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Primary production in the Delta: Then and now

October 1, 2016

To evaluate the role of restoration in the recovery of the Delta ecosystem, we need to have clear targets and performance measures that directly assess ecosystem function. Primary production is a crucial ecosystem process, which directly limits the quality and quantity of food available for secondary consumers such as invertebrates and fish. The Delta has a low rate of primary production, but it is unclear whether this was always the case. Recent analyses from the Historical Ecology Team and Delta Landscapes Project provide quantitative comparisons of the areal extent of 14 habitat types in the modern Delta versus the historical Delta (pre-1850). Here we describe an approach for using these metrics of land use change to: (1) produce the first quantitative estimates of how Delta primary production and the relative contributions from five different producer groups have been altered by large-scale drainage and conversion to agriculture; (2) convert these production estimates into a common currency so the contributions of each producer group reflect their food quality and efficiency of transfer to consumers; and (3) use simple models to discover how tidal exchange between marshes and open water influences primary production and its consumption. Application of this approach could inform Delta management in two ways. First, it would provide a quantitative estimate of how large-scale conversion to agriculture has altered the Delta's capacity to produce food for native biota. Second, it would provide restoration practitioners with a new approach—based on ecosystem function—to evaluate the success of restoration projects and gauge the trajectory of ecological recovery in the Delta region.

Publication Year 2016
Title Primary production in the Delta: Then and now
DOI 10.15447/sfews.2016v14iss3art1
Authors James E. Cloern, April Robinson, Amy Richey, Letitia Grenier, Robin Grossinger, Katharyn E. Boyer, Jon Burau, Elizabeth A. Canuel, John F. DeGeorge, Judith Z. Drexler, Chris Enright, Emily R. Howe, Ronald Kneib, Anke Mueller-Solger, Robert J. Naiman, James L. Pinckney, Samuel M. Safran, David H. Schoellhamer, Charles A. Simenstad
Publication Type Article
Publication Subtype Journal Article
Series Title San Francisco Estuary and Watershed Science
Index ID 70178591
Record Source USGS Publications Warehouse
USGS Organization California Water Science Center; National Research Program - Western Branch