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Ecological systems theory

Scott Ferrenberg, Alexander S Martinez, Akasha M Faist
BACKGROUND: Understanding patterns of biodiversity is a longstanding challenge in ecology. Similar to other biotic groups, arthropod community structure can be shaped by deterministic and stochastic processes, with limited understanding of what moderates the relative influence of these processes. Disturbances have been noted to alter the relative influence of deterministic and stochastic processes on community assembly in various study systems, implicating ecological disturbances as a potential moderator of these forces...
2016: PeerJ
Carl R May, Mark Johnson, Tracy Finch
BACKGROUND: Context is a problem in research on health behaviour change, knowledge translation, practice implementation and health improvement. This is because many intervention and evaluation designs seek to eliminate contextual confounders, when these represent the normal conditions into which interventions must be integrated if they are to be workable in practice. DISCUSSION: We present an ecological model of the ways that participants in implementation and health improvement processes interact with contexts...
October 19, 2016: Implementation Science: IS
Ricky-John Spencer, James U Van Dyke, Michael B Thompson
Ecological traps are threats to organisms, and exist in a range of biological systems. A subset of ecological trap theory is the "ethological trap," whereby behaviors canalized by past natural selection become traps when environments change rapidly. Invasive predators are major threats to imperiled species and their ability to exploit canalized behaviors of naive prey is particularly important for the establishment of the predator and the decline of the native prey. Our study uses ecological theory to demonstrate that invasive predator controls require shifts in management priorities...
October 2016: Ecological Applications: a Publication of the Ecological Society of America
Perry J Williams, Mevin B Hooten
Statistical decision theory (SDT) is a sub-field of decision theory that formally incorporates statistical investigation into a decision-theoretic framework to account for uncertainties in a decision problem. SDT provides a unifying analysis of three types of information: statistical results from a data set, knowledge of the consequences of potential choices (i.e., loss), and prior beliefs about a system. SDT links the theoretical development of a large body of statistical methods, including point estimation, hypothesis testing, and confidence interval estimation...
September 2016: Ecological Applications: a Publication of the Ecological Society of America
Thomas L McKenzie
Physical activity is place-based, and being able to assess the number of people and their characteristics in specific locations is important both for public health surveillance and for practitioners in their design of physical activity spaces and programs. Although physical activity measurement has improved recently, many investigators avoid or are at a loss regarding the assessment of physical activity in explicit locations, especially in open environments where many people come and go in a seemingly indiscriminate fashion...
October 17, 2016: Research Quarterly for Exercise and Sport
Sylvain Billiard, Pierre Collet, Régis Ferrière, Sylvie Méléard, Viet Chi Tran
Horizontal transfer (HT) of heritable information or 'traits' (carried by genetic elements, plasmids, endosymbionts, or culture) is widespread among living organisms. Yet current ecological and evolutionary theory addressing HT is scant. We present a modeling framework for the dynamics of two populations that compete for resources and horizontally exchange (transfer) an otherwise vertically inherited trait. Competition infuences individual demographics, thereby affecting population size, which feeds back on the dynamics of transfer...
October 11, 2016: Journal of Theoretical Biology
J David Smith, Alexandria C Zakrzewski, Jennifer M Johnson, Jeanette C Valleau
Categorization's great debate has weighed single-system exemplar theory against the possibility of alternative processing systems. We take an evolutionary perspective toward this debate to illuminate it in a new way. Animals are crucial behavioral ambassadors to this area. They reveal the roots of human categorization, the basic assumptions of vertebrates entering category tasks, and the surprising weakness of exemplar memory as a category-learning strategy. These results have joined neuroscience results to prompt important changes in categorization theory...
August 2016: Current Directions in Psychological Science
James C Stegen, Allen H Hurlbert, Ben Bond-Lamberty, Xingyuan Chen, Carolyn G Anderson, Rosalie K Chu, Francisco Dini-Andreote, Sarah J Fansler, Nancy J Hess, Malak Tfaily
The number of microbial operational taxonomic units (OTUs) within a community is akin to species richness within plant/animal ("macrobial") systems. A large literature documents OTU richness patterns, drawing comparisons to macrobial theory. There is, however, an unrecognized fundamental disconnect between OTU richness and macrobial theory: OTU richness is commonly estimated on a per-individual basis, while macrobial richness is estimated per-area. Furthermore, the range or extent of sampled environmental conditions can strongly influence a study's outcomes and conclusions, but this is not commonly addressed when studying OTU richness...
