滇池中华青鳉的分布、行为及生理对克氏原螯虾、食蚊鱼入侵的响应

Biological invasions have been the big challenge of current ecology.Invasions of alien species have caused the dramatic decline of native species diversity. In a previous research, we found that the invasive species of mosquitofish Gambusia affinis and crayfish Procambarus clarkii had co-invaded into the habitats of the endangered species, the Chinese medaka Oryzias sinensis,in Dianchi drainages of Yunnan, China, which would be the main reasons of extinction of this small fish from Dianchi Lake. It is desiderated to determine the effects of co-invasions of these two invaders on the indigenous fish. In this project, investigations on the predation mechanism of the two invaders on medaka, the changes of history strategies of Chinese medaka under the threat of these two invaders and the interspecific relationship between native species and invaders will be conducted at three levels: laboratory, micro-ecosystem and fields. By the common ecological technique, micro-ecosystem technique and in situ technique,we attempted to clarify the mechanism of co-invasions of mosquitofish and crayfish to the plateau wetland ecosystem and their effectes on the survival of Chinese medaka. And also,we try to clarify the ecological process of interaction between the indigenous species and invaders, and to determine the effects of co-invasions of the two invaders on Chinese medaka as well. The results of this project will greatly improve our understanding on the mechanisms of how a common species becoming endangered species in recent times, and will upgrade our knowledge on the mechanism and effects of co-invasions of mosquitofish and crayfish in different zone. Fially,it will be greatly promote the advance of the theory of aquatic invasion ecology.

生物入侵致使当今生物多样性剧烈下降。前期研究发现，食蚊鱼Gambusia affinis与克氏原螯虾Procambarus clarkii的协同入侵可能是导致云南滇池流域中华青鳉Oryzias sinensis濒危的主要原因。本项目拟以种群分布格局、行为机制及生理生态研究等为重点，围绕食蚊鱼与克氏原螯虾协同入侵与中华青鳉濒危的关系及其作用机制这一核心科学问题，利用常规生态学方法、微生态系统技术及原位实验技术，在实验室、微生态系统和野外三个水平揭示入侵者对云南滇池流域高原湿地生态系统的联合入侵机制及中华青鳉的应对策略。阐明中华青鳉濒危机制对于了解广布种在近代以来如何迅速濒危化这一普遍性问题有重要科学意义。云南高原湿地生态系统在世界范围内具有特有性和典型性，项目的开展必将大大加深对食蚊鱼及克氏原螯虾在不同生境下的协同入侵机制及生态学影响的了解，必将进一步促进水生生物入侵生态学理论的完善和发展。

生物入侵致使当今生物多样性剧烈下降。本项目针对食蚊鱼Gambusia affinis与克氏原螯虾Procambarus clarkii的协同入侵对云南滇池流域中华青鳉Oryzias sinensis生态学效应及作用机制进行了研究。以种群分布格局、行为机制及生理生态研究等内容为重点展开研究。主要研究结果：.1、经过2012-2017年跨度6年观察表明尽管克氏原螯虾对中华青鳉具有捕食作用，但这种捕食作用对中华青鳉种群无显著影响。在入侵区域，食蚊鱼与中华青鳉最高食物重叠指数可达0.82，表明两者存在严重食物竞争。其入侵在5年内导致研究区域三家村水库种群完全灭绝；入侵2年内导致三家村水库坝下盆地局部种群数量显著下降。揭示了克氏原螯虾与食蚊鱼协同入侵情况下，食蚊鱼对中华青鳉起主要作用；中华青鳉对食蚊鱼入侵十分敏感，无法在野外寿命周期（一周年）内作用适应性响应。食蚊鱼对中华青鳉的主要作用机制为食物竞争及对仔鱼的捕食作用。.2、尽管中华青鳉对食蚊鱼入侵敏感，无论对全国各主要区域还是对滇池流域的调查均显示，由于仍存在食蚊鱼仍未入侵区域，中华青鳉在野外仍分布一定数量种群。持续性对入侵初期的食蚊鱼种群清除研究则表明，食蚊鱼一旦入侵将难以清除；中华青鳉种群随食蚊鱼入侵时间的延长种群数量显著下降。针对性保护中华青鳉的有效措施是严格限制食蚊鱼入侵。.3、对中华青鳉种群不同地理种群间及同一种群年际遗传多样性研究显示，其种群遗传多样性存在周年波动，尚未发现入侵种入侵能显著改变其种群遗传多样性的确切证据。.本项目开展明确证实克氏原螯虾入侵对中华青鳉种群不具有显著影响；明确观察到食蚊鱼入侵导致中华青鳉局部种群灭绝，并揭示了其作用机制为食物竞争及对仔鱼的捕食；初步揭示了克氏原螯虾与食蚊鱼对中华青鳉不具有协同作用效应。项目的主要研究结果加深对食蚊鱼及克氏原螯虾在不同生境下的协同入侵机制及生态学影响的了解，进一步促进水生生物入侵生态学理论的完善和发展。