The Structure of Ecological Networks Across Levels of Organization

2020 ◽  
Vol 51 (1) ◽  
pp. 433-460 ◽  
Author(s):  
Paulo R. Guimarães
Keyword(s):  
Food Webs ◽  
Ecological Systems ◽  
Ecological Networks ◽  
Ecological Communities ◽  
Ecological Interactions ◽  
Biological Organization ◽  
Architectural Patterns ◽  
Fundamental Challenge ◽  
Spatiotemporal Scales ◽  
Multiple Levels

Interactions connect the units of ecological systems, forming networks. Individual-based networks characterize variation in niches among individuals within populations. These individual-based networks merge with each other, forming species-based networks and food webs that describe the architecture of ecological communities. Networks at broader spatiotemporal scales portray the structure of ecological interactions across landscapes and over macroevolutionary time. Here, I review the patterns observed in ecological networks across multiple levels of biological organization. A fundamental challenge is to understand the amount of interdependence as we move from individual-based networks to species-based networks and beyond. Despite the uneven distribution of studies, regularities in network structure emerge across scales due to the fundamental architectural patterns shared by complex networks and the interplay between traits and numerical effects. I illustrate the integration of these organizational scales by exploring the consequences of the emergence of highly connected species for network structures across scales.

scholarly journals Early adaptation in a microbial community is dominated by mutualism-enhancing mutations

2021 ◽  
Author(s):  
Sandeep Venkataram ◽  
Huan-Yu Kuo ◽  
Erik F. Y. Hom ◽  
Sergey Kryazhimskiy
Keyword(s):  
Species Interactions ◽  
Evolutionary Dynamics ◽  
Ecological Communities ◽  
Ecological Interactions ◽  
Biological Organization ◽  
Adaptive Mutations ◽  
Fitness Effects ◽  
Multiple Levels ◽  
Lineage Tracking ◽  
Different Levels

Evolutionary dynamics in ecological communities are often repeatable, but how species interactions affect the distribution of evolutionary outcomes at different levels of biological organization is unclear. Here, we use barcode lineage tracking to experimentally address this gap in a facultatively mutualistic community formed by the alga Chlamydomonas reinhardtii and the yeast Saccharomyces cerevisiae. We find that interactions with the alga alter the magnitude but not the sign of the fitness effects of adaptive mutations in yeast, changing the distribution of mutants contending for fixation. In the presence of alga, most contending mutants reinforce the mutualism and make evolution more repeatable at the community level. Thus, ecological interactions not only alter the trajectory of evolution but also dictate its repeatability at multiple levels of biological organization.

Predator Ecology

2021 ◽  
Author(s):  
John P. DeLong
Keyword(s):  
Food Webs ◽  
Functional Response ◽  
Behavioral Ecology ◽  
Evolutionary Dynamics ◽  
Ecological Systems ◽  
Ecological Communities ◽  
Functional Responses ◽  
Predator Prey ◽  
Top Predators ◽  
Integrative Science

Predator-prey interactions form an essential part of ecological communities, determining the flow of energy from autotrophs to top predators. The rate of predation is a key regulator of that energy flow, and that rate is determined by the functional response. Functional responses themselves are emergent ecological phenomena – they reflect morphology, behavior, and physiology of both predator and prey and are both outcomes of evolution and the source of additional evolution. The functional response is thus a concept that connects many aspects of biology from behavioral ecology to eco-evolutionary dynamics to food webs, and as a result, the functional response is the key to an integrative science of predatory ecology. In this book, I provide a synthesis of research on functional responses, starting with the basics. I then break the functional response down into foraging components and connect these to the traits and behaviors that connect species in food webs. I conclude that contrary to appearances, we know very little about functional responses, and additional work is necessary for us to understand how environmental change and management will impact ecological systems

Ecological networks: From structure to dynamics

2020 ◽  
pp. 143-160
Author(s):  
Sonia Kéfi
Keyword(s):  
Mathematical Models ◽  
Numerical Simulations ◽  
Network Structure ◽  
Ecological Systems ◽  
Ecological Networks ◽  
Ecological Communities ◽  
Ecological Dynamics ◽  
Structure And Dynamics ◽  
Different Types ◽  
Recent Developments

