Matrix projection model for the polar bear Ursus maritimus, with
5 matrices corresponding to years 2001-2005. The matrices are based on a
population in the southern Beaufort Sea. During 2001-2003, ice conditions were
classified as "good", but in 2004-2005, ice conditions were classified as
"poor". Poor ice conditions lead to worse population performance. Stages are
based on age and
reproductive status:
Stage-1: 2-year-old
Stage 2: 3-year-old
Stage 3: 4-year-old
Stage 4: adult (5+ years old), available to breed
Stage 5: adult, with cub (0-1 years old)
Stage 6: adult, with yearling (1-2 years old).