Location: Pest Management Research
2019 Annual Report
Objectives
Objective 1: Identify and bridge critical knowledge gaps in the taxonomy, native origin, population structure, and reproductive strategies of key invasive weeds, as necessary to support the successful development of classical biological control programs. [NP304, Component 1, Problem Statements 1A, 1B, and 1C; Component 2, Problem Statement 2B2]
Subobjective 1.A: Determine the correct taxonomy and extent of hybridization of invasive weeds.
Subobjective 1.B: Determine the origins, population structure and reproductive mode of invasive weeds.
Objective 2: Develop novel, effective biological weed control and rangeland restoration methods that synergize ecological interactions, such as herbivory, weed population heterogeneity, invasion-dynamics, competition between weeds and native vegetation, and plant-soil interactions. [NP304, Component 2, Problem Statements 2B2, 2B3 and 2B4]
Subobjective 2.A: Understand insect community composition and assembly in response to restoration and prior to the release of Russian olive biological control.
Subobjective 2.B: Determine plant population, community and soil characteristics that contribute to the control of invasions.
Approach
Weeds in pastures and croplands in the U.S. result in billions of dollars per year in lost production and control costs. The goal of our project is to decrease weed abundance by increasing the efficacy of biological control agent development and improving the establishment success of plant community restorations that resist invasion. Our team’s research spans multiple aspects of weed control, from the taxonomy required for effective development of weed management strategies, demographic and ecological research to optimize biological control management efficacy, and identification of the inputs required in restoration that support productive invasion-resistant landscapes. We will address critical gaps in genotype-specific information regarding the reproductive strategies, origin and invasiveness of some of the most important invasive weeds in the U.S., thus guiding effective control methods including effective biological control agents. We will identify ecological, demographic, and biological factors limiting invasion potential for weeds with different life histories. This will generate strategies that limit the spread of target weeds and provide a general framework of biologically- and ecologically-based weed control methods. We will also create realistic targets for restoration that benefit landscapes. This work develops science-based, economical weed management that reduces costs, promotes food security and minimizes negative environmental impacts of weed control.
We focus on rangeland weeds in the Northern Great Plains and extend this research nationally across a range of habitats. By communicating our results through on-going relationships with land management agencies, farmers and ranchers, academic societies, industry and state extension services, this research supports innovative strategies vital to the sustainability and health of U.S. agroecosystems.
Progress Report
ARS scientists in Sidney, Montana, continued DNA collections of critical invasive species in the western U.S. and from their putative origins in Eurasia, including Russian knapweed, leafy spurge, dyers woad, mullein and flowering rush. They are now using molecular markers to determine the correct invasive species identification, major mode of reproduction, as well as specific origin of these invasions. This information is being used to develop more effective foreign biological control agents to fight against invasive plants in the U.S. As part of a $2M U.S. Department of Agriculture's National Institute of Food and Agriculture (NIFA) Organic Agriculture Research and Extension Initiative grant, scientists in Sidney, Montana, have begun genetic sampling of bindweed and Canada thistle to determine their modes of reproduction in organic cropping systems, which will help producers control these top two weeds in organic systems. Objective 1.
So far, data on energy development and restoration impacts to plants, soils and insects show reclaims have reduced plant cover and more weedy/invasive plants than nearby rangeland, likely because soils remain degraded. Reclaims also have more crop pest grasshoppers, but spiders and soil biota appear to have recovered. Data suggest that early variation in reclamation success due to site conditions decreases over time; invasive weeds become a major determinant of site quality by the third year after reclamation. Subobjective 2a.
Under a U.S. Forest Service Biological Control of Invasive Native and Non-Native Plants (BCIP) grant, a multi-state, multi-stakeholder project quantifying the efficacy of leafy spurge biocontrol across broad habitat gradients was initiated, with the goal of developing management recommendations and informing future biocontrol agent development. The multiple biocontrol agents released for leafy spurge have proven to be a valuable tool for farmers, ranchers, and land managers, particularly in areas where chemical control is unfeasible. This study should provide the information needed to improve biological control of leafy spurge in habitats and regions where biocontrol management has had uncertain success. Subobjective 2b.
