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Invasive grass reduces aboveground carbon stocks in shrublands of the Western US
Author(s) -
BRADLEY BETHANY A.,
HOUGHTON R. A.,
MUSTARD JOHN F.,
HAMBURG STEVEN P.
Publication year - 2006
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/j.1365-2486.2006.01232.x
Subject(s) - shrubland , carbon sink , bromus tectorum , environmental science , sink (geography) , carbon sequestration , grassland , climate change , carbon cycle , ecosystem , terrestrial ecosystem , biogeochemical cycle , blue carbon , ecology , invasive species , carbon dioxide , geography , biology , cartography
Understanding the terrestrial carbon budget, in particular the strength of the terrestrial carbon sink, is important in the context of global climate change. Considerable attention has been given to woody encroachment in the western US and the role it might play as a carbon sink; however, in many parts of the western US the reverse process is also occurring. The conversion of woody shrublands to annual grasslands involves the invasion of non‐native cheatgrass ( Bromus tectorum ) which in turn leads to increased frequency and extent of fires. We compared carbon storage in adjacent plots of invasive grassland and native shrubland. We scaled‐up the impact of this ecosystem shift using regional maps of the current invasion and of the risk of future invasion. The expansion of cheatgrass within the Great Basin has released an estimated 8±3 Tg C to the atmosphere, and will likely release another 50±20 Tg C in the coming decades. This ecosystem conversion has changed portions of the western US from a carbon sink to a source, making previous estimates of a western carbon sink almost certainly spurious. The growing importance of invasive species in driving land cover changes may substantially change future estimates of US terrestrial carbon storage.