Wang Jiang, Li Shao-Peng, Ge Yuan, Wang Xiao-Yan, Gao Song, Chen Tong, Yu Fei-Hai
School of Life Science/Zhejiang Provincial Key Laboratory of Plant Evolutionary Ecology and Conservation, Taizhou University, Taizhou, Zhejiang, China.
Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, School of Ecological and Environmental Sciences, East China Normal University, Shanghai, China.
Ecology. 2023 Jan;104(1):e3850. doi: 10.1002/ecy.3850. Epub 2022 Sep 29.
Although phylogenetic distance between native and exotic species has a close link with their interactions, it is still unclear how environmental stresses and species interactions influence the relationship between phylogenetic distance and biological invasions. Here we assessed the effect of invader-native phylogenetic distance on the growth of the invader (Symphyotrichum subulatum) under three levels of drought (no, moderate, or intense drought). Under no drought, interspecific competition between close relatives was the dominant process and native communities more closely related to the invader showed higher resistance to invasion, supporting Darwin's naturalization hypothesis. In contrast, under intense drought, facilitation between close relatives by mutualism with arbuscular mycorrhizal fungi (AMF) became more important, and the invader became more successful in their more closely related native communities, supporting the preadaptation hypothesis. The colonization rate of AMF of the invader was higher in more closely related native communities regardless of the drought treatment, but it was only positively related to invader biomass under intense drought. Therefore, the shift of species interactions from competition to facilitation may be ascribed to the promotion of AMF to invasion occurring under intense drought, which leads to the effect of closely related natives on the invader shifting from negative to positive. Our results provide a new angle to resolve Darwin's naturalization conundrum from the change of species interactions along a stress gradient, and provide important clues for invasion management when species interactions change in response to global climatic change.
尽管本地物种和外来物种之间的系统发育距离与其相互作用密切相关，但环境压力和物种相互作用如何影响系统发育距离与生物入侵之间的关系仍不清楚。在此，我们评估了入侵物种与本地物种的系统发育距离在三种干旱水平（无干旱、中度干旱或重度干旱）下对入侵物种（针叶天蓝绣球）生长的影响。在无干旱条件下，近缘种间的种间竞争是主导过程，与入侵物种亲缘关系更近的本地群落对入侵表现出更高的抵抗力，这支持了达尔文归化假说。相反，在重度干旱条件下，与丛枝菌根真菌（AMF）共生的近缘种间的促进作用变得更加重要，入侵物种在与其亲缘关系更近的本地群落中更成功，这支持了预适应假说。无论干旱处理如何，入侵物种的AMF在与其亲缘关系更近的本地群落中的定殖率都更高，但仅在重度干旱条件下与入侵物种生物量呈正相关。因此，物种相互作用从竞争向促进的转变可能归因于重度干旱条件下AMF对入侵的促进作用，这导致亲缘关系近的本地物种对入侵物种的影响从负面变为正面。我们的研究结果从沿压力梯度的物种相互作用变化角度为解决达尔文归化难题提供了新视角，并为应对全球气候变化导致物种相互作用变化时的入侵管理提供了重要线索。
