The Relationship between Population Density and Body Size: The Role of Extinction and Mobility

Oikos ◽  
1995 ◽  
Vol 73 (2) ◽  
pp. 225 ◽  
Author(s):  
Bo Ebenman ◽  
Anders Hendenström ◽  
Uno Wennergren ◽  
Börje Ekstam ◽  
Jan Landin ◽  
...  
Keyword(s):  
Body Size ◽  
Population Density ◽  
The Relationship

scholarly journals Is the relationship between population density and body size consistent across independent studies? A meta-analytical approach

2001 ◽  
Vol 61 (1) ◽  
pp. 1-6 ◽  
Author(s):  
L. M. BINI ◽  
A. S. G COELHO ◽  
J. A. F. DINIZ-FILHO
Keyword(s):  
Body Size ◽  
Population Density ◽  
Regression Model ◽  
Phylogenetic Relationships ◽  
Analytical Approach ◽  
Analytical Procedure ◽  
Significant Heterogeneity ◽  
Sampling Variation ◽  
Homogeneity Hypothesis ◽  
The Relationship

The Energetic Equivalence Rule (EER) is a controversial issue in ecology. This rule states that the amount of energy that each species uses per unit of area is independent of its body size. Here, we perform a meta-analytical procedure to combine and compare the slopes of population density and body size relationships across independent studies of mammals and birds. We then compared a distribution of 50,000 bootstrap combined slopes with the expected slope (b = -0.75) under the EER. The combined slopes obtained for mammals and birds separately were -0.755 and -0.321, respectively. The homogeneity hypothesis (i. e. within studies the slopes differ by no more than would be expected due sampling variation) was rejected in both cases. So, EER cannot be supported since the use of an exponent of -0.75 is, in fact, an oversimplification. Significant heterogeneity of slopes within each group (mammals and birds) is an indicator of inferential problems related with variation in body size, spatial scale, the regression model adopted and phylogenetic relationships among species. So, we consider that questions regarding the estimation and validity of slopes is the next challenge of density-body size relationship studies.

scholarly journals Rapid Anthropocene realignment of allometric scaling rules

2020 ◽  
Author(s):  
Luca Santini ◽  
Nick J.B. Isaac
Keyword(s):  
Global Change ◽  
Population Density ◽  
Allometric Scaling ◽  
Negative Relationship ◽  
Change Scenario ◽  
Anthropogenic Pressures ◽  
Size Dependent ◽  
Energetic Constraints ◽  
The Relationship

AbstractThe negative relationship between body size and population density (SDR) in mammals is often interpreted as resulting from energetic constraints. In a global change scenario, however, this relationship might be expected to change, given the size-dependent nature of anthropogenic pressures and vulnerability to extinction. Here we test whether the SDR in mammals has changed over the last 50 years. We show that the relationship has shifted down and became shallower, corresponding to a decline in population density of 32-72%, for the largest and smallest mammals, respectively. However, the SDRs become steeper in some groups (e.g. carnivores) and shallower in others (e.g. herbivores). The Anthropocene reorganization of biotic systems is apparent in macroecological relationships that were previously believed to be immutable, reinforcing the notion that biodiversity pattens are contingent upon conditions at the time of investigation. We call for an increased attention on the role of global change on macroecological inferences.

scholarly journals Bisexual stereotypes apply differently by body size: An assessment of bisexual prototypicality, trait application, and body size

2021 ◽  
Author(s):  
Flora Oswald ◽  
Amanda champion ◽  
Devinder Singh Khera ◽  
Cory Pedersen
Keyword(s):  
Body Size ◽  
Person Perception ◽  
Online Survey ◽  
Bisexual Men ◽  
Bisexual Women ◽  
Body Sizes ◽  
And Bisexual ◽  
Fat Bodies ◽  
The Relationship

We blend person perception work with queer appearance psychology to examine the relationship between body size and bisexuality. In an online survey (N= 472, Mage= 25.15, 63.8% women), we examined the specific traits associated with a range of computer-modelled bodies identified as bisexual. We found that average body sizes were perceived as most prototypical of both bisexual men and bisexual women, skinny and fat bodies were more associated with clusters of traits which contrast with common stereotypes about bisexuality. Additionally, we found that bisexual men were associated with increased masculinity and decreased femininity relative to bisexual women, and found a general, though nonsignificant trend such that bisexual men were perceived as having heightened androcentric desire relative to women. Finally, we found evidence for the role of typicality as a mediator of perceived prejudice; less prototypical bodies tended to be perceived as experiencing greater prejudice based on body size.

scholarly journals Exceptional body sizes but typical trophic structure in a Pleistocene food web

2016 ◽  
Vol 12 (5) ◽  
pp. 20160228 ◽  
Author(s):  
Angel M. Segura ◽  
Richard A. Fariña ◽  
Matías Arim
Keyword(s):  
Body Size ◽  
Trophic Position ◽  
Negative Relationship ◽  
Additional Energy ◽  
Quaternary Period ◽  
Species Vulnerability ◽  
Body Sizes ◽  
Energetic Constraints ◽  
The Relationship

In this study, we focused on the exceptionally large mammals inhabiting the Americas during the Quaternary period and the paramount role of body size in species ecology. We evaluated two main features of Pleistocene food webs: the relationship between body size and (i) trophic position and (ii) vulnerability to predation. Despite the large range of species sizes, we found a hump-shaped relationship between trophic position and body size. We also found a negative trend in species vulnerability similar to that observed in modern faunas. The largest species lived near the boundary of energetic constraints, such that any shift in resource availability could drive these species to extinction. Our results reinforce several features of megafauna ecology: (i) the negative relationship between trophic position and body size implies that large-sized species were particularly vulnerable to changes in energetic support; (ii) living close to energetic imbalance could favour the incorporation of additional energy sources, for example, a transition from a herbivorous to a scavenging diet in the largest species (e.g. Megatherium ) and (iii) the interactions and structure of Quaternary megafauna communities were shaped by similar forces to those shaping modern fauna communities.

