Staff Profile
Ian Davidson Photo



My research focuses on patterns of marine biodiversity, the drivers of species distributions, and the impacts of anthropogenic change on benthic systems.  These studies range from local to ocean biogeographic scales using combinations of field work, experimental manipulations, and large-scale data sets.  Biological invasions and anthropogenic dispersal of organisms have been major components of my recent research, serving the dual function of informing science-based environmental management and acting as a model for studying community and population dynamics in the sea.

Education & Employment

2014-present: Ecologist, Smithsonian Environmental Research Center, Edgewater, Maryland, USA

2005-2013: Research Associate, Environmental Science & Management, Portland State University, Portland, Oregon

2004-2005: Postdoctoral Fellow, Portland State University, Portland, Oregon

2003-2004: Part-time consultant, Marine Environmental Impact Assessment, Aquatic Services Unit, University College Cork, Ireland

2001-2004: PhD Marine Ecology, University College Cork, Ireland

1996-2000: BSc Applied Ecology, First Class Honors, University College Cork, Ireland


Ashton GV, Davidson IC, Geller J, Ruiz GM  (2016) Disentangling the biogeography of ship biofouling: barnacles in the Northeast Pacific. Global Ecology & Biogeography. 25: 739-750.

Davidson I, Scianni C, Hewitt C, Everett R, Holm E, Tamburri M, Ruiz G (2016) Mini Review: Assessing drivers of ship biofouling management- aligning industry and biosecurity goals. Biofouling. 32:411-428.

Zabin CJ, Ashton GV, Brown CW, Davidson IC, Sytsma MD, Ruiz GM (2014) Small boats provide connectivity for nonindigenous marine species between a highly invaded international port and nearby coastal harbors. Management of Biological Invasions. 5:97-112.

Ashton G, Davidson I, Ruiz G (2014) Transient small boats as a long-distance coastal vector for dispersal of biofouling organisms. Estuaries and Coasts. 37:1572-1581.

Williams SL, Davidson IC, Pasari JR, Ashton GV, Carlton JT, Crafton RE, Fontana RE, Grosholz ED, Miller AW, Ruiz GM, Zabin CJ (2013) Managing multiple vectors for marine invasions in an increasingly connected world. BioScience. 63:952-966.

McCann L, Holzer K, Davidson I, Ashton G, Chapman M, Ruiz G (2013) Promoting Invasive species control and eradication in the sea: options for managing the tunicate invader Didemnum vexillum in Sitka, Alaska. Marine Pollution Bulletin. 77:165-171.

Simkanin C, Davidson IC, Dower JF, Jamieson G, Therriault TW. (2012) Anthropogenic structures and the infiltration of natural benthos by invasive ascidians. Marine Ecology. 33: 499-511.

Darling J, Herborg L-M, Davidson I. (2012) Intracoastal shipping drives patterns of regional population expansion by an invasive marine invertebrate. Ecology & Evolution. 2: 2557-2566

Davidson I, Simkanin C (2012) The biology of ballast water 25 years later. Biological Invasions. 14: 9-13.

Davidson IC, Zabin C, Chang A, Brown C, Sytsma M, Ruiz G. (2010) Recreational boats as potential vectors of marine organisms at an invasion hotspot. Aquatic Biology. 11: 179-191.

Davidson IC, Brown CW, Sytsma MD, Ruiz GM. (2009) The role of containerships as transfer mechanisms of marine biofouling species. Biofouling. 25: 645-655.

Simkanin C, Davidson I, Faulkner M, Sytsma M, Ruiz G. (2009) Intra-coastal ballast water flux and the potential for secondary spread of non-native species on the U.S. West Coast. Marine Pollution Bulletin. 58: 366-374.

Davidson I, Simkanin C (2008) Skeptical of assisted colonization. Science. 322: 1048-1049.

Davidson IC, McCann LD, Sytsma MD, Ruiz GM (2008). Interrupting a multi-species bioinvasion vector: The efficacy of in-water cleaning for removing biofouling on obsolete vessels. Marine Pollution Bulletin. 56: 1538-1544.

Davidson IC, McCann LD, Fofonoff PW, Sytsma MD, Ruiz GM (2008). The potential for hull-mediated species transfers by obsolete ships on their final voyages. Diversity & Distributions. 14: 518-529.

Davidson IC (2005). Structural gradients in an intertidal hard bottom community: examining vertical, horizontal and taxonomic clines in zoobenthic biodiversity. Marine Biology. 146: 827-839.

Davidson IC, Crook AC, Barnes DKA (2004). Macrobenthic migration and its influence on the intertidal diversity dynamics of a meso-tidal system. Marine Biology. 145: 833-842.

Davidson IC, Crook AC, Barnes DKA (2004). Quantifying spatial patterns of intertidal biodiversity: Is movement important? Marine Ecology. 25: 15-34.

Barnes DKA, Verling E, Crook AC, Davidson IC, O’Mahoney M (2002). Local population extinction follows (20 years after) cycle collapse in a pivotal species. Marine Ecology Progress Series. 226: 311-313.