California Exotic Plant Management Team's Trip Report of Work Conducted at Devils Postpile National Monument

Simpson, Bobbi

Overview and Recommendations: The park consists of 800 acres that have been largely influenced by glacial and volcanic activity, with high elevation, ranging from 7200 to 8200 feet. The Sequoia and Kings Canyon National Parks (SEKI) exotic plant management crew completed their first Vascular Plant Inventory of Devil’s Postpile National Monument (DEPO) in the summer of 2001 and is scheduled to continue surveying for invasives on an annual basis. The California Exotic Plant Management Team (CAEPMT) targeted removal and inventory efforts on previously identified populations as well as highly prized ecosystem niches. Survey’s were conducted along trails and in cross-country. Exotic plants do not appear to have significantly altered DEPO’s rather pristine native vegetation. The CAEMT’s August trip was mostly inventory, with removal efforts in a few areas with medium density concentrations of Cirsium vulgare (bull thistle). The greatest effort involved traversing the abundantly beautiful, but steep and rugged terrain. Annual inspections with minor removal efforts will be important to deter future invasions and protect this rather unique ecosystem. These inspections should take place before biennial bull thistle (Cirsium vulgare) has begun flowering so clipping of seed heads is not necessary (estimated timing based upon phenology of thistle during this year’s stint would make for ideal removal to occur in late June to early July).2 The Rainbow fire (1992) burned 80+ percent of DEPO at Moderate to low intensities, while patches of high-intensity fire burned adjacent to the monument. Two pack stations nearby provide daily horse packing trips along the John Muir Trail. It will be important to examine the influence of these activities as it relates to weed invasions (i.e. establish monitor these areas in particular). Deana Dulen emphasized a few hotspots on Forest Service land outside and adjacent to the park boundary that would have been likely corridors for weed movement into the park. In response to this suggestion, approximately 25% of the 2002 California EPMT survey and removal efforts occurred in this area in an effort to curtail likely movement into the park.