Professor of Biological Sciences
Marine Community Ecology
Hopkins Marine Station
Tel. (831) 655-6250
My research focuses on the processes and interactions shaping coastal marine communities and incorporating this understanding in the management and conservation of marine ecosystems. I am most interested in how disturbance and interactions between species underlie the organization, spatial variation, and temporal change in marine communities. In addition to addressing these basic ecological questions, my research seeks to apply community ecology to increase our understanding of human impacts on the marine environment and to design conservation and restoration strategies. Examples include quantifying the joint effects of fishing and climate change on marine ecosystems and incorporating our understanding of diversity patterns, species interactions, habitat-species linkages, and patterns of human use of natural resources in the design, management and evaluation of marine reserve networks and marine zoning.
The questions I ask include: (1) What is the role of species interactions in structuring marine communities? How does the strength and consequences of interactions vary along physical gradients? How commonly and under what conditions do indirect effects (e.g., trophic cascades) occur? (2) What levels of diversity and what types of communities are compatible with different types and intensities of anthropogenic disturbance to coastal marine ecosystems? How do anthropogenic disturbances compare and combine with natural disturbances to influence marine communities? (3) What factors and processes influence the persistence and recovery of populations that have been reduced to low levels by overexploitation, predators, or disease? (4) How does human alteration of the structure and diversity of marine communities influence their ecological function? What are the trajectories of recovery of community structure and function once human disturbance is removed (e.g., within marine reserves)? (5) How can ecology increase our understanding and guide management of human-natural systems in coastal environments? What information and criteria should guide the design and evaluation of marine protected areas and other ecosystem-based approaches to marine management and conservation?
To tackle these questions, I use a combination of approaches, including field experiments, comparative field studies utilizing physical gradients and variation of human impacts in time and/or space, synthesis of existing data, and modeling. This choice is motivated by the need to address different scales of organization when dealing with complex multi-species systems and with processes shaping such systems over local to regional scales. Thus, while experiments allow for a mechanistic understanding of the dynamics of simpler systems and sets of interactions, these need to be placed in a broader and more realistic context using comparative and synthetic studies. I have studied a variety of marine ecosystems, including tropical and temperate estuaries, rocky shores, rocky reefs, deep-sea hydrothermal vents, marine pelagic ecosystems, and coral reefs. Over the past years, my research interests have focused increasingly on temperate and tropical reefs.
In addition to experimental approaches, in past and current research, I have used marine reserves in the Caribbean, the Mediterranean, California and Baja California as large-scale experiments 'manipulating' the intensity of human use of temperate and tropical reefs. In Baja California, we continue to monitor reserves established voluntarily by local communities and we work collaboratively with the Mexican NGO Comunidad y Biodiversidad to use these no-take areas to investigate responses of kelp forest populations and assemblages to climate-induced hypoxic events we gave recently documented. In the Mediterranean Sea, as a Pew fellow in marine conservation, I am using gradients in the types and intensity of human uses of the coastal marine environment to investigate community responses to these multiple stressors, and establish what types and combinations of activities may be compatible with the maintenance of healthy coastal ecosystems and different economic sectors. My goal is to increase our understanding of how multiple stressors influence Mediterranean marine ecosystems, inform management of existing marine protected areas, and guide future marine spatial planning.
Coastal marine ecosystems are complex systems influenced by the feedbacks between biophysical and human processes, uncertainties in factors shaping these processes, and unique behaviors of their individual components. Developing interdisciplinary collaborations and approaches for studying the complex linkages and feedbacks between natural and human systems in coastal environments is a key component of my research program and one on which I intend to continue to build in the future. Over the past decade, I have been part of projects funded by the National Science Foundation – Biocomplexity in the Environment Program, that integrate science in marine management and conservation in the Bahamas and in Baja California.
