A new special issue of more than 20 papers—published in the open access journal Arctic Science—presents findings from 30 years of research and monitoring by the International Tundra Experiment (ITEX), a collaborative research network established in 1990 to study the effects of environmental change on tundra ecosystems.
“Sharing knowledge is essential for climate action, especially in areas experiencing rapid change, like the Arctic. Open exchange of knowledge is a pillar of ITEX and Arctic Science, and the freely available papers in this collection are invaluable contributions to our understanding of the tundra biome,” shared Dr. Greg Henry, founding and consulting Editor at Arctic Science, former Chair of ITEX, and Professor Emeritus at the University of British Columbia.
The longitudinal body of work in the special issue details how a warming Arctic has changed the vegetation, which has implications for circumarctic communities who use plants for food and cultural practices, and for the structure and function of tundra systems.
Notably, the ITEX studies provide robust evidence of increased cover and height of woody shrubs across the Arctic. This phenomenon, known as “shrubification,” has cascading effects on ecosystem function. For example, a study in northern Sweden showed increases in shrubs in all tundra types. A paper led by Dr. Jeremy May, postdoctoral researcher at the University of Florida, describes how shade of taller shrubs reduces the number of flowers grown by shorter, berry-producing plants.
Complex effects of warming revealed with a simple device
Results from ITEX warming experiments provide insights into how plants could respond to warmer temperatures in the future; these conditions are created using clear enclosures called open-top chambers (OTCs), which passively warm air by 1–3 °C. “They essentially replicate a warm year at a site and show realistic responses to warming,” explained Dr. Robert Hollister, Grand Valley State University, who is a co-Chair of ITEX. This was clearly shown in a study of the effect of an extreme cold year (2018) at a site in the Canadian High Arctic where some plants only produced seeds inside the OTCs.
Spanning the tundra biome, these plots (approximately 2 square metres in area) reveal how responses of vegetation and soils to warming can be site-specific. One ITEX study examined whether tea bags decomposed faster in OTCs—a proxy for decomposition of plant litter—and varied depending on location.
“We used sites in Iceland’s subarctic and Norway’s high Arctic. We could not find responses to the warming in the high Arctic, but in Iceland decomposition increased with warming,” explained lead author Katrín Björnsdóttir, a PhD student at the University of Gothenburg. “These results indicate that warming may lead to faster decomposition of plant litter. This can be linked to more carbon going into the atmosphere.”
Collaborative work yields phenomenal datasets
With more than 30 study sites throughout the Arctic, researchers from 11 countries have collected hundreds of thousands of measurements and observations on tundra ecosystems, including: changes in the diversity of tundra vegetation, the date a plant first flowered, toughness of a leaf, types of microbes in the soil, essential oil content of leaves, diversity of insect visitors, recovery after vehicle damage, and the presence of animal fecal pellets indicating herbivory.
Data are analyzed in relation to factors directly related to climatic change including air temperature and snow depth, duration, and distribution—the latter of which is of particular importance as the winter season is warming more than the summer season in the Arctic.
These data are also shared. Data sharing is a founding principle of ITEX. The tremendous tundra phenology dataset, described by Dr. Janet Prevéy (U.S. Geological Survey) and ITEX colleagues, is available for download and use at the Polar Data Catalogue.
Setting priorities for the decades to come
As for what the next 30 years will be for ITEX, the members of the scientific steering committee emphasize the need for more integrative studies and the importance of community engagement:
"ITEX sites have traditionally been located in remote research stations or sites familiar to the researchers. Locating research sites in proximity of northern communities [would allow] possibilities of knowledge exchange and linking the studies with local schools... New research questions of interest to local people emerge with these interactions and can make the studies directly relevant to those living in the rapidly changing Arctic."
All content in this Arctic Science special issue—Impacts of climate change on tundra ecosystems: Three decades of results from the International Tundra Experiment (ITEX)—is freely available online for anyone to read and download at: https://cdnsciencepub.com/toc/as/8/3
Please cite Arctic Science as the source of this story and include a hyperlink to the special issue: https://cdnsciencepub.com/toc/as/8/3
About Arctic Science
Published by Canadian Science Publishing (CSP), Arctic Science is an open-access peer-reviewed journal publishing original research from all areas of natural science and applied science and engineering related to northern polar regions. The focus on basic and applied science includes the Traditional Knowledge and observations of the Indigenous Peoples of the region, as well as developments in biological, chemical, physical, and engineering science in all northern environments. cdnsciencepub.com/as
About the International Tundra Experiment (ITEX)
The International Tundra Experiment (ITEX) is a collaborative effort involving scientists from more than 11 countries, including all the Arctic nations. ITEX seeks to examine the response of circumpolar cold adapted plant species and tundra ecosystems to environmental change, specifically to an increase in summer temperature. gvsu.edu/ite
Article Publication Date
17-Oct-2022