Submitted to: International Journal of Remote Sensing
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/4/2003
Publication Date: 2/10/2004
Citation: Anderson, G.L., Carruthers, R.I., Ge, S., Gong, P. 2004. Monitoring of invasive tamarix distribution and effects of biological control with airborne hyperspectral remote sensing. International Journal of Remote Sensing. 26(12):2487-2489. Interpretive Summary: Hyperspectral remotes sensing is a relative new method of identifying plant species using aerial survey techniques. A digital imaging device scans the target substrate across a wide range of different wavelengths. Using complex multi-spectral analysis procedures this research was able not only to detect the invasive plant species, saltcedar, but also to locate areas where insect natural enemies had caused extensive defoliation to this pest plant. This work is being used as the basis for assessing the effectiveness of a multi-agency effort to control saltcedar in six western states using biological control agents imported by USDA-ARS from China.
Technical Abstract: Although remote sensing has previously been used to detect invasive species, limited success has been achieved because of low spatial and spectral resolution of some data sources. In this research, the hyperspectral CASI (Compact Airborne Spectrographic Imager) is used to detect the distribution and abundance of saltcedar, and to monitor the control effects of a new biological control agent that USDA released during the summer of 2001. CASI was used to collect images in six different states where the beetles were released. In one release area in Nevada, CASI data were acquired from two different flight missions before and after the beetle caused its feeding damage to the test saltcedar. Through comparison of these images we can easily see the feeding damage caused by this beetle to the target tamarix plants and track the infestation status as it spreads to new areas. The defoliation in this site covered approximately 2 hectares of nearly contiguous saltcedar. These beetles multiplied readily in the Nevada release site and now have increased to many hundreds of thousands of beetles that are expected to spread more extensively in the spring and summer of 2003. In the future, we will continue to use CASI imagery to track the spread and impact of these beneficial insects at a large scale. The hyperspectral imagery captured by the CASI II is ideal for this work because of the systems ability to rapidly change both spatial and spectral resolutions to meet specific needs. The images in this article show false color composites of three CASI bands. The three bands of the before-defoliation image are centered at 767.7 nm, 539.0 nm, 652.8 nm, displayed in red, green and blue, respectively. For the after defoliation image, the three bands are 777.4 nm, 548.4nm, and 669.9 nm, displayed in red, green and blue, respectively. This research is the basis for extensive monitoring technology that will be used to track natural enemy spread and impact in a multiple state biological control program that is now being implemented by USDA-APHIS.