Dynamics of Consumer-Resource Systems

2013 ◽  
Author(s):  
André M. de Roos ◽  
Lennart Persson
Keyword(s):  
Model Organism ◽  
Growth Dynamics ◽  
Population Cycles ◽  
Food Density ◽  
Juvenile Period ◽  
Ecological Processes ◽  
Resource Dynamics ◽  
Cladoceran Zooplankton ◽  
The Individual ◽  
Consumer Resource

This chapter focuses on consumer-resource dynamics in systems where consumers of different sizes compete for a shared resource. It considers the implications of three important aspects of consumer life history: the explicit handling of a juvenile period leading to a delay between the time when an individual is born to when it starts to reproduce; the rate by which individual ecological processes scale with body size; and whether the rate by which the individual grows is dependent on food density or not. The chapter examines the effects of different resource growth dynamics to illustrate the fundamental differences between population cycles driven by interactions between individuals of different sizes, and classical predator–prey cycles driven by interactions between the consumer and the resource, also referred to as paradox of enrichment cycles. It also discusses experiments with the model organism, the cladoceran zooplankton Daphnia, to elucidate our current understanding of cycles driven by cohort interactions in this organism.

scholarly journals The Stochastic Nature of Functional Responses

Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 575
Author(s):  
Gian Marco Palamara ◽  
José A. Capitán ◽  
David Alonso
Keyword(s):  
Stochastic Systems ◽  
Empirical Studies ◽  
Spatial Dynamics ◽  
Stochastic Approach ◽  
Linear Functions ◽  
Functional Responses ◽  
Ecological Processes ◽  
Feeding Experiments ◽  
Resource Dynamics ◽  
Consumer Resource

Functional responses are non-linear functions commonly used to describe the variation in the rate of consumption of resources by a consumer. They have been widely used in both theoretical and empirical studies, but a comprehensive understanding of their parameters at different levels of description remains elusive. Here, by depicting consumers and resources as stochastic systems of interacting particles, we present a minimal set of reactions for consumer resource dynamics. We rigorously derived the corresponding system of ODEs, from which we obtained via asymptotic expansions classical 2D consumer-resource dynamics, characterized by different functional responses. We also derived functional responses by focusing on the subset of reactions describing only the feeding process. This involves fixing the total number of consumers and resources, which we call chemostatic conditions. By comparing these two ways of deriving functional responses, we showed that classical functional response parameters in effective 2D consumer-resource dynamics differ from the same parameters obtained by measuring (or deriving) functional responses for typical feeding experiments under chemostatic conditions, which points to potential errors in interpreting empirical data. We finally discuss possible generalizations of our models to systems with multiple consumers and more complex population structures, including spatial dynamics. Our stochastic approach builds on fundamental ecological processes and has natural connections to basic ecological theory.

scholarly journals Crystal growth of clathrate hydrate formed with H2 + CO2 mixed gas and tetrahydropyran

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Meku Maruyama ◽  
Riku Matsuura ◽  
Ryo Ohmura
Keyword(s):  
Crystal Growth ◽  
Synthesis Gas ◽  
Water System ◽  
Hydrate Formation ◽  
Growth Dynamics ◽  
Operating Conditions ◽  
Mixed Gas ◽  
Thermodynamic Conditions ◽  
The Individual ◽  
And Storage

AbstractHydrate-based gas separation technology is applicable to the CO2 capture and storage from synthesis gas mixture generated through gasification of fuel sources including biomass. This paper reports visual observations of crystal growth dynamics and crystal morphology of hydrate formed in the H2 + CO2 + tetrahydropyran (THP) + water system with a target for developing the hydrate-based CO2 separation process design. Experiments were conducted at a temperature range of 279.5–284.9 K under the pressure of 4.9–5.3 MPa. To simulate the synthesis gas, gas composition in the gas phase was maintained around H2:CO2 = 0.6:0.4 in mole fraction. Hydrate crystals were formed and extended along the THP/water interface. After the complete coverage of the interface to shape a polycrystalline shell, hydrate crystals continued to grow further into the bulk of liquid water. The individual crystals were identified as hexagonal, tetragonal and other polygonal-shaped formations. The crystal growth rate and the crystal size varied depending on thermodynamic conditions. Implications from the obtained results for the arrangement of operating conditions at the hydrate formation-, transportation-, and dissociation processes are discussed.

