scholarly journals Spatial heterogeneity enhance robustness of large multi-species ecosystems

2021 ◽  
Vol 17 (10) ◽  
pp. e1008899
Author(s):  
Susanne Pettersson ◽  
Martin Nilsson Jacobi
Keyword(s):  
Spatial Heterogeneity ◽  
Species Interactions ◽  
Equilibrium Dynamics ◽  
Body Of Knowledge ◽  
Spatially Extended ◽  
Species Abundances ◽  
Spatial Locations ◽  
Stability Limits ◽  
The Impact ◽  
Plant Pollinator

Understanding ecosystem stability and functioning is a long-standing goal in theoretical ecology, with one of the main tools being dynamical modelling of species abundances. With the help of spatially unresolved (well-mixed) population models and equilibrium dynamics, limits to stability and regions of various ecosystem robustness have been extensively mapped in terms of diversity (number of species), types of interactions, interaction strengths, varying interaction networks (for example plant-pollinator, food-web) and varying structures of these networks. Although many insights have been gained, the impact of spatial extension is not included in this body of knowledge. Recent studies of spatially explicit modelling on the other hand have shown that stability limits can be crossed and diversity increased for systems with spatial heterogeneity in species interactions and/or chaotic dynamics. Here we show that such crossing and diversity increase can appear under less strict conditions. We find that the mere possibility of varying species abundances at different spatial locations make possible the preservation or increase in diversity across previous boundaries thought to mark catastrophic transitions. In addition, we introduce and make explicit a multitude of different dynamics a spatially extended complex system can use to stabilise. This expanded stabilising repertoire of dynamics is largest at intermediate levels of dispersal. Thus we find that spatially extended systems with intermediate dispersal are more robust, in general have higher diversity and can stabilise beyond previous stability boundaries, in contrast to well-mixed systems.

scholarly journals Predicting abundances of plants and pollinators using a simple compartmental mutualistic model

2015 ◽  
Vol 282 (1808) ◽  
pp. 20150592 ◽  
Author(s):  
Hugo Fort ◽  
Muhittin Mungan
Keyword(s):  
Species Interactions ◽  
Animal Species ◽  
Species Coexistence ◽  
Aggregation Method ◽  
Interaction Coefficients ◽  
Robust Model ◽  
Species Abundances ◽  
Intrinsic Complexity ◽  
Mediterranean Community ◽  
Plant Pollinator

Key gaps to be filled in population and community ecology are predicting the strength of species interactions and linking pattern with process to understand species coexistence and their relative abundances. In the case of mutualistic webs, like plant–pollinator networks, advances in understanding species abundances are currently limited, mainly owing to the lack of methodological tools to deal with the intrinsic complexity of mutualisms. Here, we propose an aggregation method leading to a simple compartmental mutualistic population model that captures both qualitatively and quantitatively the size-segregated populations observed in a Mediterranean community of nectar-producing plant species and nectar-searching animal species. We analyse the issue of optimal aggregation level and its connection with the trade-off between realism and overparametrization. We show that aggregation of both plants and pollinators into five size classes or compartments leads to a robust model with only two tunable parameters. Moreover, if, in each compartment, (i) the interaction coefficients fulfil the condition of weak mutualism and (ii) the mutualism is facultative for at least one party of the compartment, then the interactions between different compartments are sufficient to guarantee global stability of the equilibrium population.

scholarly journals The impact of interactions on invasion and colonization resistance in microbial communities

2021 ◽  
Vol 17 (1) ◽  
pp. e1008643
Author(s):  
Helen M. Kurkjian ◽  
M. Javad Akbari ◽  
Babak Momeni
Keyword(s):  
New Species ◽  
Microbial Communities ◽  
Species Interactions ◽  
Species Interaction ◽  
Colonization Resistance ◽  
Community Resistance ◽  
Species Abundances ◽  
The Impact ◽  
Species Being ◽  
A New Species

