Community and species-specific responses of plant traits to 23 years of experimental warming across subarctic tundra plant communities

Gaurav Baruah,Ulf Molau,Yang Bai,Juha M Alatalo

doi:10.1038/s41598-017-02595-2

Abstract

To improve understanding of how global warming may affect competitive interactions among plants, information on the responses of plant functional traits across species to long-term warming is needed. Here we report the effect of 23 years of experimental warming on plant traits across four different alpine subarctic plant communities: tussock tundra, Dryas heath, dry heath and wet meadow. Open-top chambers (OTCs) were used to passively warm the vegetation by 1.5–3 °C. Changes in leaf width, leaf length and plant height of 22 vascular plant species were measured. Long-term warming significantly affected all plant traits. Overall, plant species were taller, with longer and wider leaves, compared with control plots, indicating an increase in biomass in warmed plots, with 13 species having significant increases in at least one trait and only three species having negative responses. The response varied among species and plant community in which the species was sampled, indicating community-warming interactions. Thus, plant trait responses are both species- and community-specific. Importantly, we show that there is likely to be great variation between plant species in their ability to maintain positive growth responses over the longer term, which might cause shifts in their relative competitive ability.

Highlights

Recent anthropogenic global warming is likely to pose a major threat to biodiversity[1]
Recent modelling studies based on plant functional trait and co-occurrence data have shown that unexpected climate-driven community changes can occur, that interactive indirect effects can overcome direct effects and that the timing of species responses is an important driver of community dynamics[17]
A recent 16-year study on plant traits in five common vascular plant species in three plant communities in Arctic Canada found that tundra plants maintained positive responses in terms of increased leaf size and height after many years of warming[37], while similar results have been found in a 19-year study in Alaska[38]

Summary

Introduction

Recent anthropogenic global warming is likely to pose a major threat to biodiversity[1]. A recent 16-year study on plant traits in five common vascular plant species in three plant communities in Arctic Canada found that tundra plants maintained positive responses in terms of increased leaf size and height after many years of warming[37], while similar results have been found in a 19-year study in Alaska[38]. We aimed to identify species likely to increase their competitive advantage following long-term warming in terms of increased leaf area and plant height, two of the three functional plant traits responsible for competitive interactions[13]. Another aim was to determine whether within-species responses are consistent across contrasting plant communities. We tested the hypothesis that plant traits show positive responses to long-term experimental warming similar to those reported in High Arctic environments

Objectives

Methods

Results

Conclusion