贡嘎山区石松类与蕨类植物种类多样性与保育研究

Being part of the Hengduan Mountain Ranges, Mt. Gongga (Minya Gonkar) is the highest mountain with the most significant relative height differences on the south-eastern edge of the Qinghai-Tibet Plateau in southwest China. As a natural region, there reserve plenty of species diversities and biological resources as well. However, we still far from completely understand the plants species distributing in this area and are lack of detailed data on plant species diversity and their patterns of space distribution. The present speeding climate warming will make it more unpredicted for the future habitats suitable for plants to survive and propagate. Under the future uncertainty of environmental changes, informative biodiversity data will contribute a lot to the management of regional biological resources and the implementation of conservation priorities. In this proposed project, we will concentrate our study in a high mountain area where we assume the future global warming will greatly affect the local environments, and we will focus our study on the present species diversity and conservation measures on the lycophytes and ferns, the plant groups that are much sensitive to environmental changes. The most updated technological combinations of recording geographical information and field imaging documentation will be applied during the repeatedly extensive field investigations, and physical plant specimens, DNA samples and mature spores if available will also be collected at the same time. Morphological comparison of specimens will be supplemented by molecular, palynological and ecological evidences in order to correctly identify species. The purpose of the project is to clarify the present species diversity of lycophytes and ferns in Mt. Gongga region, to reveal evolutional relationships of the taxa representing the regional floristic characters, and to set up data bases of species-geographic information and spore morphology. The mature spores will be stored under ultra-frozen conditions and long-term experimental tests will be conducted to assess the feasibility of conserve genetic resources of lycophyts and ferns via spore banks.

贡嘎山是青藏高原东南缘横断山系垂直高差显著，生物多样性和生物资源丰富的自然区域；但我们对该区域植物种类的认识还不够，尚缺乏完整的物种多样性及空间分布资料。当今气候变化加剧使得未来植物生存环境更难以预测，详实的物种多样性资料将有助于区域性生物资源管理和实施优先保护措施。本项目拟选择可能受未来气候变暖影响较大的高山为研究区域，以对环境变化响应较为敏感的石松类和蕨类植物为研究对象，使用当前新颖的地理信息和野外图像记录技术，拟将多次广泛的野外考察、采集植物标本及DNA和孢子材料等，通过标本比较形态研究并借助分子、孢子形态和生态特征等综合证据，澄清研究区域的石松类和蕨类植物种类多样性以及（结合前期工作和现有分子证据）揭示代表区系特征类群的系统演化关系，并建立种类空间分布的地理信息数据库和孢子形态特征库；也拟将成熟孢子长期超低温冷冻保存并评估以孢子库形式保存石松类和蕨类植物遗传资源的可行性。

贡嘎山区石松类与蕨类植物种类多样性资料20多年来未得到更新，为了解全球气候变化和区域经济发展对山地特定植物类群多样性的影响和为资源管理部门确定优先保护的植物类群提供依据，有必要对该区域的石松类和蕨类植物种类现状做全面普查。在一年的项目实施中，我们对四川泸定县、康定县、九龙县和石棉县环绕贡嘎山主峰的的区域做了为期40余天的野外考察，采集到石松类与蕨类植物标本800余号，结合我们近几年积累的1000余号标本，通过比较形态研究确定已获得了该区域75%以上有历史记录的种类现状资料和植物标本，以及约60%种类的分子材料和20%的成熟孢子。基于上述标本和实验材料，我们对贡嘎山区的耳蕨属、鳞毛蕨属、凤尾蕨属、卷柏属等类群做了比较详尽的标本比较和分子证据分析，对这些类群的分类和系统演化问题取得了一些初步认识。耳蕨属在贡嘎山记录的种类占国产种数的1/5以上，但部分种类可能不成立，如伴藓耳蕨极可能是轴果耳蕨的异名；部分有芽胞的种类其芽胞有无和多寡与现今的属下分类划分并不一致，并且得不到分子证据支持；一些特别适生高海拔的种类划分需要更进一步的分子和其他证据支持，特别是被认为是贡嘎山区或邻近区域的特有类群。鳞毛蕨属在研究区域的存在的所有种都不具泡状鳞片，因而从形态学上判断贡嘎山区为鳞毛蕨属是否具有泡状鳞片种类的东西分界线，但造成这种分布格局的内因尚需深入研究。卷柏属的平卷柏从形态上判断接近伏地卷柏，分子证据支持其与后者共聚在一个支系。这些类群的分子证据也有力补充了国内外合作者从更大尺度上分析耳蕨属的空间传播、凤尾蕨属及其近缘类群的系统关系、卷柏属的属下类群划分等研究。此外，我们在研究区域发现不少蕨类植物的实际分布海拔高度比文献或标本记录的要高至少200m，以及一些蕨类植物和被子植物分布新纪录。我们还在贡嘎山东坡发现一个植株数较多，分布海拔较低且为已知有标本记录的纬度最高的扇蕨居群。本项目还需一定时间的后续研究，以便完成研究区域的石松类与蕨类植物最新编目和甄别需要优先保护的种类及居群。