2016: Frontiers in Microbiology
Duarte Araújo, Keith Davids
Individual players act as a coherent unit during team sports performance, forming a team synergy. A synergy is a collective property of a task-specific organization of individuals, such that the degrees of freedom of each individual in the system are coupled, enabling the degrees of freedom of different individuals to co-regulate each other. Here, we present an explanation for the emergence of such collective behaviors, indicating how these can be assessed and understood through the measurement of key system properties that exist, considering the contribution of each individual and beyond These include: to (i) dimensional compression, a process resulting in independent degree of freedom being coupled so that the synergy has fewer degrees of freedom than the set of components from which it arises; (ii) reciprocal compensation, if one element do not produce its function, other elements should display changes in their contributions so that task goals are still attained; (iii) interpersonal linkages, the specific contribution of each element to a group task; and (iv), degeneracy, structurally different components performing a similar, but not necessarily identical, function with respect to context...
2016: Frontiers in Psychology
A K Carlson, Q E Phelps, B D S Graeb
Otolith chemistry is an effective technique for evaluating fish environmental history, but its utility in fisheries management has not been comprehensively examined. Thus, a review of otolith chemistry with emphasis on management applicability is presented. More than 1500 otolith chemistry manuscripts published from 1967 to 2015 are reviewed and descriptive case studies are used to illustrate the utility of otolith chemistry as a fisheries management tool. Otolith chemistry publications span a wide variety of topics (e...
October 5, 2016: Journal of Fish Biology
Alex D Washburne, Joshua W Burby, Daniel Lacker
Systems as diverse as the interacting species in a community, alleles at a genetic locus, and companies in a market are characterized by competition (over resources, space, capital, etc) and adaptation. Neutral theory, built around the hypothesis that individual performance is independent of group membership, has found utility across the disciplines of ecology, population genetics, and economics, both because of the success of the neutral hypothesis in predicting system properties and because deviations from these predictions provide information about the underlying dynamics...
September 2016: PLoS Computational Biology
Henry Brink, Robert J Smith, Kirsten Skinner, Nigel Leader-Williams
It is argued that trophy hunting of large, charismatic mammal species can have considerable conservation benefits but only if undertaken sustainably. Social-ecological theory suggests such sustainability only results from developing governance systems that balance financial and biological requirements. Here we use lion (Panthera leo) trophy hunting data from Tanzania to investigate how resource ownership patterns influence hunting revenue and offtake levels. Tanzania contains up to half of the global population of free-ranging lions and is also the main location for lion trophy hunting in Africa...
2016: PloS One
Heather L Storer, Katyayani R Strohl
Teen dating violence (TDV) is a significant public health issue. Preventing TDV requires attention to risk and protective factors across ecological system levels. The media is one of the primary cultural drivers of societal-level social scripts about the causes of TDV. Framing theory asserts that the media's portrayal of social issues, including what contextual information is included and/or excluded, affects individual-level attitudes about TDV and potential policy responses. This study investigates the representation of TDV in young adult (YA) literature, a media genre that is marketed to adolescent audiences...
September 18, 2016: Violence Against Women
Ehsan Negahbani, D Alistair Steyn-Ross, Moira L Steyn-Ross, Luis A Aguirre
Growth of critical fluctuations prior to catastrophic state transition is generally regarded as a universal phenomenon, providing a valuable early warning signal in dynamical systems. Using an ecological fisheries model of three populations (juvenile prey J, adult prey A and predator P), a recent study has reported silent early warning signals obtained from P and A populations prior to saddle-node (SN) bifurcation, and thus concluded that early warning signals are not universal. By performing a full eigenvalue analysis of the same system we demonstrate that while J and P populations undergo SN bifurcation, A does not jump to a new state, so it is not expected to carry early warning signs...
