HABITAT 100,000 DELTA D E LTA ~ 2015 ~ 2002 ~ 1800 0 . . S TAT U S . . Poor . . . .T R E N D . . . . B AY . . S TAT U S . . No change Fair None available . . . .T R E N D . . . . Improving .....BENCHMARK..... 100,000 acres TIDAL MARSH I N B I G PATC H E S > 500 ACRES 50 Poor ~ 2002 ~ 1800 0 Poor 25 DELTA Fair 75 BAY Good 100% Fair Analysis of trends in the second indicator sug- gests that the proportion of tidal marsh habitat in big patches (greater than ~ 500 acres) has decreased since 1800. This trend is much more pronounced in the Delta than in the Bay. In the Bay, the current proportion of total tidal marsh 200,000 ~ 2009 ~ 1800 By contrast, the regional extent of tidal marsh in the Delta has only grown by 260 acres since 2002. The Delta had about 8,000 acres in 2002. This area is 4% of the 180,000 acre reference value; 10% of the 78,000 acre reference value; and 47% of the 17,000 acre reference value. 300,000 ACRES Good that the regional extent of tidal marsh in the Bay has recently grown by thousands of acres. In 2009, the Bay had about 45,000 acres, or 45% of the 100,000-acre goal. Since 2009, an additional 6,300 acres have been opened to the tides. Much of this restored habitat is expected to transition into tidal marsh in the future and, if counted in full, would bring the regional extent of tidal marsh to 51% of the goal (see table). BAY 400,000 Fair Poor STATUS & TRENDS Analysis suggests Tidal marsh restoration efforts in the Delta lag behind those underway the Bay. Part of this can be explained by the extensive subsid- ence of the Delta’s peat islands — while these extensive areas once supported tidal marsh, many now sit 10-25 feet below sea-level at an elevation that is much too low for vegetation to grow. This still leaves about 70,000 acres, mostly diked lands on the Delta periphery, as suitable in elevation for restoration according to landscape analyses. This acreage does not, however, account for what percentage of the area will actually be available for restoration given other priority land uses. Looking forward, restoration and mitigation projects expected to break ground within the next two years would, if successful, add approximately 4,650 acres of tidal marsh to the current Delta total. TIDAL MARSH EXTENT Good For the patch size indicator, the benchmark derives from the proportion of tidal marsh area belonging to a patch greater than ~500 acres in size, a value that seems to support maximum densities of certain marsh birds. In terms of general trends, the area of tidal marsh in the Bay continues to increase towards the regional goal of 100,000 acres. A major milestone passed in January 2015, when back- hoes breached the levees at Cullinan Ranch in the North Bay. With this breach, the area of existing tidal marshes plus restored intertidal wetlands moved past the regionwide goal’s halfway mark of 50,000 acres. Over the next 20-30 years, an additional 24,000 acres of tidal marsh will likely be added to the Bay as part of already funded or permitted projects. ~ 2015 ~ 2009 ~ 1997 ~ 1800 Benchmarks used for tidal marsh extent are different for the Bay and Delta. For the Bay, scientists used 100,000 acres. This goal, which was established and described in the 1999 Bay- lands Ecosystem Habitat Goals Report, reflects a consensus on the habitat needs of tidal marsh species and the changes needed to improve the Bay’s ecological functioning and biodiversity. Since no similar quantitative goals exist for the Delta, this assessment instead presents three reference values: 180,000 acres (half the histori- cal extent); 78,000 acres (current marsh area plus diked lands at intertidal elevations); and 17,000 acres (California Eco Restore goal). 33 TIDAL MARSH