1. The mechanisms important to community structure and function at local and regional spatial scales in dune, estuary, and rocky intertidal communities.

Our work involves using observational and experimental methods to explore the relative importance of local versus regional effects on community structure and function in dune, estuary, and rocky intertidal communities.

For our estuary and rocky shore research, we are using observations and experiments at sites across the latitudinal range from Washington to Oregon to northern California to understand how variable nutrients, phytoplankton productivity, and ocean acidification produced by ocean upwelling influence the interactions among dominant community members.

Here are some selected references for our recent work:

  • Barner, A.K., S.D. Hacker, B.A. Menge, and K.J. Nielsen. 2016. The complex net effect of reciprocal interactions and recruitment facilitation maintains an intertidal kelp community. Journal of Ecology 104:33-43.
  • Hessing-Lewis, M., S.D. Hacker, B.A. Menge, S. McConville, J. Henderson. 2015. Are large macroalgal blooms necessarily bad? Nutrient impacts on seagrass in upwelling-influenced estuaries. Ecological Applications 25:1330-1347.
  • Menge, B.A., T.C. Gouhier, S.D. Hacker, F. Chan and K. Nielsen. 2015. Are metaecosystems organized hierarchically? A model and test in rocky intertidal habitats. Ecological Monographs 85:213–233.
  • Hessing-Lewis, M.L., S.D. Hacker. 2013. Latitudinal trends in macroalgal blooms and seagrass production in northeast Pacific upwelling-influenced estuaries. Limnology and Oceanography 58:1103–1112.
  • Gouhier, T.C., B.A. Menge, S.D. Hacker. 2011. Recruitment facilitation can promote coexistence and buffer population growth in metacommunities. Ecology Letters 14:1201–1210.
  • Moulton O.M., S.D. Hacker. 2011. Congeneric variation in surfgrasses and ocean conditions influence macroinvertebrate community structure. Marine Ecology Progress Series 433:53-63.


2. The protective role of ecosystems in mitigating coastal vulnerability from climate change.

Coastal ecosystems, particularly beaches and dunes, are gaining recognition as important arbiters of the effects of extreme storms, sea level rise, and tsunamis. We study the biophysical interactions between coastal vegetation and sand supply to better understand the implications for large-scale variation in coastal geomorphology and coastal protection. We have studied these biophysical interactions in the Pacific Northwest coast where invasive beach grasses have significantly changed the ecosystem structure, function, and services of coastal dunes. We are also studying these interactions in the Central Atlantic coast where native beach grasses experience erosion and overtopping on a regular basis. Our work has been inspired by a collaborative project at the National Center for Ecological Analysis and Synthesis that considered the ecosystem services of coastal interface habitats and their usefulness in coastal management.

Here are some selected references for our recent work:

  • Zarnetske, P., P. Ruggiero, S.D. Hacker, E. Seabloom. 2015. Coastal foredune evolution: the relative influence of vegetation and sand supply in the US Pacific Northwest. Journal of the Royal Society Interface 12: http://dx.doi.org/10.1098/rsif.2015.0017.
  • Zarnetske, P., T. Gouhier, S.D. Hacker, E. Seabloom, V. Bokil. 2013. Indirect effects and facilitation among native and non-native species promote invasion success along an environmental stress gradient. Journal of Ecology doi: 10.1111/1365-2745.12093.
  • Seabloom, E.W., P. Ruggiero, S.D. Hacker, J. Mull, P.L. Zarnetske. 2013. Invasive grasses, climate change, and exposure to storm-wave overtopping in * coastal dune ecosystems. Global Change Biology 19:824-832. Hacker S.D., P. Zarnetske, E. Seabloom, P. Ruggiero, J. Mull, S. Gerrity, C. Jones. 2012. Subtle differences in two non-native congeneric beach grasses significantly affect their colonization, spread, and impact. Oikos 121:138–148.
  • Zarnetske, P., S.D. Hacker, E.W. Seabloom, P. Ruggiero, J.R. Killian, T.B. Maddux, D. Cox. 2012. Biophysical feedback mediates effects of invasive * grasses on coastal dune shape. Ecology 93:1439-1450.
  • Barbier E., S.D. Hacker, C. Kennedy, E. Koch, B. Silliman, A.D. Stier. 2011. The value of estuarine and coastal ecosystem services. Ecological Monographs 81:169-193.
  • Koch E.W., E.B. Barbier, B. Silliman, G.M.E. Perillo, D.J. Reed, S.D. Hacker, E. Wolanski, J. Primavera, E. Granek, S. Polasky, S. Aswani, L.A. Cramer, D. Stoms, C. Kennedy, D. Bael, C. Kappel. 2009. Nonlinearity in ecosystem services: temporal and spatial variability in coastal protection. Frontiers in Ecology and the Environment 7:29–37.
  • Barbier E.B., E.W. Koch, B. Silliman, S.D. Hacker, E. Wolanski, J. Primavera, E. Granek, S. Polasky, S. Aswani, L.A. Cramer, D. Stoms, C. Kennedy, D. Bael, C. Kappel, G.M.E. Perillo, D.J. Reed. 2008. Coastal ecosystem-based management with non-linear ecological functions and values. Science 319: 321-323.


