Functional group, biomass, and climate change effects on ecological drought in semiarid grasslands

Journal of Geophysical Research G: Biogeosciences
By: , and 

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Abstract

Water relations in plant communities are influenced both by contrasting functional groups (grasses, shrubs) and by climate change via complex effects on interception, uptake and transpiration. We modelled the effects of functional group replacement and biomass increase, both of which can be outcomes of invasion and vegetation management, and climate change on ecological drought (soil water potential below which photosynthesis stops) in 340 semiarid grassland sites over 30‐year periods. Relative to control vegetation (climate and site‐determined mixes of functional groups), the frequency and duration of drought were increased by shrubs and decreased by annual grasses. The rankings of shrubs, control vegetation, and annual grasses in terms of drought effects were generally consistent in current and future climates, suggesting that current differences among functional groups on drought effects predict future differences. Climate change accompanied by experimentally‐increased biomass (i.e. the effects of invasions that increase community biomass, or management that increases productivity through fertilization or respite from grazing) increased drought frequency and duration, and advanced drought onset. Our results suggest that the replacement of perennial temperate semiarid grasslands by shrubs, or increased biomass, can increase ecological drought both in current and future climates.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Functional group, biomass, and climate change effects on ecological drought in semiarid grasslands
Series title Journal of Geophysical Research G: Biogeosciences
DOI 10.1002/2017JG004173
Volume 123
Issue 3
Year Published 2018
Language English
Publisher American Geophysical Union
Contributing office(s) Forest and Rangeland Ecosystem Science Center
Description 14 p.
First page 1072
Last page 1085