Jon D. Witman Professor of Biology

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.

Brown Affiliations

Research Areas

scholarly work

Witman, J.D., R. W. Lamb and J. E. K. Byrnes. In press. Towards an integration of scale and complexity in marine ecology.  Ecological Monographs (Centennial Issue)

Palardy, J. E and J. D. Witman 2014. Flow, recruitment limitation, and the maintenance of diversity in marine benthic communities. Ecology 95: 286-297.

Weissburg, M.. B. Helmuth and J. Witman. 2014. The physical context of marine communities.  Pp. 11-36, Chapter 2 in Bertness, M.  J. Bruno, B. Silliman and J. Stachowicz eds. Marine Community Ecology and Conservation  Sinauer Press

Altieri, A.H. and J. D. Witman 2014. Modular mobile foundation species as reservoirs of biodiversity. Ecosphere 5(10):124. 1 – 11.

Witman, J.D., P.K. Dayton, S. Arnold, R.S. Steneck and C. Birkeland 2013. Scuba revolutionizes marine science. Pp 3 -11. Smithsonian Contributions to Marine Science no 39.,Washington DC

Witman, J. D. 2013 Are regional effects on local diversity more important in marine than in terrestrial communities ? Oikos. 122: 301-305

Brandt, M., J.D. Witman and A. Chiriboga 2012. Influence of a dominant consumer species reverses at increased diversity.  Ecology 93:  868-878.

Dee, L. E, J.D. Witman and M. Brandt. 2012 . Refugia and top-down control of the pencil urchin Eucidaris galapagensis in the Galapagos Marine Reserve. Journal of Experimental Marine Biology and Ecology. 416-417: 135-143.

Palardy, J. and J.D. Witman 2011. Water flow drives biodiversity by mediating rarity in marine benthic communities. Ecology Letters 14:63-68  

Witman, J.D., M. Brandt and F. Smith 2010. Coupling between subtidal prey and consumers along a mesoscale upwelling gradient in the Galapagos Islands. Ecological Monographs 80: 153-177.

Lee, D. E., J.H. Robinson, J.D. Witman, S.E. Copeland, F. Smith, E.M. Harper and M. Lamare.  2010 Observations on recruitment, growth and ecology in a diverse living brachiopod community, Doubtful Sound, Fiordland, New Zealand. Special Papers in Paleontology 84:177-191. 

Irving, A. D. and J.D. Witman 2009. Positive effects of damselfish override negative effects of urchins to prevent a habitat switch. Journal of Ecology 97: 337-347.

Kotta, J. and J.D. Witman 2009. Regional scale patterns Pp 89-99. In: Hard Bottom Communities: patterns, scales, functions, shifts. M. Wahl (Ed), Springer-Verlag, Berlin, Germany 

Witman, J.D. and K. Roy 2009 Marine Macroecology. Edited book, University of Chicago Press.

Witman, J.D. and K. Roy 2009.Introduction. Chapter 1 in Marine Macroecology. University of Chicago Press. Pp. vii – xv. J.D. Witman and K. Roy editors 

Roy, K.R. and J.D. Witman 2009.  Species diversity of shallow marine invertebrates: patterns, processes and prospects. Chapter 4 in Marine Macroecology Pp. 101-121. University of Chicago Press. J.D. Witman and K. Roy editors 

Leichter, J.J. and J.D. Witman. 2009 Basin-scale oceanographic influences on marine macroecological patterns. Chapter 8 in Marine Macroecology. Pp. 203-226. University of Chicago Press. J.D. Witman and K. Roy editors

Witman, J. D. and K. R. Roy 2009. Experimental marine macroecology.  Chapter 13 in Marine Macroecology. University of Chicago Press. Pp. 341-356 J.D. Witman and K. Roy editors 

Witman, J. D., M. Cusson, P. Archambault, A. J. Pershing and N. Mieszkowska. 2008. The relation between productivity and species diversity in temperate – Arctic marine ecosystems.  Ecology 88: S66­S80. 

Ellis, J.C., M. J. Shulman, M. Wood, J. D. Witman, and S.  Lozyniak 2007. Regulation of intertidal food webs by avian predators on New England rocky shores . Ecology 88: 853-863. 

Witman, J.D.  2007 Benthic - pelagic coupling.  Pp 68-71.  In: Encyclopedia of tidepools and rocky shores M.W. Denny and S.D. Gaines (eds.) University of California Press, Berkeley, CA 

Ellis, J.C., Fariña, J.M., and Witman, J.D. 2006.  Nutrient transfer from sea to land: the case of gulls and cormorants in the Gulf of Maine.  Journal of Animal Ecology.75: 565- 574.

Lindsey, E, L., Altieri, A.H. and J.D.Witman 2006. Influence of biogenic habitat on the recruitment and distribution of a subtidal xanthid crab. Marine Ecology Progress Series 306: 223-231.

