Primary succession in the lucidophyllous forest zone with special reference to the lava flows in Sakurajima, Japan

Abstract

In order to clarify the primary succession in Sakurajima, Japan, we studied the volcanic vegetation on the Showa, Taisho, Anei, and Bunmei lava flows, which erupted from Mt. Sakurajima in 1946, 1914, 1779, and 1471, respectively, and the natural forest on pumiceous sand. The species composition was compared among forests I, II, III, IV and V on the Showa, Taisho, Anei, and Bunmei lava flows and pumiceous sand, respectively. Forests I and II were recognized as middle seral stages in the primary succession. Forests III and IV, which had similar dominant species, species composition, and species richness, were recognized as at the same seral stage in the secondary succession. Forest V, which was characterized by the absence of many lucidophyllous forest elements, was at a later or climax stage. The species richness (number of lucidophyllous forest elements) and years of succession on the Showa and Taisho lava flows had a high positive relationship. The sere in the primary succession in the warm temperate zone (lucidophyllous forest zone) consisted of five seral stages from the lichen and bryophyte community to the herbaceous community, the Pinus thunbergii forest, the Machilus thunbergii forest, and the Castanopsis sieboldii forest. It probably takes about 600 years to arrive at the climax stage (the Castanopsis sieboldii forest) in the primary succession.