Response of aboveground carbon balance to long-term, experimental enhancements in precipitation seasonality is contingent on plant community type in cold-desert rangelands

Oecologia
By: , and 

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Abstract

Semi-arid rangelands are important carbon (C) pools at global scales. However, the degree of net C storage or release in water-limited systems is a function of precipitation amount and timing, as well as plant community composition. In northern latitudes of western North America, C storage in cold-desert ecosystems could increase with boosts in wintertime precipitation, in which climate models predict, due to increases in wintertime soil water storage that enhance summertime productivity. However, there are few long-term, manipulative field-based studies investigating how rangelands will respond to altered precipitation amount or timing. We measured aboveground C pools and fluxes at leaf, soil, and ecosystem scales over a single growing season in plots that had 200 mm of supplemental precipitation added in either winter or summer for the past 21 years, in shrub- and exotic-bunchgrass-dominated garden plots. At our cold-desert site (298 mm precipitation during the study year), we hypothesized that increased winter precipitation would stimulate the aboveground C uptake and storage relative to ambient conditions, especially in plots containing shrubs. Our hypotheses were generally supported: ecosystem C uptake and long-term biomass accumulation were greater in winter- and summer-irrigated plots compared to control plots in both vegetation communities. However, substantial increases in the aboveground biomass occurred only in winter-irrigated plots that contained shrubs. Our findings suggest that increases in winter precipitation will enhance C storage of this widespread ecosystem, and moreso in shrub- compared to grass-dominated communities.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Response of aboveground carbon balance to long-term, experimental enhancements in precipitation seasonality is contingent on plant community type in cold-desert rangelands
Series title Oecologia
DOI 10.1007/s00442-017-3814-7
Volume 183
Issue 3
Year Published 2017
Language English
Publisher Springer
Contributing office(s) Forest and Rangeland Ecosystem Science Center
Description 14 p.
First page 861
Last page 874
Country United States
State Idaho
Other Geospatial Idaho National Laboratory