Browsing by Author "Blommel, Caroline, author"
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Item Embargo Determining the impact of harvest and climate change on the demography of black brant (Branta bernicla nigricans)(Colorado State University. Libraries, 2024) Blommel, Caroline, author; Koons, David, advisor; Aubry, Lise, committee member; Webb, Colleen, committee memberAs a coastal long-distance migrant, black brant (Branta bernicla nigricans) are vulnerable to climate and land-use change while also facing harvest pressure from sport hunting along the Pacific Coast. To examine impacts of harvest pressure and environmental change on brant survival and reproductive components of fitness, I combined band-recovery data with live recapture and resighting data from 1990 to 2023 for the Tutakoke River breeding colony of brant on the Yukon-Kuskokwim Delta in western Alaska. I fit multiple Bayesian multistate mark-recapture models to these data to estimate temporal changes in cause-specific mortality and breeding probabilities over the last 33 years. Harvest rate increased over time and is significantly impacted by bag limit across sex and age groups. Adult non-harvest mortality has remained stable over the study period but is higher in years of extreme El NiƱo and Aleutian Low Beaufort Sea Anticyclone events. Breeding probability for previous breeders increased over time while breeding probability for previous non-breeders decreased, driven largely by differing responses to spring timing. My work describing brant demographic response to environmental change and harvest provides valuable information on how to manage brant most effectively across their migratory range.