Movement Patterns And Population Structure Of Harlequin Ducks Wintering In The Strait Of Georgia British Columbia

Author : Frances Cassirer
Publisher :
ISBN 13 :
Total Pages : 106 pages
Book Rating : 4.:/5 (3 download)

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Download or read book Harlequin Duck (Histrionicus Histrionicus) Conservation Assessment and Strategy for the United States Rocky Mountains written by Frances Cassirer and published by . This book was released on 1996 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: Harlequin ducks (Histrionicus histrionicus) are sea ducks that migrate to mountain streams to breed. The species is classified as a U.S. forest Service sensitive species in the Northern, Rocky Mountain, and Pacific Northwest Regions, a state sensitive species in Oregon, a priority habitat species in Washington, and a species of special concern in Idaho, Montana, and Wyoming. Harlequin ducks are also classified as migratory waterfowl covered under general waterfowl or sea duck regulations throughout their range. This Conservation Assessment and Strategy addresses the status and conservation of harlequin ducks in the Rocky Mountains of Idaho, Montana, and Wyoming. The Conservation Assessment summarizes available information on the ecology and population status of the harlequin duck in Idaho, Montana, and Wyoming, and identifies potential threats to the species' viability in this region. The Conservation Strategy identifies management actions and information needed in order to maintain viable populations and protect and maintain critical habitats to ensure that listing is not warranted, in accordance with the Endangered Species Act (ESA) of 1973, as amended. The Conservation Assessment is based on inventory, monitoring, and research data collected in the U.S. Rocky Mountains since 1974. Approximately 300 pairs of harlequin ducks are estimated to breed in 57 breeding or probable breeding occurrences in the U.S. Rocky Mountains. A breeding occurrence is considered a single "breeding area", but may contain portions of several streams not separated by more than 10 km of unsuitable habitat, or 20 km of unoccupied, suitable habitat. Data gathered from marked individuals indicates a high degree of fidelity to these breeding occurrences. The harlequin duck breeding occurrences identified in the U.S. Rocky Mountains are comprised of reaches on 128 streams. Over 90% of the harlequin duck breeding occurrences in the U.S. Rocky Mountains occur on federal lands, primarily managed by the U.S. Forest Service and National Park Service. However, approximately 25% of these do cross some privately-owned land. The remaining 7% (4 breeding occurrences) are located predominately on state and privately-owned land. Not all Rocky Mountain breeding occurrences have been located. Potential breeding habitat is identified as 2nd-order or larger streams containing reaches with a average gradient of 1% - 7%, riffle habitat, clear water, gravel to boulder-sized substrate, and forested bank vegetation. Additional characteristics that may increase likelihood of use by harlequin ducks include: proximity to occupied habitat, overhanging bank vegetation, woody debris, loafing sites, absence of human activity, and inaccessibility. Potential threats to harlequin ducks in the U.S. Rocky Mountains include activities that affect riparian habitats, water yield, water quality, and increase disturbance during the breeding season. Habitat conditions in migratory and coastal areas are also critical to conservation of harlequin ducks. Harlequin ducks breeding in the Rocky Mountains have been located off the coasts of Oregon, Washington, and British Columbia. Harvest in coastal areas, while apparently low, could also potentially affect harlequin ducks in the Rocky Mountains. The Conservation Strategy emphasizes and adaptive approach for maintaining riparian and instream harlequin duck habitat. Guidelines are designed to maintain habitat quality by avoiding degradation form timber harvest, road construction and maintenance, mining, livestock grazing, water developments, and recreation. Guidelines include establishing stream buffers, maintaining instream flows and water quality, and reducing or not increasing human disturbance. Inventory and monitoring protocols are included for assessing the U.S. Rocky Mountain harlequin duck population size and trend and for individual project inventory and monitoring. Finally, areas where additional information is needed regarding basic ecology and management and methods to increase knowledge of management personnel and the public about harlequin duck and their conservation are identified.