Stachowicz Lab University of California, Davis


Positive Interactions and Mutualisms


Ecological investigations of the past several decades have focused on negative interactions (competition and predation) and how they affect population and community structure. Although positive interactions (interactions in which one at least one species benefits and neither is harmed were studied decades ago, there has been limited effort to factor them into our models or thinking about factors impacting populations and communities. My work tries to balance this by using experimental investigations of positive interactions to study the population biology of the participants and the effects of these interactions on communities as a whole.

Mithrax living in its coral host coral.

Ostracods living in the filaments of the algae Cladophora. Cladophora gives them a home while the ostracods extrete nutrients for the algae.
My recent work in this area has focused on the integration of facilitation and positive interactions into mainstream ecological theory. Most of our models implicitly or explicitly are derived from niche theory that essentially ignores positive interactions. With colleagues at UNC and Brown, I assessed how the most tried and true conceptual models of community ecology are changed as a result of the consideration of positive interactions. My most recent empirical work in this area focuses on how communities of mutualists interact with one another and whether multiple mutualists affect the host in different ways than either does alone (either synergistically or antagonistically.
Relevant Papers

Bruno, J. F., J. J. Stachowicz, and M. D. Bertness. 2003. Inclusion of facilitation into ecological theory. Trends in Ecology & Evolution 18:119-125. [-pdf-]

Stachowicz, J. J. 2001. Mutualism, facilitation, and the structure of ecological communities. BioScience 51:235-246. [-pdf-]

Stachowicz, J. J., and R. B. Whitlatch. 2005. Multiple mutualists provide complementary benefits to their seaweed host. Ecology 86:2418-2427. [-pdf-]

Bracken, M. E. S., C. A. Gonzalez-Dorantes, and J. J. Stachowicz. 2007. Whole-community mutualism: Associated invertebrates facilitate a dominant habitat-forming seaweed. Ecology 88:2211-2219. [-pdf-]