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...
Environmental stress can negatively affect the ability of organisms to reproduce. Energetic trade-offs exist in all organisms, and under stress, energy may be allocated away from reproduction and towards physiological defense and repair mechanisms. The rocky intertidal environment is ideal for investigating the influence of environmental stress, as organisms are...
The symbiosis between cnidarians, such as corals and sea anemones, and photosynthetic dinoflagellates belonging to the genus Symbiodinium spp. is one of the most productive in the marine environment. This mutualistic endosymbiosis allow reef-building corals to lay down the foundation of coral reef ecosystems, which supports a highly biodiverse community...
Spotted-wing drosophila (SWD, Drosophila suzukii) is an invasive fruit fly species native of Southeast Asia. In vineyards, SWD lays eggs in damaged and intact fruit of the most soft-skinned varieties, and feeds on damaged fruits during the harvest period. Feeding and oviposition activities increase the likelihood of vectoring spoilage bacteria,...
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...
Gradients of physical disturbance are central to
theories of community organization yet rarely are studies
performed in which physical factors are experimentally
manipulated. Pothole tidepool algal communities exhibit
distinct zonation patterns from top to bottom that result
from scouring by rocks and other debris in the pools.
Scouring is easily...
Ocean Acidification (OA) has emerged as a major threat to marine ecosystems, particularly regarding calcifying organisms. A growing body of literature describing laboratory investigations into pH stress indicates broadly deleterious effects for calcifiers, but responses vary greatly across taxa and can be influenced by variations in other environmental characteristics. Scaling...
Recruitment of larvae from the plankton is an important determinant of
community structure in marine systems. In populations of many marine species,
recruitment determines the basic demographic parameters of immigration, emigration,
and reproduction. Moreover, the effect of recruitment as an "ecological subsidy" can
determine the strength of interactions among species...
Ecologists must increasingly balance the need for accurate predictions about how ecosystems will be affected by climate change, against the fact that making such predictions at the ecosystem-level may be infeasible. Although information about responses of individual species to a changing environment is increasing, scaling such information to the community...
Organismal tolerance to abiotic environmental stresses contributes significantly to setting the distribution limits of organisms, as demonstrated by vertical zonation patterns in the marine intertidal zone. In this thesis, the ultimate (evolutionary) and proximate (mechanistic) causes of tolerance to temperature and emersion stresses associated with the intertidal zone were examined...
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...
The term "interaction" in evolutionary biology and ecology
describes the relationships among variables in two classes of causal
models. In the first, "interaction" refers to the influence of a
single putatively causal variable on a variable of interest. In the
second class of models, the term applies when a third...
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...
As ecologists are being called upon to predict the consequences of human
perturbations to natural communities, an important goal is to understand what factors
drive variability or consistency in nature.
In the rocky intertidal of San Juan Island, Washington, a comparative
experimental approach was used to investigate spatial and temporal...
This dissertation focuses on science relevant to the design and implementation of marine reserves. The chapters explore a range of topics related to among-site variation in population, community, and ecosystem dynamics. My results demonstrate the value and feasibility of integrating this knowledge into more comprehensive conservation and management approaches. While...
Foundation species are important components of ecosystems because they provide habitat and ameliorate stressful conditions for residents. This thesis considers the role of surfgrasses (Phyllospadix spp.) as dynamic foundation species on the coast of Oregon in two studies. Chapter 2, which presents an observational survey of two Phyllospadix congeners, investigates...
I studied the feeding behavior of marked individuals of the
carnivorous marine snail Thais melones in a rocky shore habitat of
Pacific Panama. The population of snails consume a variety of
invertebrate species such as bivalves, limpets, and polychaetes.
Individuals exhibited a range of diet breadth, with some
specialized, but...
With continual and worldwide human population growth, our impact on the natural environment expands and intensifies every day. We consume natural resources, burn fossil fuels, and release toxic compounds into the air, water, and earth. We build roads that fragment the landscape, construct new settlements, and develop agricultural lands in...
The influence of loss of diversity on community dynamics and ecosystem functioning has recently received considerable attention. Although study of biodiversity has a long history within ecology, empirical investigations exploring consequences of loss have been rare. Because many factors confound diversity comparisons, experimental manipulations of diversity offer the most direct...
Most climate change predictions focus on the response of individual species to changing local conditions and ignore species interactions, largely due to the lack of a sound theoretical foundation for how interactions are expected to change with climate and how to incorporate them into climate change models. Much of the...
Cnidarians, such as anemones and corals, engage in an intracellular symbiosis with
photosynthetic dinoflagellates. Corals form both the trophic and structural foundation of
reef ecosystems. Despite their environmental importance, little is known about the
molecular basis of this symbiosis. In this dissertation we explored the cnidariandinoflagellate symbiosis from two perspectives:...
The multifaceted role of the environment in regulating the structure and dynamics of biological communities has long fascinated ecologists and motivated much debate and research. Now, in a time of accelerated global changes due to human impacts, the need to understand how the environment shapes communities has gained new urgency....