Structural diversity of naturally regenerating Chinese yew (Taxus wallichiana var. mairei) populations in an ex situ conservation

The Chinese yew (Taxus wallichiana var. mairei) is ranked among the first class of important wild endangered plants in China. However, due to its overexploitation, it now occurs scattered in the forest undergrowth along the Yangtze River Valley. To improve this tree’s conservation management, we used structural indices to investigate the structural diversity of naturally regenerating yew populations that have established via ex situ conservation. The results show that most yews had larger non-yew tree neighbors; these were 30–70% larger than their reference trees. Collectively, the average distances between the yews and the three nearest-neighboring trees were short (<3 m). This result suggests that the yews likely face strong interspecific competition from neighbors. In these two forest stands, most of the pole-sized yews are found beneath a single tall neighboring tree (height ≥10 m), and their growth was enhanced under a single neighboring tree but not under two, three or zero nei...

南方红豆杉（Taxus wallichiana var. mairei）被列为中国国家一级重点保护野生濒危植物。但由于过度开发利用，目前该物种仅零散分布于长江流域的林下生境中。为优化该树种的保护管理策略，本研究采用结构指数，对通过迁地保护建立的天然更新红豆杉种群的结构多样性展开调查。结果显示，多数红豆杉个体的邻株为非红豆杉树种，其个体体量较目标红豆杉大30%~70%；整体而言，红豆杉与其最近3株邻株的平均距离较短（<3米）。该结果表明，红豆杉大概率面临来自邻株的强烈种间竞争压力。在这两个林分中，多数中径级红豆杉个体生长于单株高邻株（树高≥10米）的冠下，且仅在单株邻株的生境下其生长得到促进，而在有2株、3株或无邻株的生境中则未出现此效果。