tundra

The Arctic tundra is a vast, treeless biome characterised by permafrost and extremely low annual temperatures.北极苔原是一个广阔、无树的生物群落，其特征是永久冻土和极低的年气温。

Climate change is causing the gradual southward expansion of shrub vegetation into previously open tundra landscapes.气候变化正导致灌木植被逐渐向南扩展，进入以前开阔的苔原景观中。