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Desert grassland dynamics estimated from carbon isotopes in grass phytoliths and soil organic matter
Author(s) -
McClaran Mitchel P.,
Umlauf Marcelle
Publication year - 2000
Publication title -
journal of vegetation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.1
H-Index - 115
eISSN - 1654-1103
pISSN - 1100-9233
DOI - 10.2307/3236777
Subject(s) - grassland , vegetation (pathology) , isotopes of carbon , δ13c , organic matter , soil organic matter , soil carbon , environmental science , soil water , ecology , total organic carbon , stable isotope ratio , soil science , biology , medicine , physics , pathology , quantum mechanics
. We document the potential for using carbon isotopes in both soil organic matter (SOM) and grass phytoliths in soil to increase the temporal and taxonomic resolutions of long term vegetation dynamics. Carbon isotope values from both SOM and phytoliths are expected to describe both the age of material through 14 C dating, and the photosynthetic pathway of the source plant material through ratios of 12 C/ 13 C. Taxonomic resolution is increased because the phytoliths examined are specific to grasses, whereas the SOM reflects the contribution of all the vegetation. Temporal resolution is increased because phytoliths are less mobile in the soil profile than SOM, and can therefore provide older dates from the same soil depth. Our results, from a desert grassland site in southwestern North America, largely confirm these expectations, and show that C 4 species have dominated the grass composition for the last 8000 yr, C 3 non‐grass vegetation increased about 100–350 yrBP, and no significant C 3 grass or non‐grass vegetation existed between 350–2000 yr BP.