Enhanced Vegetation Index (EVI)

-3 10

Relative Habitat Suitability for Tamarisk

Less Suitable Highly Suitable

National Aeronautics and Space Administration

SCIENCE SERVING SOCIETY: INVASIVE SPECIES

The ISFS provides more 

accurate and extensive 

information to land managers 

than previously available and 

improves the efficiency of efforts 

to control invasive species, 

such as tamarisk, hogweed and 

garlic mustard, whose spread 

can have significant negative 

economic impacts.

www.nasa.gov

Products derived using data from 

NASA’s Earth observing satellites 

help resource managers control the 

spread of invasive species. Shown 

here is a color-composite map of 

the Moderate Resolution Imaging 

Spectroradiometer’s (MODIS) Enhanced 

Vegetation Index (EVI) data product 

(top). EVI is an indicator of the vigor of 

vegetation. The greener the area is on 

this map of the United States, the more 

vigorous the vegetation.

The USGS, with assistance from NASA 

data and system engineering, created 

an on-line forecast tool called the 

Invasive Species Forecasting System 

(ISFS). NASA data-products, such as 

EVI (above), are part of the input to the 

ISFS. The ISFS produces predictive 

maps that show the relative suitability 

to sustain a particular invasive plant 

species. The lower map shows habitat 

suitability for tamarisk, an invasive 

plant with major economic impact in 

the Western United States.
LG-2006-1-100-GSFC (rev. May 2006)

SCIENCE SERVING SOCIETY: INVASIVE SPECIES

National Aeronautics and Space Administration

Overview of the Program 

At present, an array of Earth observing satellites are in orbit, and additional 

launches both by NASA and others will continue throughout the next 

decade. Our ability to observe our home planet from space has never been 

greater. Increasingly, studies of the Earth focus on understanding the Earth’s 

land, atmosphere, oceans, and life as a whole integrated system rather than 

as individual independent elements. NASA is an important contributor in this 

systems approach to Earth science studies.

In addition to providing Earth observing capabilities, NASA forms strategic 

partnerships with other government, academic, private, and international 

organizations. Through these partnerships, NASA’s Earth science 

observations and measurements are linked to practical applications. 

NASA data, information, and predictive models help NASA’s partners, and 

nontraditional users of Earth science, make timely and accurate decisions 

regarding management of resources and development of policy. The 

agency’s goal is to maximize the benefit of science and technology to 

stakeholders by smoothly flowing Earth science data and information from 

NASA satellites to society.

Invasive Species

Invasive species may be defined as a non-native plant, animal, or microbe 

whose introduction causes, or is likely to cause, harm to the economy, 

the environment, or human health. Increasing globalization—the rapid 

transportation of people and goods throughout the Earth—provides the 

opportunity and the mechanism for such species to enter the United States 

and thrive in new habitats. Each year, the U.S. incurs direct losses of 

approximately $120 billion due to these invasive species—an annual cost 

greater than most natural disasters combined. 

Once a particular invasive species becomes established in a region, it is 

difficult to remove. The cost to control and eradicate invasive species that 

are already entrenched is prohibitive, therefore, response programs are 

aimed at trying to prevent invasive species from becoming established in 

new areas. Efforts are aimed at predicting where invasive species are likely 

to appear next so that control measures can be applied when the cost is 

low and success is more likely.

Until recently, most attempts to monitor and track the spread of invasive 

species have relied almost completely on field monitoring. For the most 

part, these studies have been too slow, costly, and inefficient to be effective 

because of the rapid rate at which these species spread and the manpower 

required for field studies. Earth observing satellites offer a much more 

efficient means of monitoring the spread of invasive species. The unique 

vantage point of space offers a perspective that field observations cannot 

match. NASA has substantial expertise at collecting and analyzing Earth 

science information and makes this information available to assist in the 

study of invasive species. 

NASA works with a variety of federal, state, local, and tribal agencies to 

respond to the threat of invasive species. Earth observation data from 

NASA satellites and model outputs for monitoring land cover and climate 

are combined with ground data supplied by the agencies responsible for 

invasive species control to identify the corridors where invasive plants are 

likely to spread. NASA’s computational capabilities are utilized to develop 

systems to generate predictive maps for invasive species. 

For example, the U.S. Geological Survey (USGS) enhanced its ability to 

generate predictive maps of invasive species through the Invasive Species 

Forecasting System (ISFS) by using NASA Earth observations and systems 

engineering. The ISFS is an interactive, flexible, on-line tool that helps 

public and private users respond to the threat of invasive species. The ISFS 

will be fully operational by 2008.

One of the first species mapped using the preliminary ISFS is tamarisk, a 

prolific, non-native shrub that has spread across much of the southwestern 

United States in the past 150 years. Tamarisk thrives along stream and 

river reaches, where it competes with native vegetation and transforms the 

habitat by increasing soil salinity and consuming vast amounts of water. 

USGS is using the ISFS and the partnership with NASA to deliver up-todate information to land managers on tamarisk location and potential 

spread. Recently, the team developed a National Habitat Suitability Map 

for tamarisk using time-series data from the Moderate Resolution Imaging 

Spectroradiometer (MODIS) on Aqua and Terra (see front page). The model 

combines ecological and biological field data with remotely sensed data 

to produce a map of habitat suitability for tamarisk (i.e., where tamarisk 

can be found) and a confidence map for the prediction. Multispectral and 

hyperspectral data from the Advanced Spaceborne Thermal Emission and 

Reflection Radiometer (ASTER) on Terra and the Hyperion instrument on 

the Earth Observing-1 (EO-1) satellite have been instrumental in enhancing 

the model for tracking the spread of tamarisk and guiding ground data 

collection strategies. Research continues on improving the model by adding 

elevation, soil composition, carbon storage, and other data. 

The Earth Science Division in NASA’s Science Mission Directorate is the 

primary source of Earth observation data for the ISFS. In the next decade, 

additional data from NASA satellites will be incorporated into the ISFS as 

they become available, which will further enhance our ability to plan costeffective responses to invasive plant species.