2009 Annual Report
In cooperation with University of Nevada, we conducted a field study that quantified above- and below-ground carbon stocks in pinyon-juniper ecosystems treated with prescribed fire. Data clearly showed that prescribed burning caused immediate increases in surface soil C and N concentration, but over longer periods of time no statistically detectable change in soil C or N content occurred from burning. We also completed a study on 8 sites in northern Nevada and northeastern California in which individual and combinations of Fe, Cu, Zn, Mn, Fe, Ni, and Ag were applied to decrease enzyme activities associated with N-mineralization. We then monitored cheatgrass density and soil nutrient availability of N. At all sites, micronutrient additions have not decreased N availability or cheatgrass density relative to control plots. In another cheatgrass study, plants were collected as both green plants and mature seed at 8 different field sites. Red brome samples were also collected at 2 of these sites and one additional site. Samples are being shared with the US Forest Service’s Shrub Science Laboratory (Provo, UT) for collaborative research. DNA extractions and analyses have been completed for samples collected in 2008 and are ongoing for green plant
Three study sites were identified in northern California for long-term study of the roles of seed dispersal and seedling recruitment in the ongoing expansion of western juniper woodlands. All juniper trees on 2 of these sites were cored for aging in 2008, and tree coring is currently ongoing at the third site. Collected cores have been prepared and aged in the lab. Juniper berry production was estimated for all trees at each site during the Fall of 2008. We conducted small mammal trapping and bird surveys and deployed automated wildlife cameras to identify potentially important seed dispersing animals. Small mammal and bird species that consume juniper berries and disperse seeds have been identified at one study site using motion-activated trail monitoring camera systems. We initiated a seed trap study at the new sites to begin quantifying levels of seed predation in western juniper. The rate at which juniper berries fall from trees was quantified at 2 field sites using paired seed traps placed under berry-laden trees.
5.Significant Activities that Support Special Target Populations
The Research Unit worked with University of Nevada at Reno to develop a workshop on jobs in natural resources for Piute tribe high school students. During the 1 week summer workshop the high school students were provided an overview of jobs in natural resources on the first day and a tour of ARS and University of Nevada at Reno research facilities. On each of the following days the students were hosted by a scientist who took them to the field to demonstrate different techniques to measure abiotic and biotic parameters used to define watershed health within the Truckee river basin.
Most research conducted through this research project is in support of small farms and/or ranches that need economically viable methods of controlling invasive weeds and sustainably managing Great Basin rangelands. In particular we work closely with ranchers in central Nevada on control of salt cedar, cheatgrass and management issues related to pinyon-juniper woodlands. Through our outreach program and sponsorship of conferences and workshops over 500 people have been engaged with the project and have learned about our rapidly developing new technology and techniques to mange Great Basin rangelands.
Schierenbeck, K.A., Ellstrand, N.C. 2008. Hybridization and Evolution of Invasiveness in Plants and Other Organisms. Biological Invasions 11:1093-1105.
Weltz, M.A., Jolley, L., Nearing, M.A., Stone, J.J., Goodrich, D.C., Pierson Jr, F.B., Speath, K., Kiniry, J.R., Arnold, J.G., Bubenheim, D., Hernandez, M., Wei, H. 2008. Assessing the benefits of grazing land conservation practices. Journal of Soil and Water Conservation. 63:214-217.
Duriancik, L., Bucks, D., Dobrowolski, J.P., Drews, T., Eckles, S.D., Jolley, L., Kellogg, R.L., Lund, D. Makuch, J.R., O'Neil, M.P., Rewa, C.A., Walbridge, M.R., Parry, R., Weltz, M. 2008. The first five years of the Conservation Effects Assessment Project. Journal of Soil and Water Conservation. 63:185-197.
Longland, W.S., Aten, M., Swartz, M., Kulpa, S. 2009. Who’s Eating the Flowers of a Rare Western Nevada Range Plant?. Rangelands 31:26-30.
Rau, B.M., Johnson, D.W., Blank, R.R., Chambers, J.C. 2009. Soil carbon and nitrogen in a Great Basin pinyon-juniper woodland: Influence of vegetation, burning, and time. Journal of Arid Environments. 73(2009):472-479.
Goergen, E., Chambers, J., Blank, R.R. 2009. Effects of Water and Nitrogen Availability on Nitrogen Contribution by the Legume, Lupinus argenteus Pursh. Applied Soil Ecology. 42:200-208.