Variable Fire Severity in Alaska’s Boreal Forest: Implications for Forage Production and Moose Utilization Patterns a Thesis

Over 1 million hectares burn annually across interior Alaska’s boreal forest, altering the composition and distribution of vegetation communities that provide critical winter habitat for Alaskan moose (Alces alces gigas). Within a burn, fire severity (the amount of residual soil organic matter following a fire event) is spatially variable and drives the trajectories of post-fire succession. I examined the response of moose to patterns of regeneration resulting from variable fire severity within two burns in interior Alaska. I found significantly higher production of forage biomass (kg/ha) in high fire severity sites than in low severity sites. Proportional removal of forage biomass by moose was 36% higher on sites with higher fire severity compared with low severity sites. I used multiple regression models to examine the role of forage distribution following fire on proportional removal. The overall explanatory power of any landscape descriptors was moderate at best. Winter forage is a limiting factor for moose reproductive potential, especially in areas with low predation rates. Changes in moose habitat potential is easily measured using remote sensing and GIS techniques and should be assessed to combine field-based knowledge of moose response to variations in regeneration to large-scale patterns of vegetation regeneration following wildfires.