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Impacts of elevated atmospheric CO 2 on litter quality, litter decomposability and nitrogen turnover rate of two oak species in a Mediterranean forest ecosystem
Author(s) -
GAHROOEE FAYEZ RAIESI
Publication year - 1998
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1046/j.1365-2486.1998.00187.x
Subject(s) - litter , mineralization (soil science) , mediterranean climate , plant litter , nitrogen , chemistry , zoology , cycling , ecosystem , nitrogen cycle , environmental chemistry , botany , ecology , biology , forestry , organic chemistry , geography
Abstract Elevated CO 2 may affect litter quality of plants, and subsequently C and N cycling in terrestrial ecosystems, but changes in litter quality associated with elevated CO 2 are poorly known. Abscised leaf litter of two oak species ( Quercus cerris L. and Q. pubescens Willd.) exposed to long‐term elevated CO 2 around a natural CO 2 spring in Tuscany (Italy) was used to study the impact of increasing concentration of atmospheric CO 2 on litter quality and C and N turnover rates in a Mediterranean‐type ecosystem. Litter samples were collected in an area with elevated CO 2 (>500 ppm) and in an area with ambient CO 2 concentration (360 ppm). Leaf samples were analysed for concentrations of total C, N, lignin, cellulose, acid detergent residue (ADR) and polyphenol. The decomposition rate of litter was studied using a litter bag experiment (12 months) and laboratory incubations (3 months). In the laboratory incubations, N mineralization in litter samples was measured as well (125 days). Litter quality was expressed in terms of chemical composition and element ratios. None of the litter quality parameters was affected by elevated CO 2 for the two Quercus species. Remaining mass in Q. cerris and Q. pubescens litter from elevated CO 2 was similar to that from ambient conditions. C mineralization in Q. pubescens litter from elevated CO 2 was lower than that from ambient CO 2 , but the difference was insignificant. This effect was not observed for Q. cerris . N mineralization was higher from litter grown at elevated CO 2 , but this difference disappeared at the end of the incubation. Litter of Q. pubescens had a higher quality than Q. cerris , and indeed mineralized more rapidly in the laboratory, but not under field conditions.