Moose (Alces alces gigas) were introduced to the Copper River Delta (CRD) of SE Alaska from 1949-1958. The moose summer range on the western region of the delta encompasses 830 km2, but winter winds over the Copper River and snow conditions can restrict moose winter range to 50 km2. Stakeholder pressure is mounting to increase the current population of approximately 600 moose. However, this requires an understanding of the nutritional carrying capacity (NCC) during winter on the CRD, which is complex. In addition, because of a 1964 earthquake, the delta rose by 1.8-3.4 m, increasing drainage and accelerating the successional shift from more palatable browse species like sweetgale and willow (Myrica gale, Salix spp) to less palatable alder and spruce (Alnus viridis sinuata, Picea sitchensis). Managers implemented experimental hydro-axing in multiple stand types in 1990, 2008, and 2010 in order to counter the successional trend. We investigated responses in diversity, biomass, nutritional values, and utilization of browse species between treated and untreated stands. We found strong stand type differences in response to hydro-axing. For example, treated (1990) sweetgale-dominated stands displayed little change in species diversity but produced 46.7% greater available biomass of willows and sweetgale than untreated controls. Utilization of three core browse species, Barclay's willow (Salix barclayi), Hooker's willow (S. hookeriana), and Sitka willow (S. sitchensis), increased to three times the level observed in untreated stands, implying benefits to productivity, quality, or both. Other stand types, such as (2008) spruce-cottonwood-dominated, (2010) alder-dominated, (2010) sweetgale-dominated stands, displayed an initial decrease in diversity of less-preferred species. These analyses, combined with estimates of NCC under a range of winter scenarios, will assist managers in deciding whether the significant costs and difficulties associated with hydro-axing are practical to increase or sustain the moose herd in this area.Â
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