The Experts below are selected from a list of 4296 Experts worldwide ranked by ideXlab platform

John C Moore - One of the best experts on this subject based on the ideXlab platform.

  • linking the green and brown worlds the prevalence and effect of multichannel feeding in Food Webs
    Ecology, 2014
    Co-Authors: John C Moore, Elizabeth M Wolkovich, Stefano Allesina, Kathryn L Cottingham, Stuart A Sandin, Claire De Mazancourt
    Abstract:

    Recent advances in Food-Web Ecology highlight that most real Food Webs (1) represent an interplay between producer- and detritus-based Webs and (2) are governed by consumers which are rampant omnivores; feeding on varied prey across trophic levels and resource channels. A possible avenue to unify these advances comes from models demonstrating that predators feeding on distinctly different channels may stabilize Food Webs. Empirical studies suggest many consumers engage in such behavior by feeding on prey items from both living-autotroph (green) and detritus-based (brown) Webs, what we term “multichannel feeding,” yet we know little about how common such feeding is across systems and trophic levels, or its effect on system stability. Considering 23 empirical Webs, we find that multichannel feeding is equally common across terrestrial, freshwater, and marine systems, with >50% of consumers classified as multichannel consumers. Multichannel feeding occurred most often at the first consumer level, indicating ...

  • a landscape theory for Food Web architecture
    Ecology Letters, 2008
    Co-Authors: Neil Rooney, Kevin S Mccann, John C Moore
    Abstract:

    Ecologists have long searched for structures and processes that impart stability in nature. In particular, Food Web Ecology has held promise in tackling this issue. Empirical patterns in Food Webs have consistently shown that the distributions of species and interactions in nature are more likely to be stable than randomly constructed systems with the same number of species and interactions. Food Web Ecology still faces two fundamental challenges, however. First, the quantity and quality of Food Web data required to document both the species richness and the interaction strengths among all species within Food Webs is largely prohibitive. Second, where Food Webs have been well documented, spatial and temporal variation in Food Web structure has been ignored. Conversely, research that has addressed spatial and temporal variation in ecosystems has generally ignored the full complexity of Food Web architecture. Here, we incorporate empirical patterns, largely from macroEcology and behavioural Ecology, into a spatially implicit Food Web structure to construct a simple landscape theory of Food Web architecture. Such an approach both captures important architectural features of Food Webs and allows for an exploration of Food Web structure across a range of spatial scales. Finally, we demonstrated that Food Webs are hierarchically organized along the spatial and temporal niche axes of species and their utilization of Food resources in ways that stabilize ecosystems.

  • Food Web Ecology playing jenga and beyond
    Science, 2005
    Co-Authors: Peter C De Ruiter, Volkmar Wolters, John C Moore, Kirk O Winemiller
    Abstract:

    De Ruiter et al. argue that the old notion of a Food Web as a static arch, with a critical keystone species (whose removal would cause collapse of the arch), is outdated. Instead, they see ecosystems as dynamic, both spatially and temporally, and explain how describing them in this way reveals the basis of unexpected stabilities that occur in response to even large environmental perturbations.

Stefan Scheu - One of the best experts on this subject based on the ideXlab platform.

  • UNDERSTANDING THE MUTUAL RELATIONSHIPS BETWEEN THE DYNAMICS OF Food WebS, RESOURCES, AND NUTRIENTS
    Dynamic Food Webs, 2020
    Co-Authors: Tobias Purtauf, Stefan Scheu
    Abstract:

    This chapter demonstrates that understanding nutrient and resource dynamics requires a much more holistic view. It shows that the role of invertebrates on nutrient dynamics relates to their differential utilization or storage of limited elements in different habitats. Other contributions focus on what seems now the most difficult and diverse ecological systems. Understanding the transfer of nutrients and resources is the heart of Food Web Ecology since its early days. A formal means of dealing with the flow of energy and matter in Food Webs was ushered in with the advent of systems Ecology, and since then the Food Web approach has been adopted to analyze interrelationships among community structure, stability, and ecosystem processes. Currently, there are still strong boundaries among different approaches to Food Web analysis, both within and between systems. These differences reflect historical developments rather than being justified by scientific grounds. The multiple links between energy and element pathways above- and belowground, as well as between aquatic and terrestrial Food Webs have now been convincingly demonstrated.

