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Ecological theory

Maria Moiron, Kimberley J Mathot, Niels J Dingemanse
Adaptive theory predicts that the fundamental trade-off between starvation and predation risk shapes diurnal patterns in foraging activity and mass gain in wintering passerine birds. Foragers mitigating both types of risk should exhibit a bimodal distribution (increased foraging and mass gain early and late in the day), whereas both foraging and mass gains early (versus late) during the day are expected when the risk of starvation (versus predation) is greatest. Finally, relatively constant rates of foraging and mass gain should occur when the starvation-predation risk trade-off is independent of body mass...
March 14, 2018: Proceedings. Biological Sciences
Isaac Winkler, Sonja J Scheffer, Matthew L Lewis, Kristina J Ottens, Andrew P Rasmussen, Géssica A Gomes-Costa, Luz Maria Huerto Santillan, Marty A Condon, Andrew A Forbes
BACKGROUND: Much evolutionary theory predicts that diversity arises via both adaptive radiation (diversification driven by selection against niche-overlap within communities) and divergence of geographically isolated populations. We focus on tropical fruit flies (Blepharoneura, Tephritidae) that reveal unexpected patterns of niche-overlap within local communities. Throughout the Neotropics, multiple sympatric non-interbreeding populations often share the same highly specialized patterns of host use (e...
March 14, 2018: BMC Evolutionary Biology
Stephanie M Topp, Chanda Mwamba, Anjali Sharma, Njekwa Mukamba, Laura K Beres, Elvin Geng, Charles B Holmes, Izukanji Sikazwe
BACKGROUND: Failure to keep people living with HIV engaged in life-long care and treatment has serious implications for individual and population-level health. Nested within a four-province study of HIV care and treatment outcomes, we explored the dynamic role of social and service-related factors influencing retention in HIV care in Zambia. METHODS: From a stratified random sample of 31 facilities, eight clinics were selected, one urban and one rural from each province...
2018: PloS One
Hye-Jin Kim, Hanbyul Kim, Jin Ju Kim, Nu Ri Myeong, Taeyune Kim, Taehun Park, Eunjoo Kim, Ji-Yei Choi, Johnhwan Lee, Susun An, Woo Jun Sul
Given the higher incidence of skin diseases in more urbanized populations and its association with the skin microbiome, we questioned how the skin microbiome differed depending on the degree of urbanization. Skin microbiomes of 231 healthy subjects in five large cities in China varied mainly with environment and socioeconomic status of the cities in question. The differences among microbiomes could be explained by the predominantly niche-based assembly of microbial communities, which was supported by a dominance test, β-null deviation, and edge-length abundance distribution...
March 2018: Science Advances
David J Páez, Olivier Restif, Peggy Eby, Raina K Plowright
Bats provide important ecosystem services such as pollination of native forests; they are also a source of zoonotic pathogens for humans and domestic animals. Human-induced changes to native habitats may have created more opportunities for bats to reside in urban settings, thus decreasing pollination services to native forests and increasing opportunities for zoonotic transmission. In Australia, fruit bats ( Pteropus spp. flying foxes) are increasingly inhabiting urban areas where they feed on anthropogenic food sources with nutritional characteristics and phenology that differ from native habitats...
May 5, 2018: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
Berta Murillo Pardo, José A Julián Clemente, Luis García González, Enrique García Bengoechea, Eduardo Generelo Lanaspa
Engaging in physical activity (PA) on a regular and adequate basis generates considerable benefits for health. In developed countries, the time spent doing PA is decreasing, whilst sedentary time (ST) is increasing. A multicomponent school-based intervention programme, called 'Sigue la Huella' (Follow the Footprint), was developed to reduce sedentary lifestyles and increase PA levels. This programme has proven to be effective in increasing the daily levels of moderate to vigorous PA, in decreasing ST and in improving motivational outcomes in secondary education students, in the city of Huesca (Spain)...
