Abstract

Warming-induced expansion of trees and shrubs into tundra vegetation will strongly impact Arctic ecosystems. Today, a small subset of the boreal woody flora found during certain Plio-Pleistocene warm periods inhabits Greenland. Whether the twenty-first century warming will induce a re-colonization of a rich woody flora depends on the roles of climate and migration limitations in shaping species ranges. Using potential treeline and climatic niche modelling, we project shifts in areas climatically suitable for tree growth and 56 Greenlandic, North American and European tree and shrub species from the Last Glacial Maximum through the present and into the future. In combination with observed tree plantings, our modelling highlights that a majority of the non-native species find climatically suitable conditions in certain parts of Greenland today, even in areas harbouring no native trees. Analyses of analogous climates indicate that these conditions are widespread outside Greenland, thus increasing the likelihood of woody invasions. Nonetheless, we find a substantial migration lag for Greenland's current and future woody flora. In conclusion, the projected climatic scope for future expansions is strongly limited by dispersal, soil development and other disequilibrium dynamics, with plantings and unintentional seed dispersal by humans having potentially large impacts on spread rates.

Highlights

  • Arctic vegetation is changing in response to increasing temperatures over the past decades [1]

  • Satellite imagery indicates increased productivity [2], while repeated-photographic studies report greater shrub cover [3,4], increased tree growth at the boreal–tundra ecotone [5], and northward expansions of trees [6,7]. These vegetation changes will trigger several feedback loops with the climate system [8] and may have profound effects on ecosystems [9]. Do these changes mark the beginning of a greener future Arctic in which tundra vegetation is transformed by the expansion of a rich boreal woody flora, similar to the situation during Pliocene and certain Pleistocene warm periods? Recent evidence suggests that shrubs are currently expanding locally across the entire Arctic, at regionally varying rates [12]

  • We focused our analyses on 12 shrubs and trees native to Greenland, as well as woody species with maximum heights greater than or equal to 50 cm which occur in Arctic or subarctic areas bordering Greenland, i.e. in North America and Europe (n 1⁄4 26; see the electronic supplementary material, appendix S1 for further information)

Read more

Summary

Introduction

Arctic vegetation is changing in response to increasing temperatures over the past decades [1]. We consider future climate scenarios to quantify the climate potential for twenty-first century expansions of tree and shrub species across Greenland and assess the likelihood that Greenland will be transformed again by a re-colonization of a rich boreal woody flora, similar to that occurring during the Pliocene and some Pleistocene warm periods We do this by (i) forecasting treeline shifts and future climatically suitable areas for tree and shrub species, (ii) computing future migration lags and areas likely colonized by year 2100, based on specific dispersal distances and migration rates, and (iii) estimating extent of and distance to areas with analogous climates in Greenland, North America and Europe to highlight areas most likely to become sources or sinks for future immigrant or introduced woody species. Using the same climate variables as for the niche models, each grid cell in North America and Eurasia was compared with each grid cell in Greenland and each grid cell in Greenland was compared with each grid cell in North America and Eurasia (see the electronic supplementary material, appendix S4 for details)

Results
Discussion
70. Alley RB et al 2010 History of the Greenland ice
43. Elith J et al 2006 Novel methods improve prediction
Methods
Findings
80. Ehrich D et al 2012 The importance of willow
Full Text
Paper version not known

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.