Medusahead (Taeniatherum caput-medusae ssp. asperum (Simk.) Melderis) is a Eurasian annual grass that infests large areas of U.S. rangelands, dominating former bunchgrass/shrub sites. Squirreltail (Elymus elymoides (Raf.) Swezey) is a native perennial grass that has demonstrated the ability to establish in stands of medusahead. A study conducted on two sites near Burns, OR had the objectives of quantifying competition between medusahead and squirreltail, and determining the effect of moisture availability on competition. Two hundred plots were arranged in a factorial design. Measurements were taken of plant growth, seed production, soil moisture, and climate. Results for the two years are contrasting. The first year was very dry. Medusahead grew and reproduced well, producing a seed crop up to 10 times the amount planted; squirreltail grew poorly and did not reproduce. Samples of squirreltail seed retrieved from the plots in late summer were found to have remained dormant since seeding. The second year had above-average precipitation. Medusahead grew and reproduced well again. Squirreltail grew and reproduced abundantly on one of the sites, both on freshly-seeded plots and on plots containing dormant seeds and surviving plants from the previous year. In all cases, medusahead exhibited stronger interspecific and intraspecific competitive effects than did squirreltail seedlings. With adequate soil moisture, squirreltail reduced average weight and median seed production of individual medusahead plants, but did not reduce medusahead seed production per square meter. Medusahead succeeded in a drought year by utilizing deep soil moisture, and utilized shallower moisture in a wet year. During a wet year in plots containing mature squirreltail, medusahead utilized shallower moisture, while squirreltail strongly utilized much deeper moisture. Interspecific competitive interference by medusahead on squirreltail seedlings suggests the potential benefits of suppressing medusahead during the seeding year for squirreltail in a rehabilitation effort, especially if climatic conditions are conducive to squirreltail germination and establishment. / Graduation date: 1997

Identifying genetically appropriate plant materials for seed based restoration relies on the principle of local adaptation where the objective is to match adaptive genetic characteristics to variation in ecological clines pertinent to plant establishment and persistence. In this study, basin wildrye (Leymus cinereus (Scribn. & Merr.) Á. Löve) sources from 25 wild populations and 4 commercial varieties were planted at 4 test sites. We assessed initial establishment and short term persistance. Plantings failed at 2 sites in both 2013 and 2014, with too few plants to quantify differences. At the remaining 2 sites, local sources had higher initial establishment in just 1 of 10 comparisons. Among commercial sources, the cultivars Magnar and Trailhead initially outperformed local pooled materials at Fountain Green but not at Nephi. Initial establishment under row cover was dramatically better than uncovered controls at both sites, but only persisted for 4 years after planting at the Fountain Green site. The native forb study evaluated the effects of species, sowing depth and row cover on field emergence of 20 forbs. Overall, emergence was very low ranging between 0.2% and 1.0% for 16 of the 20 species. Four species exceeded 1% emergence. Depth effects were species, site and year dependent. The odds of emergence decreased with increasing depth for four species, increased for three species and were mixed between sites and years for the remaining species. The odds of emergence were better under row cover than for uncovered control plots. Depths evaluated were deeper than recommended for most species and likely hindered emergence for some species. Site and year had much more effect on observed emergence than depth or treatment. Developing simple diagnostics to identify subspecies is key in the restoration of sagebrush ecosystems. We evaluated the SoilWeb app as a tool to identify sagebrush in the field. We evaluated the accuracy of the Richardson et.al. (2015) technique to classify sagebrush stands and evaluated data modeling strategies to improve classification accuracy. We found the SoilWeb app to be an accurate and informative tool to identify native-wild sagebrush populations. The Richardson et.al. (2015) seed weight criteria correctly classified just 19% of our sample populations to the correct subspecies. To improve upon this, we evaluated multifactor modeling using recursive partitioning and classification trees. Our most accurate classification tree correctly classified 80% of 2x tridentata sites but just 45% of wyomingensis sites.

The potential of basin wildrye (Elymus cinereus Scribn. & Merr. 'Magnar') and tall wheatgrass [Agropyron elongatum (Host) Beav. 'Jose '] to establish on saline, arid rangelands in the Great Basin in relation to soil water and salinity was compared in field and laboratory experiments. Tall wheatgrass had higher emergence and establishment on a nonsaline and a saline soil (electrical conductivity of the saturation extract of 7 dS·m-1) over a range of spring precipitation as simulated by sprinkler irrigation. Basin wildrye will require supplemental irrigation to establish on soils of similar salinity. In the absence of precipitation, soil salinity increases and matric and osmotic potentials rapidly decrease as the surface soil dries in late spring. Germination and growth responses in relation to salinity and drought in laboratory experiments were consistent with emergence and establishment results in the field experiments. Tall wheatgrass had higher total germination, rate of germination and radicle growth under decreasing osmotic potentials and higher emergence under decreasing matric potentials than basin wildrye. Tall wheatgrass had greater root and shoot yield than basin wildrye when osmotic potentials in sand cultures were decreased by solutions of NaCl, Na2SO4 and CaCl2.Tall wheatgrass is more tolerant of salt and boron than basin wildrye, but basin wildrye is highly salt tolerant compared to most forage species. Tall wheatgrass had more rapid root elongation and more extensive root growth than basin wildrye seedlings grown in 60-cm soil columns filled with nonsaline and saline soil. Germination and growth of both species was reduced by ions in addition to the effects of water stress due to low osmotic potentials. Rate of germination and radicle growth of both species was less in salts than in isosmotic polyethylene glycol solutions. Seedlings exhibited less growth in saline than nonsaline soil even when plant water stress was minimal or when leaf water potentials were low but turgor was maintained by osmotic adjustment. Germination at low osmotic and matric potentials and root elongation in relation to salinity may be important plant responses to use in evaluating the potential for establishment of new plant materials on saline, arid rangelands.

Russian wildrye (Elymus junceus Fisch.) is a longlived perennial bunchgrass introduced to this continent from Siberia by the University of Saskatchewan in 1926 (Lawrence and Heinrichs, 1966). It is now widely distributed throughout the Northern Great Plains and Intermountain area (Figure 1). The species does well in the Northern Great Plains, but even though it is recommended for foothill ranges in the Intermountain area (Plummer, et aI, 1955), there are problems with establishment of Russian wildrye in the Intermountain area. This study was an attempt to fill in some of the gaps in the knowledge about establishment and survival of Russian wildrye on foothill ranges in Utah.

No description available.