2016: PloS One
Benjamin Dickens, Charles K Fisher, Pankaj Mehta
A fundamental problem in community ecology is understanding how ecological processes such as selection, drift, and immigration give rise to observed patterns in species composition and diversity. Here, we analyze a recently introduced, analytically tractable, presence-absence (PA) model for community assembly, and we use it to ask how ecological traits such as the strength of competition, the amount of diversity, and demographic and environmental stochasticity affect species composition in a community. In the PA model, species are treated as stochastic binary variables that can either be present or absent in a community: species can immigrate into the community from a regional species pool and can go extinct due to competition and stochasticity...
August 2016: Physical Review. E
Charlotta Söderberg
Contemporary processes of environmental policymaking in general span over several territorial tiers. This also holds for the EU Water Framework Directive system of environmental quality standards (EQS), which are part of a complex multi-level institutional landscape, embracing both EU, national and sub-national level. Recent evaluations show that many EU member states, including Sweden, have not reached the ecological goals for water in 2015. Departing from theories on policy coherence and multi-level governance, this paper therefore analyses Swedish water governance as a case to further our understanding of policy implementation in complex governance structures: how does policy coherence (or the lack thereof) affect policy implementation in complex governance structures? To answer this question, the paper maps out the formal structure of the water governance system, focusing on power directions within the system, analyses policy coherence in Swedish water governance through mapping out policy conflicts between the EQS for water and other goals/regulations and explore how they are handled by national and sub-national water bureaucrats...
December 1, 2016: Journal of Environmental Management
James E Hourston, Alison E Bennett, Scott N Johnson, Alan C Gange
Belowground tri-trophic study systems present a challenging environment in which to study plant-herbivore-natural enemy interactions. For this reason, belowground examples are rarely available for testing general ecological theories. To redress this imbalance, we present, for the first time, data on a belowground tri-trophic system to test the slow growth, high mortality hypothesis. We investigated whether the differing performance of entomopathogenic nematodes (EPNs) in controlling the common pest black vine weevil Otiorhynchus sulcatus could be linked to differently resistant cultivars of the red raspberry Rubus idaeus...
2016: PloS One
W Stanley Harpole, Lauren L Sullivan, Eric M Lind, Jennifer Firn, Peter B Adler, Elizabeth T Borer, Jonathan Chase, Philip A Fay, Yann Hautier, Helmut Hillebrand, Andrew S MacDougall, Eric W Seabloom, Ryan Williams, Jonathan D Bakker, Marc W Cadotte, Enrique J Chaneton, Chengjin Chu, Elsa E Cleland, Carla D'Antonio, Kendi F Davies, Daniel S Gruner, Nicole Hagenah, Kevin Kirkman, Johannes M H Knops, Kimberly J La Pierre, Rebecca L McCulley, Joslin L Moore, John W Morgan, Suzanne M Prober, Anita C Risch, Martin Schuetz, Carly J Stevens, Peter D Wragg
Niche dimensionality provides a general theoretical explanation for biodiversity-more niches, defined by more limiting factors, allow for more ways that species can coexist. Because plant species compete for the same set of limiting resources, theory predicts that addition of a limiting resource eliminates potential trade-offs, reducing the number of species that can coexist. Multiple nutrient limitation of plant production is common and therefore fertilization may reduce diversity by reducing the number or dimensionality of belowground limiting factors...
August 24, 2016: Nature
Dominique Gravel, François Massol, Mathew A Leibold
The diversity of life and its organization in networks of interacting species has been a long-standing theoretical puzzle for ecologists. Ever since May's provocative paper challenging whether 'large complex systems [are] stable' various hypotheses have been proposed to explain when stability should be the rule, not the exception. Spatial dynamics may be stabilizing and thus explain high community diversity, yet existing theory on spatial stabilization is limited, preventing comparisons of the role of dispersal relative to species interactions...
2016: Nature Communications
Holly V Moeller, Ian A Dickie, Duane A Peltzer, Tadashi Fukami
Theory predicts that neighboring communities can shape one another's composition and function, for example, through the exchange of member species. However, empirical tests of the directionality and strength of these effects are rare. We determined the effects of neighboring communities on one another through experimental manipulation of a plant-fungal model system. We first established distinct ectomycorrhizal fungal communities on Douglas-fir seedlings that were initially grown in three soil environments...
August 2016: Ecology and Evolution
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