The Northern California Current (NCC) ecosystem exhibits extreme seasonal, interannual and interdecadal shifts in the abiotic environment and shifts in primary and higher production. This variability is also apparent in the spatial structure of the ecosystem with nearshore-shelf waters (<150 m isobath) being highly productive and having a different community...
Variable ocean conditions can greatly impact lower trophic level prey assemblages in marine ecosystems, with effects propagating up to higher trophic levels. Our goal was to better understand how varying ocean conditions influence diets and niche overlap among a suite of low- to mid trophic level predators. We studied the...
Humans are increasing the scale and frequency of many natural disturbances, as well as adding novel disturbances to ecosystems. This thesis uses the arthropod community as a metric to examine the multi-trophic responses to disturbances in California grasslands. Chapter 2 explores how the long-term exclusion of native vertebrate herbivores has...
This dissertation focuses on the importance of pelagic subsidies in the Northeast Pacific to rocky shore community regulation. My results document the patterns of pelagic subsidy supply, determine if those subsidies are correlated with community structure, and examine if community regulation differs between areas of high- and low-subsidies. Understanding how...
In the Coast Range of western Oregon, some natural resource managers are converting red alder-dominated riparian areas to conifers to increase the future source of in-stream large wood for salmonid habitat. However, studies in Alaska have shown red alder-dominated riparian areas support greater invertebrate biomass compared to conifer-dominated areas. In...
Dislodged macroalgae and seagrasses, also known as marine wrack, frequently wash into coastal ecosystems from the ocean and are potentially important ecological resources for biological communities. These!nutrient and organic matter subsidies may be especially important on sandy beaches, where little in situ primary productivity exists for higher trophic levels. To...
The effects of harvesting Pacific hake (Merluccius productus)
were examined with a multi-species numerical model composed of
seven logistic growth equations coupled by a food web. The
food web was composed of: California sea lions (Zalophus
californianus), hake, sablefish (Anaplopoma fimbria), spiny
dogfish (Squalus acanthias), a generic rockfish species
(Sebastes...
Small pelagic fish represent a critical trophic link between plankton and large predators in marine upwelling ecosystems such as the California Current System. Populations of these fish are highly variable over time and are characterized by extreme fluctuations in abundance, which have significant ecosystem impacts. The causes driving
this instability...
Recent research conducted throughout the Northern California Current (NCC) on the ecology of Pacific salmon (Oncorhynchus spp.) indicates that variable ocean conditions affect the community composition of zooplankton in the nearshore environment which, in turn, can affect the quality of prey for fish, sea birds and mammals. Interannual variability in...
Within systems characterized by substantial spatial and temporal variability, abundances of organisms tend to be higher in localized areas. Within the northern California Current system, the identification of such marine, biological hotspots would be of great importance to resource managers, conservationists, and research planners, and is consequently a growing area...