青藏高原植物物候的变化及其影响

植物物候是植物生活史的周期性循环事件。在气候变化和人类活动的影响下,青藏高原植物物候发生了显著的变化。近年来,青藏高原的物候初始期变化总体表现为返青期和初花期提前、枯黄期推迟的趋势,而果实期则保持相对稳定;增温延长了生长季,主要是通过延长开花等繁殖物候而实现的。青藏高原的物候变化主要受温度、水分和放牧的驱动,暖湿化和适度放牧有利于植物提前或延长物候期,而暖干化则延迟或缩短物候期。物候变化对植物种群、群落、生态系统、农牧区生产以及旅游业(如赏花节)等都会产生显著的影响。然而,目前青藏高原植物物候研究仍然十分缺乏,尤其是物候变化对生态系统结构和功能的影响研究更少。针对当前青藏高原物候研究存在的问题给出了一些建议:在未来的研究中应该尽可能从生理尺度到生态系统尺度的不同视角来研究气候变化和人类活动对物候的影响,以及物候变化对生态系统结构和功能的反馈。

Changes of plant phenophases and their effects on the Qinghai-Tibetan Plateau

Plant phenology is the recurrence of life history events. Impacts of climate change and human activity on phenology weresignificant in the Qinghai-Tibetan Plateau, and warming and optimal grazing advanced the timings of green-up and flowering but delayed the end date of senescence. However, fruiting time kept relative stable compared with other phenophases. Warming prolonged the duration of plant activity period which was mainly derived from prolonged flowering duration as well as other reproductive phenophases. These changes mainly attributed to changes of temperature, moisture and grazing. Warming and wet, moderate grazing contributed to advance and lengthen phenophases, whereas warming and drought led to delay and shorten phenophases. Changes ofphenophases had significant influences on structure and function of populations, community, ecosystem and productions and lives of pastoral and tourism. However, there were few studies on phenology, especially the effects of changes of phenology on structure and function of ecosystem on the Tibetan plateau. Therefore, we suggest that we should pay more attentions to effects of climate change and human activity on alpine plant phenology from physiology-level to ecosystem-level, and to feedbacks of phenology on ecosystems in the future.