Approximately 70–80% of the entire population of the Trumpeter Swan (Cygnus buccinator) depends for reproduction on wetlands in Alaska. This makes the identification of important habitat features and the effects of human interactions important for the species' long-term management. We analyzed the swan's habitat preferences in five areas throughout the state and found that swan broods occupied some wetland types, especially larger closed-basin wetlands such as lakes and ponds, at rates much higher than they occupied other wetland types, such as shrubby or forested wetlands. We also found a negative effect of transportation infrastructure on occupancy by broods in and around the Minto Flats State Game Refuge, Kenai National Wildlife Refuge, and Tetlin National Wildlife Refuge. This finding is of particular interest because much of the Minto Flats refuge has recently been licensed for oil and gas exploration and parts of the Kenai refuge have been developed in the past. We also investigated the potential effects of the shrinkage of closed-basin ponds on habitat occupancy by nesting Trumpeter Swans. We compared nesting swans' use of ponds with changes in the ponds' size and other characteristics from 1982 to 1996 and found no relationships between occupancy and changes in pond size. However, we believe that the recent and rapid growth of Trumpeter Swan populations in Alaska may become limited by available breeding habitat, and anthropogenic and climate-induced changes to the swan's breeding habitats have the potential to limit future production.
How to translate text using browser tools
1 May 2009
Environmental and Human Influences on Trumpeter Swan Habitat Occupancy in Alaska
Joshua H. Schmidt,
Mark S. Lindberg,
Devin S. Johnson,
Joel A. Schmutz
ACCESS THE FULL ARTICLE
The Condor
Vol. 111 • No. 2
May 2009
Vol. 111 • No. 2
May 2009
anthropogenic effects
Cygnus buccinator
habitat occupancy
trumpeter swan
wetland loss