scholarly journals Existence and construction of large stable food webs

2017 ◽  
Author(s):  
Jan O. Haerter ◽  
Namiko Mitarai ◽  
Kim Sneppen
Keyword(s):  
Food Webs ◽  
Weak Interactions ◽  
Apparent Competition ◽  
Species Interaction ◽  
Volterra Equations ◽  
Interaction Patterns ◽  
Functional Responses ◽  
Nonlinear Functional ◽  
Starting Point ◽  
Simple Product

AbstractEcological diversity is ubiquitous despite the restrictions imposed by competitive exclusion and apparent competition. To explain the observed richness of species in a given habitat, food web theory has explored nonlinear functional responses, self-interaction or spatial structure and dispersal — model ingredients that have proven to promote stability and diversity. We here instead return to classical Lotka-Volterra equations, where species-species interaction is characterized by a simple product and spatial restrictions are ignored. We quantify how this idealization imposes constraints on coexistence and diversity for many species. To this end, we introduce the concept of free and controlled species and use this to demonstrate how stable food webs can be constructed by sequential addition of species. When we augment the resulting network by additional weak interactions we are able to show that it is possible to construct large food webs of arbitrary connectivity. Our model thus serves as a formal starting point for the study of sustainable interaction patterns between species.

More Modules

2011 ◽  
Author(s):  
Kevin S. McCann
Keyword(s):  
Population Dynamics ◽  
Food Webs ◽  
Empirical Evidence ◽  
Intraguild Predation ◽  
Weak Interactions ◽  
Apparent Competition ◽  
Trade Offs ◽  
Variable Population ◽  
The Stability

This chapter considers four-species modules and the role of generalism (effectively a three-species module with a consumer feeding on two resources). It first examines how generalists affect the dynamics of food webs by focusing on a set of modules that contrast generalist consumer dynamics relative to the specialist case. It then discusses organismal trade-offs that play a role in governing the diamond food web module and the intraguild predation module, arguing that such tradeoffs influence the flux of matter, the organization of interaction strengths, and ultimately the stability of communities. The chapter also reviews empirical evidence showing that apparent competition and the diamond module with and without intraguild predation are ubiquitous, and that weak interactions in simple modules seem to promote less variable population dynamics.

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

Predator-dependent functional responses and interaction strengths in a natural food web

2004 ◽  
Vol 61 (11) ◽  
pp. 2215-2226 ◽  
Author(s):  
Timothy E Essington ◽  
Sture Hansson
Keyword(s):  
Food Webs ◽  
Functional Response ◽  
Gadus Morhua ◽  
Prey Species ◽  
Clupea Harengus ◽  
Natural Food ◽  
Functional Responses ◽  
Predation Mortality ◽  
Highly Sensitive ◽  
Predator Abundance

Predator-dependent functional responses decouple predation mortality from fluctuations in predator abundance and therefore can prevent strong "top-down" interaction strengths in food webs. We evaluated whether contrasts in the functional response of Baltic Sea cod (Gadus morhua) were consistent with the contrasting population dynamics of two prey species, herring (Clupea harengus) and sprat (Sprattus sprattus): sprat abundance increased nearly threefold following a sharp decline in the cod population (a strong interaction), whereas herring abundance failed to increase (a weak interaction). We found striking differences in the functional response of cod on alternative prey, and these were consistent with the observed patterns in interaction strengths. Cod predation was the dominant source of mortality for age-1 and age-2 sprat but was only important for age-1 herring. Moreover, the magnitude of predation mortality on age-1 and age-2 sprat was highly sensitive to cod biomass, whereas predation mortality on herring was only moderately sensitive to cod biomass. These analyses suggest the possibility that food webs are comprised of linkages that vary with respect to the magnitude and importance of predation mortality and how this mortality varies with changes in predator abundance.

scholarly journals Vulnerable species interactions are important for the stability of mutualistic networks

2019 ◽  
Author(s):  
Benno I. Simmons ◽  
Hannah S. Wauchope ◽  
Tatsuya Amano ◽  
Lynn V. Dicks ◽  
William J. Sutherland ◽  
...  
Keyword(s):  
Species Interactions ◽  
Species Coexistence ◽  
Species Interaction ◽  
Interaction Networks ◽  
Ecological Communities ◽  
Ecological Context ◽  
Intrinsic Properties ◽  
Network Stability ◽  
Starting Point ◽  
The Stability

