A clash of plants : Vegetation succession and its interaction with permafrost dynamics in the Arctic lowland tundra

• Main Author: Li, Bingxi
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: Wageningen University 2017
• Subjects: arctic regions; ecological succession; ecology; lowland areas; permafrost; plant succession; siberia; tundra; vegetation; arctische gebieden; ecologie; ecologische successie; laaglandgebieden; plantensuccessie; siberië; toendra; vegetatie; Arctic; Arctagrostis latifolia; Betula nana; Climate change; Ice; Tundra; Siberia
• Online Access: https://research.wur.nl/en/publications/a-clash-of-plants-vegetation-succession-and-its-interaction-with-; https://doi.org/10.18174/418367

Arctic ecosystems have been affected by severe climate change during the last decades. The increase in temperature in the Arctic has been almost double of the global rate of warming since the beginning of the 20th century. Like other ecosystems in the high latitude region, Arctic tundra appears to be extremely sensitive to the continuous warming of the past decades, which has led to dramatic vegetation changes such as rapid shrub expansion. While researchers are keen to talk about the shrubification of the Arctic tundra, there has been rather little attention for alternative vegetation shifts, such as those related to local permafrost collapse in lowland tundra. The general vegetation succession route of the ice-rich lowland tundra ecosystem is yet largely unknown. Therefore, we choose a typical Arctic lowland site (Kytalyk natural reserve) in the Northeastern Siberia to explore how vegetation is changing in this ecosystem, and how changes in the abiotic environment and vegetation succession interact. On the basis of field observations I assumed that the plant species composition of each vegetation patch at the study site changes continuously following cycles over time. To test this assumption, two multiple-year field experiments (Chapter 2 and Chapter 3) were carried out. In addition, we applied dendrochronological techniques (Chapter 4 and Chapter 5) and molecular tools (Chapter 4). On the basis of the results of these studies, I depicted a complete vegetation succession loop in the Arctic lowland tundra, which is closely related to the dynamics of the permafrost. In this vegetation succession loop, four stages with distinctive vegetation types have been identified. The Betula nana L. shrubs mainly dominate the well-drained elevated areas. In a field experiment, removal of B. nana shrubs resulted in abrupt permafrost degradation, rapid soil moisture increase and invasion of the grass species Arctagrostis latifolia (R. Br.) Griseb. After a short time period, when small ponds or drainages had developed, this ...