Spatial distribution patterns and implications for conservation ofScrophularia takesimensis (Scrophulariaceae), an endangered endemic species on Ulleung Island, Korea

摘要

As part of an on-going effort to conserve endangered and endemicScrophularia takesimensis (Scrophulariaceae), we analyzed its spatial distribution patterns by applying an index of dispersion, plant-to-all-plant distances, and the varying quadrat size method. Three indices — Dispersion, Morisita, and Standardized Morisita — all revealed clumping with small aggregates, and distances between aggregates were more or less regular. The asymptote level occurred at a distance of 20 to 30 m; the distance showing 90% of cumulative frequency coincided with 20 to 21 m; 95%, 24 to 25 m; and 99%, 31 to 32 m. The 20 m× 20 m and 40 m×40 m quadrats contained 25 and 40 plants, respectively. We conclude that this number of individuals and size of area are the minimum required for the conservation of this species.