Look again: revising ideas about the greening of Alaska's Arctic tundra.
Alaska's Arctic tundra is one of the most rapidly warming regions in the world. For years, scientists have been working to interpret the effects of its changing climate and determine what these changes may mean for the rest of the planet. Coarse-scale satellite imagery of much of this region shows the tundra is becoming greener. This has been widely attributed to shrub expansion. To better understand vegetation dynamics in the region, research ecologist Robert Pattison and his colleagues compared satellite imagery of this greening with data that Janet Jorgenson, a botanist with the U.S. Fish and Wildlife Service, collected for more than 25 years from field plots in the Arctic National Wildlife Refuge. Their findings showed few changes in plant species composition from 1984 to 2009; increases in shrub cover were limited to a riparian shrubland plot. On the tundra, small differences in topography and substrate can make a difference in plant composition. A fine-scale assessment of the landscape is needed to develop a more complete picture of the patterns and determinants of change in the far north. This research advances our understanding of the effects of climate change and may help in the management of various Arctic wildlife, including caribou herds that are important to the subsistence of Alaska Native communities.