This page has moved, as Dr. Byrnes is now a postdoc at UCSB. The Stachowicz Lab
Stachowicz Lab University of California, Davis

Jarrett Byrnes

Graduate Student in Population Biology
University of California - Davis
CV: [-doc-]

Molgula manhattensis, an introduced tunicate on the west coast of North America.

Styela clava, an introduced solitary tunicate from Asia.

Current Projects
  • To examine the effects of predator diversity on trophic cascades, I have been manipulating three predators (Cancer magister, C. productus, and Pycnopodia helianthoides) in mesocosms with fixed high diversity community of herbivores and kelp. Thus Measurements indicate that increasing predator diversity while holding abundance constant will increase kelp growth. Further experiments have shown that this is due to different herbivores responding behaviorally to different predators.

  • Examining lists of marine species invasions and extinctions, my colleagues and I have found that consumers and predators tend to be more likely to go extinct while invaders tend to be filter feeders and deposity feeders. I am currently manipulating community consumer diversity in the field to look at how this might change the community structure of sessile invertebrates on highly invaded docks, as well as the number of cover of non-native species.

  • Increasing invasive filter feeder diversity may change either rates of water filtration or the types of species being filtered out of the water column. To test how changing invasive versus native species diversity may alter filtration in slow-flowing dock communities, I am manipulating filter feeder diversity in mesocosms over 24 hours. I am examining both changes to in vivo chlorophyll and actual community composition using flow cytometry. I am also assessing rates of nutrient regeneration.

  • I am currently analyzing photos of native and invasive species in founling communities taken in harbors, marinas, and jetties from Arcata to San Diego in California. As these samples can be nested into a variety of spatial scales, I am hoping to tease apart at what spatial scale biotic interactions become more important in determining community invasibility than more regional abiotic factors.

  • While we all love Light's Manual, field ecologists taking data from visual samples in the field often don't have the leisure to go through a complete taxonomic identification of every species in their quadrats. This is particularly true for the often difficult to identify bryozoans and tunicates. Along with other collaborators, I am working on compiling a visual catalog of byrozoans and tunicates of the Pacific west coast available on the web. If you are interested in contributing to this project, or would like to start up a similar ID gallery for another phyla or another geographic locale, contact me, and I'd be more than happy to help.

  • As an Invasive Species IGERT long term fellow, I am currently participating working on a documentary of the Lake Davis Northern Pike invasion. The project seeks to focus on the various causes and consequences of invasive species control, using an the Lake Davis story of what can go wrong, and garner lessons of how to more successfully work with communities to control harmful invasives in the future.

    The Introduced Eastern Wild Turkey, Meleagris gallopavo.

  • Research Interests
    As a graduate student in the Population Biology program, I am primarily interested in the functional consequences of biodiversity. While a great deal of research has focused on the effects on differing levels of diversity in trophically basal species, I am interested in the community and trophic consequences of changes in both herbivore and predator diversity in rocky subtidal communities as well as dock fouling communities.

    High diversity systems have also been suggested to be more resistant to bioinvaders. While at a small spatial scale, competition may keep out bioinvaders, when sampling at large spatial scales, the same factors that increase local native diversity will also increase invader diversity. I'm interested in using fouling communities to examine the role of diversity at different spatial scales in conferring resistance to bioinvaders.

    The invasive tunicate Didemnum lahillei (formerly Didemnum vexillum), an invader on both coasts of America, New Zealand, and possibly elsewhere. I am currently working with Bob Miller and others to map the spread of this invader.

    The Northern Pike, an invader in California and Alaska Aquatic ecosystem. It has already caused problems for the salmon industry in Alaska, and is predicted to have a serious deleterious impact of fisheries in Califronia if it is able to escape into the Delta.

    Convoluta convoluta, an introduced acoel from Europe found in the Gulf of Maine subtidal.

    Hughes A.R., Byrnes J.E., Kimbro D.L. & Stachowicz J.J. 2007. Reciprocal relationships and potential feedbacks between biodiversity and disturbance. Ecology Letters, 10, 849-864. [-pdf-] [-link-]

    Byrnes J.E., Reynolds P.L., and Stachowicz J.J. 2007. Invasions and Extinctions Reshape Coastal Marine Food Webs. PLoS ONE 2: e295. [-pdf-] [-link-]

    Bullard S.G., Lambert G, Carman MR, Byrnes J.E., et al. 2007. The invasive colonial ascidian Didemnum sp.: current distribution, basic biology, and potential threat to marine communities of the northeast and west coasts of North America. Journal of Experimental Marine Biology and Ecology. 341: 99-108. [-link-]

    Stachowicz, J.J. and Byrnes, J.E. 2006. Species diversity, invasion success and ecosystem functioning: combining experimental and observational approaches to assess the roles of resource competition, facilitation and extrinsic factors. Marine Ecology Progress Series. 311: 251-262. [-pdf-] [-link-]

    Byrnes J.E., Stachowicz J.J., Hultgren K.M., Hughes A.R., Olyarnik S.V. & Thornber C.S. 2006. Predator diversity strengthens trophic cascades in kelp forests by modifying herbivore behavior. Ecology Letters. 9. 61-71. [-pdf-] The definitive version is available at

    Flag in the Ground Productions (Byrnes, J.E., Lead Editor). 2005. Fear and Fishing in Lake Davis. A documentary exploring the scientific and societal issues surrounding the eradication of invasive Northern Pike in Lake Davis, California. To order a copy or see a preview, go here. Flag in the Ground Production is: Byrnes, J.E., Chamberlin, E.C., Elmendorf, S.C., Fischer, R.A., Olyarnik, S.V., and Wright, A.N.

    Byrnes, J.E. and Witman, J.D. 2003. Impact assessment of an invasive flatworm, Convoluta convoluta, in the southern Gulf of Maine. Journal of Experimental Marine Biology and Ecology. 293. 173-191. [-pdf-] [-link-]

    My research blog
    Invertebrate Songs
    The Ascidian News
    Nonindigenous Species Database Metasearch
    Invasive Species Information Node
    Aquatic Invasions Research Database
    Nonindigenous Aquatic Species
    Didemnum sp. A home page

    The R Project for Statistical Computing - open source flexible stats software
    A Quick and (Very) Dirty Intro to Doing Your Statistics in R by Byrnes, J.E.
    GNU Octave - an open source MATLAB replacement.
    X11 for MacOSX from apple
    The Fink Project - UNIX applications for OSX computers