全球变化对外来种无瓣海桑扩散和建群的驱动效应

Sonneratia apetala, a mangrove species native to Bangladesh, is currently used extensively for mangrove restoration in China because of its fast growth and adaptation properties. However, precisely because of its fast growth and successful establishment in new habitats, its potential invasiveness has become an increasing concern. Global changes are likely to significantly increase the invasion potential of some non-native plants, potentially leading to population explosions. Thus, there is an urgent need to investigate how S. apetala's major invasion processes-such as propagule dispersal, seedling establishment and interspecies competition with native mangrove species-will be affected by climate-related changes. .We hypothesis that global changes, such as warming and sea level rise, will strongly promote the invasiveness of S. apetala in Chinese mangroves. To investigate this, field observations of population structures, seed products, and dispersal characteristics will be conducted in reforestation sites along a latitude gradient. We will also construct in-field elevation platforms for native and non-native mangrove seedlings in order to simulate the impacts of varying sea levels under current and projected climate conditions; these will also be located in multiple field sites across a range of latitudes. Through these field experiments, we aim to indentify the mechanisms of growth rate, stress adaptation and competitive advantage of non-native S. apetala. Furthermore, we will investigate the responses of native and non-native mangrove seedlings to global warming and sea level rise in manipulated greenhouse experiments, wherein tanks will closely mimic tidal fluctuations. The aim of this research is to identify the mechanisms of global changes on propagule dispersal, seedling establishment and interspecies competition of the non-native S. apetala, and also to recognize the likely invasiveness of this plant under current and future climate scenarios. We believe this information will be valuable to policy makers and forest managers to develop appropriate strategies for managing the invasion.

无瓣海桑是原产于孟加拉国的速生红树植物，是广泛应用于我国红树林湿地恢复的造林树种。在我国，无瓣海桑的扩散、速生和生态位竞争能力引起了人们对其入侵性的担忧。气候变暖和海平面上升是影响红树林生长和分布的关键因子，将改变甚至加剧无瓣海桑的入侵。本研究围绕气候变暖和海平面上升对无瓣海桑扩散、种群建立和种间竞争的驱动效应这一科学问题，在不同纬度引种区内，采用野外调查、野外控制实验和温室人工潮汐控制实验等手段，模拟大气增温、海平面上升和种间竞争等多因子协同作用，研究不同纬度无瓣海桑与乡土红树植物秋茄的繁殖体特性、生长和潮间带适应性。在揭示无瓣海桑的扩散特性和速生机理的同时，阐明全球变化驱动下无瓣海桑入侵潜力演变的过程和机制。研究结果将为准确评估和预测无瓣海桑的入侵性，及其对未来气候变化的响应和适应策略具有极其重要的理论和实践意义，将为红树林湿地恢复的实践工作提供理论依据。

无瓣海桑是原产于孟加拉国的速生红树植物，是广泛应用于我国红树林湿地恢复的造林树种。在我国，无瓣海桑的扩散、速生和生态位竞争能力引起了人们对其入侵性的担忧。做为影响红树林生长和分布的关键因子，气候变暖和海平面上升大大改变了无瓣海桑的竞争和扩散能力。本研究围绕气候变暖和海平面上升对无瓣海桑扩散、种群建立和种间竞争的驱动效应这一科学问题，在不同纬度引种区内，采用野外调查、野外控制实验和温室人工潮汐控制实验等手段，模拟大气增温、海平面上升和种间竞争等多因子协同作用，研究不同纬度无瓣海桑与乡土红树植物秋茄的繁殖体特性、生长和潮间带适应性。研究结果表明：1）在我国的红树林分布区内，同龄无瓣海桑的基径和树高等群落结构指标受到温度因子（包括年均气温、极端低温等）的抑制较为显著；2）纬度的升高显著降低了无瓣海桑繁殖体的数量和质量，进而在低纬度区域无瓣海桑具有更高的繁殖体和种苗数量与扩散能力；3）未来海平面的上升和气温升高对幼苗生长具有一定的协同作用，特别是在红树林植物的苗期；但随着植株的长高，气温升高对于无瓣海桑生长和生物量积累的固定量显著增高，进而增加其生态位竞争能力；4）未来全球变暖有利于无瓣海桑向高纬度地区扩散，低纬度的中潮带区域是外来种无瓣海桑与乡土红树植物发生生态位竞争的主要区域，是防控无瓣海桑发生生物入侵的关键区域。本研究揭示了无瓣海桑的扩散特性和速生机理，及其响应全球变化的过程和机制。研究结果将为准确评估和预测无瓣海桑的入侵性，及其对未来气候变化的响应和适应策略具有极其重要的理论和实践意义，将为红树林湿地恢复的实践工作提供理论依据。