Progress 02/09/10 to 12/01/12
Outputs
Progress Report Objectives (from AD-416): The University of Nevada at Reno is undertaking a cooperative project with the Agricultural Research Service and to investigate (1) the ability of key Great Basin native annual species to compete with cheatgrass as well as (2) their ability to facilitate the establishment of Great Basin native perennial bunchgrasses. The ultimate goal of this project is to assess the suitability of key Great Basin native annual species for use in restoration seedings. Approach (from AD-416): The University of Nevada at Reno will assist in developing, implementing, and analyzing experiments to assess the ability of Great Basin native forb species to compete with cheatgrass and facilitate establishment of native perennial grasses. This will include collaborating with ARS on greenhouse and field experiments, as well as the writing of scientific manuscripts. This is the final report for this project which was terminated on December 1, 2012. This agreement is established in support of objective 4 of the in-house project, "Develop restoration methodologies to prevent the invasion of annual grasses (such as cheatgrass, medusahead rye, and/ or red brome) following destructive events (such as fire) in rangeland ecosystems". In arid systems, facilitation may be an important component of vegetation recovery after disturbance. Establishment of native perennial species in disturbed western rangelands is desirable, but is severely limited by the presence of the highly competitive exotic annual grass, cheatgrass (Bromus tectorum). Greater restoration success may be achieved with seed mixes that mimic natural succession in Great Basin systems, which include native annuals as a key component of the post-disturbance community. Due to overlapping phenology, there is the potential for strong competitive interactions between native and exotic annuals, which could indirectly facilitate establishment of perennial species. The objectives of this study were to (1) Determine the effect of select native annual forbs on the performance of cheatgrass and big squirreltail (Elymus multisetus) under field and greenhouse conditions and (2) Determine if the presence of native annual forbs increases the performance of big squirreltail when grown with cheatgrass. In greenhouse and field experiments, seedlings of a native perennial grass, big squirreltail, were grown individually with each of five native annual forbs (bristly fiddleneck [Amsinckia tesselata], common fiddlehead [A. intermedia], Veatch�s blazingstar [Mentzelia veatchiana], rough eyelashweed [Blephariappus scaber], and western tansymustard [Descurania pinnata]) and with an annual forb mix (bristly fiddleneck, Veatch�s blazingstar, wingnut cryptantha [Cryptantha pterocarya], and Great Basin woollystar [Eriastrum sparsiflorum]). Half of the replicates were seeded with cheatgrass. We recorded the number of green leaves on big squirreltail plants after planting to assess treatment effects on growth rate and measured aboveground biomass of big squirreltail and neighboring plants after one growing season. Additionally, cheatgrass was grown with native annuals in the greenhouse and field to determine the effect of native annual forbs on cheatgrass biomass and seed production. Structural equation modeling (SEM) was also used to examine the direct and indirect effects of native annual forbs on big squirreltail performance under greenhouse and field conditions. Bristly fiddleneck and common fiddleneck were the most competitive native annuals with Cheatgrass, suppressing biomass and seed production more than other forb species. In the greenhouse, big squirreltail growth and seasonal biomass production were lower when grown with cheatgrass than with any of the native annuals. Additionally, when in competition with cheatgrass, big squirreltail�s growth performance was best when Veatch�s blazingstar was also present, and growth rates were significantly greater when any of the annual forbs were also present. Although bristly fiddleneck was beneficial to big squirreltail in the greenhouse, under field conditions, the fiddleneck had a negative effect on the squirreltail performance. However, over time, these negative effects decreased and could potentially lead to facilitation of big squirreltail later in the season because of it�s perennial habitat and longer growing season.