The Relationship between Athletic Participation and Perceptions of Body Size and Weight Control in Adolescent Girls: The Role of Sport Type

2006 ◽  
Vol 23 (3) ◽  
pp. 248-272 ◽  
Author(s):  
Sarah R. Crissey ◽  
Joy Crissey Honea
Keyword(s):  
Weight Loss ◽  
Body Size ◽  
Adolescent Girls ◽  
Weight Control ◽  
Sport Participation ◽  
White Girls ◽  
Sport Type ◽  
Weight Loss Strategies ◽  
The Relationship

This study examines the relationship between sport participation and perceptions of body size and weight-loss strategies among adolescent girls. Using a sample of 7,214 girls, ages 12–18 years, from the National Longitudinal Study of Adolescent Health, we find that girls who participate in stereotypically feminine sports are more likely to report feeling overweight, attempt to lose weight, and use multiple weight-loss strategies compared with nonathletes. We also find that the associations for weight loss, but not overweight perception, are generally weaker for non-White girls. These findings suggest that participation in stereotypically feminine sports, particularly for White girls, might exacerbate body image and dieting problems associated with dominant gender roles, but participation in stereotypically masculine sports does not.

scholarly journals A Review of Effects of Environment on Brain Size in Insects

Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 461
Author(s):  
Thomas Carle
Keyword(s):  
Body Size ◽  
Social Behaviour ◽  
Brain Size ◽  
Social Brain ◽  
Encephalization Quotient ◽  
The Social ◽  
Relative Brain Size ◽  
The Relationship ◽  
Development And Evolution

Brain size fascinates society as well as researchers since it is a measure often associated with intelligence and was used to define species with high “intellectual capabilities”. In general, brain size is correlated with body size. However, there are disparities in terms of relative brain size between species that may be explained by several factors such as the complexity of social behaviour, the ‘social brain hypothesis’, or learning and memory capabilities. These disparities are used to classify species according to an ‘encephalization quotient’. However, environment also has an important role on the development and evolution of brain size. In this review, I summarise the recent studies looking at the effects of environment on brain size in insects, and introduce the idea that the role of environment might be mediated through the relationship between olfaction and vision. I also discussed this idea with studies that contradict this way of thinking.

scholarly journals The role of social capital in COVID-19 deaths

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Janaki Imbulana Arachchi ◽  
Shunsuke Managi
Keyword(s):  
Social Capital ◽  
Population Density ◽  
Social Trust ◽  
Ageing Population ◽  
Community Attachment ◽  
Four Dimensions ◽  
Related Data ◽  
Hospital Beds ◽  
The Relationship

Abstract Background The COVID-19 pandemic has shown a continuously increasing trend with a large variation in the number of COVID-19 deaths across countries. In response, many countries have implemented non pharmaceutical methods of intervention, such as social distancing and lockdowns. This study aims to investigate the relationship of four dimensions of social capital (community attachment, social trust, family bond, and security) and several control variables with COVID-19 deaths. Methods We retrieved data from open access databases and a survey. COVID-19 death-related data were collected from the website “Centre for Systems Science and Engineering (CSSE) at Johns Hopkins University”. Social capital-related data were collected from a large-scale survey that included web-based and face-to-face surveys covering 100,956 respondents across all regions/provinces/states of 37 countries in 2017. Data regarding population density, number of hospital beds, and population aged 65 or older were retrieved from the World Development Indicators (WDIs). Data on country lockdowns were obtained from the website “National responses to the 2019-20 coronavirus pandemic”. Linear regressions were applied to identify the relationship between social capital and COVID-19 deaths. Results We found that COVID-19 deaths were associated with social capital both positively and negatively. Community attachment and social trust were associated with more COVID-19 deaths, and family bond and security were associated with fewer deaths. COVID-19 deaths were positively associated with population density, ageing population, and interactions between four dimensions of social capital-related factors and the ageing population. Furthermore, the number of hospital beds and early lockdown policy were negatively associated with COVID-19 deaths. Conclusions The results indicate that the role of social capital in dynamically evolving threats, such as the current COVID-19 pandemic, is not always negative or positive. Therefore, people’s behaviour should be changed to support countries’ response to the COVID-19 threat.

scholarly journals Population density and the SARS-CoV-2 pandemic: comparing the geography of the first and second wave in the Netherlands

2021 ◽  
Author(s):  
Willem Rogier Boterman
Keyword(s):  
Population Density ◽  
The Netherlands ◽  
Urban Areas ◽  
Mitigation Measures ◽  
Simple Diffusion ◽  
Panel Regressions ◽  
National Networks ◽  
The Relationship ◽  
Second Wave

The COVID-19 pandemic has boosted public and scholarly debate about the relationship between infectious disease and the urban. Cities are considered contagious because they are hubs in (inter)national networks and contain high densities of people. However, the role of the urban and population density in the spread of pathogens is complex and is mediated by the wider bio-social environment. This paper analsyes the role of population density in the outbreak of COVID-19 in the densely and highly urbanized context of the Netherlands. It compares the geography of the different phases in the epidemic and assesses when and where density plays a role. Using municipal data on the rate of infections and hospitalizations this paper reveals that spatial patterns differ substantially in time, which does not appear to be simple diffusion. Using panel regressions it is demonstrated that population density plays a role in those stages in which containment and mitigation measures were least strict, while in periods of lock down other factors such as household size are associated with higher infection rates. It concludes that lock downs may have greater effect in urban areas as key elements of urbanity are temporarily cancelled out.

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