Mutualisms are relationships between organisms of different species in which each individual benefits from the activity of the other. These
relationships are hugely important in nature. Essential services provided by mutualists include pollination, seed dispersal and the constitution
of global cycles of carbon and other nutrients. Mycorrhizal or rhizobial symbioses (associations between plants and fungi or bacteria) occur in
most terrestrial habitats. Despite their obvious importance, ecologists have only recently started to explore the implications of various elements
of global change on mutualisms.
Previous work by C·I·B Director Dave Richardson and colleagues showed that many types of
mutualisms mediate the success of alien plants, and that invasive species
have huge potential to disrupt native mutualisms; this often leads to
population declines, reduced biodiversity, and altered ecosystem functioning. This is a very active field of research and new exciting insights
In a recent paper published in Annual
Review of Ecology, Evolution & Systematics, Dave Richardson and Spanish collaborator and C·I·B Fellow Anna Traveset review
the mechanisms whereby such positive interactions mediate invasions and are in turn influenced by invasions. They focus on three main types of
mutualisms (pollination, seed dispersal, and plant-microbial symbioses) and draw on examples from many types of ecosystems and from species- and
This review provides further evidence that “diffuse” mutualisms are the norm in most ecosystems and across most categories of
mutualisms and that is allows many alien species to infiltrate recipient communities. The authors identify key traits that influence invasiveness
(e.g. selfing capacity in plants, animal behavioural traits) or invasibility (e.g. partner choice in mycorrhizas and rhizobia) through mutualistic
Biological invasions are causing disruptions to mutualisms on a much greater scale than is generally recognized, and cascading effects of such
disruptions are becoming common. In many cases, invasions act synergistically with other elements of global change to affect mutualisms. Such complex
impacts are seldom considered when the impacts of invasive species are enumerated. Consequently, potential impacts of many invasive species are
Most insights on the roles of mutualisms in invasions are from observations, and more manipulative experiments are needed to elucidate the full
complexity of species interactions to understand fully the mechanisms involved.
Potential effects of biological invasions on different types of mutualisms compared with effects caused by other drivers of global change. Symbols: ∆ changes in; ↑ increases in; ↓ decreases in.
Read the paper:
Traveset, A. & Richardson, D.M. (2014).
Mutualistic interactions and biological invasions. Annual Review of Ecology, Evolution, and Systematics. 45: 89-113
For further information, contact Dave Richardson