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Assessment Project - Wyoming Component

 David Kazmer

Question 1. What major problem or issue is being resolved and how are you resolving it?

Leafy spurge (Euphorbia esula) is an exotic perennial weed that infests over 5 million acres of grazing lands and wildlands in the upper Midwest and additional infestations in at least 35 states and 6 Canadian provinces. As a part of The Ecological, Areawide Management (TEAM) - Leafy Spurge project, we are participating in A) a large-scale assessment of biological control agent releases on leafy spurge and B) remote sensing research to develop large-scale inventory methods.

Question 2. How serious is the problem? Why does it matter?

Economic impacts of leafy spurge infestations are estimated at $144 million annually in Montana, North Dakota, South Dakota and Wyoming alone. Environmental impacts include ground water contamination due to excessive herbicide use, greatly reduced plant species diversity in infested areas, and degradation of wildlife habitat.

Question 3. How does it relate to the National Program(s) and National Program Component(s)?

The TEAM Leafy Spurge project is a part of the USDA/ARS Area-Wide Management Program. It is a component of Crop and Commodity Pest Biology, Control and Quarantine (304). TEAM Leafy Spurge complements efforts to develop new and improved pest control technologies and assess component technologies for integrated pest management (IPM) systems.

Question 4. What was your most significant accomplishment this past year?

Leafy spurge (Euphorbia esula) is an exotic perennial weed that infests over 5 million acres of grazing lands and wildlands in the upper Midwest and additional infestations in at least 35 states and 6 Canadian provinces. Monitoring of vegetation and biological control agent densities was performed at the 109 long-term study sites in Crook County, Wyoming. Remote sensing data including color and color-infrared imagery, Landsat TM satellite imagery, SPOT IV satellite imagery, and AVIRIS imagery were obtained and analyzed for the Wyoming study area, and ground reflectance data of leafy spurge, vegetation, soils, and other prominent features in the study area were obtained. The major transfer of technology to date has been a better understanding of the habitat requirements for optimum establishment and success of insect biocontrol agents.

Question 5. Describe your major accomplishments over the life of the project, including their predicted or actual impact.

In 1998 a study area in Crook County, Wyoming was selected about 5 miles west of Devil's Tower National Monument. The area was characterized by topological position as upland, draw, or riparian. The vegetation was classified into three main types: woodland/grass, prairie/grass, and sagebrush/grass. Plots were established in areas of extensive spurge within each of the three topographical position types, and also in each of the vegetation types (Table 1). During May and June, 109 study plots were located and permanently marked in spurge infestations. Each plot location was also recorded using a GPS receiver. Vegetation measurements and flea beetle (Aphthona sp.) sampling were performed at each site. Six digital pictures were taken at each site including 5 pictures from an aerial perspective (COAST System) to document spurge cover and one site picture. On June 25 and June 26, 1998, flea beetles were released on 77 of the 109 sites. Each of the 77 sites received 3,000 black flea beetles and 3,000 brown flea beetles.

In June and July of 1999 and 2000, each of the 109 sites were revisited. Spurge and other vegetation cover were recorded and flea beetle sampling was performed. Methods used during the 1999 and 2000 field seasons were the same as those described above for 1998. In addition, soil samples were collected at 30 of the permanent sites in 1999.

Prior to the 1999 field season, a Landsat TM image (7 bands, visible through MIR + thermal, 30 m pixel size) of the study area acquired on June 14, 1991 was used to perform an initial vegetation classification of the study area. This classification provided a ground-truthing and sampling framework prior to the 1999 field season and further acquisition of remotely sensed data in 1999. Aerial photographs taken near the peak flowering period were used in combination with orthophoto quadrangle maps as additional remote sensing data and for verification of cover types in combination with field ground truthing. Both color and CIR aerial photos were taken in late June of 1998. The color photography was taken by Gerry Anderson (USDA, ARS, Sydney, MT) at a scale of 1:10,000. The CIR photography was taken by Horizon Air at a scale of 1:10,000. During 1999, 246 stratified (by vegetation type and presence or absence of leafy spurge) random locations in the study area were visited on the ground. At each site the dominant vegetation type was recorded and the percent cover of leafy spurge was recorded. In addition, the presence of yellow sweet clover was noted.

An Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) image was acquired over the study area on July 6, 1999. With its hyperspectral capabilities, it provides the best resolution (spectrally, radiometrically, and spatially) for detecting leafy spurge. Initial analysis of the AVIRIS scene has been completed. A scene from the SPOT IV satellite (4 bands, G- R-NIR-MIR, 20 m pixel resolution) was acquired over the study area on June 3, 2000; and a July 6, 1998 Landsat TM 5 scene was acquired of the study area. From this imagery, spectral analysis techniques will be used to determine areas composed predominantly of leafy spurge.

During June of 1999 and 2000, we also collected ground reflectance data of leafy spurge, vegetation, soils, and other prominent features in the study area. These spectra are being used as a "library" of known spectra in the image to perform spectral mixing analysis on the AVIRIS scene. They were also used to calibrate the AVIRIS imagery. An accuracy assessment of the ability to map leafy spurge from the AVIRIS, SPOT, and Landsat images will be completed this year using the 1999 field ground truthing sites and the aerial photography.

Question 6. What do you expect to accomplish year by year, over the next three years?

A) Continued monitoring of the 109 long-term study sites in Wyoming. B) Further exploration and application of remote sensing as a tool for large-scale inventory of weed infestations and the large-scale impacts of weed management programs.

Question 7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology?

Biological control agents were released on public and private lands in the first year of the project. Historically, the uncertain and slow impact of the current biological control agents for leafy spurge has been a significant barrier to broad adoption of this method. However, our releases have produced dramatic impacts after two years that has rekindled strong interest in using biological control for leafy spurge.

Question 8. List your most important publications in the popular press (no abstracts) and presentations to non-scientific organizations, and articles written about your work (NOTE: this does not replace your peer-reviewed publications which are listed below).

Kazmer, D.J. 1999. Annual Biological Control Update. 55th Annual Wyoming Weed & Pest Conference, Sheridan.

Kazmer, D.J. 1999. Biological Control of Weeds in Wyoming. Converse County Farmer/Rancher Day, Douglas.

Kazmer, D.J. 1999. Field Demonstration on Biological Weed Control. Cheyenne River Weed Management CRM Field Tour, Weston County.

Kazmer, D.J. 1999. Field Demonstration on Biological Weed Control. Cheyenne River Weed Management CRM Field Tour, Niobrara County.

Parker, A.E. 2000. Remote sensing and biocontrol of leafy spurge in Crook County, Wyoming. Univ. of Wyoming Botany Department Seminar.

Parker, A.E. 2000. Biocontrol and mapping of leafy spurge in Crook County, Wyoming. Univ. of Wyoming Renewable Resources Department Seminar.

Question 9. Scientific publications

None.

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