Fiorenza Micheli

Assistant Professor of Biological Sciences
Marine Community Ecology
Tel. (831) 655-6250
E-mail: micheli@stanford.edu
CV

My research focuses on evaluating and understanding the processes and interactions shaping coastal marine communities, and incorporating this understanding in the management and conservation of marine ecosystems. I direct my efforts towards both basic and applied ecological issues. Fishing, coastal development, and other human activities directly and indirectly affect marine organisms and habitat and cause major alterations of entire ecosystems. My research seeks to apply marine 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 increased nutrient loading and fishing on marine ecosystems, and incorporating our understanding of diversity patterns, species interactions, and habitat-species linkages in the design and evaluation of marine reserve networks. I am a fellow of the Aldo Leopold Leadership Program, a member of the Ecological Society of America "Ecological Visions Project", and of the Monterey Bay National Marine Sanctuary research activity panel.

The questions I ask include: (1) How do species interactions structure marine communities? How do the patterns and effects of biotic 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 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, primarily fisheries, in coastal environments? What criteria should guide the design and evaluation of marine protected areas and other spatial approaches to marine management and conservation?

To tackle these questions, I use field experiments, comparative field studies utilizing physical gradients and variation of human impacts in time and/or space, synthesis of existing data, and modeling. I have conducted research in estuaries, mangroves, deep-sea hydothermal vents, and more recently in rocky shores, and temperate and coral reefs.

Ongoing projects focus on species interactions, habitat-organism relationship, and disturbances in rocky shores and temperate reefs of California, California estuaries, and coral reefs and associated coastal habitats in the Bahamas to increase our understanding of population and community variability across different spatial and temporal scales, and apply this understanding to spatial management, conservation, and restoration of coastal marine ecosystems.

In addition to providing an important conservation and fisheries management tool, marine protected areas provide unique human-exclusion "experiments", allowing for an examination of human impacts on coastal marine communities over spatial and temporal scales that cannot be addressed through manipulative field experiments. We have established a series of field studies comparing community and population patterns and processes among central California marine protected areas that have been protected to varying degrees and for different amounts of time (reports). These studies are designed to determine the separate and joint effects of human disturbance to rocky shore assemblages from trampling and collecting of invertebrates and algae, and of natural disturbance from waves. Comparisons of diversity and community structure along gradients of human use and wave exposure are complemented with ongoing manipulative experiments examining responses of assemblages to controlled levels of disturbance. We are also investigating the processes underlying the persistence and possible recovery of black, Haliotis cracherodii, and red, H. rufescens, abalone populations in central California. Abalone populations have undergone precipitous decline in California starting in the late 1960s, and all commercial and sport fishing south of San Francisco was halted in 1997. White abalone, H. sorenseni, was the first marine invertebrate to be included in the U.S. Endangered Species List, and black abalone is now under evaluation for listing. Intense fishing effort, El Nino events affecting feeding and reproduction, predation by sea otters, and disease all contributed to the decline. A major challenge for ecology, conservation, and management is determining what factors and processes allow marine populations to persist and recover after they have been reduced to low levels through fishing or through natural disturbances. We compared abalone abundances and size structure among eight different areas, protected from 10 to 70 years, and resumed a 30-year study initiated by J. Pearse and colleagues in 1972 within the Hopkins Marine Life Refuge (HMLR). Results to date indicate that abalone populations have remained at low densities despite protection, and that densities and size structure have been remarkably stable over the past 30 years, despite intense predation by sea otters. We are currently investigating the demographic and ecological processes that may underlie these patterns by quantifying recruitment, growth and mortality rates of abalone in the field. The next step will be to combine these empirical data with demographic models and stochastic simulations to examine alternative scenarios for persistence or recovery of these populations.

Through my continued involvement in working groups at NCEAS (specifically "Development of tools for the practical design of marine reserves", led by A. Hastings and L. Botsford, "Linking marine biodiversity to ecosystem functions and services", led by B. Worm and E. Sala, and "Putting ocean wilderness on the map: building a global GIS atlas of 'pristine' marine environments", led by B. S. Halpern, F. Micheli, and H. S. Lenihan), I addressed the general question of what are the patterns and temporal scales of recovery in marine communities using meta-analytical techniques. Synthesis of studies of fish assemblages in marine reserves spanning 1-25 years of protection showed that: (1) only species that are targeted by fishing or by aquarium trade showed overall enhanced abundances in protected areas; (2) positive effects of protection on abundances of top predators increase through time; (3) up to a third of species in different studies (19% on average) are negatively affected by protection, indicating that indirect effects of protection through competitive or predatory interactions may be common; and (4) variation and lags in species responses to protection resulted in protected assemblages diverging from reference conditions, with greater proportions of total fish biomass at top trophic levels in protected compared to fished assemblages. These results indicate that marine reserves are effective in enhancing local abundances of exploited species and restoring the structure of whole communities, though these changes occur through a series of transient states and, for some communities, over long time frames (decades). In collaboration with members of these working groups, we are currently developing modeling studies attempting to separate population recovery due solely to decreased fishing mortality from possible enhancement of recruitment, meta-analyses examining how patterns of recovery from fishing compare to those following natural catastrophic events, such as major storms or predators outbreaks, and how recovery of ecological functions may map onto changes in community structure, and analyses of global threats to marine ecosystems.

In addition to these local studies, I am currently involved in two projects, both 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 D. 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 (CBC Bahamas, Stanford Report). In 2000, the Bahamas Government committed to protecting 20% of the Bahamian marine ecosystem. The commitment of the Bahamian Government to establishing 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. I am also the principal investigator in a project studying environmental, social, and economic influences on the dynamics and sustainability of small-scale fisheries along the Pacific coast of Baja California, Mexico. This interdisciplinary project involves faculty and students from a suite of institutions, including Stanford University, University of California-Santa Barbara, Rutgers University, University of Texas-Austin, University of Maine, and the Centro de Investigaciones Biologicas del Noroeste, La Paz, Baja California Sur. Small-scale fisheries employ 50 of the world's 51 million fishers and produce over half of the world's annual marine fish catch, supplying 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, which were granted exclusive fishing rights on local stocks, including abalone, lobsters, oysters, clams, and shrimp. Cooperatives throughout 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 success of the small-scale fisheries of Baja California. Through my involvement in these multi-disciplinary research program 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 am hoping to be able to make significant contributions to better integrating ecological understanding into conservation of marine seascapes and associated assemblages.