2007 Progress Report: Thresholds And Multiple Stable States In Southern New England Shallow Water Estuarine Communties

EPA Grant Number: R832448
Title: Thresholds And Multiple Stable States In Southern New England Shallow Water Estuarine Communties
Investigators: Osman, Richard W. , Whitlatch, Robert B. , Zajac, Roman N.
Institution: Smithsonian Environmental Research Center
EPA Project Officer: Hiscock, Michael
Project Period: September 1, 2005 through August 31, 2007 (Extended to August 31, 2008)
Project Period Covered by this Report: September 1, 2006 through August 31, 2007
Project Amount: $299,694
RFA: Exploratory Research: Understanding Ecological Thresholds In Aquatic Systems Through Retrospective Analysis (2004) RFA Text |  Recipients Lists
Research Category: Aquatic Ecosystems , Ecosystems , Water

Objective:

We are using a number of different modeling approaches to investigate threshold dynamics in a representative set of shallow-water communities of the southern New England region. Our goal is to determine how the distribution of distinct, easily-recognized alternate communities can be used to develop and measure the success of management decisions on local to regional scales. The main system is the Long Island Sound (LIS) estuary and its complex system of multiple habitats, sub-estuaries and rivers with multiple land uses and environmental stresses, both natural and anthropogenic. This system has a diverse set of management concerns that span site-specific to habitat to regional in scale. We are focusing on the diverse set of benthic invertebrate communities that are integral to multiple habitats within LIS, have diversity of species and life-histories, and exist in at least four known community states. Our modeling is directed at the transitions among these communities. The two main objectives are:

  1. To use existing data to first examine the potential global, regional, and local processes that cause switches among threshold states of the communities in LIS and under what conditions these states remain resilient and unchanged.
  2. To contrast and evaluate adaptive management strategies for this system in the face of climate change.

Progress Summary:

In Year 2 we have used 4 separate modeling approaches to address both Objectives 1 and 2., the developing and testing the necessary models for examining the processes contributing to thresholds as well as causing shifts among alternate threshold states. To date we have:

  • Conducted a third project evaluation and planning workshop in early 2007 to review progress and develop strategies for future modeling efforts and their integration.
  • Participated in and presented our results to date at the EPA Program Workshop in June, 2007.
  • Finished the critical assembling, cataloguing, and standardization of all data critical to model development and testing. These core biological, ecological, geographic, and environmental data are being applied to the various models under the direction of different investigators.
  • Developed a set of defined threshold characteristics that can be used in evaluating models. It is critical to define a priori what model outputs will be interpreted as system resilience and threshold states as well as what changes will be interpreted as a breakdown in a threshold, the absence of threshold behavior, or the transition to a new threshold state. The degree of variability that can be accommodated as part of any stable state also was defined.
  • Developed and applied qualitative loop models to analyze the stability of the four defined states within the system and analyze what changes would lead to instability.
  • Completed the development and application of population and community models using Matlab. This research is the focus of Dr. Munguia. He has concentrated on the role and level of environmental disturbance necessary to change the spatial-temporal distribution of the four community states within the system. This research will be submitted for publication in 2008.
  • Modifying and expanding the spatially-explicit, hydrographic model developed by Dr. John Hamilton, a postdoctoral fellow with Dr. Whitlatch. This model has been expanded to examine a larger geographic area, to include a greater diversity of species life-history characteristics that encompass the key threshold species and communities, and to encompass defined threshold states. Model output has also been greatly expanded to allow a greater flexibility in questions addressed and increased statistical rigor. Model input has been expanded to increase applicability to management decisions.
  • A geographic information system (GIS) risk assessment model has been developed to analyze the risk to temperate coastal systems of invasive fouling species. The initial results from this modeling effort will be presented at the 2008 Benthic Ecology Meetings in Providence, RI.
  • Continued the development of methods to integrate models and define overlapping scales for models. A key element in this integration has been examining the same questions using the different modeling approaches and contrasting predictions.
  • Continued integrating new information on a new invader in the region, the colonial ascidian, Didemnum sp. The recent invasion of this species has the potential to change threshold states or, possibly add a new state to the system being modeled. Other projects being conducted by several of the principal investigators are addressing the ecology of this species and these data are being integrated into the modeling efforts. Management issues for this species may be quite different for this species because it can occur in high abundances in deeper water habitats outside marinas. Its spread may be linked to bottom trawling of these habitats and its ability to thrive and spread as colony fragments created by trawling activities.

