Understanding Plant Community Change in Long-term Vegetation Monitoring Sites in Northern Alaska
Abstract
Warming in high latitudes has been documented and is expected to continue. Observations from sites established in the mid-1990s as part of the International Tundra Experiment (ITEX) are used to predict how Arctic vegetation will change with global climate change. The four sites used in this study are in northern Alaska, where there is a wet meadow site and a dry heath site at Barrow (71°17‧44″N 156°45‧59″W) and at Atqasuk (70°28'40"N 157°25‧5″W). Each site consists of 24 experimental plots warmed by passive open-topped chambers and 24 control plots. The cover of plant species was sampled using a point-frame method four times from the establishment of the sites until the most recent sampling in 2012. The change in cover in response to warming was assessed for each species. To help understand the causes underlying species change, species responses were lumped into various groups based on information previously known about the species. A two-way ANOVA was used to compare difference in cover among groups between the warmed and control plots. If the groups within a grouping scheme responded significantly differently to the warming treatment (i.e., there was an interaction between warming treatment and grouping scheme), then that grouping scheme was considered useful for predicting change in tundra communities. Of the grouping schemes used for this analysis, some were based on geographic distribution, such as distribution zones defined by Young 1971, some were based on phenology of the species, such date of flower opening as observed in these sites, and some were based on other morphological and life history traits, such as the wintering state of buds as defined by Sørensen 1971. The response to warming by species often varied from site to site, thus the usefulness of an individual grouping scheme also varied by site. The observed changes were often driven by the increase or decrease in cover of a few abundant species, Carex aquatilis in particular. The grouping schemes were considered useful for increasing our understanding of how and why plant community composition is changing; however, given the complexity in species response to warming detailed monitoring is necessary to fully document vegetation change and better predict future change.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2012
- Bibcode:
- 2012AGUFMGC21A0943L
- Keywords:
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- 0476 BIOGEOSCIENCES / Plant ecology;
- 1632 GLOBAL CHANGE / Land cover change