Estuarine and Wetland Ecosystems

 

BETWEEN LAND AND SEA

Estuaries and wetlands encompass soft-sediment habitats, including tidal mudflats, eelgrass beds and areas of open water. The Marine Life Protection Act defines the shoreward boundary of these ecosystems as the extent of tidal reach and salt-water-associated vegetation. Estuaries throughout California’s coastline can differ significantly, including physical differences in the estuary shape, geomorphology, seawater input, freshwater input and nutrient supply. As expected, each estuary can harbor different habitat-forming species and ecological communities.

Given their accessibility, these habitats are popular areas for consumptive and non-consumptive activities including fishing, waterfowl hunting, clam digging, bird watching, boating, and kayaking.

 

FROM A SOFT-BEDDED NURSERY TO A MIGRATORY INTERLUDE

Eelgrass beds and marshes play an important ecological function as foraging and nursery habitat for a diverse range of fish and invertebrate species including Pacific gaper clam, littleneck clam, mud shrimp, ghost shrimp, shiner surfperch, and other surfperches. Many of these fish species inhabit estuaries as juveniles before moving to kelp forests and other offshore habitats as adults.

Shorebirds, waterfowl, and piscivorous birds are key species in this ecosystem, making use of this landscape as a cornerstone foraging and nesting area. As well, estuaries, coastal bays, and beaches serve as a critical interlude point for thousands of migrating shorebirds and waterfowl.

 

VULNERABLE TO CHANGE

Estuarine and wetland ecosystems provide important habitat linkages between marine, aquatic and terrestrial ecosystems. In turn, ecological health is closely tied to surrounding watersheds – making water quality strongly vulnerable to human runoff and anthropogenic influence. In addition, invasive species in estuaries have the potential to dramatically alter species composition and ecosystem functioning. These broader influences need to be incorporated into analyses of MPA monitoring results to facilitate detection and interpretation of MPA-related effects.