Ecological systems are undeniably complex, including many species interacting in different ways with each other (e.g., predation, competition, facilitation, parasitism). One way of visualizing, describing, and studying this complexity is to represent them as networks, where nodes are typically species and links are interactions between these species. The study of these networks allows understanding of the rules governing the topology of their links, and assessing how network structure drives ecological dynamics. Studies on different types of ecological networks have suggested that they exhibit structural regularities, which in turn affect network dynamics and resilience to perturbations. Although the use of networks to represent ecological communities dates back to the early stages of the discipline, the last two decades have seen rapid progresses in our understanding of ecological networks, as data are collected at a faster rate and better resolution, as metrics are continuously developed to better characterize network structure and as numerical simulations of mathematical models have allowed investigating how network structure and dynamics are related in more comprehensive and realistic ecological networks. This chapter describes some of the recent developments and challenges related to the study of ecological networks. After defining networks in general, and ecological networks more specifically, recent results regarding the structure of different types of ecological networks, and what is known about their dynamics and resilience, are presented.

scholarly journals Individual variation and interactions explain food web responses to global warming

2020 ◽  
Vol 375 (1814) ◽  
pp. 20190449 ◽  
Author(s):  
Anna Gårdmark ◽  
Magnus Huss
Keyword(s):  
Global Warming ◽  
Food Web ◽  
Food Webs ◽  
Biomass Production ◽  
Marine Conservation ◽  
Large Temperature ◽  
Species Variation ◽  
Ecological Interactions ◽  
Biological Organization ◽  
Research Perspectives

Understanding food web responses to global warming, and their consequences for conservation and management, requires knowledge on how responses vary both among and within species. Warming can reduce both species richness and biomass production. However, warming responses observed at different levels of biological organization may seem contradictory. For example, higher temperatures commonly lead to faster individual body growth but can decrease biomass production of fishes. Here we show that the key to resolve this contradiction is intraspecific variation, because (i) community dynamics emerge from interactions among individuals, and (ii) ecological interactions, physiological processes and warming effects often vary over life history. By combining insights from temperature-dependent dynamic models of simple food webs, observations over large temperature gradients and findings from short-term mesocosm and multi-decadal whole-ecosystem warming experiments, we resolve mechanisms by which warming waters can affect food webs via individual-level responses and review their empirical support. We identify a need for warming experiments on food webs manipulating population size structures to test these mechanisms. We stress that within-species variation in both body size, temperature responses and ecological interactions are key for accurate predictions and appropriate conservation efforts for fish production and food web function under a warming climate. This article is part of the theme issue ‘Integrative research perspectives on marine conservation'.

Ambiguous terminology in animal personality research: a self-report questionnaire and a systematic review

2021 ◽  
Author(s):  
Alfredo Sánchez-Tójar ◽  
Maria Moiron ◽  
Petri Toivo Niemelä
Keyword(s):  
Literature Review ◽  
Animal Personality ◽  
Self Report ◽  
Behavioural Ecology ◽  
Biological Organization ◽  
Personality Research ◽  
Conceptual Definition ◽  
Multiple Levels ◽  
Definition Of ◽  
Key Questions

Whether animal personality studies provide insights of broader evolutionary and ecological relevance to behavioural ecology is frequently questioned. One source of controversy is the vast, but often vague conceptual terminology used. From a statistical perspective, animal personality is defined as repeatable among-individual variance in behaviour; however, numerous conceptual definitions of animal personality exist. Here, we performed a 1) self-report questionnaire and 2) systematic literature review to quantify how researchers interpret conceptual and statistical definitions commonly used in animal personality research. We also investigated whether results from the questionnaire agree with those of the literature review. Among the 430 self-reported researchers that participated in our questionnaire, we observed discrepancies in key questions such as the conceptual definition of animal personality or the interpretation of repeatability. Our literature review generally confirmed the global patterns revealed by the questionnaire. Overall, we identified common disagreements in animal personality research and discussed potential solutions. We advocate for the usage of statistically-oriented terminology because conceptual definitions can seemingly be interpreted at multiple levels of biological organization. We expect that adopting such statistically-oriented terminology will, at least partly, avoid the confusion generated by the label “animal personality”, and ultimately help to clarify and move the field forward.

High-resolution propagation time from meteorological to agricultural drought at multiple levels and spatiotemporal scales

2022 ◽  
Vol 262 ◽  
pp. 107428
Author(s):  
Yifei Li ◽  
Shengzhi Huang ◽  
Hanye Wang ◽  
Xudong Zheng ◽  
Qiang Huang ◽  
...  
Keyword(s):  
High Resolution ◽  
Agricultural Drought ◽  
Propagation Time ◽  
Spatiotemporal Scales ◽  
Multiple Levels

Hormesis is central to toxicology, pharmacology and risk assessment

2010 ◽  
Vol 29 (4) ◽  
pp. 249-261 ◽  
Author(s):  
Edward J Calabrese
Keyword(s):  
Risk Assessment ◽  
Dose Response ◽  
Low Dose ◽  
Assessment Practices ◽  
Biological Organization ◽  
Setting Process ◽  
Toxicological Research ◽  
Multiple Levels ◽  
Dose Responses ◽  
Chemical Class

