| Abstract: | We outline a population model proposed to accommodate the full life cycle of the mallard (Anas platyrhynchos}. Events during the breeding season are better understood than events at other times of the year, but recent findings suggest the importance of phenomena away from the breeding grounds. Several processes are discussed relative to mallard population dynamics. Compensatory mortality is a poorly understood concept, but one that can overwhelm many other components of a population model. Diseases and environmental contaminants can inflict indirect as well as direct mortality and can reduce reproduction. They interact with numerous other variables in complex and yet unknown ways. Recent evidence of a wintering-ground effect on subsequent recruitment provides one avenue for modeling phenomena occurring at different times of the year. Finally, the role of heterogeneity among individuals is widely acknowledged but not fully appreciated. We illustrate with an example the importance of heterogenicity to population processes, including compensatory mortality. |
| Genre: | Book chapter |
| ProdID: | 5210078 |
| Citation Author: | Johnson, D.H.; Nichols, J.D.; Conroy, M.J.; Cowardin, L.M. |
| Citation Contributing Office: | Patuxent Wildlife Research Center |
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| Citation Editor: | Weller, Milton W. (editor) |
| Citation End Page: | 20 |
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| Citation Language: | English |
| Citation Larger Work Title: | Waterfowl in Winter |
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| Citation Phsyical Description: | xx, 624 |
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| Citation Publisher: | University of Minnesota Press |
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| Citation Search Results Text: | Some considerations in modeling the mallard life cycle; 1988; Book chapter; Waterfowl in Winter; Johnson, D.H.; Nichols, J.D.; Conroy, M.J.; Cowardin, L.M. |
| Citation Start Page: | 9 |
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| Citation Year: | 1988 |
| Type: | citation/reference |
| Text: | Some considerations in modeling the mallard life cycle; 1988; Book chapter; Waterfowl in Winter; Johnson, D.H.; Nichols, J.D.; Conroy, M.J.; Cowardin, L.M. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Tue, 9 Jun 2009 09:23 -0500 |
| Publisher: | University of Minnesota Press |