Shelton, A O., D. A. Woodby, K. Hebert and J. D. Witman 2006. Evaluating age determination and spatial patterns of growth of the red sea urchin (Strongylocentrotus franciscanus) in southeast Alaska.   Transactions of American Fisheries Society 135: 1670-1680.  

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.

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

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.

Witman, J.D., M.R. Patterson and S.J. Genovese. 2004 Benthic pelagic linkages in subtidal communities: influence of food subsidy by internal waves.  Pp 133-153 in Polis, G.A., M.E. Power and G.R. Huxel Ed. Food webs at the landscape level. University of Chicago Press. 

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.

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.

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

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

Hill, M.F., J.D. Witman and H. Caswell 2002. Spatio-temporal variation in Markov Chain models of subtidal community succession. Ecology Letters, 5: 665-675

Lucky, A., T.L. Erwin and J.D. Witman 2002. Temporal and spatial diversity and distribution of  arboreal Carabidae in a Western Amazonian Rain Forest. Biotropica 34: 376 – 386.  

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.

Bruno, J.F., C. Siddon, J.D. Witman and P.L. Colin. 2001. El Niño related coral bleaching in Palau, Western Caroline Islands. Coral Reefs. 20: 127-136 

Witman, J.D and K.R. Grange. 1998. Links between rain, salinity and predation in a rocky subtidal community. Ecology 79: 2429-2447 

Smith, F. and J.D. Witman. 1999.  Species diversity in subtidal landscapes: maintenance by physical processes and larval recruitment. Ecology 80: 51-69

Genovese, S.J and J.D. Witman. 1999. Interactive effects of flow speed and particle concentration on growth rates of an active suspension feeder. Limnology and Oceanography. 44: 1120- 1131 

Leichter, J.J. and J.D. Witman. 1997. Water flow over subtidal rock walls: effects on distribution and growth of suspension feeders. Journal of Experimental Marine Biology and Ecology 209: 293-307. 

Pile, A.J., M.R. Patterson and J.D. Witman. 1996. In situ grazing on plankton < 10 um by the boreal sponge Mycale lingua. Marine Ecology Progress Series. 141: 95-102

Bruno, J.F. and J.D.Witman. 1996. Defensive mechanisms of scleractinian cup corals against overgrowth by colonial invertebrates. Journal of Experimental Marine Biology and Ecology. 207: 229-241. 

Andres, N. G. and J.D. Witman 1995. Trends in community structure on a Jamaican reef. Marine Ecology Progress Series. 118: 305-310. 

Lesser, M.P, J.D. Witman and K.P. Sebens. 1994. Effects of flow and seston availability on scope for growth of benthic suspension feeding invertebrates from the Gulf of Maine. Biological Bulletin. 187:319­335 

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.

Sheild, C.J. and J. D. Witman. 1993. The impact of Henricia sanginolenta predation on the finger sponges, Isodictya spp. Journal of Experimental Marine Biology and Ecology 166: 107 -133.  

Dumas, J.V. and J.D. Witman 1993. Predation by gulls on two rocky intertidal crabs, Cancer irroratus and Carcinus maenus. Journal of Experimental Marine Biology and Ecology 169: 89 – 101 

Witman, J. D. and K. P. Sebens. 1992. Regional variation in fish predation intensity: a historical perspective in the Gulf of Maine.  Oecologia  90: 305 - 315.

Witman, J. D. 1992. Physical disturbance and community structure of exposed and protected reefs: a case study from St. John, U.S. Virgin Islands. American Zoologist 32: 641-634. 

Edmunds, P.J and J.D. Witman. 1991. Effect of Hurricane Hugo on the primary framework of a reef along the south shore of St. John, US Virgin Islands. Marine Ecology Progress Series 78: 201-204. 

Witman, J. D. 1988. Stability of Atlantic kelp forests.  Trends in Ecology and Evolution. 3: 285- 286.

Witman, J. D.  1988. Effects of predation by the fireworm Hermodice carunculata on milleporid hydrocorals. Bulletin of Marine Science. 42: 446-458. 

Witman, J. D. 1987. Subtidal coexistence:  storms, grazing, mutualism, and the zonation of kelps and mussels.  Ecological Monographs 57:  167-187. 

Witman, J. D. 1985. Refuges, biological disturbance, and rocky subtidal community structure in New England. Ecological Monographs 55:  421-445

Witman, J.D. and T.H. Suchanek. 1984. Mussels in flow: drag and dislodgment by epizoans. Marine Ecology Progress Series.16: 259 - 268. 

Witman, J.D. and R.A. Cooper. 1983. Disturbance and contrasting patterns of population structure in the brachiopod Terebratulina septentrionalis from two subtidal habitats. Journal of Experimental Marine Biology and Ecology. 73: 57-79. 

research overview

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.

research statement

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.

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).