Impacts
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Publications
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Progress 10/01/11 to 09/30/12
Outputs
Progress Report Objectives (from AD-416): The University of Nevada at Reno is undertaking a cooperative project with the Agricultural Research Service and to investigate (1) the ability of key Great Basin native annual species to compete with cheatgrass as well as (2) their ability to facilitate the establishment of Great Basin native perennial bunchgrasses. The ultimate goal of this project is to assess the suitability of key Great Basin native annual species for use in restoration seedings. Approach (from AD-416): The University of Nevada at Reno will assist in developing, implementing, and analyzing experiments to assess the ability of Great Basin native forb species to compete with cheatgrass and facilitate establishment of native perennial grasses. This will include collaborating with ARS on greenhouse and field experiments, as well as the writing of scientific manuscripts. This research supports objective 1: Identify and characterize biotic and abiotic conditions and processes that affect plant community factors and ecosystem dynamics on healthy and degraded rangelands to improve the ability to predict how rangelands will respond to changing environmental conditions and alternative management practices. Specifically Sub- objective 1.1: Determine how land management history, the reproductive ecology of invasive annuals, and biotic interactions affect the structure and function of selected Great Basin ecosystems. This research examines an ecologically and economically rational strategy for management of B. tectorum invaded rangelands. By utilizing principles of natural succession of Great Basin rangelands, two goals are met: (1) restoring rangelands to their proper functioning using native plant materials and (2) an ecological and economic benefit to land managers through increased restoration success. Understanding if native annual forbs can increase establishment of E. multisetus in degraded rangelands will allow managers and seed producers to take the following steps to maintain healthy systems: (1) include highly competitive annual forbs in restoration of seed mixes to promote establishment of early successional perennial grasses such as E. multisetus, (2) target annual forbs that have the greatest positive effect on E. multisetus and negative effect on B. tectorum biomass and reproduction for seed increase programs, and (3) manage and maintain sites with high annual forb diversity, as these populations may be a vital component for successful restoration of disturbed rangelands. The greenhouse and field experiments have been completed, and data has been analyzed. The results of these experiments support the idea that the presence of certain native annual forbs can enhance the establishment of E. multisetus in B. tectorum invaded rangelands. A manuscript entitled: �Native annual forbs reduce Bromus tectorum biomass and indirectly facilitate establishment of a native perennial grass� is in review at the Journal of Applied Ecology.
Impacts
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Publications
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Progress 10/01/10 to 09/30/11
Outputs
Progress Report Objectives (from AD-416) The University of Nevada at Reno is undertaking a cooperative project with the Agricultural Research Service and to investigate (1) the ability of key Great Basin native annual species to compete with cheatgrass as well as (2) their ability to facilitate the establishment of Great Basin native perennial bunchgrasses. The ultimate goal of this project is to assess the suitability of key Great Basin native annual species for use in restoration seedings. Approach (from AD-416) The University of Nevada, Reno will assist in developing, implementing, and analyzing experiments to assess the ability of Great Basin native forb species to compete with cheatgrass and facilitate establishment of native perennial grasses. This will include collaborating with ARS on greenhouse and field experiments, as well as the writing of scientific manuscripts. This research is in support of Objective 2 of the in-house project, �Devise management guidelines, technologies, and practices for conserving and restoring Great Basin rangelands�. The goals of this work are to investigate (1) the potential for Great Basin native annual forbs to effectively compete with Bromus tectorum and facilitate the establishment success of native perennial grasses (2) the germination ecology of key Great Basin native annual forbs. The ultimate goal of this work is to determine whether it would be useful to include native annuals in postfire rehabilitation seed mixes. This aspect of the research is being conducted in combination with University Nevada, Reno (UNR). During this FY, results from 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 are being written up for a manuscript. 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. We also finished a field experiment, with 240 small plots planted with combinations of Amsinckia intermedia, Amsinckia tesselata, Blepharipappus scaber, Descurainia pinnata, Mentzelia veatchiana, and Bromus tectorum. The experiment examined 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 collected 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.
Impacts
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Publications
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Progress 10/01/09 to 09/30/10
Outputs
Progress Report Objectives (from AD-416) The University of Nevada at Reno is undertaking a cooperative project with the Agricultural Research Service and to investigate (1) the ability of key Great Basin native annual species to compete with cheatgrass as well as (2) their ability to facilitate the establishment of Great Basin native perennial bunchgrasses. The ultimate goal of this project is to assess the suitability of key Great Basin native annual species for use in restoration seedings. Approach (from AD-416) The University of Nevada at Reno will assist in developing, implementing, and analyzing experiments to assess the ability of Great Basin native forb species to compete with cheatgrass and facilitate establishment of native perennial grasses. This will include collaborating with ARS on greenhouse and field experiments, as well as the writing of scientific manuscripts. Documents SCA with U of NV. The goals of this work are to investigate (1) the potential for Great Basin native annual forbs to effectively compete with B. tectorum and facilitate the establishment success of native perennial grasses (2) the germination ecology of key Great Basin native annual forbs. The ultimate goal of this work is to determine whether it would be useful to include native annuals in postfire rehabilitation seed mixes. 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.
Impacts
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Publications
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