IMAGE-ANALYSIS OF LEAFY SPURGE (EUPHORBIA-ESULA) COVER

We examined whether image analysis could separate leafy spurge from ot her plant species and objects by comparing: image analysis to the ocul ar method of estimating cover. Image analysis was acceptably precise a l low and medium cover levels. Image analysis was as repeatable as the ocular method at all sites and cover revels and acceptably reliable a t low and medium cover levels but estimated cover lower by 12 to 22% t han the ocular method at high cover levels. The average error levels o f image analysis and the ocular method did not differ. Estimating leaf y spurge cover with a 10% error required only 20 quadrats when image a nalysis was used, while twice as many quadrats were needed when cover was measured ocularly. Image analysis was recommended as a measurement tool because quantification was efficient, the equipment is inexpensi ve, and the color prints provide a permanent photo record of the study .