  • Invited contribution The soil Food Web: structure and perspectives
    2020
    Co-Authors: Stefan Scheu
    Abstract:

    This review outlines directions for future research in soil Food Web Ecology. Two lines of research are considered to be most important: the adoption of new methodologies to investigate Food relationships and the strengthening of experimentation to investigate the interaction strength between Food Web components. For a better understanding of Food relationships molecular methods, particularly fluorescence in situ hybridization, and stable isotope methodology, including the analysis of variations in the abundance of 13 C and 15 N, are thought to be most promising. Implications of results of the studies which employed these methodologies for the structure and function of soil Food Webs are highlighted. © 2002 Editions scientifiques et medicales

  • The physical structure of soil: Determinant and consequence of trophic interactions
    Soil Biology & Biochemistry, 2020
    Co-Authors: Amandine Erktan, Dani Or, Stefan Scheu
    Abstract:

    Abstract Trophic interactions play a vital role in soil functioning and are increasingly considered as important drivers of the soil microbiome and biogeochemical cycles. In the last decade, novel tools to decipher the structure of soil Food Webs have provided unprecedent advance in describing complex trophic interactions. Yet, the major challenge remains to understand the drivers of the trophic interactions. Evidence suggests that small scale soil physical structure may offer a unifying framework for understanding the nature and patterns of trophic interactions in soils. Here, we review the current knowledge of how restrictions on soil organisms’ ability to sense and access Food resources/prey inherent to soil physical structure essentially shape trophic interactions. We focus primarily on organisms unable to deform the soil and create pores themselves, such as bacteria, fungi, protists, nematodes and microarthropods, and consider pore geometry, connectivity and hydration status as main descriptors of the soil physical structure. We point that the soil physical structure appears to mostly limit the sensing and accessibility to Food resources/prey, with negative effects on bottom up controls. The main mechanisms are (i) the reduced transport of sensing molecules, notably volatiles, through the soil matrix and (ii) the wide presence of refuges leading to pore size segregation of consumer/predators and Food sources/prey in pores of contrasting size. In addition, variations in the connectivity of the soil pores and the water film is suggested as a central aspect driving encounter probability between consumers/predator and Food source/prey and hence locally decrease or increase top-down controls. Constraints imposed by the soil physical structure on trophic interactions are thought to be major drivers of the soil diversity and local community assemblage, notably by favoring a variety of adaptations to feed in this dark labyrinth (Food specialists/flexible/generalists) and by limiting competitive exclusion through limited encounter probability of consumers. We conclude with possible future ways for an interdisciplinary and more quantitative research merging soil physics and soil Food Web Ecology.

  • Into the soil labyrinth: soil physical structure as a driver of trophic interactions and soil biodiversity
    2020
    Co-Authors: Amandine Erktan, Dani Or, Stefan Scheu
    Abstract:

    <p>The high diversity of densely packed organisms occurring in small volumes of soils has long been intriguing and we still poorly understand what drives such diversity. Exploring the role of small scale physical structure of the soil, constituting the habitat of these organisms offers unprecedented clues for explaining how organisms interact, notably through trophic interactions and how, in turn, these interactions drive this extraordinary diversity. We review here how restrictions on soil organisms’ ability to sense (e.g. volatiles) and access Food resources/prey imposed by the soil physical structure and aqueous habitats within are important drivers for trophic interactions, and consequently, of soil biodiversity. Examples from micro- to macrofauna are presented, focusing on organisms unable to create their own pore space, such as bacteria, fungi, protists, nematodes and microarthropods. Finally, we discuss interdisciplinary challenges to develop research merging soil physics and soil Food Web Ecology.</p>

  • the soil Food Web structure and perspectives
    European Journal of Soil Biology, 2002
    Co-Authors: Stefan Scheu
    Abstract:

    Abstract This review outlines directions for future research in soil Food Web Ecology. Two lines of research are considered to be most important: the adoption of new methodologies to investigate Food relationships and the strengthening of experimentation to investigate the interaction strength between Food Web components. For a better understanding of Food relationships molecular methods, particularly fluorescence in situ hybridization, and stable isotope methodology, including the analysis of variations in the abundance of 13 C and 15 N, are thought to be most promising. Implications of results of the studies which employed these methodologies for the structure and function of soil Food Webs are highlighted.

