HABITAT RELATIONSHIPS OF MOOSE ON THE COPPER RIVER DELTA IN COASTAL SOUTH-CENTRAL ALASKA

River deltas have been presumed to provide high quality habitats for m oose (Alces alces). Moose were introduced to the Copper River Delta, A laska, in the 1950's, but little was known about their habitat relatio nships. This study was conducted during 1987-89 to characterize and ev aluate moose habitat quality and moose ecology on a large river delta. Mean (+/-SE) annual home range size was 59 +/- 5 km(2). Eight of 15 r adio-collared females and 1 of 4 males were seasonally migratory. Migr ations were related to snow depth and persistence. Moose relocations ( >90%) occurred in 5 habitat types, which were used either for feeding or bedding; use varied among years, seasons, and sexes. At the landsca pe scale, moose established home ranges in areas that had more habitat s that were high in forage productivity and were relatively stable. At the home range scale, moose selected early seral habitats that provid ed both food and cover, or primarily cover. Spring-early summer diets were the most diverse and highest in quality due to the use of emergen t aquatic plants. Winter diets were second in diversity and lowest in quality and late summer-fall diets were the least diverse and intermed iate in quality. Seasonal changes in diets, habitat selection, and act ivity budgets tracked changes in forage abundance and quality. The eco logical carrying capacity of the study area was estimated to be 380 an d 1,424 moose for severe and mild winters, respectively. These estimat es would result in densities of 0.5-2.0/km(2) for the entire area and 10-12/km(2) on the primary winter ranges. The population could be incr eased beyond the present size to meet the high demands for moose. Calf production averaged 1 calf/female/year, the maximum twinning rate was 40%, mean annual calf survival rates ranged from 0.03 to 0.25, and fa ll recruitment averaged 30 calves/100 females. Calf deaths were associ ated with spring weather and predation by brown bears (Ursus arctos); >90% of adult mortality was due to legal harvest. Habitat quality on t he Delta was dependent on disturbance regimes that differed in frequen cy and landscape extent. Glacial outwash dynamics produced a low varia nce, steady-state shifting mosaic over 30% of the Delta. Great earthqu akes that occur every 600-800 years result in high variance, nonequili brium habitat dynamics that currently favor moose.