![]() |
The subalpine fir has a mutualistic relationship with belowground fungi. Photo Credit: Khilav Majmudar, University of Minnesota |
Cooperation between species to help each other's survival is known as mutualism. It is seen among many types of organisms, such as plants and fungi that exchange nutrients with one another, plants that provide bees with nectar in exchange for pollination, and sea anemones that provide protection for clown-fish in exchange for excreted nutrients. Recently, scientists have found evidence that some invasive plants become even more invasive in the presence of helpful partners, as can happen with certain pine trees and fungi or fig trees and wasps. But other studies have suggested that species that didn't rely on mutualist partners were more invasive.
Recent research at the University of Minnesota, published in the journal Ecology, attempted to identify the conditions under which a mutualistic partner could make a species more or less invasive. To study this, they built mathematical models called integro-difference equations (IDEs). IDEs take into account the effects of mutualism on growth and dispersal of species and are useful tools to model spatial processes. Mathematical models are helpful in understanding ecological processes like invasion that occur over many years and can be difficult to study in the field.