title: Leaf unfolding of Tibetan alpine meadows captures the arrival of monsoon rainfall.
abstract: The alpine meadow on the Tibetan Plateau is the highest and largest pasture in the world, and its formation and distribution are mainly controlled by Indian summer monsoon effects. However, little is known about how monsoon-related cues may trigger spring phenology of the vast alpine vegetation. Based on the 7-year observations with fenced and transplanted experiments across lower to upper limits of Kobresia meadows in the central plateau (4400-5200 m), we found that leaf unfolding dates of dominant sedge and grass species synchronized with monsoon onset, regardless of air temperature. We also found similar patterns in a 22-year data set from the northeast plateau. In the monsoon-related cues for leaf unfolding, the arrival of monsoon rainfall is crucial, while seasonal air temperatures are already continuously above 0 °C. In contrast, the early-emerging cushion species generally leafed out earlier in warmer years regardless of precipitation. Our data provide evidence that leaf unfolding of dominant species in the alpine meadows senses the arrival of monsoon-season rainfall. These findings also provide a basis for interpreting the spatially variable greening responses to warming detected in the world's highest pasture, and suggest a phenological strategy for avoiding damages of pre-monsoon drought and frost to alpine plants.
authors: University of Chinese Academy of Sciences, Beijing 100049, China.|Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
authors: Ruicheng
authors: R
authors: Li
authors: Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.|CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China.
authors: Tianxiang
authors: T
authors: Luo
authors: Climate System Research Group, Institute of Geography, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen 91058, Germany.
authors: Thomas
authors: T
authors: Mölg
authors: Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
authors: Jingxue
authors: J
authors: Zhao
authors: Key Laboratory of Alpine Ecology and Biodiversity, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China.
authors: Xiang
authors: X
authors: Li
authors: University of Chinese Academy of Sciences, Beijing 100049, China.
authors: Xiaoyong
authors: X
authors: Cui
authors: National Institute for Agro-Environmental Sciences, Tsukuba 305-8604, Japan.
authors: Mingyuan
authors: M
authors: Du
authors: National Institute for Environmental Studies, Tsukuba 305-8506, Japan.
authors: Yanhong
authors: Y
authors: Tang
mesh_terms: D065948:Grassland; D018515:Plant Leaves / Q000502:physiology*; D011891:Rain; D012621:Seasons; D018609:Tibet