Recent greening driven by species-specific shrub growth characteristics in Nunatsiavut, Labrador, Canada

Taylor Larking, Emma Davis, Robert Way, Luise Hermanutz, Andrew Trant
2021 Arctic Science  
Satellite remote sensing is a popular approach for identifying vegetation change in northern environments; however, disentangling ecological processes causing variability in spectral indices remains a challenge. Here, we aim to determine how shrub characteristics differ between low and rapidly greening areas near Nain, Nunatsiavut, Canada. Using a cross-scale approach, we combined remotely sensed spectral greening trends (Normalized Difference Vegetation Index; Landsat Collection 1; 1985-2018)
more » ... ith shrub dynamics derived from ring-widths of green alder (Alnus alnobetula) and dwarf birch (Betula glandulosa). Differentiation of spectral greening classes appears to be driven by the distribution of shrub species. Alder were taller, grew faster, had more recent stem initiation than dwarf birch, and were dominant in rapid greening subplots. In low greening subplots, alders were co-dominant with dwarf birch, whose dominant stems initiated more gradually, were shorter, and had lower rates of vertical growth. The radial growth of both shrub species was favoured by warm winter temperatures and precipitation, whereas rapid greening alder was also favoured by warm summer temperatures. Further shrub growth will likely be enhanced under continued climate warming if moisture does not become limiting. This research demonstrates the importance of species identity in determining rates of spectral greening in northern environments.
doi:10.1139/as-2020-0031 fatcat:gkthjlgocjaqbngzp4b3aopuym