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Title: Using aerial photography and image analysis to measure changes in giant reed populations

Author
item Everitt, James
item Yang, Chenghai

Submitted to: Journal of Aquatic Plant Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/15/2010
Publication Date: 9/1/2010
Citation: Everitt, J.H., Yang, C. 2010. Using aerial photography and image analysis to measure changes in giant reed populations. Journal of Aquatic Plant Management. 48:47-51.

Interpretive Summary: The invasion and spread of undesirable plant species present serious problems to resource managers. Giant reed is an invasive perennial grass that invades riparian sites in many areas of the world. A study was conducted on the Rio Grande in southwest Texas to evaluate color-infrared aerial photography coupled with computer image analysis to quantify changes in giant reed populations over a 6-year period. Aerial photographs from 2002 and 2008 of seven study sites were compared. Results showed that giant reed populations increased on all sites over the 6-year period, with an average increase in cover of 32%. These results indicate that color-infrared aerial photographs and image analysis techniques are useful tools to monitor and quantify changes in giant reed populations over time. These findings should be of interest to weed scientists, and wildlife and rangeland resource managers.

Technical Abstract: A study was conducted along the Rio Grande in southwest Texas to evaluate color-infrared aerial photography combined with supervised image analysis to quantify changes in giant reed (Arundo donax L.) populations over a 6-year period. Aerial photographs from 2002 and 2008 of the same seven study sites were studied. Results showed that giant reed populations increased on all sites over the 6-year period. With the exception of site 3 where giant reed had a 3.2% increase in cover from 2002 to 2008, it had increases ranging from 21.9% to 49.9% for the other six sites over the 6-year period. Most of the increases in giant reed populations were due to its displacement of mixed herbaceous vegetation and encroachment on bare soil areas. These results indicate that color-infrared aerial photographs coupled with image analysis techniques can be useful tools to monitor and quantify changes in giant reed populations over time.