Research Report: A rapid, invasive plant survey method for national park units with a cultural resource focus

Young, Craig; Haack, Jennifer

In this study we evaluated a rapid invasive plant survey method on six national parks that emphasize cultural resource management. Observers searched for 126 high-priority invasive plant species (HPIPs) along 3- to 12-m- (9.8- to 39.4-ft) wide belt transects within approximately 2-acre (0.8-ha) search units. Using a foliar cover scale, the abundance of encountered HPIPs was estimated in the widest belt possible given site conditions. Calculations of plant abundance on each transect accounted for the imprecision resulting from the foliar cover scale and variable transect widths, but were prone to overestimate plant abundance. We identified a total of 53 HPIPs that occupied at least 165.1 acres (66.9 ha) on the six parks. A few highly abundant species accounted for the majority of the invasive plant cover encountered in the parks. For example, 58.5% of HPIPs accounted for a cover of less than 2 acres (0.8 ha) on the six parks, while only 11.3% of HPIPs potentially (i.e., based on a maximum foliar cover estimate) occupied more than 100 acres (40.5 ha). Overall, the survey method covered a large proportion of park acreage, identified numerous HPIPs, and provided an estimate of abundance and a map that were sufficient for guiding park management. The ability of the survey to detect change in plant abundance may be limited depending on park management needs. In the most conservative scenario, the survey method would detect change in plant abundance for 4.4%, 33.6%, 24.8%, and 37.2% of the HPIPs identified on each park following three, four, five, and six doubling times, respectively.

Research Report: A rapid, invasive plant survey method for national park units with a cultural resource focus

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