ARS | Publication request: Aerial Assessment of Leafy Spurge (Euphorbia esula L.) on Idaho's Deep Fire Burn

Submitted to: Society for Range Management Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 9, 2009
Publication Date: February 22, 2010
Citation: Booth, D.T., Cox, S.E., Teel, D. 2010. Aerial Assessment of Leafy Spurge (Euphorbia esula L.) on Idaho's Deep Fire Burn. In: Proceedings of the Society of Range Management and Weed Science Society of America joint annual meeting, "Working landscapes, providing for the future." Abstract O-320. p. 188.

Technical Abstract: Invasive species constitute a leading threat to native vegetation in wildland settings removed from areas of housing and ranchette development. Monitoring for these species is essential to preserving native-plant community integrity and historic wildland character. Infestations continue to increase and monitoring with conventional ground or lower-resolution aerial data may be part of the problem since these tools are of questionable value for detecting small or dispersed weed populations. In July 2006, we conducted a dual-camera aerial survey acquiring 1- and 10-mm GSD imagery of portions of the Medicine Lodge Management Unit (MLMU). The MLMU survey included most of the 2003 Deep Fire Burn. Survey data were used to determine leafy spurge (Euphorbia esula L. [Euphorbiaceae]) distribution on burned and unburned lands and to relate spurge distribution to ecosystem structure, associated vegetation, and control efforts. Leafy spurge was detected in 10% of 10-mm GSD samples versus 8% of 1-mm GSD samples. We conclude that 10-mm GSD is best for detecting leafy spurge because it optimizes the balance between resolution and field of view. Litter was about 4% greater where spurge was present than where it was not, and spurge occurrence was associated with significant decreases in cover of native grasses, forbs, and sagebrush (Artemisia sp. Authority. [Asteraceae]). Leafy spurge proximity to water was higher than a random distribution would predict. We conclude that leafy spurge remains a significant problem on the MLMU, but that high-resolution aerial surveys, such as described in this report, are an effective means for monitoring new and dispersed infestations across extensive areas of wildland.