Future Activities:

Present modeling efforts and model integration will continue and be expanded. It is anticipated that as simpler models are tested and validated they will be expanded in complexity in order that they can be adapted to address the broadest array of management questions. We will also continue to update and integrate new data and re-evaluate models. Activities planned include:

  • A workshop in early 2008 to evaluate progress and plan final project modeling efforts. This workshop will focus on project productivity including publications, presentations at national meetings, and outreach to the management community.
  • A final project workshop is also planned for the late summer to examine all results, evaluate the project, and prepare materials for publication and the final report.
  • Publication of project results. At present three publications are in draft form and will be submitted in 2008.
  • The presentation of results at one or more international scientific meetings. At least two presentations will be given at the Benthic Ecology Meetings in Providience, RI.
  • Expand specific project pages on existing web sites. At present the project is described in general terms. The additions will supply specific model results and provide links for researchers and managers to access the models.
  • Present model applications to local or regional managers. This may be done as a small forum or as a one-day workshop.
  • Presentation of the threshold concept, implications, and applications to resource management and environmental concerns to the general public. This will be done through normal outreach activities of the principal investigators.


Journal Articles on this Report : 4 Displayed | Download in RIS Format

Other project views: All 34 publications 8 publications in selected types All 8 journal articles
Type Citation Project Document Sources
Journal Article Altman S, Whitlatch RB. Effects of small-scale disturbance on invasion success in marine communities. Journal of Experimental Marine Biology and Ecology 2007;342(1):15-29. R832448 (2006)
R832448 (2007)
R832448 (Final)
R830877 (Final)
  • Full-text: Science Direct Full Text
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  • Abstract: Science Direct Abstract
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  • Other: Science Direct PDF
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  • Journal Article Bullard SG, Lambert G, Carman MR, Byrnes J, Whitlatch RB, Ruiz G, Miller RJ, Harris L, Valentine PC, Collie JS, Pederson J, McNaught DC, Cohen AN, Asch RG, Dijkstra J, Heinonen K. The colonial ascidian Didemnum sp. A: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 2007;342(1):99-108. R832448 (2006)
    R832448 (2007)
    R832448 (Final)
    R830877 (Final)
  • Full-text: Science Direct
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  • Abstract: Science Direct Abstract
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  • Other: Science Direct PDF
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  • Journal Article McCarthy A, Osman RW, Whitlatch RB. Effects of temperature on growth rates of colonial ascidians: a comparison of Didemnum sp. to Botryllus schlosseri and Botrylloides violaceus. Journal of Experimental Marine Biology and Ecology 2007;342(1):172-174. R832448 (2006)
    R832448 (2007)
    R832448 (Final)
    R830877 (Final)
  • Full-text: Science Direct Full Text
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  • Abstract: Science Direct Abstract
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  • Other: Science Direct PDF
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  • Journal Article Osman RW, Whitlatch RB. Variation in the ability of Didemnum sp. to invade established communities. Journal of Experimental Marine Biology and Ecology 2007;342(1):40-53. R832448 (2006)
    R832448 (2007)
    R832448 (Final)
    R830877 (2005)
    R830877 (Final)
  • Full-text: Science Direct Full Text
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  • Abstract: Science Direct Abstract
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  • Other: Science Direct PDF
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  • Supplemental Keywords:

    Ecological thresholds, multiple stable states, global climate, marine, estuary, ecological effects, ecosystem indicators, ecology, modeling, Northeast,, RFA, Scientific Discipline, Air, Ecosystem Protection/Environmental Exposure & Risk, Aquatic Ecosystems & Estuarine Research, climate change, Air Pollution Effects, Aquatic Ecosystem, Environmental Monitoring, Ecology and Ecosystems, Ecological Risk Assessment, Atmosphere, anthropogenic stress, estuarine research, ecological thresholds, anthropogenic impact, ecosystem indicators, modeling ecosystem change, aquatic ecosystems, water quality, ecosystem stress, riverine ecosystems, trophic interactions, ecosystem response

    Relevant Websites:

    http://www.serc.si.edu/labs/benthic_ecology/index.jsp Exit
    http://www.marinesciences.uconn.edu/teamb/Pages/Team%20Benthos.htm Exit
    http://newton.newhaven.edu/rzajac/index.html Exit

    Progress and Final Reports:

    Original Abstract
  • 2006 Progress Report
  • Final Report