Small World Phenomena Found in Ecosystem
The article, Herbivores in a small world: network theory highlights vulnerability in the function of herbivory on coral reef, discusses how the application of network theory has been relevant in field ecology. Using a mathematical network model, researchers have been able to discover how herbivorous fish are linked as nodes in a “grazing network” that maintains an ideal algae and coral balance that is crucial for ecosystem stability. Network structures were examined and have exposed how vulnerable the interconnectivity of the herbivorous fish was in regards to the ecosystems they support by their consumption of coral algae. The coral and algae balance is a key role in the ecosystem’s stability. Three species were tracked over 12 months using acoustic telemetry data. The data showed that the individual fish carried out most of their activities within small sections of available reef which the movements of their activities occurred on predictable paths. This showed that all three species relied heavily on well-interconnected sections of the reef (nodes) which translated into an “ultra-small-world” network. This discovery shows how truly vulnerable the entire system is: removal of certain fish or removal of parts of the reef can significantly alter the network and cause a complete collapse of the herbivory network.
This article relates to class due to our recent discussion of the “small world theory” or the “six degrees of separation” in chapter two in Networks, Crowds and Markets. As Milgram displayed in his “small world phenomenon” research, a global friendship network has surprisingly short paths. The article, Herbivores in a small world: network theory highlights vulnerability in the function of herbivory on coral reef, states that all three species of fish examined were undoubtedly reliant on one another when they do not even realize how their individual actions support such a crucial part of their ecosystem’s function. This statement can be considered as a derivative of Milgram’s statement “six short steps becomes six worlds apart,” because the examined species work so closely together in their ecosystem and their herbivorous activity keeps the algae and reef balance in check. It is almost that the species are in their own “worlds” but are “three steps apart” since they are located in the same ecosystem without affecting the other species directly. Originally, I thought Milgram’s discovery could only be applied to a global network, such as a global social network, but I found it very interesting that such a phenomena in a specialized ecosystem can exist as well.
Link can be found at:
http://onlinelibrary.wiley.com.proxy.library.cornell.edu/doi/10.1111/1365-2435.12190/full