Long-Term Vegetation Trends on the Idaho National Laboratory

Investigators and Affiliations

Amy D. Forman, Plant Ecologist, Environmental Surveillance, Education and Research Program, S.M. Stoller Corporation, Idaho Falls, ID
Roger D. Blew, Ecologist, Environmental Surveillance, Education and Research Program, S.M. Stoller Corporation, Idaho Falls, ID
Jackie R. Hafla, Natural Resources Scientist, Environmental Surveillance, Education and Research Program, S.M. Stoller Corporation, Idaho Falls, ID

Funding Sources

U.S. Department of Energy Idaho Operations Office


In 1950 at the request of the Division of Biology and Medicine of the Atomic Energy Commission requested a background survey for naturally occurring radioactive materials in the vicinity of what is now known at the INL. One of the legacies of that background survey in 1950 remains today in the form of the Long-Term Vegetation (LTV) plots. The LTV plots originally consisted of 110 plots on and near the INL. Over the years some of the plots have been lost due to agricultural and other development activities and 92 plots remain. These plots were surveyed in 1950, 1957, 1965, 1975, 1985, 1995 and 2001. A subset of 35 or 36 plots were also surveyed in 1978, 1983, and 1990.

The plots originally consisted of two transects 50 ft (15.24 m) in length. Vegetative cover of shrub crown and grass basal area was measured using line intercept and density was measured in quadrats placed at intervals of 5 ft (1.52 m) along the two transects. In 1985, a third transect 65.6 ft (20 m) in length was added to each plot to support measurement of cover using point interception. Also, a photographic record of each plot has been made during each survey beginning in 1957.

Although the original intent of the LTV plots were to provide information on presence of naturally occurring radioactive materials in the environment, the data from these plots have also been used to assess the potential impact of nuclear energy research and development and other activities on ecological resources native to the INL. The LTV plots have provided important background information for assessing potential impact to ecological resources in numerous Environmental Assessments and Environmental Impact Statements at the INL.

Also, the LTV data have become an invaluable resource for research on the structure and function of native sagebrush steppe vegetation communities. The INL LTV plots represent one of the most intensive (in terms of the amount and kinds of data available for each plot) and one of the most extensive (in terms of its geographical and temporal extents) datasets for the sagebrush steppe ecosystem type. The significance of this dataset to the broader scientific and natural resource management communities is further amplified when considering that it represents the largest remnant of good condition sagebrush steppe. This significance is illustrated by the paper by Anderson and Inouye (2001) that provided a summary of this dataset through 1995. In the first five years following publication, this paper was cited more than 40 times in the scientific literature.


There are three primary goals for current activities associated with the LTV project. They include surveying plots in 2006, analyzing data and preparing reports and manuscripts in 2007, and archive all data collected since 1959 and incorporating that archive into the Conservation Management Plan Ecological Data Management System. Research objectives for this effort include investigating methods for studying the population ecology of native bunchgrasses, the role of annual forbs in the ecology of sagebrush steppe communities and environmental controls on diversity of forbs.

Accomplishments through 2006

Data collection began in June 2006 and continued through July. We surveyed all of the 92 remaining LTV plots. Field crews were trained in late May and early June on survey methods and plant identification. We conducted QA/QC audits on all data collected as they were brought in from the field. There was a lag of no more than one week between data collection and these audits.

Once the field data collection was completed, we began data analysis. Because of the short amount of time between the completion of data collection and the end of the fiscal year, data analysis in 2006 was limited to transforming the data so that it is in a format consistent with the needs of the statistical analysis.


Because only limited data manipulation was completed in 2006, no results are available to be reported here.

Plans for Continuation

In 2007 we plan to complete the data analysis and report preparation. We also plan to begin work on at least two manuscripts based on the results of the study. In 2007 and continuing into 2008, we will begin the process of archiving the LTV data into the CMP data management system. This will include converting all of the photographic negatives into digital format.


Anderson, J., and R. Inouye. 2001. Landscape scale changes in species abundance and biodiversity of a sagebrush steppe over 45 years. Ecological Monographs 71:531-556.


Home | Background | SurveillanceLand Management | Education | Research | Risk Assessment | Publications |  Links | Feedback | Opportunities