In human microbiota, the prevention or promotion of invasions can be crucial to human health. Invasion outcomes, in turn, are impacted by the composition of resident communities and interactions of resident members with the invader. Here we study how interactions influence invasion outcomes in microbial communities, when interactions are primarily mediated by chemicals that are released into or consumed from the environment. We use a previously developed dynamic model which explicitly includes species abundances and the concentrations of chemicals that mediate species interaction. Using this model, we assessed how species interactions impact invasion by simulating a new species being introduced into an existing resident community. We classified invasion outcomes as resistance, augmentation, displacement, or disruption depending on whether the richness of the resident community was maintained or decreased and whether the invader was maintained in the community or went extinct. We found that as the number of invaders introduced into the resident community increased, disruption rather than augmentation became more prevalent. With more facilitation of the invader by the resident community, resistance outcomes were replaced by displacement and augmentation. By contrast, with more facilitation among residents, displacement outcomes shifted to resistance. When facilitation of the resident community by the invader was eliminated, the majority of augmentation outcomes turned into displacement, while when inhibition of residents by invaders was eliminated, invasion outcomes were largely unaffected. Our results suggest that a better understanding of interactions within resident communities and between residents and invaders is crucial to predicting the success of invasions into microbial communities.

scholarly journals On The Contribution of Interest Expense (Income) on Total Output

2021 ◽  
Vol 4 (1) ◽  
pp. 31-56
Author(s):  
Ahmed Mehedi Nizam
Keyword(s):  
Interest Rate ◽  
Aggregate Demand ◽  
Total Output ◽  
Response Analysis ◽  
Panel Var ◽  
Intuitive Reasoning ◽  
Body Of Knowledge ◽  
Interest Income ◽  
Structural Panel ◽  
The Impact

Abstract A decrease in interest rate in traditional view of monetary policy transmission is linked to a lower cost of borrowing which eventually results into a greater spending in investment and a bigger GDP. However, a decrease in interest rate is also linked to a decrease in interest income which, in turn, affects the aggregate demand and total GDP. So far, no concerted effort has been made to investigate this positive inter-relation between interest income and GDP in the existing literature. Here in the first place we intuitively describe the inter-relation between interest income and output and then provide a micro-foundation of our intuitive reasoning in the context of a small endowment economy with finitely-lived identical households. Then we try to uncover the impact of nominal interest income on the macroeconomy using multiplier theory for a panel of some 04 (four) OECD countries. We define and calculate the corresponding multiplier values algebraically and then we empirically measure them using impulse response analysis under structural panel VAR framework. Large, consistent and positive values of the cumulative multipliers indicate a stable positive relationship between nominal interest income and output. Moreover, variance decomposition of GDP shows that a significant portion of the variance in GDP is attributed to interest income under VAR/VECM framework. Finally, we have shown how and where our analysis fits into the existing body of knowledge.

scholarly journals The importance of species interactions in eco-evolutionary community dynamics under climate change

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Anna Åkesson ◽  
Alva Curtsdotter ◽  
Anna Eklöf ◽  
Bo Ebenman ◽  
Jon Norberg ◽  
...  
Keyword(s):  
Climate Change ◽  
Species Interactions ◽  
Community Dynamics ◽  
Evolutionary Dynamics ◽  
Negative Impact ◽  
Trophic Levels ◽  
Temperature Dependent ◽  
Modeling Framework ◽  
Impact Of Climate Change ◽  
The Impact

AbstractEco-evolutionary dynamics are essential in shaping the biological response of communities to ongoing climate change. Here we develop a spatially explicit eco-evolutionary framework which features more detailed species interactions, integrating evolution and dispersal. We include species interactions within and between trophic levels, and additionally, we incorporate the feature that species’ interspecific competition might change due to increasing temperatures and affect the impact of climate change on ecological communities. Our modeling framework captures previously reported ecological responses to climate change, and also reveals two key results. First, interactions between trophic levels as well as temperature-dependent competition within a trophic level mitigate the negative impact of climate change on biodiversity, emphasizing the importance of understanding biotic interactions in shaping climate change impact. Second, our trait-based perspective reveals a strong positive relationship between the within-community variation in preferred temperatures and the capacity to respond to climate change. Temperature-dependent competition consistently results both in higher trait variation and more responsive communities to altered climatic conditions. Our study demonstrates the importance of species interactions in an eco-evolutionary setting, further expanding our knowledge of the interplay between ecological and evolutionary processes.

scholarly journals Sensory-based niche partitioning in a multiple predator–multiple prey community

2015 ◽  
Vol 282 (1808) ◽  
pp. 20150520 ◽  
Author(s):  
Jay J. Falk ◽  
Hannah M. ter Hofstede ◽  
Patricia L. Jones ◽  
Marjorie M. Dixon ◽  
Paul A. Faure ◽  
...  
Keyword(s):  
Species Interactions ◽  
Prey Species ◽  
Niche Partitioning ◽  
Signal Evolution ◽  
Signal Design ◽  
Predator Species ◽  
Mate Attraction ◽  
Communication Signals ◽  
Signal Features ◽  
The Impact

