Phenological changes offset the warming effects on biomass production in an alpine meadow on the Qinghai–Tibetan Plateau. (5th November 2020)

• Record Type: Journal Article
• Authors: Ganjurjav, Hasbagan; Gornish, Elise; Hu, Guozheng; Wu, Jianshuang; Wan, Yunfan; Li, Yue; Gao, Qingzhu
• Editors: Lamb, Eric
• Is Part Of: Journal of ecology. Volume 109:Number 2(2021)
• Page Start: 1014
• Page End: 1025
• Publication Date: 2020-11-05
• Subjects: above‐ground biomass -- climate change -- cold ecosystem -- dry alpine meadow -- growth form -- hydro‐thermal conditions -- phenological events; Plant ecology -- Periodicals; 577.05
• DOI: 10.1111/1365-2745.13531
• Languages: English
• ISSNs: 0022-0477

Abstract

Abstract: Phenology is an important indicator of plant responses to environmental changes and is closely correlated with biomass production. However, how changes in phenological events affect plant biomass production when exposed to changing temperature and precipitation remain unclear. We conducted a 4‐year manipulative experiment of warming and precipitation addition to explore phenology–biomass interactions under climate change in a dry alpine meadow on the central Qinghai–Tibetan Plateau from 2015 to 2018. In dry and warm years, warming delayed phenology and precipitation addition advanced them. Warming decreased the biomass of Kobresia pygmaea in 2018 and the biomass of Poa pratensis in 2015, 2017 and 2018. However, precipitation addition significantly increased the biomass of Poa pratensis and Potentilla multifida in most of the experimental years. Phenological changes regulated the responses of biomass to treatments. Specifically, delay of green up of P. pratensis and delay of withering of K. pygmaea induced by warming can increase biomass production, but it can be offset by the direct negative effects of warming on biomass. Synthesis . Here we show how warming‐induced drought tend to decrease the biomass production of graminoids and the negative effects of warming on the biomass of P. pratensis and K. pygmaea were partially offset by green up postponement and withering postponement respectively. Our results highlights phenology is a crucial regulator for biomass production under climate change. Hence, both direct and indirect effects of warming and precipitation addition on phenology and biomass cannot be ignored when predicting biomass responses to climate change. Abstract : Here we show how warming‐induced drought tend to decrease the biomass production of graminoids and the negative effects of warming on the biomass of P. pratensis and K. pygmaea were partially offset by green up postponement and withering postponement respectively. Our results highlights phenology is a crucial regulator for biomass production under climate change. Hence, both direct and indirect effects of warming and precipitation addition on phenology and biomass cannot be ignored when predicting biomass responses to climate change. 摘要: 物候是反映植物对环境变化响应的重要指标，且与植物生物量显著相关。目前，温度和降水变化条件下植物物候期改变对植物生物量的调控机制仍不明确。 为了揭示气候变化条件下植物物候与生物量之间的关系，2015‐2018年，我们在青藏高原核心区的高寒草甸开展了为期四年的增温和增水原位模拟实验。 研究结果表明，在气候暖干年份，增温推迟植物物候期，而增水则使物候期提前。增温在2018年显著降低高山嵩草生物量，在2015/2017和2018年降低早熟禾生物量。然而，在大多年份，增水显著增加早熟禾和多裂委陵菜生物量。植物物候期变化可以调控生物量对实验处理的响应。例如，增温可以使早熟禾推迟返青，使高山嵩草推迟枯黄；上述物候期变化可以增加植物生物量，但增温早熟禾和高山嵩草生物量具有直接的负面效应，两者间存在抵消作用。 我们揭示了增温引起的干旱会导致禾状草生物量降低，但增温对早熟禾生物量的负面影响被其返青期推迟部分抵消，增温对高山嵩草生物量的副作用被其枯黄期推迟部分抵消。我们的结果明确了物候是调控植物生产力对气候变化响应的重要因素。因此，在预估生产力对气候变化响应时，不仅要考虑温度升高和降水增加对物候期和生产力的直接影响，其产生的间接影响也不容忽视。