Depth of Water Acquisition by Invading Shrubs and Resident Herbs in a Sierra Nevada Meadow

TitleDepth of Water Acquisition by Invading Shrubs and Resident Herbs in a Sierra Nevada Meadow
Publication TypeJournal Article
Year of Publication2006
AuthorsDarrouzet-Nardi A., D'Antonio C.M, Dawson T.E
JournalPlant and Soil
Volume285
Pagination31-43
Date PublishedJul
ISBN Number0032-079X
Accession NumberWOS:000240532200004
Keywordscommunity, ecosystems, hydraulic lift, juncus balticus, kern plateau, mixing model, mulkey meadow, oxygen stable isotopes, plants, resource, riparian vegetation, shrub encroachment, soil-water, stable isotope composition, streambank erosion, trees
Abstract

Woody plant encroachment into semiarid ecosystems has become a global trend in recent decades. Due to stream channel incision, the semiarid riparian montane meadows of the southern Sierra Nevada Mountains, USA are experiencing long-term declines in soil moisture. A woody shrub, Artemisia rothrockii A. Gray (Rothrock sagebrush, Asteraceae) is invading these herbaceous meadows. We used an analysis of the stable oxygen isotope ratios of plant and soil water to measure the depth of plant water acquisition during the early stages of this woody plant encroachment. Sagebrush used deeper water on average than most herbs, but it also acquired 10-30% of its water from shallow (< 30 cm) soil. Most of the young sagebrush seedlings (1-3 years old, < 15 cm) that we sampled used deep water like the older shrubs. Many, but not all of the herb species we sampled were also able to acquire deep water. These findings are consistent with a scenario of shrub encroachment in which channel incision causes shallow-water-dependent herbs to die back, allowing shrub seedlings to establish in disturbed areas during wet years. At least during the early stages of the invasion, some herbs appear to coexist with sagebrush by using deep root systems to cope with the declining shallow soil moisture.

Short TitlePlant SoilPlant Soil
Alternate JournalPlant Soil