冰川冻融对末端高寒草甸真菌群落结构和功能的影响

Effects of Seasonal Glacier Freeze-Thaw on Fungal Structure and Function in Alpine Meadow

作为“第三极”的青藏高原是全球中低纬度冰川最为发育的地区,被称为亚洲“水塔”。但是由于气候变暖等原因,青藏高原冰川的季节性消融导致大量的冰川融水季节性流入下游草甸生态系统,对生态系统结构和功能产生影响。由于真菌群落的结构和功能对水分变化十分敏感,冰川融水的季节性变化必然将显著影响冰川末端高寒草甸土壤真菌群落结构和功能。但是关于冰川融水增加对冰川区高寒草甸土壤真菌群落的影响的认识还十分有限。2019年在青藏高原唐古拉山龙匣宰陇巴冰川末端通过双向移栽试验和高通量测序方法研究了冰川融水的增加和减少对土壤真菌群落的影响,发现融水增加显著改变了真菌群落组成和降低了香农多样性指数,同时增加了上层土壤植物病原型和腐生型真菌的相对含量。融水减少改变了真菌群落组成并增加了真菌的α多样性,但是对真菌的影响与融水增加过程并不具有对称性。由于真菌的重要生态功能,研究结果对于更好地认识气候变化和冰川消融情形下,青藏高原冰川区高寒草甸的生态系统过程和功能变化具有重要意义。

As the world’s third pole,Qinghai-Tibetan Plateau is the most developed glacial area in the low and middle latitudes of the earth,so-called Asia’s water tower.However,dramatically melting glaciers results in tremendous water flooding in closed alpine meadow ecosystems due to climate warming.The structure and function of soil fungi communities are susceptible to moisture changes,which will be inevitably affected by the seasonal variation of melting glaciers.However,little is known about the responses of soil fungal communities to seasonal melting water changes in the alpine meadows in glacial areas.In this study,we conducted a reciprocal soil transplantation experiment in an alpine meadow at the end of Longxiazailongba glacier,Tanggula Mountains,central Tibetan Plateau,in 2019.The effects of glacial melting water increase and decrease on soil fungal communities were investigated by high-throughput sequencing technology.The results showed that more glacial meltwater significantly changed the composition of the fungal communities and decreased Shannon diversity.At the same time,the increasing relative content of pathotroph and saprotroph fungi was observed in the upper soil.Reduced melting water changed the composition of the fungal communities and increased theirαdiversity.But this effect was not symmetric with increased melting water.In conclusion,the results of this study will enhance our understanding of the changes in ecosystem processes and functions of alpine meadows in the glacial region of the Tibetan Plateau under climate change and glacier melting.