Monday, February 13, 2017

GIS and Invasive Species (Saltcedar)

Remote sensing has been an important tool in evaluating ecosystem health and invasive species monitoring, mapping and management.  In the early 1800s, several species of Tamarix were introduced to the United States.  Three of these, all commonly referred to as saltcedar have become “one of the most threatening invasive species in the United States over the next ten years” (Wang L. et al., 2012, p.3).  The saltcedar have dominated the basin in the southwestern US and northern Mexico’s semiarid climate, due to its hardy nature and ability to tolerate the dry conditions.  
Due to the importance of accurately identifying, mapping, and inventorying this invasive plant, researchers have turned to several different remote sensing capabilities to determine which offered the best capabilities to take on this task.  In a study by Wang L. et al., the researchers chose QuickBird, AISA and Landsat TM to determine which would offer better multiresolution and multiresource remote sensing imagery.   

The study site was located near Candelaria, TX, along the Rio Grande river, among the many canyons and valleys of this semiarid region.  The flora is mostly composed of saltcedar with some willow mixed in.  Researchers then began composing data from all three image producing methods.  Once researchers had their data, they were able to complete a comprehensive study of the imagery and determine which would better work for reconnaissance of the invasive species.
QuickBird remote sensing has been used for detecting invasive species in the past but had been reported to have limitations with detecting small strands of scattered trees.  Airborne Imaging Spectroradiometer for Applications (ASIA) is known for its ability to provide data at a very fine resolution, (between 1-4 meters), but can be quite costly.  Landsat TM is reported to be ideal due to its wide coverage and low cost.  Researchers concluded that out of the three, ASIA outperformed QuickBird in saltcedar identification and achieved high scores in accuracy. Landsat TM showed similar accuracy to AISA methods, but was significantly better with computing efficiency.
The ability to use remote sensing in reconnaissance of threatening invasive species will allow for better potential for mapping, monitoring and managing a serious problem in the United States.  This study outlines the classification accuracy between each method, allowing for better quality reconnaissance.

Le Wang, José L. Silván-Cárdenas, Jun Yang & Amy E. Frazier (2012): Invasive Saltcedar (Tamarisk spp.) Distribution Mapping Using Multiresolution Remote Sensing Imagery, The Professional Geographer, DOI:10.1080/00330124.2012.679440


  1. Very interesting study! Does the article mention anything about how state/ federal land management agencies apply the data from remote sensing for invasive species management? It would be awesome to utilize this remote sensing strategy to help categorize the invasive plants in the SU Ecolab and monitor their distribution.

  2. Unfortunately, state/federal land management agencies application was not mentioned in this study, other then to say that these remote sensing applications have been used to manage invasive species in the past. It would be interesting to see how we could use these applications in the ecolab!

  3. I didn't know that invasive species dealt with trees as well. I know that many environmentalists have concerns of repopulating the forests but I never thought it could run the risk of being classified as invasive.

  4. This information could be very helpful in preventive measures. It could be used to save animals, as well as people, and also could be used as a way to get rid of unwanted and harmful plants and species. I'm really interested to see how this data will be used in the future.