Faculty Profile: Jon Witman, PHD

Jon Witman
Jon Witman, PHD
Professor of Biology
Ecology & Evolutionary Biology
Work: +1 401-863-3936
My research is directed toward understanding the dynamics of populations and communities living in marine hard substrate habitats. Our lab is conducting research focused around three themes: 1) physical forcing of marine benthic ecosystems, 2) studies on the origin vs. the maintenance of pattern, and 3) marine biodiversity. How community structuring processes vary with scale is a consideration that pervades all aspects of our research.


Growing up near the broad horizon of the ocean undoubtedly influenced my interest in large-scale marine ecology. I was trained in marine benthic ecology as a high school student at Sandy Hook Marine Lab, NJ. Studying the impacts of sewage and dredge spoil dumping on offshore marine life impressed upon me the need to mitigate anthropogenic impacts on the ocean. As an undergraduate, I was fortunate to conduct a year long independent study of animal-sediment relations in a New Zealand estuary. This experience taught me how to do science and it helped develop my world view of ecology and sense of belonging to a global human community. I spent another year and a half in the South Pacific, working my way through the Fiji and New Hebrides Islands to see pristine coral reefs before they were altered by human disturbance. I began to learn the spectacularly diverse marine invertebrate fauna of the western Pacific during this time, which helped enormously when I began a global biodiversity study nearly two decades later. I re-entered the academic community at the University of New Hampshire. Excited about the opportunities in marine community ecology, I went straight through for a PhD with Larry Harris. A post-doc at Northeastern University's Marine Science Center with Ken Sebens led to my first faculty position. I helped develop the East West Marine Biology Program there and enjoyed teaching marine benthic ecology in Nahant and coral reef ecology in Jamaica. I am deeply committed to training the next generation of ecologists and to developing the best marine conservation science. I moved to Brown University in 1994. I have been fortunate to conduct research in six out of seven oceans of the world.



Research Description

The perspective that patterns of local (m - km spatial scale) community structure are created by an interplay of local and regional (> 100 km) processes has been overlooked until recently. I believe that one can't understand how local communities tick without studying the influence of larger scale regional processes as well as local processes. Consequently, my overarching research goal is to integrate traditional community ecological, oceanographic, and new macroecological approaches to understand the structure and functioning of local marine communities. I have spent a substantial portion of my research life at sea conducting field work at many local sites in order to develop this broader perspective for marine subtidal communities. Our lab is particularly interested in framing our research questions so that they are relevant to conservation needs. More details on the predominant themes of my research program are presented below.

Regulation of food webs: A key question in ecology is what controls food web dynamics. I have focused primarily on the themes of bottom-up regulation by oceanographic processes and top-down predatory control, but have also investigated human impacts. My current food web research is examining the role of upwelling as an agent of bottom up - top down control of subtidal food webs in the Galápagos Marine Reserve (GMR), and human impacts on cod - dominated trophic cascades in the Gulf of Maine (GOM). In the GMR, this research is testing the general hypothesis that upwelling sites have high rates of algal and sessile invertebrate prey production, attracting consumers, and creating bottom-up and top-down linkages. We hypothesize that diversity at upwelling sites is enhanced by high predation on competitive dominants and by a diverse larval supply. Barnacles are the focal prey species since they are abundant throughout the Galápagos subtidal; they consume upwelling production and are heavily predated by whelks, fish and sea urchins. Consistent patterns of high barnacle recruitment and predation at 5 upwelling sites were revealed by working at 12 sites across a 120 km region of the GMR. In the GOM, we are revisiting offshore sites where cod dominated the food web in the late 1980's to test the hypothesis that overfishing of cod since then has changed top-down control of cod prey (crabs, etc.).

Coupling of physical and biological processes. A few decades ago the prevailing idea was that the subtidal zone was physically benign, characterized by low environmental variability. To the contrary, our lab has documented high environmental stress in the subtidal zone caused by large hydrodynamic forces, wide fluctuations of temperature, salinity, and hypoxia. We continue to test predictions of environmental stress models for these systems. The rocky subtidal zone is greatly influenced by pelagic events as we found for internal waves driving a pulsed food supply regime to the sea floor across large spatial scales in the GOM. Internal wave driven coupling appears to be an important engine of productivity for topographically high areas of the sea floor in general. Current research goals in the area of benthic pelagic coupling are to develop a general model of upwelling effects for subtidal communities and to test the hypothesis that upwelling confers higher resilience to communities, warranting conservation.

