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Postcatastrophe Population Dynamics and Density Dependence of an Endemic Island Duck
Author(s) -
SEAVY NATHANIEL E.,
REYNOLDS MICHELLE H.,
LINK WILLIAM A.,
HATFIELD JEFF S.
Publication year - 2009
Publication title -
the journal of wildlife management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.94
H-Index - 111
eISSN - 1937-2817
pISSN - 0022-541X
DOI - 10.2193/2007-420
Subject(s) - anas , population , density dependence , population density , gompertz function , range (aeronautics) , population size , geography , statistics , ecology , biology , demography , mathematics , materials science , sociology , composite material
Laysan ducks ( Anas laysanensis ) are restricted to approximately 9 km 2 in the Northwestern Hawaiian Islands, USA. To evaluate the importance of density dependence for Laysan ducks, we conducted a Bayesian analysis to estimate the parameters of a Gompertz model and the magnitude of process variation and observation error based on the fluctuations in Laysan duck abundance on Laysan Island from 1994 to 2007. This model described a stationary distribution for the population at carrying capacity that fluctuates around a long‐term mean of 456 ducks and is between 316 to 636 ducks 95% of the time. This range of expected variability can be used to identify changes in population size that warn of catastrophic events. Density‐dependent population dynamics may explain the recovery of Laysan duck from catastrophic declines and allow managers to identify population monitoring thresholds.