Gates of the Arctic

National Park Service U.S. Department of the Interior Gates of the Arctic National Park and Preserve Snowshoe Hare Project A volunteer carefully searches a plot for snowshoe hare pellets. Each plot is 2 inches wide by 10 feet long, delineated by an elastic band wrapped around plastic stakes at each end. The fact that snowshoe hare populations cycle dramatically from very low to very high densities over a 10 year period is fairly common knowledge. What is not as well understood is what causes this cycling and what controls the amplitude of hare population peaks. Some hare populations in and around Gates of the Arctic National Park consume mineral soils when their populations become more dense. Hare populations in these areas seem to reach higher densities than hare populations that do not consume such minerals. Questions about how hare populations in “mineral” vs. “non-mineral” areas differ are a primary focus of this project. 7th Annual Pellet Count During the 7th annual pellet count in 2013, a total of 221 pellets were counted in 408 plots at six sites. This continues the downward trend from the mini-peak a few years ago in the non-mineral sites of Rosie Creek and Snowshoe Hare Annual Pellet Counts Cathedral Mountain south of Coldfoot. At Slate Creek, also a mineral site, and at the mineral sites (Wiseman Creek, Jennie Creek and Gold Creek), which did not experience pronounced increases, the trend of low numbers of hares continues (Figure 1). 6.00 Figure 1. Number of snowshoe hare pellets/plot deposited annually at six study sites in the snowshoe hare study area in and near Gates of the Arctic National Park near Wiseman, Alaska. # Pellets/Plot 5.00 Cathedral Rosie 4.00 Slate 3.00 Wiseman Jennie 2.00 Gold 1.00 0.00 2007 2008 2009 2010 EXPERIENCE YOUR AMERICA™ 2011 2012 2013 The last major peak in hare densities in our area was in 1998-2001, which we documented in the park (our current “Wiseman” site) using winter track counts that began in 1997. National Park Service U.S. Department of the Interior Gates of the Arctic National Park and Preserve Establishment of New Site This grid may eventually replace the nearby Jennie grid. This large bluff lies across the Hammond River from the Jennie Creek pellet plot grid. During the last major peak in snowshoe hare densities, hares purportedly risked exposure to predators to visit this bluff and consume its soils. In addition to checking the established pellet plots, we cleared pellets from 47 plots in the new Hammond grid, established in 2012. This grid may eventually replace the nearby Jennie grid if the miner there bulldozes his entire claim (on which the Jennie grid lays). The new site is as close to the large Jennie Creek bluff as we could put it (where we believe hares consume soil during extreme peak population densities) while being outside the mining claim area. With the grid cleared of all old pellets, we will be ready to conduct the first annual count at Hammond in 2014. Absolute Tree Densities at Jennie and Hammond Sites In August, we made a second trip to the snowshoe hare study area, mainly to collect vegetation data from the new Hammond site. We recorded tree and shrub densities and vegetation strata from 50% of the plots on the Hammond grid. Density data show that the Hammond site has an even lower density of trees than Jennie (Jennie already having the lowest tree density of the other six sites) (Figure 2). However, shrub density at Hammond is greater than at Jennie (Figure 3), which has the second greatest density of shrubs of all study sites. Absolute Shrub Densities at Jennie and Hammond Sites 70,000 600 Picea glauca Ribes triste 60,000 500 Vaccinium uliginosum no trees (open) 400 Salix bebbiana Betula papyrifera 300 50,000 Rosa acicularis Juniperus communis 40,000 Potentilla fruticosa Alnus crispa Populus balsamifera 200 Populus balsamifera 30,000 Betula glandulosa Picea glauca Ledum palustre 20,000 100 0 Alnus crispa Shepherdia canadensis 10,000 Jennie Hammond Salix spp. 0 Figure 2. Comparison of absolute tree densities on the Jennie Creek grid and neighboring Hammond River grid in the snowshoe hare study area near Wiseman, Alaska. Tree density here is relatively low. The Hammond site may need to replace Jennie if mining operations in the area continue to spread. Jennie Hammond Figure 3. Comparison of absolute shrub densities on the Jennie Creek grid and neighboring Hammond River grid in the snowshoe hare study area near Wiseman, Alaska. The Hammond site has the second greatest shrub density (after Cathedral Mountain) of all seven sites in the snowshoe hare study area. Gates of the Arctic National Park & Preserve For more information on Gates of the Arctic National Park and Preserve’s snowshoe hare project, contact Donna DiFolco at (907) 455-0625 or email her at Donna_DiFolco@nps.gov. EXPERIENCE YOUR AMERICA™