Many predators and parasites eavesdrop on the communication signals of their prey. Eavesdropping is typically studied as dyadic predator–prey species interactions; yet in nature, most predators target multiple prey species and most prey must evade multiple predator species. The impact of predator communities on prey signal evolution is not well understood. Predators could converge in their preferences for conspicuous signal properties, generating competition among predators and natural selection on particular prey signal features. Alternatively, predator species could vary in their preferences for prey signal properties, resulting in sensory-based niche partitioning of prey resources. In the Neotropics, many substrate-gleaning bats use the mate-attraction songs of male katydids to locate them as prey. We studied mechanisms of niche partitioning in four substrate-gleaning bat species and found they are similar in morphology, echolocation signal design and prey-handling ability, but each species preferred different acoustic features of male song in 12 sympatric katydid species. This divergence in predator preference probably contributes to the coexistence of many substrate-gleaning bat species in the Neotropics, and the substantial diversity in the mate-attraction signals of katydids. Our results provide insight into how multiple eavesdropping predator species might influence prey signal evolution through sensory-based niche partitioning.

Adherence to the Internal Audit Core Principles and Threats to Internal Audit Function Effectiveness

2021 ◽  
Author(s):  
Christopher G Calvin
Keyword(s):  
Corporate Governance ◽  
Future Development ◽  
Internal Audit ◽  
Internal Auditors ◽  
The Core ◽  
Body Of Knowledge ◽  
Internal Audit Function ◽  
Lower Likelihood ◽  
Practitioner Survey ◽  
The Impact

I investigate the impact that adherence to the Institute of Internal Auditors' Core Principles has on the likelihood that an internal auditor's effectiveness is threatened through pressure to modify valid audit findings. I use responses from the Institute of Internal Auditors' 2015 Common Body of Knowledge Practitioner Survey to show that higher adherence to the Core Principles by both internal audit staff and CAEs is associated with a lower likelihood of being pressured to modify audit findings. I also explore which of the ten Core Principles are dominant in explaining these associations to inform the future development of the internal audit profession. Finally, I investigate the sources of pressure to modify audit findings and explore the effect the Core Principles have in mitigating pressure from each source. My findings are relevant to the Institute of Internal Auditors, internal audit practitioners, and academics interested in internal audit or corporate governance.

The Impact of Service Innovation on Tourist Satisfaction: Evidence from the Malaysian Tourism Industry

2014 ◽  
Vol 2 (3) ◽  
pp. 93-106
Author(s):  
Boon Liat Cheng
Keyword(s):  
Product Innovation ◽  
Service Innovation ◽  
Services Marketing ◽  
Process Innovation ◽  
Tourism Industry ◽  
Organisational Innovation ◽  
Marketing Innovation ◽  
Tourist Satisfaction ◽  
Body Of Knowledge ◽  
The Impact

Objective - This study proposed a model to test the impacts of the four dimensions of service innovation (i.e., process innovation, organisational innovation, marketing innovation and product innovation) on tourist satisfaction in the Malaysian tourism. Methodology/Technique - Measurement items for the dimensions of service innovation were developed through focus group interviews. A convenience sampling approach was adopted with the distribution of 400 questionnaires among local and foreign tourists. Statistical tolls in the Statistical Package for the Social Sciences (SPSS) were adopted to analyse the reliability of items and the hypothesised relationships in the proposed research model. Findings - The findings reveal that the respective dimensions of service innovation are significantly related to tourist satisfaction. These findings contribute to the services marketing body of knowledge by providing insight on the impact of service innovation on tourist satisfaction. Novelty - Limited studies have been done to examine the impact of service innovation dimensions on tourist satisfaction.The findings of this study contribute to the services marketing body of knowledge by providing insight on the impact of service innovation on tourist satisfaction. At the same time to address the practical implications by recommending relevant and effective service innovation strategies for the tourism industry in Malaysia. This knowledge is useful for benchmarking better service innovation practices among the industry practitioners. Type of Paper - Empirical Keywords: Service Innovation; Process Innovation; Organisational Innovation; Marketing Innovation; Product Innovation; Tourist Satisfaction

The Call of the Faithful: The Integration of Spiritual and Social Work Practice in the Time of COVID-19

