Electronic Resource
Oxford, UK
:
Blackwell Publishing Ltd
Marine mammal science
15 (1999), S. 0
ISSN:
1748-7692
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Initial appraisals of the status of endangered large-mammal populations may have to depend on indices of population trend. Such indices may possibly be improved by using auxiliary variables. Various models were studied for populations of the Florida manatee (Trichechus manatus latirostris), Yellowstone grizzly bear (Ursus arctos horribilis), and Hawaiian monk seal (Monachus schauinslandi). Several criteria for checking validity of the fitted models were considered, and the simple R2 criterion appears to provide useful comparisons. Multiple regression models overestimated the rate of change of the East Coast manatee population as determined from three other sources (a covariance model, a non-linear model, and the rate estimated from reproductive and survival data). A multiple regression model for grizzly bears using three auxiliary variables exhibited a fairly high R2 (0.84) and appeared to provide a better fit than did a non-linear model. A beach count index for Hawaiian monk seals seemed to be unreliable for year-to-year comparisons in contrast to total population counts and estimates from a capture-recapture method. The use of auxiliary variables for checking and improving trend index data appears feasible and well worthwhile.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1748-7692.1999.tb00842.x
|
Location |
Call Number |
Expected |
Availability |