Robert D. Holt - One of the best experts on this subject based on the ideXlab platform.

  • Toward an integration of landscape and Food Web Ecology: The dynamics of spatially subsidized Food Webs
    Annual Review of Ecology and Systematics, 1997
    Co-Authors: Gary A Polis, Wendy B. Anderson, Robert D. Holt
    Abstract:

    We focus on the implications of movement, landscape variables, and spatial heterogeneity for Food Web dynamics. Movements of nutrients, detritus, prey, and consumers among habitats are ubiquitous in diverse biomes and can strongly influence population, consumer-resource, Food Web, and community dynamics. Nutrient and detrital subsidies usually increase primary and secondary productivity, both directly and indirectly. Prey subsidies, by movement of either prey or predators, usually enhance predator abundance beyond what local resources can support. Top-down effects occur when spatially subsidized consumers affect local resources by suppressing key resources and occasionally by initiating trophic cascades. Effects on community dynamics vary with the relative amount of input, the trophic roles of the mobile and recipient entities, and the local Food Web structure. Landscape variables such as the perimeter/area ratio of the focal habitat, permeability of habitat boundaries, and relative productivity of trophically connected habitats affect the degree and importance of spatial subsidization.

  • Temporal and Spatial Aspects of Food Web Structure and Dynamics
    Food Webs, 1996
    Co-Authors: Robert D. Holt
    Abstract:

    Ecologists of all persuasions are becoming increasingly aware of the importance of dispersal, patchiness, and spatial heterogeneity (Gilpin and Hanski, 1991; Ricklefs and Schluter, 1993; Kareiva, 1994). The significance of temporal environmental variation is also an increasingly important theme (Pimm, 1991), as is the role of life histories in determining the effects of such variation on communities (Winemiller, Chapter 28). The chapters in this section of the volume are a testament to the importance of spatial, temporal, and life history effects in Food Web Ecology.

  • Food Webs in Space: An Island Biogeographic Perspective
    Food Webs, 1996
    Co-Authors: Robert D. Holt
    Abstract:

    All ecologists are familiar with graphical portrayals of Food Webs such as that shown in Figure 29.1a—tinkertoy constructions of nodes (e.g., species) connected by lines (feeding relations). This depiction of Food Webs (or, more formally, its matrix equivalent) has without question helped articulate many important questions in community Ecology (e.g., Pimm (1982), Pimm et al. (1991), and Cohen et al (1990)). Yet, as with any powerful conceptual schemata in science, this characterization of community organization both liberates—organizing one’s thoughts in fruitful directions—and enslaves—subtly constraining the questions one tends to ask. In particular, most descriptions of, and models about, Food Web structure make no explicit reference to space. But all ecological interactions, including trophic relations, are necessarily played out in a spatial arena. For some purposes this observation may well be irrelevant. However, it is becoming increasingly clear that the resolution of many classical problems in community Ecology, from the coexistence of competitors (e.g., Hanski (1983)), to the stabilization of predator-prey interactions (e.g. Hassell et al. (1991), to the interpretation of species richness patterns (Cornell and Lawton, 1992), requires a consideration of spatial dynamics. Food Web Ecology, too, should profit from an explicit incorporation of spatial perspectives.

Cristian J Monaco - One of the best experts on this subject based on the ideXlab platform.

  • personality foraging behavior and specialization integrating behavioral and Food Web Ecology at the individual level
    Oecologia, 2016
    Co-Authors: Benjamin J Toscano, Natasha J Gownaris, Sarah M Heerhartz, Cristian J Monaco
    Abstract:

    Behavioral traits and diet were traditionally thought to be highly plastic within individuals. This view was espoused in the widespread use of optimality models, which broadly predict that individuals can modify behavioral traits and diet across ecological contexts to maximize fitness. Yet, research conducted over the past 15 years supports an alternative view; fundamental behavioral traits (e.g., activity level, exploration, sociability, boldness and aggressiveness) and diet often vary among individuals and this variation persists over time and across contexts. This phenomenon has been termed animal personality with regard to behavioral traits and individual specialization with regard to diet. While these aspects of individual-level phenotypic variation have been thus far studied in isolation, emerging evidence suggests that personality and individual specialization may covary, or even be causally related. Building on this work, we present the overarching hypothesis that animal personality can drive specialization through individual differences in various aspects of consumer foraging behavior. Specifically, we suggest pathways by which consumer personality traits influence foraging activity, risk-dependent foraging, roles in social foraging groups, spatial aspects of foraging and physiological drivers of foraging, which in turn can lead to consistent individual differences in Food resource use. These pathways provide a basis for generating testable hypotheses directly linking animal personality to ecological dynamics, a major goal in contemporary behavioral Ecology.