2021 ◽  
Vol 48 (4) ◽  
pp. 379-392
Author(s):  
Shirley Newton-Guest ◽  
Claudia Sofia Moreno ◽  
Marla Coyoy ◽  
Roxanna Najmi ◽  
Tonia Martin ◽  
...  
Keyword(s):  
Social Work ◽  
Social Workers ◽  
Interpersonal Violence ◽  
Work Practice ◽  
Social Work Practice ◽  
Health Crisis ◽  
The Public ◽  
Body Of Knowledge ◽  
Unaccompanied Children ◽  
The Impact

This has been a season of change worldwide. It has become virtually impossible to ignore distressing news about the state of our world. COVID-19 has changed the way we live, work, how we think, and even how we grieve. Every day, Americans are bombarded with reports of rising death tolls, massive unemployment, economic turmoil, and dismal foreseeable predictions. This health crisis has put an enormous amount of pressure on the global community, and this is especially true for our clients who are new immigrants. This pressure has manifested in mental health challenges. Social workers have reported that for many clients the uncertainty and pressure are becoming too much to handle. Typically, clients are experiencing anxiety, depression, substance use disorder, and in some cases interpersonal violence (Brodhead, 2020; Endale et al. 2020; Saltzman et al.,2020). Now imagine the impact on unaccompanied minors arriving at our borders. Prior to the pandemic, the unaccompanied children were dealing with three crises simultaneously: 1) parental and home country separation; 2) trauma from a harsh journey; and 3) language barrier and cultural shock. These issues alone are overwhelming and cause powerful emotions such as anxiety in these children. So how can these emotions be managed, coupled with the dangers of COVID-19? How can social workers provide comfort and support when they may be experiencing the same emotions? This article brings this hidden reality into the public view and enrich the existing social work body of knowledge by demonstrating the restorative power of faith, spirituality, and self-care.      

Predicates, parts, and impermanence: a contemporary version of some central Buddhist tenets

2017 ◽  
Vol 54 (4) ◽  
pp. 475-488
Author(s):  
MATTHEW McKEEVER
Keyword(s):  
Natural Language ◽  
Recent Work ◽  
Analytic Philosophy ◽  
Buddhist Philosophy ◽  
Logical Constant ◽  
Good Sense ◽  
Buddhist Doctrine ◽  
Spatially Extended ◽  
Temporal Parts ◽  
Spatial Locations

AbstractIn this article, I argue that recent work in analytic philosophy on the semantics of names and the metaphysics of persistence supports two theses in Buddhist philosophy, namely the impermanence of objects and a corollary about how referential language works. According to this latter package of views, the various parts of what we call one object (say, King Milinda) possess no unity in and of themselves. Unity comes rather from language, in that we have terms (say, ‘King Milinda’) which stand for all the parts taken together. Objects are mind- (or rather language-)generated fictions. I think this package can be cashed out in terms of two central contemporary views. The first is that there are temporal parts: just as an object is spatially extended by having spatial parts at different spatial locations, so it is temporally extended by having temporal parts at different temporal locations. The second is that names are predicates: rather than standing for any one thing, a name stands for a range of things. The natural language term ‘Milinda’ is not akin to a logical constant, but akin to a predicate.Putting this together, I'll argue that names are predicates with temporal parts in their extension, which parts have no unity apart from falling under the same predicate. ‘Milinda’ is a predicate which has in its extension all Milinda's parts. The result is an interesting and original synthesis of plausible positions in semantics and metaphysics, which makes good sense of a central Buddhist doctrine.

scholarly journals (Non)Places of Bangalore: Where the East Meets the West in Bharati Mukherjee’s Miss New India

2019 ◽  
pp. 83-90
Author(s):  
Izabella Kimak
Keyword(s):  
South Asia ◽  
South Asian ◽  
Asian American ◽  
The Novel ◽  
The West ◽  
South Asian American ◽  
Primary Location ◽  
Spatial Locations ◽  
The Impact

This essay constitutes an attempt at reading Bharati Mukherjee’s 2011 novel, Miss New India, through the prism of spatial locations depicted in it. Unlike many of the texts in the late South Asian American author’s oeuvre, which depict migration from the East to the West, Miss New India is located exclusively within South Asia. This notwithstanding, the novel focuses on the impact the West used to and continues to exert on the East. I would like to argue that through her depictions of places and non-places of Bangalore-the novel’s primary location-Mukherjee points to the spatial interconnectedness of the East and the West as well as to the temporal interconnectedness of the colonial past and postcolonial, late-capitalist present.

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