Biodiversity. I am interested in the origin and maintenance of biological diversity. A large part of my research has focused on the question of whether the numbers of species in local communities are primarily due to local processes such as competition, predation, disturbance, etc., or simply reflect a sink from the regional source pool of species that has assembled over evolutionary time due to processes of speciation, immigration, and extinction. By directly sampling the local species richness of epifaunal invertebrate communities in subtidal rock wall habitats on a global scale, we found that the richness of the regional species pool could explain 73 - 76 % of local richness. We are using our global data base of > 1500 diversity quadrats for further macroecological analyses of marine diversity patterns, specifically: 1) the relation between productivity, biodiversity, and body size from local-global spatial scales, 2) latitudinal variation in beta diversity and species rarity, 3) dispersal mode and the local regional diversity relationship, and 4) testing the neutral model of species diversity. One of the initial findings was that the proportion of regional biota represented in local communities increased from the tropics toward high latitude communities. Consequently, we are increasing the sampling of high latitude communities to test hypotheses explaining this effect, and are sampling the diversity of subtidal communities on the Alaskan peninsula in the summer of 2006. Since this work underscores the importance of source pools for local species richness, my students and I are investigating aspects of supply-sided ecology, but from a diversity rather than from a population standpoint. Despite the fact that the relationship between biodiversity and ecosystem functioning is critical for the conservation of biodiversity, little is known about this relation in marine communities. We have started to investigate how the biodiversity of grazers (urchins, fish) influences one measure of ecosystem function, productivity, in the Galápagos Marine Reserve.

Grants and Awards

1983 Best Paper in Ecology Award, Annual Meeting of the American Society of Zoologists



November 2005: Proposal Review Panel Member, NOAA West Coast National Undersea Research Program, Monterey, CA

September 2005: Census of Marine Life, Planning Priorities for Coastal Biodiversity in the Gulf of Maine Workshop, Portland, ME

September 2005–present: Advisor for Henry David Thoreau Foundation, Somerville, MA

August 2005: Primary organizer (with K. Roy) of Marine Macroecology Symposium at Annual Meeting of the Ecological Society of America, ESA-INTECOL meetings

April 2005: Marine Ecosystem Based Management, Princeton University, co-chair of working group on connectivity and EBM

July 2005: CORONA (trans Atlantic marine ecology) workshop, Roscoff, France , co-chair of working group on productivity – diversity relations in the North Atlantic

2003: Participant, 1st National Workshop on Census of Marine Life

2002: Participant & Steering Committee Member Workshop on Coordinating Research on the North Atlantic (CORONA)

2002: Participant, Workshop on Ocean Exploration in North Atlantic (NOAA)

2000–2003: Research advisor, NSF REU program at Shoals Marine Lab, Maine

Funded Research


2006-2007 Sloan Foundation/Gulf of Maine Census of Marine Life, "Human impacts on cod-dominated trophic cascades in the Gulf of Maine", 4/2006 ($32,000).

2002-present: NSF Biological Oceanography, "Developing a regional perspective for rocky subtidal communities: upwelling, biotic interactions and diversity regulation in the Galapagos Marine Reserve" ($480,000).

2005–present: National Undersea Research Program (NOAA), "Investigating Alaskan epifaunal communities in the context of latitudinal diversity gradients" ($77,433).

2005 Sea Grant, "Effects of hypoxia in Narragansett Bay" (Addendum to J. Witman and A. Altieri) ($5,000).

2003-2004 Sea Grant, "Effects of hypoxia on benthic communities of Narragansett Bay" (with Andrew Altieri) ($50,000).

2002-2004: NSF Division of Environmental Biology Dissertation Improvement Award for support of Julie C. Ellis's PhD research: "Gulls as cross ecosystem vectors in coastal New England food webs" ($20,000).

2000–2002 Andrew Mellon Foundation, "Marine biogeography and ecology: contrasting patterns and processes between hemispheres" (Co-PI with M.D. Bertness) ($250,000).

2001-2003 Technology Planning and Management Corporation, "Stellwagen Bank National Marine Sanctuary Seafloor Habitat Recovery Monitoring Program" ($45,000).

1998-2001 National Science Foundation, "How important are regional processes in determining the local species richness of marine communities" (Co-PI with R.Etter, UMASS, Boston) ($217,768 to Brown University).

2000–2001 National Undersea Research Program, NOAA, "Assessing decadal-scale changes in biodiversity at Pigeon Hill, Gulf of Maine" (7 days ship time with NITROX dive support) ($35,450).

2000–2001 NSF Research Opportunities at Undergraduate Universities, collaborator on multi-investigator grant submitted by Cornell University for research at Shoals Marine Laboratory (no funds to Brown; leader of 2-3 undergraduate research projects per year, support for grad students at SML).

