Changes to dryland rainfall result in rapid moss mortality and altered soil fertility

Nature Climate Change
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Abstract

Arid and semi-arid ecosystems cover ~40% of Earth’s terrestrial surface, but we know little about how climate change will affect these widespread landscapes. Like many drylands, the Colorado Plateau in southwestern United States is predicted to experience elevated temperatures and alterations to the timing and amount of annual precipitation. We used a factorial warming and supplemental rainfall experiment on the Colorado Plateau to show that altered precipitation resulted in pronounced mortality of the widespread moss Syntrichia caninervis. Increased frequency of 1.2 mm summer rainfall events reduced moss cover from ~25% of total surface cover to <2% after only one growing season, whereas increased temperature had no effect. Laboratory measurements identified a physiological mechanism behind the mortality: small precipitation events caused a negative moss carbon balance, whereas larger events maintained net carbon uptake. Multiple metrics of nitrogen cycling were notably different with moss mortality and had significant implications for soil fertility. Mosses are important members in many dryland ecosystems and the community changes observed here reveal how subtle modifications to climate can affect ecosystem structure and function on unexpectedly short timescales. Moreover, mortality resulted from increased precipitation through smaller, more frequent events, underscoring the importance of precipitation event size and timing, and highlighting our inadequate understanding of relationships between climate and ecosystem function in drylands.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Changes to dryland rainfall result in rapid moss mortality and altered soil fertility
Series title Nature Climate Change
DOI 10.1038/nclimate1596
Volume 2
Issue 10
Year Published 2012
Language English
Publisher Nature Publishing Group
Publisher location London, U.K.
Contributing office(s) Southwest Biological Science Center
Description 4 p.
First page 752
Last page 755
Country United States
Other Geospatial Colorado Plateau