WRA is implementing the long-term management plan for a conservation bank that supports habitat for California red-legged frog and Callippe Silverspot butterfly, two species listed under the federal Endangered Species Act. Part of the habitat monitoring and management includes mapping and controlling invasive artichoke thistle that is prevalent on ranches in the region. This enhances habitat for both species by encouraging even grazing by cattle and reducing competition between the weeds and native forbs used by the butterfly.
To do this, WRA uses an unmanned aerial vehicle (UAV or drone), to produce a very high resolution aerial photograph. This can be done very efficiently to produce an aerial photograph of the property with 2 cm accuracy. This is high enough resolution that individual artichoke thistles can be easily identified. WRA uses remote sensing software (eCognition) to classify the pixels representing the weed into like polygons. The resulting polygons are then imported into GIS to assess cover and acreage. WRA has developed algorithms to automatically classify the resulting output into cover classes. This process is much more accurate than traditional field methods and highly repeatable from year to year. The result is a more efficient and less expensive mapping effort with more accurate results. This translates to more accurate bidding of weed abatement activities by contractors.