Diminished response of arctic plants to warming over time.

Kelseyann S Kremers,Steven F Oberbauer,Robert D Hollister

doi:10.1371/journal.pone.0116586

Kelseyann S Kremers, Steven F Oberbauer + Show 1 more

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https://doi.org/10.1371/journal.pone.0116586

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Abstract

The goal of this study is to determine if the response of arctic plants to warming is consistent across species, locations and time. This study examined the impact of experimental warming and natural temperature variation on plants at Barrow and Atqasuk, Alaska beginning in 1994. We considered observations of plant performance collected from 1994–2000 “short-term” and those from 2007–2012 “long-term”. The plant traits reported are the number of inflorescences, inflorescence height, leaf length, and day of flower emergence. These traits can inform us about larger scale processes such as plant reproductive effort, plant growth, and plant phenology, and therefore provide valuable insight into community dynamics, carbon uptake, and trophic interactions. We categorized traits of all species monitored at each site into temperature response types. We then compared response types across traits, plant growth forms, sites, and over time to analyze the consistency of plant response to warming. Graminoids were the most responsive to warming and showed a positive response to temperature, while shrubs were generally the least responsive. Almost half (49%) of response types (across all traits, species, and sites combined) changed from short-term to long-term. The percent of plants responsive to warming decreased from 57% (short-term) to 46% (long-term). These results indicate that the response of plants to warming varies over time and has diminished overall in recent years.

Highlights

Higher latitudes show among the greatest and earliest responses to changing climate [1]
We considered the analysis over years 1994–2000 the “short-term” response (ST) to warming and the analysis over years 2007–2012 the “long-term” response (LT)
When we examined the consistency of the temperature response types of all traits of all monitored species at the four sites, we found 49% (44 occurrences out of 89 reported) of the temperature response types changed between the short-term and long-term observations (Table 2, Fig. 2, Fig. 3); the proportion would be 37% if we did not distinguish between dominant and subordinate response types (++ and + or – and -)

Summary

Introduction

Higher latitudes show among the greatest and earliest responses to changing climate [1]. The harsh climate of the region limits arctic plant growth, and a small increase in temperature may have a great effect on arctic plant communities [2]. Shifts in the composition and abundance of plant species will have important effects on organisms at all trophic levels, as well as many ecosystem processes including nutrient cycling, carbon storage, and solar energy absorption [3]. Shifts to a shrub-dominated community can reduce albedo [4, 5, 6], which may impact snowmelt processes and surface radiation budgets [6, 7]. Increased dominance of shrubs and evergreens may slow

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