Birds affected the community structure of an Oregon rocky shore by
preying upon mussels (Mytilus spp.) and limpets (Collisella spp.). The
impact of such predation is potentially great, as mussels are the
competitively dominant mid-intertidal space-occupiers, and limpets are
important herbivores in this community.
Prey selection by birds reflects differences...
The stability of a limpet-dominated community was
assessed in a experiment in which an consumer was
temporarily removed. Compared to unmanipulated plots,
the limpet-exclusion plots developed greater algal
abundance and altered species composition of both algae
and barnacles. The community was not perturbed beyond
its capacity to recover, since the...
The feeding ecology of a common temperate mesoherbivore, the oligophagous sea slug Placida dendritica (Gastropoda: Opisthobranchia: Ascoglossa), was examined from April 1985 to June 1989. Along the central coast of Oregon, Placida consumed three host species: the low intertidal green algae Codium setchellii, C. fragile, and Bryopsis corticulans. Individual slugs...
Factors affecting the persistence of mussels (Mytilus californianus) and their associated epibiont species were studied along the central Oregon coast. Interactions between mussels and their algal epibionts (Endocladia
muricata) varied in sign and strength with environmental conditions. In extreme temperatures mussel—epibiont interactions determined survival of individual mussels,
and persistence of...
I examined the biomechanical factors that influence the sizes of intertidal macroalgae by studying a population of Fucus gardneri at Fogarty Creek Point, OR. I constructed a mathematical model to predict optimal sizes and probabilities of survival for Fucus under conditions of high and low wave exposure. Predicted optimal sizes...
The relationship between nutrients and community structure is poorly understood in open-coast habitats. I created a system of artificial tidepools, of identical age and physical dimensions, at two sites that differed in wave exposure, and manipulated nutrient levels and the abundance of herbivores. Using these unique field mesocosms, I explored...
The influence of large-scale processes on natural communities has become one of the central issues of modern ecology. I combined field and laboratory studies to investigate the effects of variation in coastal upwelling on rocky intertidal communities along the central Oregon coast. I examined whether the growth of intertidal barnacles...
Rockfish of the genus Sebastes are important components of Oregon reef communities. I examined patterns of age and growth in young-of-year rockfish across two nested spatial scales – local and regional – along the Oregon coast. Using otolith microstructural examination, I examined the relative importance of local versus regional factors...
Two of the most powerful ways in which humans have altered ecosystems are by increasing productivity and changing the densities of important consumers. The bottom-up effects of productivity and the top-down effects of consumers have been identified as primary determinants of biological diversity, though the links between them remain unclear....