Comparison of the distribution and phenology of Arctic Mountain plants between the early 20th and 21st centuries

作者：Andrew S. MacDougall, Paul Caplat, Johan Olofsson, Matthias Siewert, Colin Bonner, Ellen Esch, Malie Lessard‐Therrien, Hannah Rosenzweig, A I Schafer, Pia Raker, Hassan Ridha, Kjell Bolmgren, Thore C. E. Fries, Keith Larson · 发表于：Global Change Biology · 年份：2021 · DOI：10.1111/gcb.15767 · 被引用次数：24 · 研究领域：Climate change and permafrost、Species Distribution and Climate Change、Tree-ring climate responses

Arctic plants are adapted to climatic variability, but their long-term responses to warming remain unclear. Responses may occur by range shifts, phenological adjustments in growth and reproduction, or both. Here, we compare distribution and phenology of 83 arctic and boreal mountain species, sampled identically in the early 20th (1917-1919) and 21st centuries (2017-2018) from a region of northern Sweden that has warmed significantly. We test two compensatory hypotheses to high-latitude warming-upward shifts in distribution, and earlier or extended growth and reproduction. For distribution, we show dramatic upward migration by 69% of species, averaging 6.1 m per decade, especially boreal woodland taxa whose upward expansion has reduced arctic montane habitat by 30%. Twenty percent of summit species showed distributional shifts but downward, especially moisture-associated snowbed flora. For phenology, we detected wide inter-annual variability in the onset of leafing and flowering in both eras. However, there was no detectable change in growing-season length, relating to two mechanisms. First, plot-level snow melt data starting in 1917 demonstrated that melt date, rather than vernal temperatures, better predicts plant emergence, with snow melt influenced by warmer years having greater snowfall-warmer springs did not always result in earlier emergence because snowbeds can persist longer. Second, the onset of reproductive senescence between eras was similar, even when plant emerge...