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26 STATE OF THE ESTUARY • • In San Francisco Bay, the regional extent of tidal marsh has grown by thousands of acres in recent years. Just prior to completion of the Bay- lands Ecosystem Habitat Goals in 1999, the Bay had about 40,000 acres; by 2009 there were about 45,000 acres; and 6,300 acres have been added since then. • In January 2015, with the breach at the North Bay’s Cullinan Ranch, the region reached a major milestone as Cullinan and other restored areas evolve and mature, the regional extent of Bay tidal marsh is expected to sur- pass the halfway point of the 100,000-acre target set in the 1999 Baylands Ecosystem Habitat Goals Report. • • In the Delta, the regional extent of tidal marshes has grown by 260 acres since 2009. Tidal marsh restoration efforts in the Delta are just beginning. Across the Estuary, tidal marsh patch size has decreased since the early 1800s. This change is much more pronounced in the Delta than in the Bay. Large patches are associated with healthier populations of marsh-depen- dent species. TAKE HOMES • ua T TA r NCI TA DE SC O B AY & RA Habitat chapter cover photo of tidepools: Rick Lewis ar TA TE of the est ua TA r of the est u ar NCI TE DE S C O B AY & of the est ua r y y y S RA N of the est u L TE SA TE DE CISC O B AY & TA This chapter summarizes data and materials written by the WildlifE authors listed on page 12 and provided in full in the technical appendix for the State of the Estuary 2015 report. Go to: WATER http://sfestuary.org/about-the-estuary/soter/ F L L F N N TA AN SUPPORTING MATERIALS SA SA FR ar y Habitat f the est E o u TA of the est S TE In the Delta, woody riparian habitat has been reduced by 64% over the past two centuries. Many of the remaining patches of this habitat are nar- row, small, highly fragmented, and mostly found on artificial levees. y Native oyster beds currently cover less than one percent of the Estuary’s subtidal and intertidal shorelines. TA • S In San Francisco Bay, the acreage covered by eelgrass peaked in 2011 at 4,000 acres, but by 2014 had declined to 2,790 acres. Scientists note, however, that eelgrass beds are a dynamic, variable habitat. S In the Delta, reverse flow conditions, in which pumping pulls fish and other organisms toward water export facilities, have become more frequent and severe. Historically in the Bay and the Delta, more than 95% of the tidal marsh area was part of a large patch (greater than 500 acres in size). Today, the proportion is only slightly lower in the Bay (85%), but dramatically lower in the Delta (30%). TA The quality and quantity of low salinity, open water habitat in the upper Estuary has declined, and conditions are now poor in most years. y • • • • S Wetlands, eelgrass beds, riparian forests, and other estu- Photo: Rick Lewis arine habitats are critical components of ecosystem health, not just in their extent, but also in terms of configuration across the landscape and quality of resources within the habitat. In a region so heavily impacted by urban and agricultural development, sustaining diverse wildlife involves conserv- ing remaining habitats and restoring new ones. Factors such as habitat connec- tivity determine whether wildlife are able to move when necessary to find things like better living conditions, a breeding territory, or a safe place to wait out a king tide. Factors such as habitat quality also influence whether wildlife can find enough hiding places, nest sites, or food to feed their young. The indicators in this report focus on some of the Estuary’s most important habitats, including those that harbor endangered species and provide a multitude of ecosystem services. The indicators evaluate habitat extent, quality and connectivity. These aspects of habitat translate into ecological outcomes like the health of wildlife populations and the food web, which are addressed in later chapters. Also raised in this later discussion is the critical importance of restoring the process- es that create and sustain habitats over time. In the South Bay, new managed pond habitats in former salt ponds near Alviso are now a productive nursery for grass shrimp, leopard sharks, threespine stickleback, Pacific staghorn sculpin, and other young native fish, as well as for overwintering longfin smelt, a listed species. S OVERVIEW 2015