I am part of a team of ecologists, oceanographers, resource economists and anthropologists, led by Daniel Brumbaugh (American Museum of Natural History, NY), conducting field and modeling studies of the function of marine reserve networks in conserving biodiversity, sustaining fisheries, and promoting sustainable uses of coral reef ecosystems in the Bahamas. In 2000 the Bahamian Government committed to protecting 20% of the Bahamian marine ecosystem. The commitment of the Bahamian Government to establish a comprehensive marine reserve network represents a unique opportunity for integrating science in marine conservation throughout the different phases of the design, establishment, and evaluation of reserves, including investigating how existing reserves function in protecting and restoring coral reef ecosystems. Our collaborative project has addressed the physical and biological connectivity within the Archipelago, the configuration and ecological linkages in seascapes, and how people use and value the services that these ecosystems provide. I am part of a subgroup focusing on the population dynamics of key fisheries species, the patterns and processes underlying variation in fish and benthic communities across the archipelago, and the linkages between habitat and the ecological functions and ecosystem services provided by these coastal ecosystems. Thus, our group is addressing ecological questions on the structure and function of Bahamian seascapes and integrating results with those generated by empirical and modeling studies focused on socioeconomics, genetics, and physical oceanography being conducted by other members of the team.
I have also been the principal investigator of a program studying environmental, social, and economic influences on the dynamics and sustainability of small-scale fisheries along the Pacific coast of Baja California, Mexico. Small-scale fisheries employ 50 of the world's 51 million fishers, produce over half of the world's annual marine fish catch, and supply most of the fish consumed in the developing world. Despite the overwhelming social and economic importance of small-scale fisheries and the widespread degradation of the associated marine resources and ecosystems these systems are poorly understood. Community-based management, co-management, and market incentives can all foster long-term stewardship and ecosystem protection, but their applicability and success to date has varied. Beginning in the 1930's, the nearshore fisheries of Baja California were organized into local cooperatives that were granted exclusive fishing rights on local stocks including abalone, lobsters, oysters, clams, and shrimp. Cooperatives along the coast operate under different permits that give them greater or lesser degrees of control over their local resources, and vary broadly in their ecological setting and in the success and sustainability of their main fisheries (primarily for lobster and abalone). Our objective is to develop an integrated framework for addressing environmental and socioeconomic processes underlying the varying performance of the small-scale fisheries of Baja California. Performance is evaluated in terms of resource productivity, economic yield, sustainability of human activities and communities, and persistence of marine populations and ecosystems. Specific research questions include: (1) What are the relative roles and feedbacks between environmental variability and human institutions in determining the performance of small-scale fisheries? (2) How do feedbacks among biophysical and human components of small-scale fisheries vary across spatial (local to regional) and temporal (year-to-year vs. decadal) scales? (3) What fisheries management systems are more robust to uncertainty?
Ultimately, our objective is to better understand the complex interactions between small-scale fisheries of the Pacific coast of Baja California, México, and the biological resources with which they are associated in order to provide a scientific framework to better inform the management of coastal fisheries. We are developing a series of integrated biophysical, agent-based, and bioeconomic models, conducting statistical analysis and retrospective analyses of historical trends in catches, effort, and oceanographic conditions, and acquiring new data through ecological and ethnographic field studies. Three graduate students in my group have conducted their dissertation research as part of this program. We are currently continuing this research, in collaboration with COBI personnel, to investigate what processes and strategies may promote resilience of these social-ecological systems in the face of climatic impacts and resource depletion.
Through my involvement in these research programs studying the complex biophysical and socioeconomic feedbacks within two space-based approaches to marine management and conservation, marine protected areas and exclusive fishing rights, I hope to continue to make significant contributions to improving the integration of ecology into conservation of marine seascapes and their associated organisms.
My research program will continue to build on field-based and synthetic analyses of how species interactions, habitat-species linkages, and disturbance shape marine communities with a particular focus on applications to conservation, management, and restoration of marine ecosystems. Since I arrived at Stanford, I have built a research group working on basic questions in community ecology and their applications to real-world problems. Members of my lab will continue to apply a range of approaches, integrating field experiments, comparative studies, syntheses of diverse datasets, modeling, and GIS, isotopic and genetic analyses that we conduct collaboratively with the labs of colleagues at Stanford, such as Robert Dunbar (Geological and Environmental Sciences), Stephen Monismith (Civil and Environmental Engineering), Steve Palumbi, Giulio De Leo and Mark Denny (Biology) and elsewhere. We have focused on temperate and tropical reefs as our primary systems for this work, and we will continue to develop our ongoing research programs in these coastal ecosystems, both locally and internationally.