1996–2001 Andrew Mellon Foundation, "The dynamics of marine ecosystems" (Co-PI with M.D.Bertness) ($400,000).

1999 National Science Foundation, "Supplement to Development of a Variable Flow Speed Research Flume Facility" (Co-PI with G.E. Goslow M.D. Bertness, and S. Schwartz) ($43,000).

1995–1999 National Science Foundation, "Development of a Variable Flow Speed Research Flume Facility" (Co-PI with G.E. Goslow, M.D. Bertness, and S. Schwartz) ($108,000).

1996–1997 National Science Foundation, "Effects of an unusual, large scale recruitment of blue mussels in the Gulf of Maine rocky subtidal zone" ($20,000).

1996 National Undersea Research Program, NOAA, "Sampling a pulsed food and larval supply regime with replicate pumps: variation along depth gradients" (Co-PI with M.R. Patterson, VIMS; 7 days ship time with NITROX dive support) ($16,000 to Brown University).

1994–1997 National Science Foundation, "Internal waves in the rocky subtidal zone: effects of pulsed food and larval supply on suspension feeding communities" (Co-PI with M.R. Patterson, VIMS; 21 days ship time) ($229,000 to Brown University).


NSF Office of International Science and Education, "Biodiversity and Ecosystem Function in the Galapagos Marine Reserve" ($150,000 requested).

Teaching Experience

BI 42 Principles of Ecology (undergraduate) Semester II every year from 1995-2010 (except 2001,2009) enrollment 60-150 students

BI 142 Experimental Design in Ecology (senior undergraduate, graduate) Semester I, 1997, 1999, 2001, 2003, 2005,2007, 2009 enrollment : 9- 20 students

BI 243, 244 Topics in Ecology and Evolutionary Biology (graduate)
taught as Experimental Design (1996), and co-taught with M. Bertness as Tropical Ecology (1996) and Community Ecology (2000), Macroecology: Past and Present, (2001, with C. Janis), Neutral Theory in Ecology and Genetics (2008, with D. Rand), Island Ecology and Evolution (2009 with D. Sax)

GISP Special Student Initiated Course in Underwater Research, Semester I 2000

Geo 291 Biodiversity, Semester I 1994 (co-taught with J.Mustard)

BI 195/196 Independent Study in Biology (24 advanced undergraduates supervised on research projects since 1995)

Selected Publications

  • Altieri, A.H and J.D. Witman. 2006 Local extinction of a foundation species in a hypoxic estuary: integrating individuals to ecosystem. Ecology 87: 717-730. (2006)
  • Hill, M.F, J.D. Witman and H.Caswell 2004. Markov chain analysis of succession in a rocky subtidal community. American Naturalist 164: E46-E61 (2004)
  • Witman, J.D., J.C. Ellis and W.B. Anderson. 2004. The influence of physical processes, organisms and permeability on cross-ecosystem fluxes. Pp 335-349 in Polis, G.A., M.E. Power and G.R. Huxel eds. Food webs at the landscape level. Univ Chicago Press. (2004)
  • Witman, J.D, R.J. Etter and F. Smith. 2004. The relationship between regional and local species diversity in marine benthic communities: a global perspective. Proceedings of the National Academy of Sciences USA 101: 156644 - 15669. (2004)
  • Siddon, C.E and J.D.Witman 2004. Behavioral indirect interactions: multiple predator effects and prey switching in the shallow rocky subtidal. Ecology 85: 2398-2945. (2004)
  • Witman, J.D. and F. Smith. 2003. Rapid community change at a tropical upwelling site in the Galapagos Marine Reserve. Biodiversity and Conservation. 12: 25-45 (2003)
  • Witman, J.D., S.J. Genovese, J. F. Bruno, J. W. McLaughlin and B. I. Pavlin. 2003. Massive prey recruitment and the control of rocky subtidal communities on large spatial scales. Ecological Monographs 73: 441-462 (2003)
  • Witman, J.D. and P.K. Dayton. 2001. Rocky subtidal communities. Pages 229-366 in M.D. Bertness, S.D. Gaines and M.E. Hay, editors. Marine community ecology. Sinauer Associates, Inc, USA. (2001)
  • Witman, J.D and K.R. Grange. 199814.5 (1998)
  • Witman, J.D., J.J. Leichter, S.J. Genovese, and D.A. Brooks. 1993 Pulsed phytoplankton supply to the rocky subtidal zone: influence of internal waves Proceedings of the National Academy of Sciences, USA 90: 1686-1690. (1993)