This paper summarizes numerous conceptual and experimental advances over the past two decades in the study of hormesis. Hormesis is now generally accepted as a real and reproducible biological phenomenon, being highly generalized and independent of biological model, endpoint measured and chemical class/physical stressor. The quantitative features of the hormetic dose response are generally highly consistent, regardless of the model and mechanism, and represent a quantitative index of biological plasticity at multiple levels of biological organization. The hormetic dose-response model has been demonstrated to make far more accurate predictions of responses in low dose zones than either the threshold or linear at low dose models. Numerous therapeutic agents widely used by humans are based on the hormetic dose response and its low dose stimulatory characteristics. It is expected that as low dose responses come to dominate toxicological research that risk assessment practices will incorporate hormetic concepts in the standard setting process.

scholarly journals mangal - making ecological network analysis simple

2014 ◽  
Author(s):  
Timothée E Poisot ◽  
Benjamin Baiser ◽  
Jennifer A Dunne ◽  
Sonia Kéfi ◽  
Francois Massol ◽  
...  
Keyword(s):  
Network Analysis ◽  
R Package ◽  
Ecological Networks ◽  
Ecological Interactions ◽  
Ecological Network ◽  
Ecological Data ◽  
Meta Data ◽  
Ecological Network Analysis ◽  
Analysis Process ◽  
Access Data

The study of ecological networks is severely limited by (i) the difficulty to access data, (ii) the lack of a standardized way to link meta-data with interactions, and (iii) the disparity of formats in which ecological networks themselves are represented. To overcome these limitations, we conceived a data specification for ecological networks. We implemented a database respecting this standard, and released a R package ( `rmangal`) allowing users to programmatically access, curate, and deposit data on ecological interactions. In this article, we show how these tools, in conjunctions with other frameworks for the programmatic manipulation of open ecological data, streamlines the analysis process, and improves eplicability and reproducibility of ecological networks studies.

scholarly journals Reconstruction of plant–pollinator networks from observational data

2019 ◽  
Author(s):  
Jean-Gabriel Young ◽  
Fernanda S. Valdovinos ◽  
M. E. J. Newman
Keyword(s):  
Food Webs ◽  
Observational Data ◽  
Network Structure ◽  
Rare Species ◽  
Statistical Technique ◽  
Ecological Networks ◽  
Statistical Analyses ◽  
Published Data ◽  
Statistical Errors ◽  
Plant Pollinator

Empirical measurements of ecological networks such as food webs and mutualistic networks are often rich in structure but also noisy and error-prone, particularly for rare species for which observations are sparse. Focusing on the case of plant–pollinator networks, we here describe a Bayesian statistical technique that allows us to make accurate estimates of network structure and ecological metrics from such noisy observational data. Our method yields not only estimates of these quantities, but also estimates of their statistical errors, paving the way for principled statistical analyses of ecological variables and outcomes. We demonstrate the use of the method with an application to previously published data on plant–pollinator networks in the Seychelles archipelago, calculating estimates of network structure, network nestedness, and other characteristics.

scholarly journals Phylogenetic overdispersion of plant species in southern Brazilian savannas

2009 ◽  
Vol 69 (3) ◽  
pp. 843-849 ◽  
Author(s):  
IA. Silva ◽  
MA. Batalha
Keyword(s):  
Phylogenetic Relationships ◽  
Plant Traits ◽  
Environmental Filtering ◽  
Southeastern Brazil ◽  
Ecological Communities ◽  
Ecological Interactions ◽  
Ecological Processes ◽  
Phylogenetic Structure ◽  
History Of ◽  
Phylogenetic Overdispersion

Ecological communities are the result of not only present ecological processes, such as competition among species and environmental filtering, but also past and continuing evolutionary processes. Based on these assumptions, we may infer mechanisms of contemporary coexistence from the phylogenetic relationships of the species in a community. We studied the phylogenetic structure of plant communities in four cerrado sites, in southeastern Brazil. We calculated two raw phylogenetic distances among the species sampled. We estimated the phylogenetic structure by comparing the observed phylogenetic distances to the distribution of phylogenetic distances in null communities. We obtained null communities by randomizing the phylogenetic relationships of the regional pool of species. We found a phylogenetic overdispersion of the cerrado species. Phylogenetic overdispersion has several explanations, depending on the phylogenetic history of traits and contemporary ecological interactions. However, based on coexistence models between grasses and trees, density-dependent ecological forces, and the evolutionary history of the cerrado flora, we argue that the phylogenetic overdispersion of cerrado species is predominantly due to competitive interactions, herbivores and pathogen attacks, and ecological speciation. Future studies will need to include information on the phylogenetic history of plant traits.

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