Data from: Integrated population modeling provides the first empirical estimates of vital rates and abundance for polar bears in the Chukchi Sea

• Main Authors: Regehr, Eric V., Hostetter, Nathan J., Wilson, Ryan R., Rode, Karyn D., St. Martin, Michelle, Converse, Sarah J.
• Format: Dataset
• Language: English
• Published: Dryad 2019
• Subjects: vital rates; polar bear; abundance; sea ice; capture-recapture; carnivore; movement; integrated population model; Ursus maritimus; Life sciences; medicine and health care; climate change; demo; geo; Chukchi Sea; Chukchi; Sea ice; Alaska
• Online Access: https://doi.org/10.5061/dryad.692jb15

Large carnivores are imperiled globally, and characteristics making them vulnerable to extinction (e.g., low densities and expansive ranges) also make it difficult to estimate demographic parameters needed for management. Here we develop an integrated population model to analyze capture-recapture, radiotelemetry, and count data for the Chukchi Sea subpopulation of polar bears (Ursus maritimus), 2008–2016. Our model addressed several challenges in capture-recapture studies for polar bears by including a multievent structure reflecting location and life history states, while accommodating state uncertainty. Female breeding probability was 0.83 (95% credible interval [CRI] = 0.71–0.90), with litter sizes of 2.18 (95% CRI = 1.71–2.82) for age-zero and 1.61 (95% CRI = 1.46–1.80) for age-one cubs. Total adult survival was 0.90 (95% CRI = 0.86–0.92) for females and 0.89 (95% CRI = 0.83–0.93) for males. Spring on-ice densities west of Alaska were 0.0030 bears/km2 (95% CRI = 0.0016–0.0060), similar to 1980s-era density estimates although methodological differences complicate comparison. Abundance of the Chukchi Sea subpopulation, derived by extrapolating density from the study area using a spatially-explicit habitat metric, was 2,937 bears (95% CRI = 1,552–5,944). Our findings are consistent with other lines of evidence suggesting the Chukchi Sea subpopulation has been productive in recent years, although it is uncertain how long this will continue given sea-ice loss due to climate change. Regehr2018_PolarBear_IPM_GOFR code and JAGS model to run the Integrated Population Model and goodness-of-fit for Chukchi Sea polar bearsRegehr2018_jags_dataData for the Integrated Population ModelRegehr2018_state_initsInitial values for the Integrated Population ModelRegehr2018_PolarBear_NR code for density extrapolation and abundance estimation for Chukchi Sea polar bearsRegehr2018_dextrp_dataData for density extrapolation and abundance estimationRegehr2018_PolarBear_recruitmentR code for separate recruitment analyses for Chukchi Sea ...