Vegetation recovery patterns following permafrost disturbance in a Low Arctic setting: case study of Herschel Island, Yukon, Canada

The potential long-term effects of thaw slump disturbances on tundra ecosystems include a significant reorganization of tundra plant communities. In this study, vegetation sucession of stabilized retrogressive thaw slumps was investigated using four age classes: 10, 20, and 250 years old, and undisturbed areas. While still active, slumps are characterized by bare soil, pools of water and liquefied mud, and the initial colonization of graminoids and forbs. Between 0 and 20 years after stabilization, the slump vegetation is characterized by low diversity, grass-dominated vegetation communities with a high percent cover of dry bare ground. This is followed after a few hundred years by a forb, dwarf shrub, and bryophyte-dominated community with a high percent cover of litter. With future warming expected, the presence and areal extent of thaw disturbances are predicted to increase. These findings suggest that the result would be an altered tundra species composition, which remains distinct for at least several centuries.