Siberian plants shift their phenology in response to climate change
Abstract
Siberia has undergone dramatic climatic changes due to global warming in recent decades. Yet, the ecological responses to these climatic changes are still poorly understood due to a lack of data. Here, we use a unique data set from the Russian ‘Chronicles of Nature’ network to analyse the long‐term (1976–2018) phenological shifts in leaf out, flowering, fruiting and senescence of 67 common Siberian plant species. We find that Siberian boreal forest plants advanced their early season (leaf out and flowering) and mid‐season (fruiting) phenology by −2.2, −0.7 and −1.6 days/decade, and delayed the onset of senescence by 1.6 days/decade during this period. These mean values, however, are subject to substantial intraspecific variability, which is partly explained by the plants' growth forms. Trees and shrubs advanced leaf out and flowering (−3.1 and −3.3. days/decade) faster than herbs (−1 day/decade), presumably due to the more direct exposure of leaf and flower buds to ambient air for the woody vegetation. For senescence, we detected a reverse pattern: stronger delays in herbs (2.1 days/decade) than in woody plants (1.0–1.2 days/decade), presumably due to the stronger effects of autumn frosts on the leaves of herbs. Interestingly, the timing of fruiting in all four growth forms advanced at similar paces, from 1.4 days/decade in shrubs to 1.7 days/decade in trees and herbs. Our findings point to a strong, yet heterogeneous, response of Siberian plant phenology to recent global warming. Furthermore, the results highlight that species‐ and growth form‐specific differences among study species could be used to identify plants particularly at risk of decline due to their low adaptive capacity or a loss of synchronization with important interaction partners.
What the paper shows and why it matters
(AI-generated)
Phenology, the timing of life-cycle events such as leaf out or flowering, is arguably one of the most responsive signals of climate change. Most of what is known about plant responses comes from temperate Europe and North America. Yet the paper points to regional studies suggesting that the size and even the direction of shifts can depend on local climate and plant adaptation. Siberia has warmed faster than the global land average, but, to the paper’s knowledge, no ground-based phenology study existed there. The paper asks whether Siberian plants shift their timing like plants elsewhere, and how much species and growth forms differ.
The paper finds that plants in a Siberian boreal forest advanced leaf out, flowering and fruiting and delayed the onset of autumn senescence (leaf fall or dieback), at rates comparable to other cold, strongly seasonal regions, although species differ widely. It analyses weekly records of 67 species at one site, the Barguzin Nature Reserve near Lake Baikal, for 1976 to 2018. Leaf out advanced by 2.2 days per decade, flowering by 0.7 and fruiting by 1.6, as the site warmed by about 0.4 °C per decade. Leaf out became significantly earlier in 34 of the 67 species and later in three; for the other three events most species showed no significant shift. Growth form explains part of this: trees, shrubs and dwarf shrubs advanced leaf out about three times faster (2.7 to 3.3 days per decade) than herbs (1.0). The paper attributes this to woody plants’ buds being more directly exposed to ambient air, while herbs may be buffered by snow and soil.
The paper reads the results as a strong response of Siberian boreal forest to warming, not previously documented from ground observations in this region, and puts the lengthening of the growing season at about 15 days. It suggests that the longer season might have raised productivity and carbon uptake, which the paper does not test. The uneven responses, it argues, could help identify species at risk because they adapt poorly or might lose synchrony with interaction partners; mismatches with insects or fruit-eating birds are named as questions for future work. Limits remain: the record covers a single site, and growth form leaves much of the variation among species unexplained.