Daphnia as a Model for Eco-evolutionary Dynamics

2018 ◽  
pp. 403-424
Author(s):  
Matthew R. Walsh ◽  
Michelle Packer ◽  
Shannon Beston ◽  
Collin Funkhouser ◽  
Michael Gillis ◽  
...  
Keyword(s):  
Life History ◽  
Evolutionary Dynamics ◽  
Model Organism ◽  
Life History Evolution ◽  
Ecological Processes ◽  
Evolutionary Forces ◽  
Evolutionary Changes ◽  
History Evolution ◽  
Ecological Importance ◽  
The Many

Much research has shown that variation in ecological processes can drive rapid evolutionary changes over periods of years to decades. Such contemporary adaptation sets the stage for evolution to have reciprocal impacts on the properties of populations, communities, and ecosystems, with ongoing interactions between ecological and evolutionary forces. The importance and generality of these eco-evolutionary dynamics are largely unknown. In this chapter, we promote the use of water fleas (Daphnia sp.) as a model organism in the exploration of eco-evolutionary interactions in nature. The many characteristics of Daphnia that make them suitable for laboratory study in conjunction with their well-known ecological importance in lakes, position Daphnia to contribute new and important insights into eco-evolutionary dynamics. We first review the influence of key environmental stressors in Daphnia evolution. We then highlight recent work documenting the pathway from life history evolution to ecology using Daphnia as a model. This review demonstrates that much is known about the influence of ecology on Daphnia life history evolution, while research exploring the genomic basis of adaptation as well as the influence of Daphnia life history traits on ecological processes is beginning to accumulate.

scholarly journals Environmental warming induces behavioral and metabolic changes in a freshwater crustacean − aeglids as a model organism

2018 ◽  
Vol 54 ◽  
pp. 7 ◽  
Author(s):  
Gláucia Bolzan Cogo ◽  
Cristiane Biasi ◽  
Eduardo Stringini Severo ◽  
Vania Loro ◽  
Sandro Santos
Keyword(s):  
Amino Acid ◽  
Model Organism ◽  
Metabolic Changes ◽  
Activity Level ◽  
Ecological Processes ◽  
Leaf Consumption ◽  
Extra Energy ◽  
Different Temperatures ◽  
Freshwater Crustacean ◽  
Save Energy

Ecological processes in small-order streams are dependent on their community. A threat to the appropriate functioning of these processes is the water warming of streams since changes in temperature can modify the behavior, abundance, and distribution of the species. A way to predict the consequences of global warming on ecological processes in these ecosystems is to study their aquatic community. Here we evaluated behavioral and metabolic changes in Aegla longirostri at different temperatures (21 °C and 24 °C). Experiments were performed in laboratory conditions. We calculated leaf consumption and quantified glycogen, protein and amino acid composition in the hepatopancreas. We also conducted a behavioral test to investigate the activity level of aeglids. Leaf consumption did not differ between temperatures. However, the amount of protein was higher at 21 °C, and the amino acid and glycogen levels were greater at 24 °C. In the present study we evaluated only the activity of hepatopancreas, so we can assume that the organ may have used glucose through the breakdown of glycogen and also performing some protein break. However, this hypothesis needs to be confirmed by checking for muscle activity. Animals kept at 24 °C showed a lower level of activity. This strategy possibly occurs to save energy, as in elevated temperature crustaceans spend extra energy to maintain their homeostasis. This study indicates that a future increase temperature of streams will impact the populations of aeglids by changing their metabolism and behavior.

