2010 Annual Report
This aspect of the research is being conducted in combination with University Nevada, Reno (UNR). During this FY, we have completed two greenhouse experiments using a hybrid additive/replacement design to look at competition of the two native species with Bromus tectorum and establishment of Elymus multisetus with native annual forbs, with B. tectorum, and with annual forb-B. tectorum mix. Growing with competitors decreased the size of E. multisetus, however the largest decrease in size was found when grown with B. tectorum and Amsinckia tesselata. In contrast, E. multisetus grew best with Mentzelia veatchiana. When in competition with B. tectorum, E. multisetus performed best when M. veatchiana was also present. These results support the idea that the presence of certain native annual forbs can enhance the establishment of E. multisetus in B. tectorum invaded rangelands.
Results from this study also indicated that both native annual forbs examined are negatively impacted by growth with B. tectorum , but M. veatchiana was more impacted than A. tesselata. Because of temperature control problems in the greenhouse, we did not get B. tectorum to flower and so are currently repeating part of the experiment designed to quantify B. tectorum responses. This experiment will tell us whether the natives are reducing the performance of B. tectorum under greenhouse conditions.
We are also conducting a field experiment. We have established a field study to expand on the results of the greenhouse study. Last fall, we planted 240 small plots with combinations of Amsinckia intermedia, Amsinckia tesselata, Blepharipappus scaber, Descurainia pinnata, Mentzelia veatchiana, and Bromus tectorum. The experiment looks at the performance of B. tectorum or E. multisetus target plants in annual native forb monocultures, B. tectorum monoculture, or a mixture of annual native forbs and B. tectorum. We will collect data on density of natives and B. tectorum over time as well as biomass and reproductive output of E. multisetus and B. tectorum target plants.
The collaboration with UNR has involved extensive meetings with collaborators, who are all co-located with our ARS unit.