NETWORK ANALYSIS OF A BENTHIC FOOD WEB MODEL OF A PARTLY RECLAIMED ISLAND IN THE SUNDARBAN MANGROVE ECOSYSTEM, INDIA

2000 ◽  
Vol 08 (03) ◽  
pp. 263-278 ◽  
Author(s):  
SANTANU RAY ◽  
ROBERT E. ULANOWICZ ◽  
N. C. MAJEE ◽  
A. B. ROY

Network analysis is performed on a 14 species food web model of the ecosystem occupying a mudflat on a partly reclaimed island of the Sundarban mangrove ecosystem. The results demonstrate a dramatic difference between this heavily impacted mangrove ecosystem in its modes of primary and secondary production and its diminished role of detritus vis-a-vis its less disturbed counterparts. Unlike most benthic mangrove systems, the Sundarban bottom community receives a large contribution from the phytoplankton populations. In this system herbivory and detritivory are virtually equal, in contrast to the usual herbivory:detritivory ratio of 1:5. Anthropogenic impacts have changed the physiography of this system so as to increase the relative importance of zooplankton and meiobenthos as herbivores. Although a slight degree of omnivory is exhibited by the populations of larger organisms, all flows of each integer of trophic length into a food chain may be aggregated that represents the underlying trophic status of the starting food web. Only a small number of pathways of recycle can be identified (31), and the Finn cycling index for this system is quite low (8.4%). Litterfall comprises only 16% of the total system input, which is very little in comparison with most mangrove systems. Pathway redundancy is rather high in this ecosystem, indicating that the surviving system is probably highly resilient to further perturbations, as one might expect for a highly impacted system.

2014 ◽  
Vol 89 (5) ◽  
Author(s):  
Andrzej Pękalski ◽  
Janusz Szwabiński
Keyword(s):  
Food Web ◽  

2021 ◽  
pp. 639-657
Author(s):  
Ekhlas Abd Al-Husain Jabr ◽  
Dahlia Khaled Bahlool

This paper aims to study the role of a prey refuge that depends on both prey and predator species on the dynamics of a food web model. It is assumed that the food transfer among the web levels occurs according to Lotka-Volterra functional response. The solution properties, such as existence, uniqueness, and uniform boundedness, are discussed. The local, as well as the global, stabilities of the solution of the system are investigated. The persistence of the system is studied with the assistance of average Lyapunov function. The local bifurcation conditions that may occur near the equilibrium points are established. Finally, numerical simulation is used to confirm our obtained results. It is observed that the system has only one type of attractors that is a stable point, while periodic dynamics do not exist even on the boundary planes.


2016 ◽  
Vol 335 ◽  
pp. 87-100 ◽  
Author(s):  
Laura E. Koehn ◽  
Timothy E. Essington ◽  
Kristin N. Marshall ◽  
Isaac C. Kaplan ◽  
William J. Sydeman ◽  
...  

Mathematics ◽  
2018 ◽  
Vol 6 (12) ◽  
pp. 336 ◽  
Author(s):  
Ferenc Jordán ◽  
Anett Endrédi ◽  
Wei-chung Liu ◽  
Domenico D’Alelio

Species are embedded in a web of intricate trophic interactions. Understanding the functional role of species in food webs is of fundamental interests. This is related to food web position, so positional similarity may provide information about functional overlap. Defining and quantifying similar trophic functioning can be addressed in different ways. We consider two approaches. One is of mathematical nature involving network analysis where unique species can be defined as those whose topological position is very different to others in the same food web. A species is unique if it has very different connection pattern compared to others. The second approach is of biological nature, based on trait-based aggregations. Unique species are not easy to aggregate with others because their traits are not in common with the ones of most others. Our goal here is to illustrate how mathematics can provide an alternative perspective on species aggregation, and how this is related to its biological counterpart. We illustrate these approaches using a toy food web and a real food web and demonstrate the sensitive relationships between those approaches. The trait-based aggregation focusing on the trait values of size (sv) can be best predicted by the mathematical aggregation algorithms.


Public Voices ◽  
2016 ◽  
Vol 11 (1) ◽  
pp. 89
Author(s):  
Amy Probsdorfer Kelley ◽  
John C. Morris

The process to win approval to build a national memorial on the National Mall inWashington, DC is both long and complex. Many memorials are proposed, but few are chosen to inhabit the increasingly scarce space available on the Mall. Through the use of network analysis we compare and contrast two memorial proposals, with an eye toward understanding why one proposal was successful while the other seems to have failed. We conclude that the success of a specific memorial has less to do with the perceived popularity of the person or event to be memorialized, and more to do with how the sponsors use the network of people and resources available to advocate for a given proposal.


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