Long-Term Vegetation Transects


The Long-Term Vegetation (LTV) Transects and associated permanent vegetation plots (Figure 9-7) were established at the Arco Reactor Test Site, now the INL Site, in 1950 for the purpose of assessing the impacts of nuclear energy research and production on surrounding ecosystems (Singlevich et al. 1951). Vegetation abundance data were first collected in 1950 for inclusion in an ecological characterization of the Site. Samples of plant and animal tissues were also collected from these plots and analyzed for radionuclide concentrations on an annual basis for several years. The effort to collect tissue samples was eventually discontinued because the effects of fallout from nuclear reactors were determined to be negligible (Harniss 1968), at least in terms of radionuclide concentrations in the environment. However, collection of vegetation abundance data has continued on a regular basis for nearly sixty years.

The data generated from the LTV Transects comprises one of the oldest, largest, and most comprehensive vegetation data sets for sagebrush steppe ecosystems in North America. Since their establishment, the LTV Transects have been used extensively for various tasks to support the INL Site mission and have been the basis for major milestones in understanding practical and theoretical ecology of sagebrush steppe vegetation dynamics. Applications of the LTV data include;

  • Plant community classification and mapping,
  • Assessing the effects of drought and livestock grazing,
  • Understanding fire history and recovery,
  • Characterizing species invasion patterns,
  • Testing theories of vegetation succession and change,
  • As a basis for habitat suitability modeling for sensitive species,
  • Supporting NEPA processes,
  • Making appropriate land management recommendations, and
  • Developing specific revegetation recommendations.

In addition to the functions listed above, the LTV data set is still used to assess the impacts of energy development on the environment, as was intended in 1950. However, impacts beyond radioactive fallout, such as exotic species invasion, habitat fragmentation, and global climate change are of current interest.


The eleventh LTV data set was collected during the summer of 2006. Two tasks were undertaken in association with the 2006 data collection. The first task involves a major effort in updating and describing the data archives. The second includes summarization and analysis of the 2006 and all previously collected abundance data.

The last attempt at organizing and archiving the LTV data was completed in the early 1980s. Although care has been taken to format and store data collected since 1983 in a manner consistent with the protocol established at that time, the data archives have become outdated. The software available for archiving and processing data has improved substantially over the past 25 years, necessitating an update of the LTV data files. A considerable amount of the work associated with entry and summary of the 2006 data includes designing and populating a relational database for all of the LTV data from 1950-2006. Additionally, a specific sampling protocol will be developed and a thorough history included for the LTV as part of the reporting effort.

Analyses on the 2006 and previous data can be summarized under two focus areas. The first includes characterizing general plant abundance and community composition trends, similar to analyses described in previous LTV reports. The second group of analyses will concentrate on characterizing patterns of exotic species invasion and determining the effects of invasion on vegetation cover and composition of native plant communities subsequent to invasion.

Accomplishments Through 2007

Accomplishments through 2007 include collection of the 2006 data and completion of QA/QC procedures on that data set. The 2006 data were also summarized and formatted for inclusion in a comprehensive database. A specific protocol for use in collecting LTV data was designed and outlined in association with the 2006 data collection effort. A Microsoft Access database was designed to house historical LTV data and to facilitate future data collection, including straightforward processes for updating data tables. The database will also expedite current and future analyses on the complete LTV data set. Incorporation of historical and 2006 LTV data into the database was mostly completed in 2007. Data verification and validation efforts were also completed primarily in 2007. Verification and validation processes were used to ensure the integrity and completeness, as well as to resolve issues associated with taxonomic classifications and scaling, of the historical data set as it was integrated into the new database.


The database includes seven raw data and metadata tables. The general structure of the database is depicted in Figure 9-8. The metadata tables include information about plant species on the INL Site and information about each of the permanent plots on the LTV Transects. The species information data table can, and should be used for all future vegetation data collection on the INL Site. It contains standardized information for each vascular plant species documented to occur within or adjacent to the Site boundary. Information contained in the species information table will facilitate summarizing data into functional groups, and allows the definitions of functional groups to be easily changed. The species information table reconciles species codes traditionally used for data collection on the INL Site with a national standard (USDA, NRCS 2008). This data table can be readily updated in response to changes in taxonomy and contains unique numeric codes for each species so that a species is always identified correctly for summarization in current and historical data sets even though taxonomy and species codes have changed through time.

The plot information data table contains metadata about each permanent plot along the LTV macro-transects and several additional plots sampled in 1957 and 1965, referred to as the century series.

The plot information table contains data about the location and history of each plot including; coordinates, elevation, grazing allotment, plant community classification, soils information, fires, etc. An additional metadata table, the sample frequency table, contains information about the types of data collected and sample periods for collection of each type of data on each plot. The data contained in the sample frequency table is not entirely unique. For example, determining whether all three types of abundance data were collected on a specific plot in a certain year can be accomplished by querying all three abundance data tables. However, running one query against the sample frequency table streamlines the process. The sample frequency table also houses information about sampling details (i.e. only 40 point frames were sampled on plot 36 in 1995 instead of the usual 50 frames). These details are critical for obtaining accurate summary statistics.

The database contains four data tables; three tables are comprised of vegetation abundance data and one includes information about plot photos. The abundance data tables contain density/ frequency data, cover data estimated using line interception, and cover data estimated using point interception. The abundance data incorporated into the data tables were left in as raw a form as possible; however, most of the historical data archives were summarized to some extent, which dictated the level of data summarization used in the actual database. The photograph specifications data table was designed to consolidate data associated with photos taken during LTV data collection efforts including, photo dates, exposure, aperture, camera angle, etc. The photo data was designed such that the record of each photo can include a hyperlink to a digital copy of that photo. Accordingly, all of the historical photos were digitized as part of the update to the LTV archive.

Plans for Continuation

Analyses and reporting will be completed for the 2006 LTV data during 2008. Two peer-reviewed publications containing results from the current LTV data set will also be prepared and submitted as time and funding allow.

Investigators and Affiliations

Roger D. Blew, Ecologist, Environmental Surveillance, Education and Research Program, S.M. Stoller Corp, Idaho Falls, Idaho

Amy D. Forman, Plant Ecologist, Environmental Surveillance, Education and Research Program,
S.M. Stoller Corp, Idaho Falls, Idaho

Jackie R. Hafla, Natural Resource Specialist, Environmental Surveillance, Education, and Research Program, S.M. Stoller Corporation, Idaho Falls, Idaho

Funding Sources

U.S. Department of Energy, Idaho Operations Office.


Harniss, R. O. 1968. Vegetation changes following livestock exclusion on the National Reactor
Testing Station, Southeastern Idaho. Utah State University, Logan, UT.

Singlevich, W., J. W. Healy, H. J. Paas, and Z. E. Carey. 1951. Natural radioactive materials at the Arco Reactor Test Site. Radiological Sciences Department, Atomic Energy Commission, Richland, WA.

USDA, NRCS. 2008. The PLANTS Database (, 14 March 2008). National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

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