February 24, 2018: Health Promotion International
Robert Stephen Cantrell, Chris Cosner, Xiao Yu
Most classical models for the movement of organisms assume that all individuals have the same patterns and rates of movement (for example, diffusion with a fixed diffusion coefficient) but there is empirical evidence that movement rates and patterns may vary among different individuals. A simple way to capture variation in dispersal that has been suggested in the ecological literature is to allow individuals to switch between two distinct dispersal modes. We study models for populations whose members can switch between two different nonzero rates of diffusion and whose local population dynamics are subject to density dependence of logistic type...
December 2018: Journal of Biological Dynamics
Gail M Rosenbaum, Vinod Venkatraman, Laurence Steinberg, Jason M Chein
Adolescents are known to take more risks than adults, which can be harmful to their health and well-being. However, despite age differences in real-world risk taking, laboratory risk-taking paradigms often do not evince these developmental patterns. Recent findings in the literature suggest that this inconsistency may be due in part to differences between how adolescents process information about risk when it is described (e.g., in a description-based classroom intervention) versus when it is experienced (e...
March 2018: Developmental Review: DR
Umesh Srinivasan, Paul R Elsen, Morgan W Tingley, David S Wilcove
Longstanding theory predicts that competitive interactions set species' range limits in relatively aseasonal, species-rich regions, while temperature limits distributions in more seasonal, species-poor areas. More recent theory holds that species evolve narrow physiological tolerances in aseasonal regions, with temperature being an important determining factor in such zones. We tested how abiotic (temperature) and biotic (competition) factors set range limits and structure bird communities along strong, opposing, temperature-seasonality and species-richness gradients in the Himalayas, in two regions separated by 1500 km...
March 14, 2018: Proceedings. Biological Sciences
Mikael Pontarp, Owen L Petchey
Much of life's diversity has arisen through ecological opportunity and adaptive radiations, but the mechanistic underpinning of such diversification is not fully understood. Competition and predation can affect adaptive radiations, but contrasting theoretical and empirical results show that they can both promote and interrupt diversification. A mechanistic understanding of the link between microevolutionary processes and macroevolutionary patterns is thus needed, especially in trophic communities. Here, we use a trait-based eco-evolutionary model to investigate the mechanisms linking competition, predation and adaptive radiations...
March 14, 2018: Proceedings. Biological Sciences
Caleb P Roberts, Daniel R Uden, Craig R Allen, Dirac Twidwell
Mismatches between invasive species management policies and ecological knowledge can lead to profound societal consequences. For this reason, natural resource agencies have adopted the scientifically-based density-impact invasive species curve to guide invasive species management. We use the density-impact model to evaluate how well management policies for a native invader (Juniperus virginiana) match scientific guidelines. Juniperus virginiana invasion is causing a sub-continental regime shift from grasslands to woodlands in central North America, and its impacts span collapses in endemic diversity, heightened wildfire risk, and crashes in grazing land profitability...
2018: PloS One
Yadvinder Malhi, Tobias Jackson, Lisa Patrick Bentley, Alvaro Lau, Alexander Shenkin, Martin Herold, Kim Calders, Harm Bartholomeus, Mathias I Disney
Terrestrial laser scanning (TLS) opens up the possibility of describing the three-dimensional structures of trees in natural environments with unprecedented detail and accuracy. It is already being extensively applied to describe how ecosystem biomass and structure vary between sites, but can also facilitate major advances in developing and testing mechanistic theories of tree form and forest structure, thereby enabling us to understand why trees and forests have the biomass and three-dimensional structure they do...
April 6, 2018: Interface Focus
Kristin A Dalope, Leonard J Woods
Family dynamics are increasingly being influenced by digital media. Three frameworks are described to help clinicians to understand and respond to this influence. First, a social-ecological framework shows how media has both a direct and indirect impact on individuals, relationships, communities, and society. Next, family systems theory is introduced to demonstrate digital media-related interactions within families. Finally, a developmental framework explores the role of digital media in shaping parenting. These theories are then integrated into practical strategies that clinicians can use, including recommendations and resources from the American Academy of Pediatrics...
