Creatures of influence: New model identifies critical species in food webs and social networks

Nov 05, 2013

In the children's game "Jenga", removing the wrong block from a tower of wooden blocks can cause the entire tower to collapse. In the same way, removing certain species from an ecosystem can cause a collapse in ecological function. A common scientific question has been to identify these critical species in different ecosystems and an international research team has developed mathematical tools that can estimate which species are most influential in a food web.

The researchers from the University of Bristol, the Max Planck Institute for Physics of Complex Systems and the US Geological Survey have taken a new modeling approach to the question. The team, using the new mathematical tools, found that long-lived, generalist top predators—such as otters— play the most influential roles within a food web. The findings are published today in Proceedings of the Royal Society B.

Helge Aufderheide of the Max Planck Institute and University of Bristol, who led the research, said: "The interactions in an ecosystem are so complex that one can often only guess about the roles that each species plays. Therefore, knowing how to find the key players makes all the difference for understanding where to focus studies."

Long-lived, generalist top predators can highly influence ecosystems because they feed on different types of prey that occupy different parts of the food web. For example, otters feed on a wide variety of aquatic prey and can influence multiple species throughout the course of their relatively long lifespan. Removing otters from the ecosystem would cause long-term disruptions to all those species, a theory that the new models can now confirm for other species and ecosystems.

Understanding how the gain or loss of a single species affects a complex food web has been a difficult mathematical challenge, and the new findings provide fundamental insights into complex natural systems. The new study offers a rule of thumb to help other studies focus their research and data collection on in order of their expected importance, and increase the efficiency of their research effort.

Kevin Lafferty, an author of the paper from USGS, said: "As a biologist who studies , I'm hopeful that we can use this approach to help focus our field work."

The new approach has non-ecological applications as well. Even though the research team applied the computational tools on food webs, their approach also can be applied to other types of —from electricity grids to online social networks—to identify influential components.

Explore further: Dwindling wind may tip predator-prey balance

More information: Predicting community responses in the face of imperfect knowledge and network complexity by Helge Aufderheide, Lars Rudolf, Thilo Gross, and Kevin D. Lafferty, Proceedings of the Royal Society B, 6 November 2013. rspb.royalsocietypublishing.or… .1098/rspb.2013.2355

Related Stories

Do parasites upset food web theory?

Jun 11, 2013

Parasites comprise a large proportion of the diversity of species in every ecosystem. Despite this, they are rarely included in analyses or models of food webs. If parasites play different roles from other ...

A new model for understanding biodiversity

Nov 21, 2011

(PhysOrg.com) -- Animals like foxes and raccoons are highly adaptable. They move around and eat everything from insects to eggs. They and other "generalist feeders" like them may also be crucial to sustaining ...

Drawing connections between food webs

Apr 04, 2012

Ecosystems today face various threats, from climate change to invasive species to encroaching civilization. If we hope to protect these systems and the species that live in them, we must understand them — an extremely ...

Scientists find universal rules for food-web stability

Aug 06, 2009

The findings, published in this week's issue of Science, conclude that food-web stability is enhanced when many diverse predator-prey links connect high and intermediate trophic levels. The computations also reveal that s ...

Recommended for you

Dwindling wind may tip predator-prey balance

Sep 19, 2014

Bent and tossed by the wind, a field of soybean plants presents a challenge for an Asian lady beetle on the hunt for aphids. But what if the air—and the soybeans—were still?

Asian stars enlisted to fight African rhino poaching

Sep 19, 2014

Increasingly desperate South African conversationists are turning to a multi-national team of "rhino ambassadors" to try to end the scourge of poaching—and Vietnamese pop diva Hong Nhung has been recruited ...

Tropical fish a threat to Mediterranean Sea ecosystems

Sep 18, 2014

The tropical rabbitfish which have devastated algal forests in the eastern Mediterranean Sea pose a major threat to the entire Mediterranean basin if their distribution continues to expand as the climate ...

User comments : 0