Creatures of influence

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 [Wednesday 6 November] 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.