Award: DEB-1050694

Climate change is the pre-eminent problem of this century (Hoegh-Guldberg & Bruno 2010, IPCC 2013). The ubiquity of climate change means even ecosystems that are relatively undisturbed by human activity or by invasive species, like the rocky intertidal, will not escape the onslaught of rising temperatures and altered climate regimes (Harley et al 2006). I am uniquely positioned to understand and possibly even predict the consequences of climate change because of decades of research in this system. To take advantage of this experience, in 2010 I proposed a combined empirical and theoretical approach to the study of climate change impacts on a well-studied but complex, multi-species ecosystem. I asked: How will community structure, the abundance, zonation, and diversity of species in the rocky intertidal, respond to climate-related physical and biological changes? How do species interactions buffer community responses to climate change?

Discoveries include: (1) changes in abundance of the dominant space-occupier, mussels, are related to climate-driven changes in water temperature and winds, (2) additional species such as barnacles and species of seaweeds decreased and increased with increasing variation in coastal winds. (3) These changes seems driven primarily by the supply of new young "recruits" to populations of sessile invertebrates, and how this varies along the Oregon coast. Experiments testing species interactions effects and disturbance effects on space occupiers such as barnacles, mussels and algae indicate that these factors are not related to the changes summarized in (1) and (2) above.

Variation in the supply of recruits provides the mechanistic link to climate. For example, the connection to wind is through its influence on upwelling, the oceanic process that drives coastal productivity and transports the young stages of many sessile invertebrates including barnacles and mussels. Upwelling is intensifying with climate warming, thereby altering both currents and sea water temperature, and influencing coastal invertebrates and algae.  Thus, my research has demonstrated an increasing influence of climate on the patterns of abundance and diversity of coastal organisms through climate-driven changes in coastal oceanography.

Broader impacts: A recent disease epidemic hit sea stars in the last year of the project, causing dramatic declines in sea star abundance. Besides presenting a new challenge in our research activities, this event also led to greater opportunities for graduate student training, as students incorporated studies of wasting impacts on the coastal communities into their theses. It also led to new opportunities to communicate with the public, both through direct talks and through media interactions. In addition to capacity-building through graduate training, undergraduates, high school students, and citizen "scientists" have benefited from involvement in the research.

 

Last Modified: 02/01/2016
Modified by: Bruce A Menge