesis ◽  
History Of ◽  
Historical Basis ◽  
The Impact ◽  
Strategic Logic

The use of terror as a ratio for resolving internal fundamental differences is not uncommon in neo-colonial societies. This is not saying that flashes of same are not recogn ised in the developed environment. The prevalence of this alternative appears as old as the political history of Nigeria. This work underscores the theoretical and historical basis of rebellion in Nigeria primarily focusing on the rise, fundamental philosophy and the vision of the Boko Haramists. The central thesis of this work is that Boko Haram activities have negative effects on Nigeria’s external image and fundamentally, it exposes the nature and dynamics of Nigeria’s security problems. The work contributes in part to the literature on this issue but significantly, it situates the problems within strategic logic which amplifies the degeneration of the problems and the incessant rebellion against the Nigerian State.

scholarly journals Pengaruh Faktor Demografi dan Sosial Ekonomi terhadap Status Kesehatan Individu di Indonesia

2021 ◽  
Vol 5 (2) ◽  
pp. 146-157
Author(s):  
Liani Surya Rakasiwi
Keyword(s):  
Socioeconomic Status ◽  
Health Status ◽  
Low Income ◽  
The Other ◽  
Individual Health ◽  
Indonesia Family Life Survey ◽  
Individual Health Status ◽  
The Individual ◽  
Logit Regression Model ◽  
The Impact

This study analyzed the impact of demography and socioeconomic status on individual health status in Indonesia. The data used Indonesia Family Life Survey 5 (IFLS 5). The study use logit regression model for analysis with health status variable as dependent variable. The other variable such as demography and socioeconomic status as independent variables. Socioeconomic status seen from two measures, namely education and income. The result of this study concludes the demography influence significantly on individual health status in Indonesia. Individual who lives in urban area has higher probability of being health by 1,02 percent compared to individual who lives in rural area. The other variable like socioeconomic status also influences significantly on the individual health status in Indonesia. Individual with longer years of education has higher probability of being health by 3,07 percent compared to individual with less years of education. Individual with high income has higher probability of being health compared to individual with low income.

Sign in / Sign up

Export Citation Format

Share Document