Secondary succession of an unmanaged coppice woodland adjacent to late-successional, lucidophyllous forest in western Japan

Abstract

ABSTRACT The combined effects of management history and ecosystem connectivity make it difficult to predict future dynamics of abandoned and unmanaged ecosystems. In Japan, unmanaged, secondary forests (satoyama) face risk of arrested or diverted succession, due to extensive human influence across the landscape. Proximity to climax forests, which function as seed sources, could determine the course of succession of abandoned satoyama. Here, we investigated spatial/temporal variation of species composition and stand structure of abandoned satoyama adjacent to a mature lucidophyllous forest in warm-temperate Japan to elucidate the course of succession after abandonment. Two study plots were established in the unmanaged, secondary forest at varying distances from the mature lucidophyllous forest. We calculated vegetation similarity indices among the plots to elucidate spatial variation and temporal change of species composition and stand structure and visualized relationships using nMDS (non-metric multidimensional scaling) ordination. Over the past 15 years, species composition and stand structure of the secondary forest have changed following the normal course of succession. This was because shade-intolerant shrubs, such as Rhododendron, were replaced by recruitment of climax species originating from the lucidophyllous forest. However, Quercus serrata (deciduous oak) and shade-intolerant evergreen trees continued to dominate the upper-canopy. Although the adjacent lucidophyllous forest is an effective seed source for recruitment of climax species, it may take several more decades for the secondary forest to reach late-successional composition and structure, due to legacy effects of past management.