Effects of vegetation management on plant species composition and plant functional composition in <i>Quercus serrata</i> secondary forests on the Musashino terrace

<p>Abandonment of coppicing in secondary forests is thought to be one of the major causes of the recent decrease in plant species diversity in man-made landscapes.　Resuming traditional forest floor management has been attempted for conservation purposes elsewhere in Japan.　In recent years, cutting of evergreen trees invading and grown below shrub layer has also been attempted.　There are few reports that the effect of the management of forest understory was evaluated by the plant functional groups.　We examined the effect of management on plant diversity of the herb layer by comparing four management treatments:mowing understory and removing tree leaf litter （MR）, mowing understory （M）, cutting evergreen trees below the shrub layer （C）, and abandonment （A）.　Study sites were located in Quercus serrata secondary forests in the northern part of Musashino terrace, south-eastern Kanto district, Japan.　We recorded plant species occurrence and coverage in 90 plots （8×8m）, and compared species richness and the Shannon diversity index.　We classified species into seven plant functional groups （PFGs） using results of cluster analysis for nine functional traits of plants occurring in the herb layer.　We compared functional diversity and composition among the management types using CCA （Canonical Correspondence Analysis）.　Species richness, Shannon diversity index, and functional diversity of the herb layer were the highest in MR.　Effect of management treatments was stronger on PFGs composition than on species composition.　Some PFGs showed biased appearances in specific management types.　The species richness of four PFGs:PFG2 that included crowding grasses blooming in spring, pollinated by wind, fruiting in autumn, and dispersed by gravity;PFG5 that included deciduous herbs fruiting in autumn and dispersed by wind;PFG6 that included herbs blooming in spring and pollinated by insects;and PFG7 that included deciduous herbs blooming in summer or autumn and fruiting in autumn were high in MR and M.　As many threatened species were present in PFG2, PFG5, and PFG6 and many ruderal species were present in PFG7, we concluded that it was important to conserve plant species of PFG2, PFG5, and PFG6 by mowing and removing tree leaf litter as the preferred vegetation management practice for preserving biodiversity in coppice forests.　This study clarified that evaluating by functional composition reflects the influence of forest floor management rather than species composition in secondary forests.</p>