Shrub recruitment, a key component of vegetation dynamics beyond forests, is a highly sensitive indicator of climate and environmental change. Warming-induced tipping points in Arctic and alpine treeless ecosystems are, however, little understood. Here, we compare two long-term recruitment datasets of 2,770 shrubs from coastal East Greenland and from the Tibetan Plateau against atmospheric circulation patterns between 1871 and 2010 Common Era. Increasing rates of shrub recruitment since 1871 reached critical tipping points in the 1930s and 1960s on the Tibetan Plateau and in East Greenland, respectively. A recent decline in shrub recruitment in both datasets was likely related to warmer and drier climates, with a stronger May to July El Niño Southern Oscillation over the Tibetan Plateau and a stronger June to July Atlantic Multidecadal Oscillation over Greenland. Exceeding the thermal optimum of shrub recruitment, the recent warming trend may cause soil moisture deficit. Our findings suggest that changes in atmospheric circulation explain regional climate dynamics and associated response patterns in Arctic and alpine shrub communities, knowledge that should be considered to protect vulnerable high-elevation and high-latitude ecosystems from the cascading effects of anthropogenic warming.

Department of Geography Faculty of Science Masaryk University 613 00 Brno Czech Republic

Department of Geography University of Cambridge Cambridge CB2 3EN United Kingdom

Global Change Research Institute Czech Academy of Sciences 603 00 Brno Czech Republic

Instituto Pirenaico de Ecología Consejo Superior de Investigaciones Científicas 50059 Zaragoza Spain

Laboratory of Tree Ring Research University of Arizona Tucson AZ 85721

School of Natural Resources and the Environment University of Arizona Tucson AZ 85721

State Key Laboratory of Tibetan Plateau Earth System Resources and Environment Institute of Tibetan Plateau Research Chinese Academy of Sciences 100101 Beijing China

State Key Laboratory of Tibetan Plateau Earth System Resources and Environment Institute of Tibetan Plateau Research Chinese Academy of Sciences 100101 Beijing China;

Swiss Federal Research Institute 8903 Birmensdorf Switzerland

Zobrazit více v PubMed

Walker D. A., et al. , The circumpolar Arctic vegetation map. J. Veg. Sci. 16, 267–282 (2005).

Liang E., et al. , Annual increments of juniper dwarf shrubs above the tree line on the central Tibetan Plateau: A useful climatic proxy. Ann. Bot. 109, 721–728 (2012). PubMed PMC

Thompson D. W. J., Wallace J. M., The Arctic Oscillation signature in the wintertime geopotential height and temperature fields. Geophys. Res. Lett. 25, 1297–1300 (1998).

Steinman B. A., Mann M. E., Miller S. K., Atlantic and Pacific multidecadal oscillations and Northern Hemisphere temperatures. Science 347, 988–991 (2015). PubMed

Kumar K. K., Rajagopalan B., Cane M. A., On the weakening relationship between the Indian monsoon and ENSO. Science 284, 2156–2159 (1999). PubMed

Weijers S., Buchwal A., Blok D., Löffler J., Elberling B., High Arctic summer warming tracked by increased Cassiope tetragona growth in the world’s northernmost polar desert. Glob. Change Biol. 23, 5006–5020 (2017). PubMed

Myers-Smith I. H., et al. , Shrub expansion in tundra ecosystems: Dynamics, impacts and research priorities. Environ. Res. Lett. 6, 045509 (2011).

Büntgen U., et al. , Temperature-induced recruitment pulses of Arctic dwarf shrub communities. J. Ecol. 103, 489–501 (2015).

Lu X., et al. , Past the climate optimum: Recruitment is declining at the world’s highest juniper shrublines on the Tibetan Plateau. Ecology 100, e02557 (2019). PubMed

Zhang P., et al. , Abrupt shift to hotter and drier climate over inner East Asia beyond the tipping point. Science 370, 1095–1099 (2020). PubMed

Wu C., et al. , Widespread decline in winds delayed autumn foliar senescence over high latitudes. Proc. Natl. Acad. Sci. U.S.A. 118, e2015821118 (2021). PubMed PMC

Elliott G. P., Bailey S. N., Cardinal S. J., Hotter drought as a disturbance at upper treeline in the southern Rocky Mountains. Ann. Am. Assoc. Geogr. 111, 756–770 (2021).

Huang M., et al. , Air temperature optima of vegetation productivity across global biomes. Nat. Ecol. Evol. 3, 772–779 (2019). PubMed PMC

Elmendorf S. C., et al. , Global assessment of experimental climate warming on tundra vegetation: Heterogeneity over space and time. Ecol. Lett. 15, 164–175 (2012). PubMed

Buchwal A., et al. , Divergence of Arctic shrub growth associated with sea ice decline. Proc. Natl. Acad. Sci. U.S.A. 117, 33334–33344 (2020). PubMed PMC