Office of Research Coastal & Marine Sciences Institute & Delta Sciences Program Symposium - Office of Research

Coastal & Marine Sciences Institute & Delta Sciences Program Symposium

Thresholds and Ecosystem Restoration

Among the goals of habitat restoration is the recovery of a particular set of ecological functions and services. Trying to understand and predict the trajectory and pace of recovery raises a number of important questions for resource managers: What types of trajectories characterize the recovery of altered ecosystems? Is the pathway to recovery similar to the pathway of alteration? Can we predict the end states of restoration pathways? Are end states similar to the condition prior to disturbance? Answers to these questions are important for restoration decision making and the development of monitoring, and assessment plans. The traditional view of ecosystems is that they predictably return to their pre-disturbance state or trajectory following disturbance or alteration. Recently, an increasing number of studies indicate that some ecosystems may experience multiple ‘alternative states’ and possibly ‘stable equilibria’ where a change from one state to another may be discontinuous, abrupt, and have multiple trajectories. Multiple equilibrium theory suggests that feedbacks that maintain a system in an ‘alternative’ state are likely very different from that maintain the target state. This suggests that management actions that can disrupt the feedbacks responsible for maintaining an altered state are critical to restoring the system to a target state. If such processes are relevant, restoration efforts could be more efficient if they focused on the thresholds that dictate change from an altered to the target state. There are several examples where multiple states might exist diverse habitats including: 1) shallow seasonally flooded ponds vs. deep permanent ponds in the Delta, 2) native vs. non-native aquatic vegetation in Delta channels, abundant vs. scarce wetland cover or eelgrass vs. mudflat in the San Francisco estuary and kelp forests vs. urchin barrens along the California coast. However, the degree to which the basic theory of multiple states accurately describes many ecological systems, and therefore the potential relevance of thresholds to management decisions, is debated. Habitat restoration provides unique opportunities to test this theory to inform both our basic understanding of ecological systems and effective management approaches.

How can scientific understanding of ecosystem multiple states more effectively inform restoration and management, and vice versa? Addressing these questions requires scientists to understand challenges that confront managers in making a decision about ecosystem restoration, as well as managers to understand the methods available to diagnose ecosystem changes and associated uncertainties. To achieve this exchange, this one-day symposium will bring together scientists and managers considering multiple stable states in a wide variety of ecosystems. The central goals of the symposium are to (1) inform scientists about decision-making process and real-world challenges in ecosystem management and restoration, (2) inform managers of the latest decision support tools emerging from science on ecosystem multiple stable states, and (3) promote dialogue and potential collaboration among scientists and managers working on the delta-estuary-marine ecosystem continuum. 

Registration is capped at 150 attendees for this symposium due to seating capacity.

Video recording of this symposium will be available on the CMSI website within one week after the symposium.

*PLEASE NOTE: Registration for the symposium is free. We are again offering an optional prepaid catered lunch to all registrants. The registration system is automatically set-up to receive a payment of $12.00 by credit card from you for the cost of the lunch. If you do not wish to purchase the prepaid lunch, please enter STMBDQQPRX in the coupon code box on the registration page. This will zero-out the cost of lunch.

Symposium Planning Committee: Marissa Baskett (UCD), Dylan Chapple (DSP), Xiaoli Dong (UCD), Ted Grosholz (UCD), Carole Hom (UCD), and Nir Oksenberg (DSP).

Date: November 19, 2019, 8:30am-4:30pm

Location: UC Davis Student Community Center Multi-Purpose Room

Tentative Schedule:

7:30-8:30 registration/breakfast/set up posters etc.
8:30-8:45 opening remarks from DSP and CMSI
8:45-9:15 Science, Management, Restoration, Monitoring, and Policy
Alan Hastings, UC Davis

Morning Session 1. Management Perspective
9:15-10:35 Management perspectives on MSS across systems
Jim Cloern, US Geological Survey
Fred Sklar, South Florida Water Management District
Cynthia Catton, California Department of Fish and Wildlife
Ted Sommer, CA Dept of Water Resources
10:35 – 10:55 Morning Break

Morning Session 2. State of the Art in Science
10:55 -12:15 Scientific advancements and key unknowns relevant to MSS
Albert Ruhi, UC Berkeley
Deb Peters, USDA-ARS-Jornada Experimental Range
Anne Salomon, Simon Fraser University
Jim Morris, University of South Carolina
12:15-1:45 Lunch & poster session*

Afternoon Session 1. Case studies
1:45- 3:05  Examples of threshold-based restoration: what has worked and what hasn’t?
Karen Thorne, USGS
Kathy Boyer, SFSU
John Bourgeois/Dave Halsing, ESA/CA Coastal Conservancy
Jameal Samhouri, NOAA Northwest Fisheries Science Center
3:05 – 3:25 Afternoon Break

Afternoon Session 2. Identifying path forward
3:25 – 4:00 What are key management and policy unknowns and what is the path forward for science to better cope with the problems
Katie Suding, University of Colorado, Boulder
4:00 – 4:30 Panel Discussion with audience questions (Moderator: Ted Grosholz)

If you would like to submit a poster abstract, please fill out the form at


Share This Story