• Distribution of hunter groups and environmental effects on moose harvest in Interior Alaska

      Hasbrouck, Tessa R.; Brinkman, Todd; Stout, Glenn; Kielland, Knut (2018-12)
      Moose (Alces alces) is one of the most valuable wild game resources in Interior Alaska. In recent years, residents of rural indigenous communities have expressed concern that climate change and competition from non-local hunters are challenging local moose harvest opportunities. I collaborated with wildlife agencies and village tribal councils to co-design two studies to address rural community hunter concerns. The first study assessed the spatial and temporal distribution of local and non-local hunter groups to examine areas of potential competition. The second study addressed changing environmental factors and their impacts on moose harvest. Although competition among local hunters or among non-local hunters certainly occurs, competition between local and non-local hunters, or between resident and non-resident hunters is a more common and reoccurring issue. Local hunters are those who hunt in the area in which they reside whereas non-local hunters travel away from the area they reside to hunt. I assessed hunting patterns by local and non-local hunters in a remote hunting region near the interior villages of Koyukuk and Nulato to quantify moose harvest overlap between these two user groups to assess potential competition. I used Alaska Department of Fish and Game (ADFG) moose harvest records to develop a relative competition index that identified locations and time periods within the hunting season where the greatest overlap occurred from 2000-2016. I determined that the highest competition occurred between 16-20 September (i.e., peak harvest period) and was concentrated predominantly along major rivers. To decrease overlap and mitigate potential competition between hunter groups we recommend providing information on competition hotspots to hunters, or lifting the no-fly regulation in the Koyukuk Controlled Use Area with the caveat that hunting with the use of aircraft must occur 1.6 km from the Koyukuk River corridor. These actions may provide hunters information on how to re-distribute themselves across the landscape and allow hunters to use areas away from rivers, where most harvest currently occurs. Additionally, climate change and seasonal variability have anecdotally been documented to impact moose hunting opportunities. Specifically, warm temperatures, delayed leaf drop, and fluctuating water levels are concerns expressed by some local hunters. I quantified changes in temperature, leaf drop, and water level near Koyukuk and Nulato and the subsequent relationships between these environmental variables and the total number of moose harvested using linear regression models. I used temperature data, gauging station data (i.e., water level), remote sensing data (i.e., leaf drop analysis), and ADFG moose harvest records and explored previously untested hypotheses and to quantify relationships from 2000-2016. I concluded that non-local hunter harvest success was more dependent than local harvest success on environmental conditions. Non-local harvest significantly increased with higher water levels from 6-10 Sept (p=0.02), 11-15 Sept (p=0.02), and 16-20 Sept (p<0.01), and decreased with warmer temperatures in the same three time periods (p<0.01, p=0.02, p<0.01, respectively). Local harvest increased with higher water levels from 16-20 Sept (p<0.01). These results quantitatively show that environmental factors do impact hunter success. I speculate that local hunter harvest success is less dependent on environmental variability because they have the ability to harvest opportunistically, rely more heavily on the resource, and reside near the hunting area. This ability to opportunistically hunt and adapt may give them an advantage over non-local hunters as environmental conditions shift with climate change.
    • Energetics and space use of female moose during winter

      Kraft, Benjamin Robert; Hundertmark, Kris J.; Harris, Grant M.; Hunter, Christine M. (2011-05)
      Space use and resource selection are processes linked by habitat availability that have direct consequences to fitness. Knowledge of such processes allows comprehension of wildlife-habitat relationships, which can improve the efficacy of wildlife management programs. I investigated energetic and space use parameters of a population of female moose wintering in two adjacent, but distinct, landscape types (lowlands and mountains) on the Kenai Peninsula, AK, USA. I also evaluated differences between four home range models. I found that mountain females started winter in better condition, but used fat reserves at a higher rate than lowland females resulting in similar body condition estimates of moose in both landscape types in spring. I also found evidence of the functional response of habitat selection at the home range scale within landscape types. I observed a strong positive correlation between daily movement rate and home range size indicating that when females move during winter, they do so to access new areas expanding their home range. Brownian bridge, minimum convex polygon, fixed kernel, and local convex hull home range models produced different area and overlap estimates. Minimum convex polygons are least similar of model types and are not recommended to estimate areas actually used by animals.
    • Foliage and winter woody browse quality of an important Salix browse species: effects of presence of alder-derived nitrogen and winter browsing by Alaskan moose (Alces alces gigas)

      Burrows, Justin; Kielland, Knut; Wagner, Diane; Ruess, Roger (2019-12)
      In this study, I examined the relationship between soil nitrogen and winter browsing by moose on the physical and chemical characteristics of Salix alaxensis; specifically stem production, leaf nutritional quality, and stem nutritional quality of tissues produced the following growing season. I measured stem biomass production the 2013 growing season and offtake during the 2013-2014 winter browsing season at 16 sites on the Tanana River floodplain near Fairbanks, Alaska. I revisited the sites the following summer and autumn to assess regrowth and to collect soil, foliage, and stem samples. Browsing intensity and total soil nitrogen were similar in sites with and without alder, a nitrogen-fixing shrub. Soil nitrogen and browsing intensity were not consistently related to changes in stem or leaf quality, although there were significant relationships in some subsets. Soil nitrogen and browsing intensity also did not have consistent relationships with stem regrowth the following growing season. These results indicate that S. alaxensis growing in this system are able to recover from a naturally broad range of browsing utilization, including very high levels of offtake, and continue to produce nutritious leaves and stems.