Managing for Elevated Yield of Moose in Interior Alaska

• Published in: The Journal of Wildlife Management
• Main Authors: BOERTJE, RODNEY D., KEECH, MARK A., YOUNG, DONALD D., KELLIE, KALIN A., SEATON, C. TOM
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2009
• Subjects: Alces alces; Canis lupus; Ursus arctos; Alaska; Yukon
• Online Access: http://dx.doi.org/10.2193/2007-591; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.2193%2F2007-591

ABSTRACT Given recent actions to increase sustained yield of moose ( Alces alces ) in Alaska, USA, we examined factors affecting yield and moose demographics and discussed related management. Prior studies concluded that yield and density of moose remain low in much of Interior Alaska and Yukon, Canada, despite high moose reproductive rates, because of predation from lightly harvested grizzly ( Ursus arctos ) and black bear ( U. americanus ) and wolf ( Canis lupus ) populations. Our study area, Game Management Unit (GMU) 20A, was also in Interior Alaska, but we describe elevated yield and density of moose. Prior to our study, a wolf control program (1976–1982) helped reverse a decline in the moose population. Subsequent to 1975, moose numbers continued a 28‐year, 7‐fold increase through the initial 8 years of our study (λ B1 = 1.05 during 1996–2004, peak density = 1,299 moose/1,000 km 2 ). During these initial 8 hunting seasons, reported harvest was composed primarily of males ( = 88%). Total harvest averaged 5% of the prehunt population and 57 moose/1,000 km 2 , the highest sustained harvest‐density recorded in Interior Alaska for similar‐sized areas. In contrast, sustained total harvests of <10 moose/1,000 km 2 existed among low‐density, predator‐limited moose populations in Interior Alaska (≤417 moose/1,000 km 2 ). During the final 3 years of our study (2004–2006), moose numbers declined (λ B2 = 0.96) as intended using liberal harvests of female and male moose ( = 47%) that averaged 7% of the prehunt population and 97 moose/1,000 km 2 . We intentionally reduced high densities in the central half of GMU 20A (up to 1,741 moose/1,000 km 2 in Nov) because moose were reproducing at the lowest rate measured among wild, noninsular North American populations. Calf survival was uniquely high in GMU 20A compared with 7 similar radiocollaring studies in Alaska and Yukon. Low predation was the proximate factor that allowed moose in GMU 20A to increase in density and sustain elevated yields. Bears killed only 9% of the ...