The influence of humans on ecosystem dynamics
has been, and continues to be, profound. Anthropogenic
effects are expected to amplify as human populations continue
to increase. Concern over these effects has given rise to a large
number of studies focusing on impacts of human activities on
individual species or on biotic community structure and
composition. Lacking are studies on interactions, particularly
mutualisms. Because of the role of mutualisms in ecosystem
stability, such studies are critically needed if we are to begin to
better understand and predict the responses of ecosystems to
anthropogenic change. Most organisms are involved in at least
one mutualism, and many in several. Mutualisms facilitate the
ability of partners to exploit particular habitats and resources,
and play a large role in determining ecological boundaries.
When change disrupts, enhances, or introduces new organisms
into a mutualism, the outcome and stability of the
original partnership(s) is altered as are effects of the symbiosis
on the community and ecosystem as a whole. In this paper,
using examples from six microbe-insect mutualisms in forest
and savanna settings, we showcase how varied and complex
the responses of mutualisms can be to an equally varied set of
anthropogenic influences. We also show how alterations of
mutualisms may ramify throughout affected systems. We
stress that researchers must be cognizant that many observed
changes in the behaviors, abundances, and distributions of
organisms due to human activities are likely to be mediated by
mutualists which may alter predictions and actual outcomes in
significant ways.