Seeds (caryopses) of Oryzopsis hymenoides were a preferred food by species of heteromyid rodents on sandy desert rangelands. The rodents were selective in the type of Oryzopsis hymenoides seeds they put in their cheek pouches, rejecting empty seeds and polymorphic forms with reduced germination. The rodents cached some of these highly germinable seeds and emergence of seedlings from these caches was apparently the primary means of stand renewal of Oryzopsis hymenoides in these plant communities. Captivity studies with heteromyid rodents showed that germination of roughly 50% of the seeds in the caches was greatly enhanced by the rodent's removal of the indurate lemma, palea, and pericarp that induced dormancy. An estimated 0.02% of the Oryzopsis hymenoides seeds produced on a favorable moisture year germinated from rodent caches and emerged as seedlings.
Within the sagebrush steppe ecosystem, sagebrush plants influence a number of ecosystem properties, including nutrient distribution, plant species diversity, soil moisture, and temperature, and provide habitat for a wide variety of wildlife species. Recent increases in frequency and size of wildfires and associated annual grass expansion within the Wyoming big sagebrush alliance have increased the need for effective sagebrush restoration tools and protocols. Our objectives were to quantify the success of Wyoming big sagebrush transplants relative to transplant stock (nursery seedlings vs. wildlings) across different ecological sites and vegetation types and to test the hypothesis that reduction of herbaceous vegetation would increase survival of transplanted sagebrush. We used a randomized block (reps¼5) design at each of three sites-1) cheatgrass dominated, 2) native plant dominated, and 3) crested wheatgrass dominated-near Elko, Nevada. Treatments included plant stock (nursery stock or locally harvested wildlings) and herbicide (glyphosate) to reduce competition from herbaceous vegetation. Transplants were planted in the spring of 2009 and 2010 and monitored for survival. Data were analyzed for site and treatment effects using mixed-model ANOVA. Surviving plant density at and 2 yr postplanting was generally highest (up to 3-fold) on the native site (P , 0.05). Density of surviving transplants was almost 3-fold higher for nursery stock on most sites for the 2009 planting, but differences in survival by planting stock were minimal for the 2010 planting. Glyphosate application increased surviving plant density up to 300% (depending on site) for both years of planting. High labor and plant material investments (relative to traditional drilling or broadcasting) may limit the size of projects for which sagebrush transplants are practical, but these costs may be partially offset by high success relative to traditional methods. Our data indicate that sagebrush transplants can be effective for establishing sagebrush on depleted sites.
Black-tailed jackrabbit (Lepus cal~ornicus) use of 2 new rangeland seedings in northern and central Nevada was determined by fecal pellet counts for the first growing seasons following seeding establishment. Jackrabbit use was an inverse function of seeding size (as indicated by distance from seeding edges to midpoints). USC was uniformly high for a small (M-ha) seeding from its edge to its midpoint. A larger (4OtSha) seeding received significantly higher use at the edge than at 100-m intervals extending to the 400-m midpoint. Jackrabbit use of seedings was higher during late summer than during early summer. Jackrabbit abundance was significantly higher in sagebrush habitat adjacent to a new seeding than in similar habitat away from the seeding. Our results suggest that forage availability is a factor influencing use of seedings, and predation risk may also be involved.
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