Kevin S Mccann - One of the best experts on this subject based on the ideXlab platform.

  • Linking fishing pressure with ecosystem thresholds and Food Web stability on coral reefs
    Ecological Monographs, 2017
    Co-Authors: P. Houk, J. Cuetos‐bueno, Alexander M. Kerr, Kevin S Mccann
    Abstract:

    Managing fisheries for ecosystem resilience is essential, but practical guidance is limited by Food-Web complexity. Processes, mechanisms, and thresholds associated with ecosystem overfishing were investigated by combining traditional concepts in fisheries biology with recent advances in Food-Web modeling. Diverse coral-reef Food Webs were simplified by grouping species into guilds based on the way they capture, store, and transfer energy, rather than taxonomically, as is traditionally done. Biomass fluxes between the guilds were then quantified using an allometric trophic model. The model was calibrated by linking parameters describing growth, predation, and competition with known body size and metabolic constraints, and then adjusting the base rate of parameters to match fish biomass estimates from a “pristine” coral reef system. The calibrated model was then tested by replacing equilibrium fish biomasses with observations from fished systems across the Pacific, spanning nine islands and numerous major-reef habitats. Encouraging relationships were found between predicted algal accumulation and field observations, and between modelled and observed guild restructuring. In terms of Food-Web Ecology, “pristine” Food Webs were characterized by asynchronous population dynamics between the guilds (i.e., offsetting fluctuations), which maximized their persistence and the net accumulation of biomass within Food Webs. Beneficial, offsetting fluctuations were driven by the contrasting roles of density dependence, apparent competition, and predation. Fishing for predators synchronized the population fluctuations between the guilds, resulting in larger amplitudes (i.e., highs and lows), and a growing dominance of small herbivores. Continued fishing for large herbivores eventually led to an inflection point where algal biomass accumulated exponentially, revealing an ecosystem-based fisheries benchmark. Management targets that maximized fisheries yields while controlling for algal accumulation required simultaneous exploitation across the guilds; a significant challenge because maximum yields of predators, large herbivores, and small herbivores were magnitudes of order apart. This strategy also represented a departure from modern commercial fisheries policies that place catch quotas on entire fish families taxonomically, committing systems to smaller fish, higher biomass turnover, and undesirable algal accumulation. Moving forward, the model provided a flexible and adaptable framework to consider economic and ecosystem objectives of fisheries simultaneously, ultimately balancing resilient Food Webs against higher fisheries productivity.

  • The more Food Webs change, the more they stay the same.
    Philosophical Transactions of the Royal Society B, 2009
    Co-Authors: Kevin S Mccann, Neil Rooney
    Abstract:

    Here, we synthesize a number of recent empirical and theoretical papers to argue that Food-Web dynamics are characterized by high amounts of spatial and temporal variability and that organisms respond predictably, via behaviour, to these changing conditions. Such behavioural responses on the landscape drive a highly adaptive Food-Web structure in space and time. Empirical evidence suggests that underlying attributes of Food Webs are potentially scale-invariant such that Food Webs are characterized by hump-shaped trophic structures with fast and slow pathways that repeat at different resolutions within the Food Web. We place these empirical patterns within the context of recent Food-Web theory to show that adaptable Food-Web structure confers stability to an assemblage of interacting organisms in a variable world. Finally, we show that recent Food-Web analyses agree with two of the major predictions of this theory. We argue that the next major frontier in Food-Web theory and applied Food-Web Ecology must consider the influence of variability on Food-Web structure.

