Plant community responses to experimental warming across the tundra biome.
Recent observations of changes in some tundra ecosystems appear to be responses to a warming climate. Several experimental studies have shown that tundra plants and ecosystems can respond strongly to environmental change, including warming; however, most studies were limited to a single location and were of short duration and based on a variety of experimental designs. In addition, comparisons among studies are difficult because a variety of techniques have been used to achieve experimental warming and different measurements have been used to assess responses. We used metaanalysis on plant community measurements from standardized warming experiments at 11 locations across the tundra biome involved in the International Tundra Experiment. The passive warming treatment increased plant-level air temperature by 1-3 degrees C, which is in the range of predicted and observed warming for tundra regions. Responses were rapid and detected in whole plant communities after only two growing seasons. Overall, warming increased height and cover of deciduous shrubs and graminoids, decreased cover of mosses and lichens, and decreased species diversity and evenness. These results predict that warming will cause a decline in biodiversity across a wide variety of tundra, at least in the short term. They also provide rigorous experimental evidence that recently observed increases in shrub cover in many tundra regions are in response to climate warming. These changes have important implications for processes and interactions within tundra ecosystems and between tundra and the atmosphere.
Walker
Marilyn D
MD
Boreal Ecology Cooperative Research Unit, U.S. Department of Agriculture Forest Service Pacific Northwest Research Station, University of Alaska, P.O. Box 756780, Fairbanks, AK 99775-6780, USA.
Wahren
C Henrik
CH
Hollister
Robert D
RD
Henry
Greg H R
GH
Ahlquist
Lorraine E
LE
Alatalo
Juha M
JM
Bret-Harte
M Syndonia
MS
Calef
Monika P
MP
Callaghan
Terry V
TV
Carroll
Amy B
AB
Epstein
Howard E
HE
Jónsdóttir
Ingibjörg S
IS
Klein
Julia A
JA
Magnússon
Borgthór
B
Molau
Ulf
U
Oberbauer
Steven F
SF
Rewa
Steven P
SP
Robinson
Clare H
CH
Shaver
Gaius R
GR
Suding
Katharine N
KN
Thompson
Catharine C
CC
Tolvanen
Anne
A
Totland
Ørjan
Ø
Turner
P Lee
PL
Tweedie
Craig E
CE
Webber
Patrick J
PJ
Wookey
Philip A
PA
D001110:Arctic Regions; D044822:Biodiversity; D018533:Biomass; D002980:Climate; D003247:Conservation of Natural Resources; D017753:Ecosystem; D004777:Environment; D004784:Environmental Monitoring; D014644:Genetic Variation; D017752:Greenhouse Effect; D006358:Hot Temperature; D008962:Models, Theoretical; D018521:Plant Physiological Phenomena; D010944:Plants / Q000378:metabolism*; D012984:Software; D013696:Temperature