Nav: Home

Are complex networks and systems more stable than simpler ones?

October 03, 2016

A large complex system or network that sustains multiple life forms - such as the Great Barrier Reef off Australia's north coast - would seem to be more likely to be stable to disturbances than a simple one.

Logically, complexity and diversity would seem like the best way to go for everything to survive and flourish in such complex ecosystems as the Great Barrier Reef or the Amazon Rainforest in South America, but instead could this be their fatal flaw?

Research published in Nature Communications by RMIT's Professor Lewi Stone* from the School of Science (Maths discipline) confirms this could be the case. Stone said by revisiting and reviewing various studies of networks, in conjunction with his own research and methodology, he had found that we should expect more complex systems are likely to be more fragile.

"Consequently, this means we need to give great care to our highly diverse tropical rain forests and our coral reefs, because despite their greater complexity and diversity, they may be incredibly fragile," he said.

The same principle holds for a wide range of complex networks in completely different contexts including systems biology, neuronal networks, the internet, and even interconnected banking systems.

Stone looked at Robert May's celebrated theoretical work of the 1970s - Will a large complex system be stable? - in Nature 1972, which contradicted the established paradigm of the time by demonstrating that complexity leads to instability in biological systems.

May's analysis was fairly barebones and dealt purely with random systems without taking into account realistic features, for example, plant species compete among themselves, while plants and their pollinators provide mutual support to one another. These are far from random systems and much more complex.

"Simple relationships are found to govern these intractable models, and control the parameter ranges for which biological systems are stable and feasible," he said.

"These results have long been sought after, since little is known as to how systems with large-scale mutualistic aid persist given their supposed inherent instability. Until now the equations underlying these models have been too complex to analyse - no one expected the emergence of simple general principles."

An unusual aspect of Stone's work is that the analysis of model and real empirical networks is only achievable on introducing a simplifying Google-matrix reduction scheme. This completely new direction proposed by Stone's research should have many applications in the future for studying complex systems having large-scale interaction architectures.

"We use the same basic mechanism at the heart of Sergei Brin and Larry Page's "Google matrix" invented in 1998, which ranks web pages as it sifts through billions of hyperlinks across the world-wide-web."

"From this perspective, the Google matrix was made use of in Mathematical Biology some 10 years before its invention by Google, and appeared in my PhD dissertation - in 1988," Stone said.
The Google matrix controls the stability of complex structured ecological and biological networks by Professor Lewi Stone, published in Nature Communications 30 September 2016. DOI: 10.1038/ncomms12857.

For interviews: Professor Lewi Stone, +61 3 9925 1728 or +61 452 176 626, *on leave from Tel Aviv University.

For general media enquiries: Deborah Sippitts, +61 3 9925 3116 or +61 429 588 869.

RMIT University

Related Diversity Articles:

Bursts of diversity in the gut microbiota
The diversity of bacteria in the human gut is an important biomarker of health, influences multiple diseases, such as obesity and inflammatory bowel diseases and affects various treatments.
Underestimated chemical diversity
An international team of researchers has conducted a global review of all registered industrial chemicals: some 350,000 different substances are produced and traded around the world -- well in excess of the 100,000 reached in previous estimates.
New world map of fish genetic diversity
An international research team from ETH Zurich and French universities has studied genetic diversity among fish around the world for the first time.
Biological diversity as a factor of production
Can the biodiversity of ecosystems be considered a factor of production?
Fungal diversity and its relationship to the future of forests
Stanford researchers predict that climate change will reduce the diversity of symbiotic fungi that help trees grow.
Brain diseases with molecular diversity
Parkinson's and multisystem atrophy (MSA) - both of them neurodegenerative diseases - are associated with the accumulation of alpha-synuclein proteins in the brain.
United in musical diversity
Is music really a 'universal language'? Two articles in the most recent issue of Science support the idea that music all around the globe shares important commonalities, despite many differences.
Genetic diversity facilitates cancer therapy
Cancer patients with more different HLA genes respond better to treatment.
A new ranavirus threatens US amphibian diversity
In a study published in the Oct. 15 issue of Ecological Modelling, a team of University of Tennessee researchers along with a colleague from the University of Florida model how a chimeric Frog virus 3 (FV3)-like ranavirus, also known as RCV-Z2, can spread rapidly throughout a population of North American wood frog (Lithobates sylvaticus) tadpoles.
New way to target cancer's diversity and evolution
Scientists have revealed close-up details of a vital molecule involved in the mix and match of genetic information within cells -- opening up the potential to target proteins of this family to combat cancer's diversity and evolution.
More Diversity News and Diversity Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at