福寿螺对盐度胁迫的适应性进化机制及向华南沿海咸水湿地生境入侵的潜力

Golden apple snail Pomacea canaliculata Lamarck，as one of 100 worst alien invasive species in the blacklist of the world, have invaded paddy fields, ditches, ponds and lakes involved in about 246 counties of 13 provinces in the south of Yangtze river in China. Owing to its high adaptive ability, high reproductive speed, wide feeding habits and large appetites, golden apple snail invasion has affected the growth and yield of rice and other aquatic plants, and impacted biodiversity process and functions of aquatic ecosystems, hence resulting serious food security and ecological safety. Even more seriously, based on our team’s previous field investigation, as a kind of fresh-water organism, this apple snail population and its eggs occurred in the mangrove wetlands around the mouth area of the Pearl River. However, so far less researches and little attentions are put on the topic of the adaption of apple snail to water salinity stress and its possible invasion risk into coastal wetlands. For this point, we plan to employ indoor simulation experiments, in situ field experiments and regional field survey to study the survival status, growth, reproduction, tolerance responses and adaptive evolution mechanism of this apple snails to different water salinity treatments or environment, and habitat invasibility of saline wetlands for the apple snails, finally aim to explore and investigate possible “interval”, “periodical” or “long-term” invasion patterns and strategies to the coastal saline wetlands in south China. The research findings would provide some good understandings and scientific basis for the prevention and control of golden apple snail invasion risks in the coastal wetland areas.

福寿螺作为世界100种恶性外来入侵物种之一。在我国，目前已入侵到长江沿线及以南的13个省（区、市）246个县的稻田、沟渠及河湖等淡水生态系统。因其适应能力强、繁殖速度快、食性广、食量大，其入侵扩散已严重影响到水稻及其他水生植物的生长和产量，破坏了水生生态系统的生物多样性过程和功能，造成了严重的粮食安全与生态安全问题。更为严重的是，近年来本项目组的野外调查发现，在广东沿海红树林湿地中有福寿螺种群及其卵块出现。然而，目前国内外关于福寿螺对盐分胁迫的适应性及向沿海湿地入侵的生态风险的关注和研究还十分缺乏。因此，本项目拟通过室内模拟实验、实地定位实验和野外调查，探究福寿螺在不同盐度胁迫下的存活、生长、繁殖、抗逆响应与适应性进化机制以及华南滨海湿地生境的可入侵性，旨在揭示福寿螺可能向沿海咸水湿地“间歇性”、“周期性”和“长期性”入侵的机制与策略，并为及早开展有关入侵风险防控提供科学依据。

福寿螺作为世界100种恶性外来入侵物种之一，自上世纪80年代引入我国，现已入侵到长江流域及其以南广大区域的稻田、沟渠及河湖等淡水生态系统。福寿螺的适应性和耐性强，经过40多年的扩散和适应性演化，其种群是否能入侵到华南沿海咸水湿地生境是急需回答的科学问题，因此，本项目通过室内模拟实验和野外调查观测研究，探究了福寿螺种群在不同盐度胁迫下的响应、适应性、耐性范围以及向滨海湿地生境的入侵潜力及可能的模式路径。研究结果表明，不同大小的福寿螺应对不同盐度水体的急性胁迫、短期胁迫和长期胁迫，在成活率、生长率、摄食率、代谢率及其卵块孵化等方面会呈现不同的响应特征，盐分胁迫对福寿螺的摄食、代谢、繁殖、运动、生长等行为过程总体上会产生不同程度上的抑制效应。福寿螺经适度的盐水驯养可在一定程度上提高其耐盐性，且随着驯养盐度的升高，福寿螺在较高盐度中的存活及生长情况呈上升趋势。总体而言，在短期盐胁迫下，福寿螺在0~4 psu的盐度范围内可以存活，并可保持较正常的摄食和繁殖行为。福寿螺在一定时间内可耐受4~8 psu的水体盐度范围。福寿螺经过盐度6 psu的驯养后，可在一定时间内耐受更度盐度的咸水胁迫。在沿海湿地生境中，福寿螺优选淡水生境进行生活和入侵扩散，但它也可在0~2 psu咸水湿地中进行生活和长期入侵，并可向盐度2~6 psu的咸水湿地实现短期或一定时间的生存或生活，进而形成向较高盐度水体的偶发性、间歇性或周期性入侵的风险。项目研究揭示了福寿螺对水体盐度胁迫形成较强适应性和耐性的生长代谢调控、生理生化调节、分子调控、雌性优势、行为适应和形态可塑性等系列机制。研究成果可为福寿螺在全球热带亚热带沿海地区的入侵风险评估、预测预警、防控体系构建和防控措施制定等提供科学依据。