  • a landscape theory for Food Web architecture
    Ecology Letters, 2008
    Co-Authors: Neil Rooney, Kevin S Mccann, John C Moore
    Abstract:

    Ecologists have long searched for structures and processes that impart stability in nature. In particular, Food Web Ecology has held promise in tackling this issue. Empirical patterns in Food Webs have consistently shown that the distributions of species and interactions in nature are more likely to be stable than randomly constructed systems with the same number of species and interactions. Food Web Ecology still faces two fundamental challenges, however. First, the quantity and quality of Food Web data required to document both the species richness and the interaction strengths among all species within Food Webs is largely prohibitive. Second, where Food Webs have been well documented, spatial and temporal variation in Food Web structure has been ignored. Conversely, research that has addressed spatial and temporal variation in ecosystems has generally ignored the full complexity of Food Web architecture. Here, we incorporate empirical patterns, largely from macroEcology and behavioural Ecology, into a spatially implicit Food Web structure to construct a simple landscape theory of Food Web architecture. Such an approach both captures important architectural features of Food Webs and allows for an exploration of Food Web structure across a range of spatial scales. Finally, we demonstrated that Food Webs are hierarchically organized along the spatial and temporal niche axes of species and their utilization of Food resources in ways that stabilize ecosystems.

  • Fluctuations in density of an outbreak species drive diversity cascades in Food Webs
    Proceedings of the National Academy of Sciences of the United States of America, 2007
    Co-Authors: Eldon S. Eveleigh, Kevin S Mccann, Peter C. Mccarthy, Steven J. Pollock, Christopher J. Lucarotti, Benoit Morin, George A. Mcdougall, D. B. Strongman, John T. Huber, James Umbanhowar
    Abstract:

    Abstract Patterns in Food-Web structure have frequently been examined in static Food Webs, but few studies have attempted to delineate patterns that materialize in Food Webs under nonequilibrium conditions. Here, using one of nature's classical nonequilibrium systems as the Food-Web database, we test the major assumptions of recent advances in Food-Web theory. We show that a complex Web of interactions between insect herbivores and their natural enemies displays significant architectural flexibility over a large fluctuation in the natural abundance of the major herbivore, the spruce budworm (Choristoneura fumiferana). Importantly, this flexibility operates precisely in the manner predicted by recent foraging-based Food-Web theories: higher-order mobile generalists respond rapidly in time and space by converging on areas of increasing prey abundance. This “birdfeeder effect” operates such that increasing budworm densities correspond to a cascade of increasing diversity and Food-Web complexity. Thus, by integrating foraging theory with Food-Web Ecology and analyzing a long-term, natural data set coupled with manipulative field experiments, we are able to show that Food-Web structure varies in a predictable manner. Furthermore, both recent Food-Web theory and longstanding foraging theory suggest that this very same Food-Web flexibility ought to be a potent stabilizing mechanism. Interestingly, we find that this Food-Web flexibility tends to be greater in heterogeneous than in homogeneous forest plots. Because our results provide a plausible mechanism for boreal forest effects on populations of forest insect pests, they have implications for forest and pest management practices. budworm Food-Web theory foraging theory herbivore–natural enemy interactions insect outbreaks

  • The Role of Space, Time, and Variability in Food Web Dynamics
    Dynamic Food Webs, 2006
    Co-Authors: Kevin S Mccann, Joseph B. Rasmussen, James Umbanhowar, Murray M. Humphries
    Abstract:

    This chapter puts forth ideas that bridge historical contributions to recent developments and outline an emerging perspective that ecological communities are not perfectly stable, but fluctuate in response to both bottom up and top down influences. The arguments suggest that the structure created by variation in space and time is critical to Food Web dynamics. The idea that spatially distinct Food Webs tend to be coupled in space by higher order generalist consumers suggests that Food Web compartments ought to exist in lower trophic levels and become blurred at higher trophic levels. Interestingly, these suggestions have also consistently been part of the soil Food Web Ecology literature. Here, soil ecologists have argued that distinct bacterial and fungal compartments, coupled by generalist higher trophic level consumers, are of great importance for the stability of soil Food Webs. Even less explored by Food Web ecologists is the potential for compartmentation to unfold along a temporal axis. The discussion of space as a major player in Food Web dynamics suggests that other ways to decouple interactions and subsystems can be equally as important and deserve attention. Any perturbation that reduces the ability of consumers to integrate over space or unifies dynamics of different species or subsystems will excite, or destabilize, the dynamics of Food Webs.