Stories From The Field

Mapping Critical Habitats for Ecosystem-Based Management in California

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Humboldt Bay and the Eel River Estuary make up one of California’s largest estuarine systems, supporting the greatest number of wetland wildlife species between San Francisco Bay and the Columbia River. The area’s rich natural, cultural, commercial, and aesthetic resources are threatened by habitat fragmentation, degradation, and loss. The 2006 “Northern California Coastal Conservation Needs Assessment” (conducted by the California Coastal Conservancy and its partners) highlighted the need for coastal and marine spatial data to protect resources and support ecosystem-based management (EBM).


To address a number of needs identified in the assessment results, many partners coordinated their information and efforts through the Humboldt Bay EBM Program. EBM program partners described and evaluated the intertidal and subtidal habitats of Humboldt Bay and the Eel River Estuary. Their work was greatly aided by acquiring high-resolution multispectral imagery in 2009 from which they generated a benthic habitat data set of the bay and estuary.


The imagery and derived benthic habitat maps have provided more and better information on the ecological health of Humboldt Bay in the following ways: providing more accurate characterizations of the region; enhancing the ability of users to research and monitor issues affecting estuarine and nearshore habitat; and informing conservation and use decisions that consider the links between land and sea.

For example, these data have been used to evaluate potential expansion of oyster mariculture activities. Humboldt Bay National Wildlife Refuge is using the imagery to help control invasive species, monitor rare species, and determine the boundaries and acreages for habitat types and management units. Additionally, a large restoration program in the Eel River Estuary is using the images and habitat maps to locate existing channels and other geographic features as part of the restoration project design.

High-Resolution Orthoimagery showing benthic habitats for Arcata Bay, California
Benthic habitats derived from multispectral imagery are shown for Arcata Bay, California. The maps support efforts to identify and prioritize ecosystem management goals.
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