Consumer–resource dynamics in Arctic ponds

Ecology ◽  
2020 ◽  
Vol 101 (10) ◽  
Author(s):  
Melissa H. DeSiervo ◽  
Matthew P. Ayres ◽  
Ross A. Virginia ◽  
Lauren E. Culler
Keyword(s):  
Arctic Ponds ◽  
Resource Dynamics ◽  
Consumer Resource

scholarly journals A cascade of evolutionary change alters consumer-resource dynamics and ecosystem function

2012 ◽  
Vol 279 (1741) ◽  
pp. 3184-3192 ◽  
Author(s):  
Matthew R. Walsh ◽  
John P. DeLong ◽  
Torrance C. Hanley ◽  
David M. Post
Keyword(s):  
Life History ◽  
Ecosystem Function ◽  
Life History Evolution ◽  
Evolutionary Change ◽  
Ecological Impacts ◽  
Trophic Levels ◽  
Natural Setting ◽  
Resource Dynamics ◽  
History Evolution ◽  
Consumer Resource

It is becoming increasingly clear that intraspecific evolutionary divergence influences the properties of populations, communities and ecosystems. The different ecological impacts of phenotypes and genotypes may alter selection on many species and promote a cascade of ecological and evolutionary change throughout the food web. Theory predicts that evolutionary interactions across trophic levels may contribute to hypothesized feedbacks between ecology and evolution. However, the importance of ‘cascading evolutionary change’ in a natural setting is unknown. In lakes in Connecticut, USA, variation in migratory behaviour and feeding morphology of a fish predator, the alewife ( Alosa pseudoharengus ), drives life-history evolution in a species of zooplankton prey ( Daphnia ambigua ). Here we evaluated the reciprocal impacts of Daphnia evolution on ecological processes in laboratory mesocosms. We show that life-history evolution in Daphnia facilitates divergence in rates of population growth, which in turn significantly alters consumer-resource dynamics and ecosystem function. These experimental results parallel trends observed in lakes. Such results argue that a cascade of evolutionary change, which has occurred over contemporary timescales, alters community and ecosystem processes.

Spatial diffusion modelling of juvenile Atlantic salmon (Salmo salar) shows ontogenetic increase in movement rates

2017 ◽  
Vol 74 (2) ◽  
pp. 202-207 ◽  
Author(s):  
A. Foldvik ◽  
S. Einum ◽  
A.G. Finstad
Keyword(s):  
Spatial Distribution ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Continuous Distribution ◽  
Diffusion Models ◽  
Ontogenetic Changes ◽  
Ecological Processes ◽  
Breeding Sites ◽  
Atlantic Salmon Salmo Salar ◽  
The Individual

For organisms with extensive ontogenetic changes in phenotypes, knowledge of how movement of individuals changes throughout life is pivotal to understanding ecological processes. Here, we study the spatial distribution of a cohort of Atlantic salmon (Salmo salar) from hatching to their third summer of juvenile life, during which they go through a fourfold change in body size. The fish originated from three distinct breeding sites, and their distribution was mapped using electrofishing throughout the river at 10 sampling periods. The spatial distribution throughout ontogeny was analysed using diffusion models. The distribution changed from three distinct nonoverlapping distributions centred on the individual breeding sites at the early first summer stage to a single continuous distribution at the end of the study. The diffusion coefficient increased throughout ontogeny, and spatial distributions were well-described using diffusion models, explaining 46%–89% of the variation. This highlights the utility of diffusion models when considering spatial habitat structure both in conservation and research.

A newly discovered role of evolution in previously published consumer-resource dynamics

2014 ◽  
Vol 17 (8) ◽  
pp. 915-923 ◽  
Author(s):  
Teppo Hiltunen ◽  
Nelson G. Hairston ◽  
Giles Hooker ◽  
Laura E. Jones ◽  
Stephen P. Ellner
Keyword(s):  
Resource Dynamics ◽  
Consumer Resource
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