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60 STATE OF THE ESTUARY The abundance of zooplankton, critical prey at the base of the estuarine food web, has continued to decline in recent years, especially in the Delta. Overall fish abundance, another important trophic level in the food web, declined throughout most of the upper Estuary, except in the Delta’s beach zone, where populations of non-native fish are increasing. Overall there is less and less food in the upper Estuary, and regional goals of recovering and reversing declines in estuarine fishes in the upper Estuary have not been met. he es o f t Brandt’s cormorants tu ar th e enough food, on average, to o f raise e e s t have been T E o finding e h t f st ua ua TE r TA TA their young, successfully fledging enough chicks to sustain a stable popula- r tion. This reflects some stability in the upper trophic levels of the estuarine food web in the context of recent, temporary declines. y y • S S The total area of the Delta invaded by alien aquatic weeds has increased from 9,000 acres in 2004 to more than 12,500 acres today. WildlifE TA TA TE of the est ua WATER FR AN People TA TA S S Wildlife RGB 57-181-74 r y Chapter cover photo of Yolo Bypass: Bird’s Eye View L FR DE AN CISC O B AY & N TA TA r SA L N DE CISC O B AY & ua This chapter summarizes data and materials written by the authors listed on page 12 and provided in full in the tech- nical appendix for the State of the Estuary 2015 report. Habitat wildlife Processes People Go to: SA N AN TE y y Processes FR TA TA SUPPORTING o f MATERIALS the es t r S ua N of the est SA TE N TA SA Tidal wetlands need to migrate landward to keep pace with rising sea levels but very little of the undeveloped space that could accommodate this transition is protected. • • • • • SA The ocean’s influence on the Estuary will increase with global warming and rising seas. Recent changes in the ocean include a blob of warm water offshore, changes in upwelling cycles reducing krill and other food supplies, and more zones of low oxygen water that can suffocate organisms. Nutrients are impacting Bay water quality more than they used to. Scientists note a 2-3 fold increase in the biomass of summer plankton blooms in the South Bay since 1999. In the Bay as a whole, they’ve recently detected a number of harmful algae species and toxins. N • • • The frequency, magnitude and duration of beneficial floods are too low to drive and support critical ecological processes. Heron and egret productivity rates have remained close to the long term average, with a stable to slightly declining trend in the average number of WATER L FR FR young & produced in each successful nest. This E D L slight decline may F R A be worthy of D E L DE AN AN NCI CISC O B AY CISC O B AY & S C O B AY & some concern, but is small enough not to be significant. SA TAKE HOMES • • y Efforts to restore ecological processes are the new frontier in estuarine management. For decades, managers focused on habitat restoration to recov- er imperiled species or to reestablish ecosystem services. Restoring habitats alone, however, can no longer achieve these goals in a landscape so modified by humans, so invaded by non-native species, and so stressed by changes in climate and hydrology. Instead, the processes that allow ecosystems to function and maintain themselves over time need to be restored. These processes sustain resilient habitats and wildlife populations, and support the kind of ongoing suc- cession and evolution that allows natural systems to adapt to change. Finding ways to accommodate ecosystem-sustaining processes in the urban, agricultural, industrial, and open landscapes surrounding the Estuary will be a challenge and time is short. This chapter examines indicators of the current health of processes that create food, accom- modate habitat migration, deliver nutrients and sed- iment to floodplains, and nurture healthy fish and wildlife populations. It also explores factors that im- pede these processes, such TE as water management and TA the invasion of the Delta by The Marine Mammal Center non-native aquatic vegeta- tion. Decisions regarding how to manage such challenges and restore ecological Habitat processes must be made very soon given the pace of climate change. S OVERVIEW 2015 DE CISC O B AY & L