Presentation Abstract

The Fraser River Estuary is a major link in a chain of Pacific coastal habitats that support migrating and wintering waterfowl, and many birds converge here during northward and southward travels. Between 800,000 and 2.3 million waterfowl use the estuary from September through April, including significant populations of American wigeon, mallard, northern pintail, surf scoter, snow goose and brant. Waterfowl mainly use agricultural lands, freshwater and brackish wetlands, and intertidal habitats such as eelgrass beds, all of which continue to be lost or degraded by population growth and urban sprawl. We used a bioenergetic model (TRUEMET) to explicitly link waterfowl population objectives to habitat objectives for farmland conservation. TRUEMET indicates whether there is a habitat surplus or deficit for a given population level. We combined five of the most abundant species into two foraging guilds: ‘grazers’ included American wigeon and snow goose, and ‘dabblers’ included mallard, northern pintail and green-winged teal. We assessed conditions as of 2009 and tested a variety of scenarios involving changes in habitat availability, including future losses of agricultural or intertidal habitats. Model results indicated that grazers experienced an excess of energy through the nonbreeding season, but this was predicted to become to a deficit by midwinter within 20 years under likely scenarios. For dabblers, the demand exceeded supply by December, and the situation only worsened under future scenarios. Ensuring their continuing presence at current levels in the face of growing development stressors will require a multi-faceted conservation strategy for both intertidal and farmland conservation. We set a conservative foraging habitat objective of 50% of the energy needs of waterfowl on agricultural lands during the migrating and wintering periods, which equates to 15,000 x10^6 kcal of energy. From a habitat program perspective, this will require protecting farmlands and encouraging green forage cropping on the broader landscape.

Session Title

Shorebird Monitoring in the Salish Sea

Keywords

Water fowl, Bioenergetics, TruMet, Ducks Unlimited Canada

Conference Track

SSE7: Monitoring: Species and Habitats

Conference Name

Salish Sea Ecosystem Conference (Seattle, WA : 2018)

Document Type

Event

SSEC Identifier

SSE7-129

Start Date

4-4-2018 4:00 PM

End Date

4-4-2018 4:15 PM

Type of Presentation

Oral

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Geographic Coverage

Salish Sea (B.C. and Wash.)

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

text

Language

English

Format

application/pdf

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Apr 4th, 4:00 PM Apr 4th, 4:15 PM

Using a bioenergetic model to set waterfowl habitat objectives for the Fraser River delta

The Fraser River Estuary is a major link in a chain of Pacific coastal habitats that support migrating and wintering waterfowl, and many birds converge here during northward and southward travels. Between 800,000 and 2.3 million waterfowl use the estuary from September through April, including significant populations of American wigeon, mallard, northern pintail, surf scoter, snow goose and brant. Waterfowl mainly use agricultural lands, freshwater and brackish wetlands, and intertidal habitats such as eelgrass beds, all of which continue to be lost or degraded by population growth and urban sprawl. We used a bioenergetic model (TRUEMET) to explicitly link waterfowl population objectives to habitat objectives for farmland conservation. TRUEMET indicates whether there is a habitat surplus or deficit for a given population level. We combined five of the most abundant species into two foraging guilds: ‘grazers’ included American wigeon and snow goose, and ‘dabblers’ included mallard, northern pintail and green-winged teal. We assessed conditions as of 2009 and tested a variety of scenarios involving changes in habitat availability, including future losses of agricultural or intertidal habitats. Model results indicated that grazers experienced an excess of energy through the nonbreeding season, but this was predicted to become to a deficit by midwinter within 20 years under likely scenarios. For dabblers, the demand exceeded supply by December, and the situation only worsened under future scenarios. Ensuring their continuing presence at current levels in the face of growing development stressors will require a multi-faceted conservation strategy for both intertidal and farmland conservation. We set a conservative foraging habitat objective of 50% of the energy needs of waterfowl on agricultural lands during the migrating and wintering periods, which equates to 15,000 x10^6 kcal of energy. From a habitat program perspective, this will require protecting farmlands and encouraging green forage cropping on the broader landscape.