A Habitat of Lithospermum erythrorhizon Sieb. et Zucc. (Boraginaceae), a Threatened Plant, in Hirao-dai Limestone Plateau, Kyushu

Abstract

A population of Lithospermum erythrorhizon, a threatened plant in secondary grassland, was censused in a limestone grassland in northern Kyushu, Japan. Spatial distribution and size structure of the population were recorded. Plant species composition and vegetation structure in the habitat of L. erythrorhizon were also investigated. Annual control burning was conducive to establishment of L. erythrorhizon population, and limestone pinnacles affected the spatial distribution of the population. These two should be viewed as crucial factors in maintenance of L. erythrorhizon population in the study area.