ABSTRACT Invasive alien plant species (IAPs) represent one of the main biological threats to biodiversity worldwide. Information about their phenotypic plasticity are needed to increase awareness about their future invasive potential. A study about phenotypic plasticity in response to contrasting light regimes and its quantification by a plasticity index (PI) of two IAPs (Ailanthus altissima and Robinia pseudoacacia) inside a Strict Nature Reserve was conducted. R. pseudoacacia showed a 70% higher PI, with a strongly greater value at morphological leaf level, associated with a greater ability to survive and grow in forest understory, explaining its greater widespread. Otherwise, A. altissima showed its highest PI at physiological level, which was associated with the ability to colonize and grow in environments with high-light regimes. Based on these results, the conservative management has limited the presence of A. altissima by its lower ability to grow in forest understory. In fact, the small-scale gaps in the forest infrastructure, that could allow its recruitment, are originated only from the death of a single tree or small group of trees. Regarding R. pseudoacacia, it is critical to maintain this type of management because any disturbances resulting in large openings could further promote its presence inside the Reserve.

中文翻译：

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意大利严格自然保护区落叶林中两种外来入侵植物的表型可塑性

摘要 外来入侵植物物种 (IAP) 是全球生物多样性面临的主要生物威胁之一。需要有关其表型可塑性的信息，以提高对其未来侵入潜力的认识。对严格自然保护区内两种 IAP（臭椿和刺槐）的可塑性指数 (PI) 进行了一项关于响应对比光照制度的表型可塑性及其量化的研究。R. pseudoacacia 显示 70% 的 PI，在形态学叶片水平上具有更大的值，与在林下层中生存和生长的能力更强相关，解释了其更广泛的分布。否则，A. altissima 在生理水平上显示出最高的 PI，这与在高光环境中定殖和生长的能力有关。基于这些结果，保守的管理限制了 A. altissima 的存在，因为它在林下生长的能力较低。事实上，森林基础设施中可能允许其补充的小规模差距仅源于一棵树或一小群树木的死亡。对于 R. pseudoacacia，保持这种类型的管理至关重要，因为任何导致大开口的干扰都可能进一步促进其在保护区内的存在。