AbstractSpecies are central to ecology and conservation. However, it is the interactions between species that generate the functions on which ecosystems and humans depend. Despite the importance of interactions, we lack an understanding of the risk that their loss poses to ecological communities. Here, we quantify risk as a function of the vulnerability (likelihood of loss) and importance (contribution to network stability in terms of species coexistence) of 4330 mutualistic interactions from 41 empirical pollination and seed dispersal networks across six continents. Remarkably, we find that more vulnerable interactions are also more important: the interactions that contribute most to network stability are those that are most likely to be lost. Furthermore, most interactions tend to have more similar vulnerability and importance across networks than expected by chance, suggesting that vulnerability and importance may be intrinsic properties of interactions, rather than only a function of ecological context. These results provide a starting point for prioritising interactions for conservation in species interaction networks and, in areas lacking network data, could allow interaction properties to be inferred from taxonomy alone.

scholarly journals Permanence of Periodic Predator-Prey System with General Nonlinear Functional Response and Stage Structure for Both Predator and Prey

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Xuming Huang ◽  
Xiangzeng Kong ◽  
Wensheng Yang
Keyword(s):  
Functional Response ◽  
Prey Species ◽  
Stage Structure ◽  
Functional Responses ◽  
Nonlinear Functional ◽  
Predator Prey ◽  
Prey System

We study the permanence of periodic predator-prey system with general nonlinear functional responses and stage structure for both predator and prey and obtain that the predator and the prey species are permanent.

Ecology

2021 ◽  
pp. 417-452
Author(s):  
Paul Schmid-Hempel
Keyword(s):  
Climate Change ◽  
Body Size ◽  
Infectious Diseases ◽  
Food Webs ◽  
Competitive Ability ◽  
Apparent Competition ◽  
Ecological Communities ◽  
Disease Emergence ◽  
Animal Reservoir ◽  
Transient Structure

Host ecological characteristics, such as body size, longevity, or social living, affect parasitism. Host populations can be regulated in size by their parasites; they can even drive host populations to extinction, usually after hosts have been weakened by other factors. Parasites, therefore, threaten endangered populations and species. Parasites also affect host ecological communities and food webs via effects on competitive ability or with apparent competition. In diverse host communities, infectious diseases become ‘diluted’. Parasite ecological communities seem to have a variable and transient structure; no universal explanation for the observed patterns exists. Host migration can transfer parasites to new areas or leave parasites behind. Disease emergence from an animal reservoir (zoonoses) is especially important. Many human diseases have such an origin, and these have repeatedly caused major epidemics. Climate change will also affect parasitism; however, the direction of change is rather complex and depends on the particular systems.

APPARENT COMPETITION, QUANTITATIVE FOOD WEBS, AND THE STRUCTURE OF PHYTOPHAGOUS INSECT COMMUNITIES

2006 ◽  
Vol 51 (1) ◽  
pp. 187-208 ◽  
Author(s):  
F.J. Frank van Veen ◽  
Rebecca J. Morris ◽  
H. Charles J. Godfray
Keyword(s):  
Food Webs ◽  
Apparent Competition ◽  
Phytophagous Insect ◽  
Insect Communities

Stabilizing effect of intra-specific competition on prey-predator dynamics with intraguild predation

2018 ◽  
Vol 13 (3) ◽  
pp. 29 ◽  
Author(s):  
Toshiyuki Namba ◽  
Yasuhiro Takeuchi ◽  
Malay Banerjee
Keyword(s):  
Intraguild Predation ◽  
Complex Dynamics ◽  
Self Regulation ◽  
Functional Responses ◽  
Predator Species ◽  
Nonlinear Functional ◽  
High Productivity ◽  
Stable Coexistence ◽  
Stability And Bifurcation

Multi-species population models with various types of interactions are important to understand the stable coexistence of prey and predator species and the role of various factors leading to complex dynamics and extinction of one or more species. Models of two predators sharing one prey population are analyzed by some researchers and the role of nonlinear functional responses and interaction strengths are reported to be responsible for the stable coexistence of three species. However, one-prey-two-predator models with intraguild predation have received relatively less attention from researchers. Recent literature on this topic mainly focused on the study of local and global stability properties of possible equilibria and appearance of various types of bifurcations. Intra-specific competition among predator species is an important factor for coexistence of more than one predator species competing for one shared prey. Hence it is quite essential to understand the role of intra-specific competition on the stability and bifurcation behavior. In this work we wish to demonstrate the stabilizing role of intra-specific competition among intermediate and top predators when the growth rate of prey species is adequate to support both the predator species. With the help of stability and bifurcation analysis we show the stabilizing role of intra-specific competition among predators. Moreover, strong self-regulation in intraguild predator prevents extinction of intraguild prey at high productivity and resolve the contradiction between empirical and previous theoretical results on the fate of intraguild prey at high productivity. To establish our claim we present, apart from analytical results, extensive numerical simulation results and couple of bifurcation diagrams.

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