Accomplishments
1. A new exotic thistle found invading North America. All five species of the plumeless thistle genus Carduus are exotic invasives and listed by multiple states as noxious weeds. Multiple populations of an unknown plumeless thistle species were found in remote areas of the deepest river gorge in North America, Hells Canyon National Recreation Area in Oregon and Idaho. The plants were unrecognizable, so ARS researchers in Sidney, Montana, analyzed the plant’s DNA and matched it to specimens from the eastern Mediterranean. Then ARS, working with botanists from Oregon, California, and Spain, definitively identified the plants as Carduus cinereus, a weed species never before found in the Americas. Northwestern states are initiating EDRR action (Early Detection, Rapid Response) on this new invasive threat, which will allow them to control, and perhaps eradicate, this newly identified weed before it expands its range and increases its economic damage to rangeland producers.
2. Russian olive is an expanding invader along western North American rivers. Land managers currently invest considerable time and money in its control and eradication in riparian areas. Early models of Russian olive invasion did not incorporate the possibility of seed movement in water, and assumed dispersal limitation should slow population spread. As Russian olive has increased in riparian zones over the past two decades, water movement of seeds is also likely increasing, speeding up the invasion front and strengthening invasion impacts. ARS researchers in Sidney, Montana, showed that current distributions of Russian olive along the Yellowstone River are highly correlated with patterns of flooding, and resulting population estimates suggest the intervals of flooding frequency identified should substantially increase invasion risks along western rivers. However, linking Russian olive cover to patterns of flooding will allow land managers to better target vulnerable areas and timeframes for management.
Review Publications
Villar, J.L., Alonso, A.M., Juan, A., Gaskin, J.F., Crespo, M.B. 2019. Out of the Middle East: New phylogenetic insights in the genus Tamarix (Tamaricaceae). Journal of Systematics and Evolution. https://doi.org/10.1111/jse.12478.
Sylvain, Z.A., Branson, D.H., Rand, T.A., West, N.M., Espeland, E.K. 2019. Decoupled recovery of ecological communities after reclamation. PeerJ. https://doi.org/10.7717/peerj.7038.
Sylvain, Z.A., Espeland, E.K., Rand, T.A., West, N.M., Branson, D.H. 2019. Oilfield reclamation recovers productivity but not composition of arthropod herbivores and predators. Environmental Entomology. 48(2):299-308. https://doi.org/10.1093/ee/nvz012.
Bagavathiannan, M.V., Graham, S., Zhao, M., Barney, J.N., Coutts, S.R., Caicedo, A., De Clerck-Floate, R., West, N.M., Blank, L., Metcalf, A.L., Lacoste, M., Moreno, C., Evans, J.A., Burke, I., Beckie, H. 2019. Considering weed management as a social dilemma bridges individual and collective interests. Nature Plants. 5:343-351. https://doi.org/10.1038/s41477-019-0395-y.
Gaskin, J.F., Andres, J.A., Bogdanowicz, S.M., Guilbault, K.R., Hufbauer, R.A., Schaffner, U., Weyl, P., Williams III, L.H. 2019. Russian-olive (Elaeagnus angustifolia) genetic diversity in the western United States and implications for biological control. Invasive Plant Science and Management. https://doi.org/10.1017/inp.2019.16.
Lee, S., Park, H., Kim, B., Lee, J., Gaskin, J.F., Kim, Y. 2019. An unexpected genetic diversity pattern and a complex demographic history of a rare medicinal herb, Chinese asparagus (Asparagus cochinchinensis) in Korea. Nature Scientific Reports. 9:9757.
Baughman, O.W., Agneray, A.C., Forister, M.L., Kilkenny, F.F., Espeland, E.K., Fiegener, R., Horning, M.E., Johnson, R.C., Kaye, T.N., Ott, J.E., St. Clair, J.B., Leger, E.A. 2019. Strong patterns of intraspecific variation and local adaptation in Great Basin plants revealed through a review of 75 years of experiments. Royal Society Open Science. 9:6259–6275. https://doi.org/10.1002/ece3.5200.
Espeland, E.K., Sylvain, Z.A. 2019. Range size, local abundance and effect inform species descriptions at scales relevant for local conservation practice. Biodiversity and Conservation Journal. 28(4):909-920. https://doi.org/10.1007/s10531-019-01701-2.
