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.
Current 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 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


We will investigate threshold dynamics of shallow-water estuarine communities of the southern New England and study 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 alternative states we have identified reflect different biodiversity conditions and impacts of invasive species. We will model the system on several different scales with two main objectives: (a) using existing data to examine global, regional, and local processes that cause switches among the four threshold states of the communities, and what conditions enable these states remain resilient and unchanged, and (b) contrasting and evaluating adaptive management strategies for this system in the face of climate change.


Our analyses will center on four integrated modeling efforts: (a) using qualitative or loop modeling to explore and test the stability and total feedback of various simplified system configurations, (b) using a hydrodynamic/ spatial explicit recruitment model to link threshold states in different habitats and sites, (c) a coupled population/community model to examine intra- and inter-specific interactions and threshold dynamics between the various groups of species and how they are influence by long- and long-term physical forcing functions, and (d) using landscape modeling to address broader regional aspects of threshold states within the LIS system, how changes in land-use alter threshold communities, and the necessary management strategies to restore or maintain the desired mixture and distribution of threshold states.

Expected Results:

Modeling and understanding transitions among these communities will provide strong predictive capabilities for managers and can be used to develop adaptive management scenarios that maintain ecosystem health and alert them of possible significant shifts in ecosystem properties which potentially may influence strategies for conservation and restoration. A focus will be on using invasive species as a metric for evaluating management outcomes.

Publications and Presentations:

Publications have been submitted on this project: View all 34 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 8 journal articles for this project

Supplemental Keywords:

Northeast, estuary, thresholds, transition states, ecosystem, ecology, qualitative modeling, loop modeling, hydrodynamic modeling, population modeling, climate change, invasive species,, 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

Progress and Final Reports:

  • 2006 Progress Report
  • 2007 Progress Report
  • Final Report