3. The invasion, modification, and restoration dynamics of invasive coastal plants.

This aspect of our research involves exploring how non-native species invade and modify their environment, and the mechanisms involved in restoration, under different ecological contexts. In particular, we are studying beach grass invasions as described above. We have also studied the invasion of the estuarine grass Spartina anglica and the eelgrass Zostera japonica in the Pacific Northwest. Through a series of experiments, our work has produced results that inform general theories on the ecology of invasions. In particular, we find that invasion, removal, and restoration of these estuarine grasses and the habitats they engineer are highly context dependent. These results have led us to explore in more detail the ecological consequences of removing invaders; we predict that the legacy effects of highly modifying invaders can produce widely varying and alternative restoration outcomes.

Here are some selected references for our recent work:

  • Henderson, J., S.D. Hacker. 2015. Buried alive: an invasive seagrass (Zostera japonica) changes its reproductive allocation in response to sediment disturbance. Marine Ecology Progress Series 532:123–136.
  • Ruesink J.L., J. Fitzpatrick, B.R., Dumbauld, S.D. Hacker, A.C. Trimble, E.L. Wagner, L.M. Wisehart. 2012. Life history and morphological shifts in an intertidal seagrass following multiple disturbances. Journal of Experimental Marine Biology and Ecology 424-425:25-31.
  • Ruesink J.L., J-S. Hong, L. Wisehart, S.D. Hacker, B.R. Dumbauld, A.C. Trimble, M. Hessing-Lewis. 2010. Congener comparison of native (Zostera marina) and introduced (Z. japonica) eelgrass at multiple scales within a Pacific Northwest estuary. Biological Invasions 12: 1773–1789.
  • Zarnetske P.L., E.W. Seabloom, and S.D. Hacker. 2010. Non-target effects of invasive species management: Beach grass, birds, and bulldozers in coastal dunes. Ecosphere 1:13.
  • Hacker S.D., M.N. Dethier. 2009. Differing consequences of removing ecosystem–modifying invaders: significance of impact and community context to restoration potential. Pages 375–385 in: Marine Bioinvasions: Ecology, Conservation and Management Perspectives, Editors: Gil Rilov and Jeffrey Crooks, Springer-Verlag.
  • Hacker S.D., M.N. Dethier. 2006. Community modification by a grass invader has differing impacts for marine habitats. Oikos 113: 279-286.
  • Dethier M.N., S.D. Hacker. 2005. Physical factors vs. biotic resistance in controlling the invasion of an estuarine marsh grass. Ecological Applications. 15:1273-1283.
  • Hacker S.D., D. Heimer, C.E. Hellquist, T.G. Reeder, B. Reeves, T. Riordan, M.N. Dethier. 2001. A marine plant (Spartina anglica) invades widely varying habitats: potential mechanisms of invasion and control. Biological Invasions 3: 211-217.