Effects of long-rotation on biodiversity in plantations

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We studied the effects of long-rotation and related ecological variables on the biodiversity of six beetle families in larch(Larix kaempferi) plantations. Beetle diversity in the forest understory & the canopy of long-rotation and middle-aged plantations was compared. The relationships between the species richness of each beetle family and 24 ecological variables were identified. We found that beetle diversity tended to increase with long-rotation. Especially, phytophagies increased in the canopy. Among the 24 measured ecological variables, the species richness & abundance of naturally regenerated mature trees and the quality & quantity of coarse woody material had the strongest influences on beetle diversity. The former variable increased with long rotation, though the latter did not because thinned trees were left in middle-aged plantations as fallen logs. Therefore, the occurrence of naturally regenerated native trees that had grown sufficiently tall to reach canopy height in long-rotation plantations underpinned the improved biodiversity in larch plantations, contributing to native beetle species richness in these woodlands. Long-rotation makes plantations more heterogeneous, particularly in the canopy, and promotes greater native beetle diversity.