Historical Ecology
Sacramento-San Joaquin Delta Historical Ecology Study
Introduction to Project
The San Francisco Estuary Institute/Aquatic Science Center, in collaboration with the Department of Fish and Game, has initiated a historical ecology study of the Sacramento-San Joaquin Delta. The goal is to develop a clear understanding of what the Delta looked like and how it functioned ecologically and hydrogeomorphically prior to significant Euro-American modification.
The historical reconstruction will document, to the extent possible, patterns of variation and extent of habitats throughout the Delta to better understand species support functions and controlling physical processes within the native landscape. Such information will provide a basis for identifying target locations and physical conditions necessary to restore functional habitat mosaics within the projected future Delta landscape.
Given the extensive changes to the Delta, the goal of the project is not to create a literal template from which to recreate the historical Delta. Rather the objective is to understand how ecosystem function varied throughout the system in response to identifiable physical gradients (e.g. salinity, tidal range), to inform the large scale restoration strategies being considered.
Historical analysis has been an important tool for large wetland ecosystem restoration efforts in the U.S. (e.g. South Florida, Puget Sound). In these regions, historical reconstructions have enabled scientists and managers to identify practical strategies for ecosystem management within highly disturbed systems. Similar studies in the Bay Area and coastal California have led to a wide range of important insights into the complex systems we seek to enhance. While there has been some excellent prior historical research in the Delta (e.g. Brian Atwater, The Bay Institute), a tremendous amount of compelling historical information has not yet been compiled or synthesized.
Target Delta habitat characteristics include the following:
- Channel geometry and hydrodynamics: density of large and small channels, connectivity, sub-regional variation
- Tidal marsh: extent, transitions between fully tidal and occasionally tidal marsh, variation in freshwater marsh types, extent and character of floodplain basins
- Ponds and lakes: distribution, size, depth
- Riparian: downstream extent, width, composition
- Upland ecotone: characteristics, locations, and relative extent of transitions to palustrine perennial wetland, vernal pools, alkali meadows, open grassland, and oak savanna
- Ecosystem support function: species-habitat associations
In 2008, after a short pilot investigation, we presented early findings at the CALFED Science Conference. After a pause due to the State's financial crisis, we have resumed our efforts. In November, we presented initial findings at a CALFED Science Program Workshop on Historical Ecology of the Delta: Emerging Concepts of a Spatially Complex and Temporally Dynamic System.
Regular updates on project progress will be posted here.
For more information, please contact Robin Grossinger at robin
sfei.org, or Alison Whipple at alisonsfei.org
Project Downloads
Delta Historical Ecology Target Questions (PDF)
Historical Ecology of the Delta: Emerging Concepts of a Spatially Complex and Temporally Dynamic System. CALFED Science Program Workshop: Ecosystem Restoration at the Landscape Scale. November 2009 (PDF)
Pre-Modification Habitat Mosaics of the Delta: Looking to the past to envision the future. CALFED Science Conference October 2008 (PDF)
