Aug 29, 2017

Leap‐frog in slow‐motion: divergent responses of tree species and life stages to climatic warming in Great Basin sub‐alpine forests

Smithers, Brian V., North, Malcolm P., Millar, Constance I., Latimer, Andrew M.
Global Change Biology
  • States that in response to climate warming, subalpine treelines are expected to move up in elevation since treelines are generally controlled by growing season temperature
  • States that where treeline is advancing, dispersal differences and early life stage environmental tolerances are likely to affect how species expand their ranges; species with an establishment advantage will colonize newly available habitat first, potentially excluding species that have slower establishment rates
  • Uses a network of plots across five mountain ranges to describe patterns of upslope elevational range shift for the two dominant Great Basin sub-alpine species, limber pine and Great Basin bristlecone pine
  • Finds that the Great Basin treeline for these species is expanding upslope with a mean vertical elevation shift of 19.1 m since 1950, which is lower than what we might expect based on temperature increases alone
  • Finds that limber pine is successfully “leap-frogging” over bristlecone pine
  • Results indicate the potential for the species composition of treeline to change in response to climate change
  • More broadly, it shows how species differences in dispersal and establishment may result in future communities with very different specific composition