April 2018: Child and Adolescent Psychiatric Clinics of North America
W C Chuang, A Garmestani, T N Eason, T L Spanbauer, H B Fried-Petersen, C P Roberts, S M Sundstrom, J L Burnett, D G Angeler, B C Chaffin, L Gunderson, D Twidwell, C R Allen
Scholars from many different intellectual disciplines have attempted to measure, estimate, or quantify resilience. However, there is growing concern that lack of clarity on the operationalization of the concept will limit its application. In this paper, we discuss the theory, research development and quantitative approaches in ecological and community resilience. Upon noting the lack of methods that quantify the complexities of the linked human and natural aspects of community resilience, we identify several promising approaches within the ecological resilience tradition that may be useful in filling these gaps...
March 1, 2018: Journal of Environmental Management
Karen E Wood, Natalia L Komarova
When performing complex tasks, coexistence of organisms in a shared environment can be achieved by means of different strategies. For example, individuals can evolve to complete all parts of the complex task, choosing self-sufficiency over cooperation. On the other hand, they may choose to split parts of the task and share the products for mutual benefit, such that distinct groups of the organisms specialize on a subset of elementary tasks. In contrast to the existing theory of specialization and task sharing for cells in multicellular organisms (or colonies of social insects), here we describe a mechanism of evolutionary branching which is based on cooperation and division of labor, and where selection happens at the individual level...
February 27, 2018: Journal of Theoretical Biology
K K Davison, N Kitos, A Aftosmes-Tobio, T Ash, A Agaronov, Martina Sepulveda, J Haines
Despite recognition that parents are critical stakeholders in childhood obesity prevention, obesity research has overwhelmingly focused on mothers. In a recent review, fathers represented only 17% of parent participants in >600 observational studies on parenting and childhood obesity. The current study examined the representation of fathers in family interventions to prevent childhood obesity and characteristics of interventions that include fathers compared with those that only include mothers. Eligible studies included family-based interventions for childhood obesity prevention published between 2008 and 2015 identified in a recent systematic review...
February 27, 2018: Preventive Medicine
Yazhuo Deng, David R Paul
PURPOSE: This study drew upon the ecological system theory to demonstrate rural-urban differences in the relationships between the availability of recreational facilities, physical activity (PA), functional health status, and depressive symptoms in middle-aged and older Chinese adults. METHODS: Nationally representative data (n = 5949) from the Chinese Health and Retirement Longitudinal Study (CHARLS, 2011-2013) were examined using the multigroup structural equation modeling approach...
March 1, 2018: International Journal of Behavioral Medicine
Francesco Cozzoli, Tjeerd J Bouma, Pauline Ottolander, Maria Salvador Lluch, Tom Ysebaert, Peter M J Herman
We propose an empirical framework to scale the effects of bioturbation on sediment resuspension to population bioturbation activity, approximated as population metabolic rate. Individual metabolic rates have been estimated as functions of body size and extrapolated to population level. We used experimental flumes to test this approach across different types of marine, soft-sediment bioturbators. We observed that a large part of the variance in biota-mediated sediment resuspension can be explained by a positive relationship with population metabolic rate...
March 1, 2018: Scientific Reports
Gabriel R Smith, Brian S Steidinger, Thomas D Bruns, Kabir G Peay
Findings of immense microbial diversity are at odds with observed functional redundancy, as competitive exclusion should hinder coexistence. Tradeoffs between dispersal and competitive ability could resolve this contradiction, but the extent to which they influence microbial community assembly is unclear. Because fungi influence the biogeochemical cycles upon which life on earth depends, understanding the mechanisms that maintain the richness of their communities is critically important. Here, we focus on ectomycorrhizal fungi, which are microbial plant mutualists that significantly affect global carbon dynamics and the ecology of host plants...
February 28, 2018: ISME Journal
Petri T Niemelä, Niels J Dingemanse
Individual differences in behaviour characterize humans and animals alike. A hot field in behavioural ecology asks why this variation in 'personality' evolved. Theory posits that selection favours the integration of 'intrinsic state' and behaviour. Metabolism, hormones, energetic reserves and structural size have particularly been proposed as states covarying with behaviour among-individuals, either genetically or through plasticity integration. We conducted a meta-analysis estimating the amount of among-individual variation in behaviour attributable to variation in state...
February 28, 2018: Proceedings. Biological Sciences
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