Type: report

Article abstract: Vernadero Group Inc. (Vernadero) was contracted by Naval Facilities Engineering Command Southwest on behalf of Marine Corps Air Station (MCAS) Miramar to conduct a Stationwide census for willowy monardella (Monardella viminea) and monitor the species within long-term monitoring plots at MCAS Miramar in San Diego, California. We surveyed and mapped all willowy monardella on MCAS Miramar, identifying adults, mature plants, juveniles, and seedlings. A total of 972 willowy monardella clumps was found during the 2017 census; 278 clumps that had been observed and tagged during previous surveys were not found again during the 2017 census. Clumps were found in six of the nine canyons surveyed and a total of 141 living willowy monardella clumps was recorded in the 17 monitoring plots. The results from the 2017 census and plot monitoring indicate a continuing decline in the number and health of willowy monardella clumps at MCAS Miramar. The cause of the decline in willowy monardella clumps and reproduction is unknown; however, stress to plants from the long-term drought conditions that occurred for the five years prior to the 2017 surveys accompanied by large scouring events in the stream channels from large rainfall events in the 2016 and 2017 growing seasons could have caused mortality in adult willowy monardella plants, reduced the production of viable seeds during drought conditions, and displaced all viable seed produced when drought conditions were relieved by above-average precipitation in 2016 and 2017.