互花米草入侵对盐城保护区丹顶鹤越冬种群生境选择与食物可获性的影响

Understanding mechanisms of exotic invasions and their ecological consequences on native species has become an issue of critical importance. Invasive smooth cordgrass (Spartina alterniflora) has been expanding rapidly in the Yancheng national natural reserve for wetland and rare birds (YNNR) during last several dozen of years, which support the largest wintering population of endangered red-crowned crane (Grus japonensis) in the world. In this research, we try to examine the impact of smooth cordgrass on the habitat selection and food availability of red-crowned crane, and especially concern questions as follows: (1) Change of habitat types and pattern as a result of smooth cordgrass invasion and dominance in the intertidal zone, and its competitive effect on native common seepweed herb (Suaeda glauca) based on satellite remote sensing technology. (2) A multi-scale assessment of habitat suitability of red-crowned crane and their dispersal to human disturbed habitats at YNNR. (3) Distribution and community pattern of the macrobenthos as potential prey of red-crowned crane in foraging habitats. Our research will analyze the status of red-crowned crane and its population fluctuation in future in YNNR, and propose conservation strategy suggestion for the crane. This is not only helpful to protect red-crowned crane at YNNR, but also give useful experience for the ecology of Spartina invasion in costal wetland.

外来入侵物种对本土动植物种群的生态影响研究十分重要。盐城自然保护区是濒危物种丹顶鹤(Grus japonensis)最重要的越冬地，互花米草(Spartina alterniflora)经过多年入侵与扩张，在保护区潮间带形成了茂密而宽阔的米草盐沼，对丹顶鹤越冬种群的生境选择和食物可获性产生了很大影响。本项目基于卫星遥感技术获得互花米草占据潮间带光滩、挤压碱蓬(Suaeda glauca)生境导致的保护区核心区生境类型及分布格局变化；阐明米草入侵胁迫下的丹顶鹤多尺度生境选择机制及向人工干扰生境的扩散行为；分析米草入侵导致的丹顶鹤觅食生境底栖动物分布格局及变化，评价越冬期的食物可获性。研究有望揭示丹顶鹤越冬种群的现状、评估未来变动趋势，提出生境恢复与种群管理对策，这不仅对丹顶鹤种群保护有重要意义，而且对沿海湿地米草入侵理论与实践有一定价值。

外来入侵物种对本土动植物种群的生态影响研究十分重要。盐城湿地珍禽自然保护区是濒危物种丹顶鹤(Grus japonensis)最重要的越冬地，互花米草(Spartina alterniflora)经过多年入侵与扩张，在保护区潮间带形成了茂密而宽阔的米草盐沼，对丹顶鹤越冬种群的生境选择和食物可获性产生了很大影响。本项目主要研究内容和结果包括：（1）基于卫星遥感技术获得互花米草占据潮间带光滩、挤压本土植物碱蓬(Suaeda glauca)生境导致的保护区核心区生境类型及分布格局变化；（2）阐明了米草入侵胁迫下的丹顶鹤多尺度生境选择机制及向人工干扰生境的扩散行为，发现在人类活动持续多年的干扰下，丹顶鹤已经形成了向农田和人工养殖塘的扩散与适应行为对策；（3）分析了互花米草入侵导致的丹顶鹤觅食生境底栖动物分布格局及变化，发现了芦苇割伐与碱蓬生境中底栖动物的种类与数量变化，评价了这种变化对丹顶鹤越冬期的食物可获性的影响。本项目的研究揭示了盐城保护区丹顶鹤越冬种群的现状，提出了生境恢复与种群管理对策。其中，对芦苇割伐有利于丹顶鹤越冬后期的生存结果获得保护区认同，在冬季适当割伐芦苇应用到管理当中。结果不仅对丹顶鹤种群保护有重要意义，而且对沿海湿地米草入侵理论与实践有一定价值。