增温和氮添加对天山高寒草地生态系统多功能性的影响

Effects of Warming and Nitrogen Addition on the Ecosystem Multifunctionality of Alpine Grassland in the Tianshan Mountains,China

为了探究增温和氮添加对高寒草地生态系统多功能性的影响机制,在位于天山山脉南麓的巴音布鲁克高寒草地开展增温和氮添加实验.通过调查群落物种组成并测量常见的物种功能性状,分析单一生态系统功能以及生态系统多功能性对增温和氮添加的响应模式,并探究其与植物群落物种多样性、功能多样性之间的关系.结果表明:增温降低生态系统多功能性而氮添加会增加生态系统多功能性;增温通过影响初级生产力和植物养分供给影响生态系统多功能性,氮添加则通过增加初级生产力、土壤有机质和土壤肥力来提高生态系统多功能性;物种多样性和功能多样性都能很好地解释生态系统多功能性的变化,其中香农-维纳多样性指数解释效果最好.研究表明增温与氮添加这两种气候变化过程对高寒草地生态系统多功能性有着不同的作用机制,可为气候变化背景下高寒草地的生态系统功能维持提供参考依据.

In order to research the mechanisms underlying the effects of warming and nitrogen addition on the ecosystem multifunctionality of the alpine grassland ecosystem,field experiments with warming and nitrogen addition were conducted in the Bayinbuluke alpine grassland,which is located in the southern Tianshan Mountains.The response patterns of single ecosystem function and ecosystem multifunctionality to warming and nitrogen addition were analyzed,and their relationship with species diversity and functional diversity in plant communities were explored,by examining community species composition and measuring common species functional traits.The results showed that warming decreased ecosystem multifunctionality but nitrogen addition increased ecosystem multifunctionality.While nitrogen addition impacted ecosystem multifunctionality by changing primary product-ivity,soil fertility,and climate regulation,warming influenced ecosystem multifunctionality by affecting plant nutrient supply.The shift in ecological multifunctionality can be well explained by species diversity and functional diversity,Shannon-Wiener’s diversity index provides the best explaining ability in all of the indexes.Our study demonstrates that the two climate change processes“warming and nitrogen addition”have distinct mechanisms for the alpine grassland ecosystem’s multifunctionality,which might serve as a guide for maintaining alpine grassland ecosystem functions in the face of climate change.