Tuesday, August 7, 2007

PS 30-138: Detecting an invasive shrub in forest understory using remote sensing

Julian Resasco, Alison N. Maye, Mary C. Henry, and David L. Gorchov. Miami University

Some plant invasions have been mapped with remote sensing, but this

approach has not been applied to invasives under a forest canopy. We used Landsat TM

and ETM+ imagery to distinguish areas of high vs. low cover of Amur honeysuckle

(Lonicera maackii), taking advantage of the early leaf expansion and late leaf retention of

this invasive shrub. L. maackii cover was measured in eight stands and compared to 15

Landsat 5 TM and Landsat 7 ETM+ images from spring and autumn dates from 1999 to

2006. Jeffries-Matusita (JM) Distance calculations showed greater separability between

cover classes (high and low L. maackii) than within density classes on some late fall

images. The Soil Adjusted Atmospheric Resistant Vegetation Index (SARVI2) revealed

higher levels of green biomass in high L. maackii cover plots than low cover plots for

November images only. These findings justify further investigation of the effectiveness

of late fall images to map the historical spread of L. maackii and other forest understory

invasives.