Meeting Abstract

93.4  Friday, Jan. 7  Nutritional and chemical factors shaping the “foodscape” of a dietary specialist herbivore, the pygmy rabbit ULAPPA, A.C.*; SHIPLEY, L.A.; RACHLOW, J.L.; FORBEY, J.S.; Boise State Univeristy, ID; Washington State University, Pullman; University of Idaho, Moscow; Boise State University, ID amyulappa@u.boisestate.edu

Herbivory is a foraging strategy that poses special challenges, which can be partially addressed by selecting high quality forage among plants that vary nutritionally or chemically. Although several studies have demonstrated that herbivores prefer diets with the highest nutrient and lowest chemical constituents, these studies are primarily confined to laboratory feeding trials because observing diet selection in free ranging herbivores is difficult. Our field observations demonstrated that pygmy rabbits (Brachylagus idahoensis), facultative specialists on sagebrush (Artemisia tridentata), forage on specific sagebrush plants more than others within a foraging patch. We used this system to test the hypothesis that sagebrush plants heavily browsed by pygmy rabbits are nutritionally superior and preferred over rarely browsed plants. We collected pairs of sagebrush with high and low levels of browsing at 20 active pygmy rabbit burrows. First, we used a choice feeding trial to validate preference for heavily browsed plants. Captive pygmy rabbits voluntarily consumed 2.4 times more leaves from sagebrush with high levels of browsing. Second, we compared total and digestible crude protein and monoterpene amounts between sagebrush plants exhibiting high and low levels of browsing using a paired design. Amounts of total and digestible crude protein were both significantly higher and several monoterpenes were lower in highly browsed sagebrush relative to the rarely browsed plants. Predictive foraging models generated with this study can be used to map areas of palatable sagebrush across the landscape, termed “foodscapes”.